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node_modules/mongodb/src/cmap/auth/auth_provider.ts

@@ -0,0 +1,60 @@
+import type { Document } from '../../bson';
+import { MongoRuntimeError } from '../../error';
+import type { Callback, ClientMetadataOptions } from '../../utils';
+import type { HandshakeDocument } from '../connect';
+import type { Connection, ConnectionOptions } from '../connection';
+import type { MongoCredentials } from './mongo_credentials';
+
+export type AuthContextOptions = ConnectionOptions & ClientMetadataOptions;
+
+/** Context used during authentication */
+export class AuthContext {
+  /** The connection to authenticate */
+  connection: Connection;
+  /** The credentials to use for authentication */
+  credentials?: MongoCredentials;
+  /** The options passed to the `connect` method */
+  options: AuthContextOptions;
+
+  /** A response from an initial auth attempt, only some mechanisms use this (e.g, SCRAM) */
+  response?: Document;
+  /** A random nonce generated for use in an authentication conversation */
+  nonce?: Buffer;
+
+  constructor(
+    connection: Connection,
+    credentials: MongoCredentials | undefined,
+    options: AuthContextOptions
+  ) {
+    this.connection = connection;
+    this.credentials = credentials;
+    this.options = options;
+  }
+}
+
+export class AuthProvider {
+  /**
+   * Prepare the handshake document before the initial handshake.
+   *
+   * @param handshakeDoc - The document used for the initial handshake on a connection
+   * @param authContext - Context for authentication flow
+   */
+  prepare(
+    handshakeDoc: HandshakeDocument,
+    authContext: AuthContext,
+    callback: Callback<HandshakeDocument>
+  ): void {
+    callback(undefined, handshakeDoc);
+  }
+
+  /**
+   * Authenticate
+   *
+   * @param context - A shared context for authentication flow
+   * @param callback - The callback to return the result from the authentication
+   */
+  auth(context: AuthContext, callback: Callback): void {
+    // TODO(NODE-3483): Replace this with MongoMethodOverrideError
+    callback(new MongoRuntimeError('`auth` method must be overridden by subclass'));
+  }
+}

node_modules/mongodb/src/cmap/auth/gssapi.ts

@@ -0,0 +1,241 @@
+import * as dns from 'dns';
+
+import type { Document } from '../../bson';
+import { Kerberos, KerberosClient } from '../../deps';
+import {
+  MongoError,
+  MongoInvalidArgumentError,
+  MongoMissingCredentialsError,
+  MongoMissingDependencyError,
+  MongoRuntimeError
+} from '../../error';
+import { Callback, ns } from '../../utils';
+import { AuthContext, AuthProvider } from './auth_provider';
+
+/** @public */
+export const GSSAPICanonicalizationValue = Object.freeze({
+  on: true,
+  off: false,
+  none: 'none',
+  forward: 'forward',
+  forwardAndReverse: 'forwardAndReverse'
+} as const);
+
+/** @public */
+export type GSSAPICanonicalizationValue =
+  typeof GSSAPICanonicalizationValue[keyof typeof GSSAPICanonicalizationValue];
+
+type MechanismProperties = {
+  /** @deprecated use `CANONICALIZE_HOST_NAME` instead */
+  gssapiCanonicalizeHostName?: boolean;
+  CANONICALIZE_HOST_NAME?: GSSAPICanonicalizationValue;
+  SERVICE_HOST?: string;
+  SERVICE_NAME?: string;
+  SERVICE_REALM?: string;
+};
+
+export class GSSAPI extends AuthProvider {
+  override auth(authContext: AuthContext, callback: Callback): void {
+    const { connection, credentials } = authContext;
+    if (credentials == null)
+      return callback(
+        new MongoMissingCredentialsError('Credentials required for GSSAPI authentication')
+      );
+    const { username } = credentials;
+    function externalCommand(
+      command: Document,
+      cb: Callback<{ payload: string; conversationId: any }>
+    ) {
+      return connection.command(ns('$external.$cmd'), command, undefined, cb);
+    }
+    makeKerberosClient(authContext, (err, client) => {
+      if (err) return callback(err);
+      if (client == null) return callback(new MongoMissingDependencyError('GSSAPI client missing'));
+      client.step('', (err, payload) => {
+        if (err) return callback(err);
+
+        externalCommand(saslStart(payload), (err, result) => {
+          if (err) return callback(err);
+          if (result == null) return callback();
+          negotiate(client, 10, result.payload, (err, payload) => {
+            if (err) return callback(err);
+
+            externalCommand(saslContinue(payload, result.conversationId), (err, result) => {
+              if (err) return callback(err);
+              if (result == null) return callback();
+              finalize(client, username, result.payload, (err, payload) => {
+                if (err) return callback(err);
+
+                externalCommand(
+                  {
+                    saslContinue: 1,
+                    conversationId: result.conversationId,
+                    payload
+                  },
+                  (err, result) => {
+                    if (err) return callback(err);
+
+                    callback(undefined, result);
+                  }
+                );
+              });
+            });
+          });
+        });
+      });
+    });
+  }
+}
+
+function makeKerberosClient(authContext: AuthContext, callback: Callback<KerberosClient>): void {
+  const { hostAddress } = authContext.options;
+  const { credentials } = authContext;
+  if (!hostAddress || typeof hostAddress.host !== 'string' || !credentials) {
+    return callback(
+      new MongoInvalidArgumentError('Connection must have host and port and credentials defined.')
+    );
+  }
+
+  if ('kModuleError' in Kerberos) {
+    return callback(Kerberos['kModuleError']);
+  }
+  const { initializeClient } = Kerberos;
+
+  const { username, password } = credentials;
+  const mechanismProperties = credentials.mechanismProperties as MechanismProperties;
+
+  const serviceName = mechanismProperties.SERVICE_NAME ?? 'mongodb';
+
+  performGSSAPICanonicalizeHostName(
+    hostAddress.host,
+    mechanismProperties,
+    (err?: Error | MongoError, host?: string) => {
+      if (err) return callback(err);
+
+      const initOptions = {};
+      if (password != null) {
+        Object.assign(initOptions, { user: username, password: password });
+      }
+
+      const spnHost = mechanismProperties.SERVICE_HOST ?? host;
+      let spn = `${serviceName}${process.platform === 'win32' ? '/' : '@'}${spnHost}`;
+      if ('SERVICE_REALM' in mechanismProperties) {
+        spn = `${spn}@${mechanismProperties.SERVICE_REALM}`;
+      }
+
+      initializeClient(spn, initOptions, (err: string, client: KerberosClient): void => {
+        // TODO(NODE-3483)
+        if (err) return callback(new MongoRuntimeError(err));
+        callback(undefined, client);
+      });
+    }
+  );
+}
+
+function saslStart(payload?: string): Document {
+  return {
+    saslStart: 1,
+    mechanism: 'GSSAPI',
+    payload,
+    autoAuthorize: 1
+  };
+}
+
+function saslContinue(payload?: string, conversationId?: number): Document {
+  return {
+    saslContinue: 1,
+    conversationId,
+    payload
+  };
+}
+
+function negotiate(
+  client: KerberosClient,
+  retries: number,
+  payload: string,
+  callback: Callback<string>
+): void {
+  client.step(payload, (err, response) => {
+    // Retries exhausted, raise error
+    if (err && retries === 0) return callback(err);
+
+    // Adjust number of retries and call step again
+    if (err) return negotiate(client, retries - 1, payload, callback);
+
+    // Return the payload
+    callback(undefined, response || '');
+  });
+}
+
+function finalize(
+  client: KerberosClient,
+  user: string,
+  payload: string,
+  callback: Callback<string>
+): void {
+  // GSS Client Unwrap
+  client.unwrap(payload, (err, response) => {
+    if (err) return callback(err);
+
+    // Wrap the response
+    client.wrap(response || '', { user }, (err, wrapped) => {
+      if (err) return callback(err);
+
+      // Return the payload
+      callback(undefined, wrapped);
+    });
+  });
+}
+
+export function performGSSAPICanonicalizeHostName(
+  host: string,
+  mechanismProperties: MechanismProperties,
+  callback: Callback<string>
+): void {
+  const mode = mechanismProperties.CANONICALIZE_HOST_NAME;
+  if (!mode || mode === GSSAPICanonicalizationValue.none) {
+    return callback(undefined, host);
+  }
+
+  // If forward and reverse or true
+  if (
+    mode === GSSAPICanonicalizationValue.on ||
+    mode === GSSAPICanonicalizationValue.forwardAndReverse
+  ) {
+    // Perform the lookup of the ip address.
+    dns.lookup(host, (error, address) => {
+      // No ip found, return the error.
+      if (error) return callback(error);
+
+      // Perform a reverse ptr lookup on the ip address.
+      dns.resolvePtr(address, (err, results) => {
+        // This can error as ptr records may not exist for all ips. In this case
+        // fallback to a cname lookup as dns.lookup() does not return the
+        // cname.
+        if (err) {
+          return resolveCname(host, callback);
+        }
+        // If the ptr did not error but had no results, return the host.
+        callback(undefined, results.length > 0 ? results[0] : host);
+      });
+    });
+  } else {
+    // The case for forward is just to resolve the cname as dns.lookup()
+    // will not return it.
+    resolveCname(host, callback);
+  }
+}
+
+export function resolveCname(host: string, callback: Callback<string>): void {
+  // Attempt to resolve the host name
+  dns.resolveCname(host, (err, r) => {
+    if (err) return callback(undefined, host);
+
+    // Get the first resolve host id
+    if (r.length > 0) {
+      return callback(undefined, r[0]);
+    }
+
+    callback(undefined, host);
+  });
+}

node_modules/mongodb/src/cmap/auth/mongo_credentials.ts

@@ -0,0 +1,190 @@
+// Resolves the default auth mechanism according to
+import type { Document } from '../../bson';
+import { MongoAPIError, MongoMissingCredentialsError } from '../../error';
+import { emitWarningOnce } from '../../utils';
+import { GSSAPICanonicalizationValue } from './gssapi';
+import { AUTH_MECHS_AUTH_SRC_EXTERNAL, AuthMechanism } from './providers';
+
+// https://github.com/mongodb/specifications/blob/master/source/auth/auth.rst
+function getDefaultAuthMechanism(hello?: Document): AuthMechanism {
+  if (hello) {
+    // If hello contains saslSupportedMechs, use scram-sha-256
+    // if it is available, else scram-sha-1
+    if (Array.isArray(hello.saslSupportedMechs)) {
+      return hello.saslSupportedMechs.includes(AuthMechanism.MONGODB_SCRAM_SHA256)
+        ? AuthMechanism.MONGODB_SCRAM_SHA256
+        : AuthMechanism.MONGODB_SCRAM_SHA1;
+    }
+
+    // Fallback to legacy selection method. If wire version >= 3, use scram-sha-1
+    if (hello.maxWireVersion >= 3) {
+      return AuthMechanism.MONGODB_SCRAM_SHA1;
+    }
+  }
+
+  // Default for wireprotocol < 3
+  return AuthMechanism.MONGODB_CR;
+}
+
+/** @public */
+export interface AuthMechanismProperties extends Document {
+  SERVICE_HOST?: string;
+  SERVICE_NAME?: string;
+  SERVICE_REALM?: string;
+  CANONICALIZE_HOST_NAME?: GSSAPICanonicalizationValue;
+  AWS_SESSION_TOKEN?: string;
+}
+
+/** @public */
+export interface MongoCredentialsOptions {
+  username: string;
+  password: string;
+  source: string;
+  db?: string;
+  mechanism?: AuthMechanism;
+  mechanismProperties: AuthMechanismProperties;
+}
+
+/**
+ * A representation of the credentials used by MongoDB
+ * @public
+ */
+export class MongoCredentials {
+  /** The username used for authentication */
+  readonly username: string;
+  /** The password used for authentication */
+  readonly password: string;
+  /** The database that the user should authenticate against */
+  readonly source: string;
+  /** The method used to authenticate */
+  readonly mechanism: AuthMechanism;
+  /** Special properties used by some types of auth mechanisms */
+  readonly mechanismProperties: AuthMechanismProperties;
+
+  constructor(options: MongoCredentialsOptions) {
+    this.username = options.username;
+    this.password = options.password;
+    this.source = options.source;
+    if (!this.source && options.db) {
+      this.source = options.db;
+    }
+    this.mechanism = options.mechanism || AuthMechanism.MONGODB_DEFAULT;
+    this.mechanismProperties = options.mechanismProperties || {};
+
+    if (this.mechanism.match(/MONGODB-AWS/i)) {
+      if (!this.username && process.env.AWS_ACCESS_KEY_ID) {
+        this.username = process.env.AWS_ACCESS_KEY_ID;
+      }
+
+      if (!this.password && process.env.AWS_SECRET_ACCESS_KEY) {
+        this.password = process.env.AWS_SECRET_ACCESS_KEY;
+      }
+
+      if (
+        this.mechanismProperties.AWS_SESSION_TOKEN == null &&
+        process.env.AWS_SESSION_TOKEN != null
+      ) {
+        this.mechanismProperties = {
+          ...this.mechanismProperties,
+          AWS_SESSION_TOKEN: process.env.AWS_SESSION_TOKEN
+        };
+      }
+    }
+
+    if ('gssapiCanonicalizeHostName' in this.mechanismProperties) {
+      emitWarningOnce(
+        'gssapiCanonicalizeHostName is deprecated. Please use CANONICALIZE_HOST_NAME instead.'
+      );
+      this.mechanismProperties.CANONICALIZE_HOST_NAME =
+        this.mechanismProperties.gssapiCanonicalizeHostName;
+    }
+
+    Object.freeze(this.mechanismProperties);
+    Object.freeze(this);
+  }
+
+  /** Determines if two MongoCredentials objects are equivalent */
+  equals(other: MongoCredentials): boolean {
+    return (
+      this.mechanism === other.mechanism &&
+      this.username === other.username &&
+      this.password === other.password &&
+      this.source === other.source
+    );
+  }
+
+  /**
+   * If the authentication mechanism is set to "default", resolves the authMechanism
+   * based on the server version and server supported sasl mechanisms.
+   *
+   * @param hello - A hello response from the server
+   */
+  resolveAuthMechanism(hello?: Document): MongoCredentials {
+    // If the mechanism is not "default", then it does not need to be resolved
+    if (this.mechanism.match(/DEFAULT/i)) {
+      return new MongoCredentials({
+        username: this.username,
+        password: this.password,
+        source: this.source,
+        mechanism: getDefaultAuthMechanism(hello),
+        mechanismProperties: this.mechanismProperties
+      });
+    }
+
+    return this;
+  }
+
+  validate(): void {
+    if (
+      (this.mechanism === AuthMechanism.MONGODB_GSSAPI ||
+        this.mechanism === AuthMechanism.MONGODB_CR ||
+        this.mechanism === AuthMechanism.MONGODB_PLAIN ||
+        this.mechanism === AuthMechanism.MONGODB_SCRAM_SHA1 ||
+        this.mechanism === AuthMechanism.MONGODB_SCRAM_SHA256) &&
+      !this.username
+    ) {
+      throw new MongoMissingCredentialsError(`Username required for mechanism '${this.mechanism}'`);
+    }
+
+    if (AUTH_MECHS_AUTH_SRC_EXTERNAL.has(this.mechanism)) {
+      if (this.source != null && this.source !== '$external') {
+        // TODO(NODE-3485): Replace this with a MongoAuthValidationError
+        throw new MongoAPIError(
+          `Invalid source '${this.source}' for mechanism '${this.mechanism}' specified.`
+        );
+      }
+    }
+
+    if (this.mechanism === AuthMechanism.MONGODB_PLAIN && this.source == null) {
+      // TODO(NODE-3485): Replace this with a MongoAuthValidationError
+      throw new MongoAPIError('PLAIN Authentication Mechanism needs an auth source');
+    }
+
+    if (this.mechanism === AuthMechanism.MONGODB_X509 && this.password != null) {
+      if (this.password === '') {
+        Reflect.set(this, 'password', undefined);
+        return;
+      }
+      // TODO(NODE-3485): Replace this with a MongoAuthValidationError
+      throw new MongoAPIError(`Password not allowed for mechanism MONGODB-X509`);
+    }
+
+    const canonicalization = this.mechanismProperties.CANONICALIZE_HOST_NAME ?? false;
+    if (!Object.values(GSSAPICanonicalizationValue).includes(canonicalization)) {
+      throw new MongoAPIError(`Invalid CANONICALIZE_HOST_NAME value: ${canonicalization}`);
+    }
+  }
+
+  static merge(
+    creds: MongoCredentials | undefined,
+    options: Partial<MongoCredentialsOptions>
+  ): MongoCredentials {
+    return new MongoCredentials({
+      username: options.username ?? creds?.username ?? '',
+      password: options.password ?? creds?.password ?? '',
+      mechanism: options.mechanism ?? creds?.mechanism ?? AuthMechanism.MONGODB_DEFAULT,
+      mechanismProperties: options.mechanismProperties ?? creds?.mechanismProperties ?? {},
+      source: options.source ?? options.db ?? creds?.source ?? 'admin'
+    });
+  }
+}

node_modules/mongodb/src/cmap/auth/mongocr.ts

@@ -0,0 +1,47 @@
+import * as crypto from 'crypto';
+
+import { MongoMissingCredentialsError } from '../../error';
+import { Callback, ns } from '../../utils';
+import { AuthContext, AuthProvider } from './auth_provider';
+
+export class MongoCR extends AuthProvider {
+  override auth(authContext: AuthContext, callback: Callback): void {
+    const { connection, credentials } = authContext;
+    if (!credentials) {
+      return callback(new MongoMissingCredentialsError('AuthContext must provide credentials.'));
+    }
+    const username = credentials.username;
+    const password = credentials.password;
+    const source = credentials.source;
+    connection.command(ns(`${source}.$cmd`), { getnonce: 1 }, undefined, (err, r) => {
+      let nonce = null;
+      let key = null;
+
+      // Get nonce
+      if (err == null) {
+        nonce = r.nonce;
+
+        // Use node md5 generator
+        let md5 = crypto.createHash('md5');
+
+        // Generate keys used for authentication
+        md5.update(`${username}:mongo:${password}`, 'utf8');
+        const hash_password = md5.digest('hex');
+
+        // Final key
+        md5 = crypto.createHash('md5');
+        md5.update(nonce + username + hash_password, 'utf8');
+        key = md5.digest('hex');
+      }
+
+      const authenticateCommand = {
+        authenticate: 1,
+        user: username,
+        nonce,
+        key
+      };
+
+      connection.command(ns(`${source}.$cmd`), authenticateCommand, undefined, callback);
+    });
+  }
+}

node_modules/mongodb/src/cmap/auth/mongodb_aws.ts

@@ -0,0 +1,293 @@
+import * as crypto from 'crypto';
+import * as http from 'http';
+import * as url from 'url';
+
+import type { Binary, BSONSerializeOptions } from '../../bson';
+import * as BSON from '../../bson';
+import { aws4 } from '../../deps';
+import {
+  MongoAWSError,
+  MongoCompatibilityError,
+  MongoMissingCredentialsError,
+  MongoRuntimeError
+} from '../../error';
+import { Callback, maxWireVersion, ns } from '../../utils';
+import { AuthContext, AuthProvider } from './auth_provider';
+import { MongoCredentials } from './mongo_credentials';
+import { AuthMechanism } from './providers';
+
+const ASCII_N = 110;
+const AWS_RELATIVE_URI = 'http://169.254.170.2';
+const AWS_EC2_URI = 'http://169.254.169.254';
+const AWS_EC2_PATH = '/latest/meta-data/iam/security-credentials';
+const bsonOptions: BSONSerializeOptions = {
+  promoteLongs: true,
+  promoteValues: true,
+  promoteBuffers: false,
+  bsonRegExp: false
+};
+
+interface AWSSaslContinuePayload {
+  a: string;
+  d: string;
+  t?: string;
+}
+
+export class MongoDBAWS extends AuthProvider {
+  override auth(authContext: AuthContext, callback: Callback): void {
+    const { connection, credentials } = authContext;
+    if (!credentials) {
+      return callback(new MongoMissingCredentialsError('AuthContext must provide credentials.'));
+    }
+
+    if ('kModuleError' in aws4) {
+      return callback(aws4['kModuleError']);
+    }
+    const { sign } = aws4;
+
+    if (maxWireVersion(connection) < 9) {
+      callback(
+        new MongoCompatibilityError(
+          'MONGODB-AWS authentication requires MongoDB version 4.4 or later'
+        )
+      );
+      return;
+    }
+
+    if (!credentials.username) {
+      makeTempCredentials(credentials, (err, tempCredentials) => {
+        if (err || !tempCredentials) return callback(err);
+
+        authContext.credentials = tempCredentials;
+        this.auth(authContext, callback);
+      });
+
+      return;
+    }
+
+    const accessKeyId = credentials.username;
+    const secretAccessKey = credentials.password;
+    const sessionToken = credentials.mechanismProperties.AWS_SESSION_TOKEN;
+
+    // If all three defined, include sessionToken, else include username and pass, else no credentials
+    const awsCredentials =
+      accessKeyId && secretAccessKey && sessionToken
+        ? { accessKeyId, secretAccessKey, sessionToken }
+        : accessKeyId && secretAccessKey
+        ? { accessKeyId, secretAccessKey }
+        : undefined;
+
+    const db = credentials.source;
+    crypto.randomBytes(32, (err, nonce) => {
+      if (err) {
+        callback(err);
+        return;
+      }
+
+      const saslStart = {
+        saslStart: 1,
+        mechanism: 'MONGODB-AWS',
+        payload: BSON.serialize({ r: nonce, p: ASCII_N }, bsonOptions)
+      };
+
+      connection.command(ns(`${db}.$cmd`), saslStart, undefined, (err, res) => {
+        if (err) return callback(err);
+
+        const serverResponse = BSON.deserialize(res.payload.buffer, bsonOptions) as {
+          s: Binary;
+          h: string;
+        };
+        const host = serverResponse.h;
+        const serverNonce = serverResponse.s.buffer;
+        if (serverNonce.length !== 64) {
+          callback(
+            // TODO(NODE-3483)
+            new MongoRuntimeError(`Invalid server nonce length ${serverNonce.length}, expected 64`)
+          );
+
+          return;
+        }
+
+        if (serverNonce.compare(nonce, 0, nonce.length, 0, nonce.length) !== 0) {
+          // TODO(NODE-3483)
+          callback(new MongoRuntimeError('Server nonce does not begin with client nonce'));
+          return;
+        }
+
+        if (host.length < 1 || host.length > 255 || host.indexOf('..') !== -1) {
+          // TODO(NODE-3483)
+          callback(new MongoRuntimeError(`Server returned an invalid host: "${host}"`));
+          return;
+        }
+
+        const body = 'Action=GetCallerIdentity&Version=2011-06-15';
+        const options = sign(
+          {
+            method: 'POST',
+            host,
+            region: deriveRegion(serverResponse.h),
+            service: 'sts',
+            headers: {
+              'Content-Type': 'application/x-www-form-urlencoded',
+              'Content-Length': body.length,
+              'X-MongoDB-Server-Nonce': serverNonce.toString('base64'),
+              'X-MongoDB-GS2-CB-Flag': 'n'
+            },
+            path: '/',
+            body
+          },
+          awsCredentials
+        );
+
+        const payload: AWSSaslContinuePayload = {
+          a: options.headers.Authorization,
+          d: options.headers['X-Amz-Date']
+        };
+        if (sessionToken) {
+          payload.t = sessionToken;
+        }
+
+        const saslContinue = {
+          saslContinue: 1,
+          conversationId: 1,
+          payload: BSON.serialize(payload, bsonOptions)
+        };
+
+        connection.command(ns(`${db}.$cmd`), saslContinue, undefined, callback);
+      });
+    });
+  }
+}
+
+interface AWSTempCredentials {
+  AccessKeyId?: string;
+  SecretAccessKey?: string;
+  Token?: string;
+  RoleArn?: string;
+  Expiration?: Date;
+}
+
+function makeTempCredentials(credentials: MongoCredentials, callback: Callback<MongoCredentials>) {
+  function done(creds: AWSTempCredentials) {
+    if (!creds.AccessKeyId || !creds.SecretAccessKey || !creds.Token) {
+      callback(
+        new MongoMissingCredentialsError('Could not obtain temporary MONGODB-AWS credentials')
+      );
+      return;
+    }
+
+    callback(
+      undefined,
+      new MongoCredentials({
+        username: creds.AccessKeyId,
+        password: creds.SecretAccessKey,
+        source: credentials.source,
+        mechanism: AuthMechanism.MONGODB_AWS,
+        mechanismProperties: {
+          AWS_SESSION_TOKEN: creds.Token
+        }
+      })
+    );
+  }
+
+  // If the environment variable AWS_CONTAINER_CREDENTIALS_RELATIVE_URI
+  // is set then drivers MUST assume that it was set by an AWS ECS agent
+  if (process.env.AWS_CONTAINER_CREDENTIALS_RELATIVE_URI) {
+    request(
+      `${AWS_RELATIVE_URI}${process.env.AWS_CONTAINER_CREDENTIALS_RELATIVE_URI}`,
+      undefined,
+      (err, res) => {
+        if (err) return callback(err);
+        done(res);
+      }
+    );
+
+    return;
+  }
+
+  // Otherwise assume we are on an EC2 instance
+
+  // get a token
+  request(
+    `${AWS_EC2_URI}/latest/api/token`,
+    { method: 'PUT', json: false, headers: { 'X-aws-ec2-metadata-token-ttl-seconds': 30 } },
+    (err, token) => {
+      if (err) return callback(err);
+
+      // get role name
+      request(
+        `${AWS_EC2_URI}/${AWS_EC2_PATH}`,
+        { json: false, headers: { 'X-aws-ec2-metadata-token': token } },
+        (err, roleName) => {
+          if (err) return callback(err);
+
+          // get temp credentials
+          request(
+            `${AWS_EC2_URI}/${AWS_EC2_PATH}/${roleName}`,
+            { headers: { 'X-aws-ec2-metadata-token': token } },
+            (err, creds) => {
+              if (err) return callback(err);
+              done(creds);
+            }
+          );
+        }
+      );
+    }
+  );
+}
+
+function deriveRegion(host: string) {
+  const parts = host.split('.');
+  if (parts.length === 1 || parts[1] === 'amazonaws') {
+    return 'us-east-1';
+  }
+
+  return parts[1];
+}
+
+interface RequestOptions {
+  json?: boolean;
+  method?: string;
+  timeout?: number;
+  headers?: http.OutgoingHttpHeaders;
+}
+
+function request(uri: string, _options: RequestOptions | undefined, callback: Callback) {
+  const options = Object.assign(
+    {
+      method: 'GET',
+      timeout: 10000,
+      json: true
+    },
+    url.parse(uri),
+    _options
+  );
+
+  const req = http.request(options, res => {
+    res.setEncoding('utf8');
+
+    let data = '';
+    res.on('data', d => (data += d));
+    res.on('end', () => {
+      if (options.json === false) {
+        callback(undefined, data);
+        return;
+      }
+
+      try {
+        const parsed = JSON.parse(data);
+        callback(undefined, parsed);
+      } catch (err) {
+        // TODO(NODE-3483)
+        callback(new MongoRuntimeError(`Invalid JSON response: "${data}"`));
+      }
+    });
+  });
+
+  req.on('timeout', () => {
+    req.destroy(new MongoAWSError(`AWS request to ${uri} timed out after ${options.timeout} ms`));
+  });
+
+  req.on('error', err => callback(err));
+  req.end();
+}

node_modules/mongodb/src/cmap/auth/plain.ts

@@ -0,0 +1,25 @@
+import { Binary } from '../../bson';
+import { MongoMissingCredentialsError } from '../../error';
+import { Callback, ns } from '../../utils';
+import { AuthContext, AuthProvider } from './auth_provider';
+
+export class Plain extends AuthProvider {
+  override auth(authContext: AuthContext, callback: Callback): void {
+    const { connection, credentials } = authContext;
+    if (!credentials) {
+      return callback(new MongoMissingCredentialsError('AuthContext must provide credentials.'));
+    }
+    const username = credentials.username;
+    const password = credentials.password;
+
+    const payload = new Binary(Buffer.from(`\x00${username}\x00${password}`));
+    const command = {
+      saslStart: 1,
+      mechanism: 'PLAIN',
+      payload: payload,
+      autoAuthorize: 1
+    };
+
+    connection.command(ns('$external.$cmd'), command, undefined, callback);
+  }
+}

node_modules/mongodb/src/cmap/auth/providers.ts

@@ -0,0 +1,21 @@
+/** @public */
+export const AuthMechanism = Object.freeze({
+  MONGODB_AWS: 'MONGODB-AWS',
+  MONGODB_CR: 'MONGODB-CR',
+  MONGODB_DEFAULT: 'DEFAULT',
+  MONGODB_GSSAPI: 'GSSAPI',
+  MONGODB_PLAIN: 'PLAIN',
+  MONGODB_SCRAM_SHA1: 'SCRAM-SHA-1',
+  MONGODB_SCRAM_SHA256: 'SCRAM-SHA-256',
+  MONGODB_X509: 'MONGODB-X509'
+} as const);
+
+/** @public */
+export type AuthMechanism = typeof AuthMechanism[keyof typeof AuthMechanism];
+
+/** @internal */
+export const AUTH_MECHS_AUTH_SRC_EXTERNAL = new Set<AuthMechanism>([
+  AuthMechanism.MONGODB_GSSAPI,
+  AuthMechanism.MONGODB_AWS,
+  AuthMechanism.MONGODB_X509
+]);

node_modules/mongodb/src/cmap/auth/scram.ts

@@ -0,0 +1,384 @@
+import * as crypto from 'crypto';
+
+import { Binary, Document } from '../../bson';
+import { saslprep } from '../../deps';
+import {
+  AnyError,
+  MongoInvalidArgumentError,
+  MongoMissingCredentialsError,
+  MongoRuntimeError,
+  MongoServerError
+} from '../../error';
+import { Callback, emitWarning, ns } from '../../utils';
+import type { HandshakeDocument } from '../connect';
+import { AuthContext, AuthProvider } from './auth_provider';
+import type { MongoCredentials } from './mongo_credentials';
+import { AuthMechanism } from './providers';
+
+type CryptoMethod = 'sha1' | 'sha256';
+
+class ScramSHA extends AuthProvider {
+  cryptoMethod: CryptoMethod;
+  constructor(cryptoMethod: CryptoMethod) {
+    super();
+    this.cryptoMethod = cryptoMethod || 'sha1';
+  }
+
+  override prepare(handshakeDoc: HandshakeDocument, authContext: AuthContext, callback: Callback) {
+    const cryptoMethod = this.cryptoMethod;
+    const credentials = authContext.credentials;
+    if (!credentials) {
+      return callback(new MongoMissingCredentialsError('AuthContext must provide credentials.'));
+    }
+    if (cryptoMethod === 'sha256' && saslprep == null) {
+      emitWarning('Warning: no saslprep library specified. Passwords will not be sanitized');
+    }
+
+    crypto.randomBytes(24, (err, nonce) => {
+      if (err) {
+        return callback(err);
+      }
+
+      // store the nonce for later use
+      Object.assign(authContext, { nonce });
+
+      const request = Object.assign({}, handshakeDoc, {
+        speculativeAuthenticate: Object.assign(makeFirstMessage(cryptoMethod, credentials, nonce), {
+          db: credentials.source
+        })
+      });
+
+      callback(undefined, request);
+    });
+  }
+
+  override auth(authContext: AuthContext, callback: Callback) {
+    const response = authContext.response;
+    if (response && response.speculativeAuthenticate) {
+      continueScramConversation(
+        this.cryptoMethod,
+        response.speculativeAuthenticate,
+        authContext,
+        callback
+      );
+
+      return;
+    }
+
+    executeScram(this.cryptoMethod, authContext, callback);
+  }
+}
+
+function cleanUsername(username: string) {
+  return username.replace('=', '=3D').replace(',', '=2C');
+}
+
+function clientFirstMessageBare(username: string, nonce: Buffer) {
+  // NOTE: This is done b/c Javascript uses UTF-16, but the server is hashing in UTF-8.
+  // Since the username is not sasl-prep-d, we need to do this here.
+  return Buffer.concat([
+    Buffer.from('n=', 'utf8'),
+    Buffer.from(username, 'utf8'),
+    Buffer.from(',r=', 'utf8'),
+    Buffer.from(nonce.toString('base64'), 'utf8')
+  ]);
+}
+
+function makeFirstMessage(
+  cryptoMethod: CryptoMethod,
+  credentials: MongoCredentials,
+  nonce: Buffer
+) {
+  const username = cleanUsername(credentials.username);
+  const mechanism =
+    cryptoMethod === 'sha1' ? AuthMechanism.MONGODB_SCRAM_SHA1 : AuthMechanism.MONGODB_SCRAM_SHA256;
+
+  // NOTE: This is done b/c Javascript uses UTF-16, but the server is hashing in UTF-8.
+  // Since the username is not sasl-prep-d, we need to do this here.
+  return {
+    saslStart: 1,
+    mechanism,
+    payload: new Binary(
+      Buffer.concat([Buffer.from('n,,', 'utf8'), clientFirstMessageBare(username, nonce)])
+    ),
+    autoAuthorize: 1,
+    options: { skipEmptyExchange: true }
+  };
+}
+
+function executeScram(cryptoMethod: CryptoMethod, authContext: AuthContext, callback: Callback) {
+  const { connection, credentials } = authContext;
+  if (!credentials) {
+    return callback(new MongoMissingCredentialsError('AuthContext must provide credentials.'));
+  }
+  if (!authContext.nonce) {
+    return callback(
+      new MongoInvalidArgumentError('AuthContext must contain a valid nonce property')
+    );
+  }
+  const nonce = authContext.nonce;
+  const db = credentials.source;
+
+  const saslStartCmd = makeFirstMessage(cryptoMethod, credentials, nonce);
+  connection.command(ns(`${db}.$cmd`), saslStartCmd, undefined, (_err, result) => {
+    const err = resolveError(_err, result);
+    if (err) {
+      return callback(err);
+    }
+
+    continueScramConversation(cryptoMethod, result, authContext, callback);
+  });
+}
+
+function continueScramConversation(
+  cryptoMethod: CryptoMethod,
+  response: Document,
+  authContext: AuthContext,
+  callback: Callback
+) {
+  const connection = authContext.connection;
+  const credentials = authContext.credentials;
+  if (!credentials) {
+    return callback(new MongoMissingCredentialsError('AuthContext must provide credentials.'));
+  }
+  if (!authContext.nonce) {
+    return callback(new MongoInvalidArgumentError('Unable to continue SCRAM without valid nonce'));
+  }
+  const nonce = authContext.nonce;
+
+  const db = credentials.source;
+  const username = cleanUsername(credentials.username);
+  const password = credentials.password;
+
+  let processedPassword;
+  if (cryptoMethod === 'sha256') {
+    processedPassword = 'kModuleError' in saslprep ? password : saslprep(password);
+  } else {
+    try {
+      processedPassword = passwordDigest(username, password);
+    } catch (e) {
+      return callback(e);
+    }
+  }
+
+  const payload = Buffer.isBuffer(response.payload)
+    ? new Binary(response.payload)
+    : response.payload;
+  const dict = parsePayload(payload.value());
+
+  const iterations = parseInt(dict.i, 10);
+  if (iterations && iterations < 4096) {
+    callback(
+      // TODO(NODE-3483)
+      new MongoRuntimeError(`Server returned an invalid iteration count ${iterations}`),
+      false
+    );
+    return;
+  }
+
+  const salt = dict.s;
+  const rnonce = dict.r;
+  if (rnonce.startsWith('nonce')) {
+    // TODO(NODE-3483)
+    callback(new MongoRuntimeError(`Server returned an invalid nonce: ${rnonce}`), false);
+    return;
+  }
+
+  // Set up start of proof
+  const withoutProof = `c=biws,r=${rnonce}`;
+  const saltedPassword = HI(
+    processedPassword,
+    Buffer.from(salt, 'base64'),
+    iterations,
+    cryptoMethod
+  );
+
+  const clientKey = HMAC(cryptoMethod, saltedPassword, 'Client Key');
+  const serverKey = HMAC(cryptoMethod, saltedPassword, 'Server Key');
+  const storedKey = H(cryptoMethod, clientKey);
+  const authMessage = [clientFirstMessageBare(username, nonce), payload.value(), withoutProof].join(
+    ','
+  );
+
+  const clientSignature = HMAC(cryptoMethod, storedKey, authMessage);
+  const clientProof = `p=${xor(clientKey, clientSignature)}`;
+  const clientFinal = [withoutProof, clientProof].join(',');
+
+  const serverSignature = HMAC(cryptoMethod, serverKey, authMessage);
+  const saslContinueCmd = {
+    saslContinue: 1,
+    conversationId: response.conversationId,
+    payload: new Binary(Buffer.from(clientFinal))
+  };
+
+  connection.command(ns(`${db}.$cmd`), saslContinueCmd, undefined, (_err, r) => {
+    const err = resolveError(_err, r);
+    if (err) {
+      return callback(err);
+    }
+
+    const parsedResponse = parsePayload(r.payload.value());
+    if (!compareDigest(Buffer.from(parsedResponse.v, 'base64'), serverSignature)) {
+      callback(new MongoRuntimeError('Server returned an invalid signature'));
+      return;
+    }
+
+    if (!r || r.done !== false) {
+      return callback(err, r);
+    }
+
+    const retrySaslContinueCmd = {
+      saslContinue: 1,
+      conversationId: r.conversationId,
+      payload: Buffer.alloc(0)
+    };
+
+    connection.command(ns(`${db}.$cmd`), retrySaslContinueCmd, undefined, callback);
+  });
+}
+
+function parsePayload(payload: string) {
+  const dict: Document = {};
+  const parts = payload.split(',');
+  for (let i = 0; i < parts.length; i++) {
+    const valueParts = parts[i].split('=');
+    dict[valueParts[0]] = valueParts[1];
+  }
+
+  return dict;
+}
+
+function passwordDigest(username: string, password: string) {
+  if (typeof username !== 'string') {
+    throw new MongoInvalidArgumentError('Username must be a string');
+  }
+
+  if (typeof password !== 'string') {
+    throw new MongoInvalidArgumentError('Password must be a string');
+  }
+
+  if (password.length === 0) {
+    throw new MongoInvalidArgumentError('Password cannot be empty');
+  }
+
+  let md5: crypto.Hash;
+  try {
+    md5 = crypto.createHash('md5');
+  } catch (err) {
+    if (crypto.getFips()) {
+      // This error is (slightly) more helpful than what comes from OpenSSL directly, e.g.
+      // 'Error: error:060800C8:digital envelope routines:EVP_DigestInit_ex:disabled for FIPS'
+      throw new Error('Auth mechanism SCRAM-SHA-1 is not supported in FIPS mode');
+    }
+    throw err;
+  }
+  md5.update(`${username}:mongo:${password}`, 'utf8');
+  return md5.digest('hex');
+}
+
+// XOR two buffers
+function xor(a: Buffer, b: Buffer) {
+  if (!Buffer.isBuffer(a)) {
+    a = Buffer.from(a);
+  }
+
+  if (!Buffer.isBuffer(b)) {
+    b = Buffer.from(b);
+  }
+
+  const length = Math.max(a.length, b.length);
+  const res = [];
+
+  for (let i = 0; i < length; i += 1) {
+    res.push(a[i] ^ b[i]);
+  }
+
+  return Buffer.from(res).toString('base64');
+}
+
+function H(method: CryptoMethod, text: Buffer) {
+  return crypto.createHash(method).update(text).digest();
+}
+
+function HMAC(method: CryptoMethod, key: Buffer, text: Buffer | string) {
+  return crypto.createHmac(method, key).update(text).digest();
+}
+
+interface HICache {
+  [key: string]: Buffer;
+}
+
+let _hiCache: HICache = {};
+let _hiCacheCount = 0;
+function _hiCachePurge() {
+  _hiCache = {};
+  _hiCacheCount = 0;
+}
+
+const hiLengthMap = {
+  sha256: 32,
+  sha1: 20
+};
+
+function HI(data: string, salt: Buffer, iterations: number, cryptoMethod: CryptoMethod) {
+  // omit the work if already generated
+  const key = [data, salt.toString('base64'), iterations].join('_');
+  if (_hiCache[key] != null) {
+    return _hiCache[key];
+  }
+
+  // generate the salt
+  const saltedData = crypto.pbkdf2Sync(
+    data,
+    salt,
+    iterations,
+    hiLengthMap[cryptoMethod],
+    cryptoMethod
+  );
+
+  // cache a copy to speed up the next lookup, but prevent unbounded cache growth
+  if (_hiCacheCount >= 200) {
+    _hiCachePurge();
+  }
+
+  _hiCache[key] = saltedData;
+  _hiCacheCount += 1;
+  return saltedData;
+}
+
+function compareDigest(lhs: Buffer, rhs: Uint8Array) {
+  if (lhs.length !== rhs.length) {
+    return false;
+  }
+
+  if (typeof crypto.timingSafeEqual === 'function') {
+    return crypto.timingSafeEqual(lhs, rhs);
+  }
+
+  let result = 0;
+  for (let i = 0; i < lhs.length; i++) {
+    result |= lhs[i] ^ rhs[i];
+  }
+
+  return result === 0;
+}
+
+function resolveError(err?: AnyError, result?: Document) {
+  if (err) return err;
+  if (result) {
+    if (result.$err || result.errmsg) return new MongoServerError(result);
+  }
+  return;
+}
+
+export class ScramSHA1 extends ScramSHA {
+  constructor() {
+    super('sha1');
+  }
+}
+
+export class ScramSHA256 extends ScramSHA {
+  constructor() {
+    super('sha256');
+  }
+}

node_modules/mongodb/src/cmap/auth/x509.ts

@@ -0,0 +1,53 @@
+import type { Document } from '../../bson';
+import { MongoMissingCredentialsError } from '../../error';
+import { Callback, ns } from '../../utils';
+import type { HandshakeDocument } from '../connect';
+import { AuthContext, AuthProvider } from './auth_provider';
+import type { MongoCredentials } from './mongo_credentials';
+
+export class X509 extends AuthProvider {
+  override prepare(
+    handshakeDoc: HandshakeDocument,
+    authContext: AuthContext,
+    callback: Callback
+  ): void {
+    const { credentials } = authContext;
+    if (!credentials) {
+      return callback(new MongoMissingCredentialsError('AuthContext must provide credentials.'));
+    }
+    Object.assign(handshakeDoc, {
+      speculativeAuthenticate: x509AuthenticateCommand(credentials)
+    });
+
+    callback(undefined, handshakeDoc);
+  }
+
+  override auth(authContext: AuthContext, callback: Callback): void {
+    const connection = authContext.connection;
+    const credentials = authContext.credentials;
+    if (!credentials) {
+      return callback(new MongoMissingCredentialsError('AuthContext must provide credentials.'));
+    }
+    const response = authContext.response;
+
+    if (response && response.speculativeAuthenticate) {
+      return callback();
+    }
+
+    connection.command(
+      ns('$external.$cmd'),
+      x509AuthenticateCommand(credentials),
+      undefined,
+      callback
+    );
+  }
+}
+
+function x509AuthenticateCommand(credentials: MongoCredentials) {
+  const command: Document = { authenticate: 1, mechanism: 'MONGODB-X509' };
+  if (credentials.username) {
+    command.user = credentials.username;
+  }
+
+  return command;
+}

node_modules/mongodb/src/cmap/command_monitoring_events.ts

@@ -0,0 +1,301 @@
+import type { Document, ObjectId } from '../bson';
+import { LEGACY_HELLO_COMMAND, LEGACY_HELLO_COMMAND_CAMEL_CASE } from '../constants';
+import { calculateDurationInMs, deepCopy } from '../utils';
+import { Msg, WriteProtocolMessageType } from './commands';
+import type { Connection } from './connection';
+
+/**
+ * An event indicating the start of a given
+ * @public
+ * @category Event
+ */
+export class CommandStartedEvent {
+  commandObj?: Document;
+  requestId: number;
+  databaseName: string;
+  commandName: string;
+  command: Document;
+  address: string;
+  connectionId?: string | number;
+  serviceId?: ObjectId;
+
+  /**
+   * Create a started event
+   *
+   * @internal
+   * @param pool - the pool that originated the command
+   * @param command - the command
+   */
+  constructor(connection: Connection, command: WriteProtocolMessageType) {
+    const cmd = extractCommand(command);
+    const commandName = extractCommandName(cmd);
+    const { address, connectionId, serviceId } = extractConnectionDetails(connection);
+
+    // TODO: remove in major revision, this is not spec behavior
+    if (SENSITIVE_COMMANDS.has(commandName)) {
+      this.commandObj = {};
+      this.commandObj[commandName] = true;
+    }
+
+    this.address = address;
+    this.connectionId = connectionId;
+    this.serviceId = serviceId;
+    this.requestId = command.requestId;
+    this.databaseName = databaseName(command);
+    this.commandName = commandName;
+    this.command = maybeRedact(commandName, cmd, cmd);
+  }
+
+  /* @internal */
+  get hasServiceId(): boolean {
+    return !!this.serviceId;
+  }
+}
+
+/**
+ * An event indicating the success of a given command
+ * @public
+ * @category Event
+ */
+export class CommandSucceededEvent {
+  address: string;
+  connectionId?: string | number;
+  requestId: number;
+  duration: number;
+  commandName: string;
+  reply: unknown;
+  serviceId?: ObjectId;
+
+  /**
+   * Create a succeeded event
+   *
+   * @internal
+   * @param pool - the pool that originated the command
+   * @param command - the command
+   * @param reply - the reply for this command from the server
+   * @param started - a high resolution tuple timestamp of when the command was first sent, to calculate duration
+   */
+  constructor(
+    connection: Connection,
+    command: WriteProtocolMessageType,
+    reply: Document | undefined,
+    started: number
+  ) {
+    const cmd = extractCommand(command);
+    const commandName = extractCommandName(cmd);
+    const { address, connectionId, serviceId } = extractConnectionDetails(connection);
+
+    this.address = address;
+    this.connectionId = connectionId;
+    this.serviceId = serviceId;
+    this.requestId = command.requestId;
+    this.commandName = commandName;
+    this.duration = calculateDurationInMs(started);
+    this.reply = maybeRedact(commandName, cmd, extractReply(command, reply));
+  }
+
+  /* @internal */
+  get hasServiceId(): boolean {
+    return !!this.serviceId;
+  }
+}
+
+/**
+ * An event indicating the failure of a given command
+ * @public
+ * @category Event
+ */
+export class CommandFailedEvent {
+  address: string;
+  connectionId?: string | number;
+  requestId: number;
+  duration: number;
+  commandName: string;
+  failure: Error;
+  serviceId?: ObjectId;
+
+  /**
+   * Create a failure event
+   *
+   * @internal
+   * @param pool - the pool that originated the command
+   * @param command - the command
+   * @param error - the generated error or a server error response
+   * @param started - a high resolution tuple timestamp of when the command was first sent, to calculate duration
+   */
+  constructor(
+    connection: Connection,
+    command: WriteProtocolMessageType,
+    error: Error | Document,
+    started: number
+  ) {
+    const cmd = extractCommand(command);
+    const commandName = extractCommandName(cmd);
+    const { address, connectionId, serviceId } = extractConnectionDetails(connection);
+
+    this.address = address;
+    this.connectionId = connectionId;
+    this.serviceId = serviceId;
+
+    this.requestId = command.requestId;
+    this.commandName = commandName;
+    this.duration = calculateDurationInMs(started);
+    this.failure = maybeRedact(commandName, cmd, error) as Error;
+  }
+
+  /* @internal */
+  get hasServiceId(): boolean {
+    return !!this.serviceId;
+  }
+}
+
+/** Commands that we want to redact because of the sensitive nature of their contents */
+const SENSITIVE_COMMANDS = new Set([
+  'authenticate',
+  'saslStart',
+  'saslContinue',
+  'getnonce',
+  'createUser',
+  'updateUser',
+  'copydbgetnonce',
+  'copydbsaslstart',
+  'copydb'
+]);
+
+const HELLO_COMMANDS = new Set(['hello', LEGACY_HELLO_COMMAND, LEGACY_HELLO_COMMAND_CAMEL_CASE]);
+
+// helper methods
+const extractCommandName = (commandDoc: Document) => Object.keys(commandDoc)[0];
+const namespace = (command: WriteProtocolMessageType) => command.ns;
+const databaseName = (command: WriteProtocolMessageType) => command.ns.split('.')[0];
+const collectionName = (command: WriteProtocolMessageType) => command.ns.split('.')[1];
+const maybeRedact = (commandName: string, commandDoc: Document, result: Error | Document) =>
+  SENSITIVE_COMMANDS.has(commandName) ||
+  (HELLO_COMMANDS.has(commandName) && commandDoc.speculativeAuthenticate)
+    ? {}
+    : result;
+
+const LEGACY_FIND_QUERY_MAP: { [key: string]: string } = {
+  $query: 'filter',
+  $orderby: 'sort',
+  $hint: 'hint',
+  $comment: 'comment',
+  $maxScan: 'maxScan',
+  $max: 'max',
+  $min: 'min',
+  $returnKey: 'returnKey',
+  $showDiskLoc: 'showRecordId',
+  $maxTimeMS: 'maxTimeMS',
+  $snapshot: 'snapshot'
+};
+
+const LEGACY_FIND_OPTIONS_MAP = {
+  numberToSkip: 'skip',
+  numberToReturn: 'batchSize',
+  returnFieldSelector: 'projection'
+} as const;
+
+const OP_QUERY_KEYS = [
+  'tailable',
+  'oplogReplay',
+  'noCursorTimeout',
+  'awaitData',
+  'partial',
+  'exhaust'
+] as const;
+
+/** Extract the actual command from the query, possibly up-converting if it's a legacy format */
+function extractCommand(command: WriteProtocolMessageType): Document {
+  if (command instanceof Msg) {
+    return deepCopy(command.command);
+  }
+
+  if (command.query?.$query) {
+    let result: Document;
+    if (command.ns === 'admin.$cmd') {
+      // up-convert legacy command
+      result = Object.assign({}, command.query.$query);
+    } else {
+      // up-convert legacy find command
+      result = { find: collectionName(command) };
+      Object.keys(LEGACY_FIND_QUERY_MAP).forEach(key => {
+        if (command.query[key] != null) {
+          result[LEGACY_FIND_QUERY_MAP[key]] = deepCopy(command.query[key]);
+        }
+      });
+    }
+
+    Object.keys(LEGACY_FIND_OPTIONS_MAP).forEach(key => {
+      const legacyKey = key as keyof typeof LEGACY_FIND_OPTIONS_MAP;
+      if (command[legacyKey] != null) {
+        result[LEGACY_FIND_OPTIONS_MAP[legacyKey]] = deepCopy(command[legacyKey]);
+      }
+    });
+
+    OP_QUERY_KEYS.forEach(key => {
+      if (command[key]) {
+        result[key] = command[key];
+      }
+    });
+
+    if (command.pre32Limit != null) {
+      result.limit = command.pre32Limit;
+    }
+
+    if (command.query.$explain) {
+      return { explain: result };
+    }
+    return result;
+  }
+
+  const clonedQuery: Record<string, unknown> = {};
+  const clonedCommand: Record<string, unknown> = {};
+  if (command.query) {
+    for (const k in command.query) {
+      clonedQuery[k] = deepCopy(command.query[k]);
+    }
+    clonedCommand.query = clonedQuery;
+  }
+
+  for (const k in command) {
+    if (k === 'query') continue;
+    clonedCommand[k] = deepCopy((command as unknown as Record<string, unknown>)[k]);
+  }
+  return command.query ? clonedQuery : clonedCommand;
+}
+
+function extractReply(command: WriteProtocolMessageType, reply?: Document) {
+  if (!reply) {
+    return reply;
+  }
+
+  if (command instanceof Msg) {
+    return deepCopy(reply.result ? reply.result : reply);
+  }
+
+  // is this a legacy find command?
+  if (command.query && command.query.$query != null) {
+    return {
+      ok: 1,
+      cursor: {
+        id: deepCopy(reply.cursorId),
+        ns: namespace(command),
+        firstBatch: deepCopy(reply.documents)
+      }
+    };
+  }
+
+  return deepCopy(reply.result ? reply.result : reply);
+}
+
+function extractConnectionDetails(connection: Connection) {
+  let connectionId;
+  if ('id' in connection) {
+    connectionId = connection.id;
+  }
+  return {
+    address: connection.address,
+    serviceId: connection.serviceId,
+    connectionId
+  };
+}

node_modules/mongodb/src/cmap/commands.ts

@@ -0,0 +1,703 @@
+import type { BSONSerializeOptions, Document, Long } from '../bson';
+import * as BSON from '../bson';
+import { MongoInvalidArgumentError, MongoRuntimeError } from '../error';
+import { ReadPreference } from '../read_preference';
+import type { ClientSession } from '../sessions';
+import { databaseNamespace } from '../utils';
+import type { CommandOptions } from './connection';
+import { OP_MSG, OP_QUERY } from './wire_protocol/constants';
+
+// Incrementing request id
+let _requestId = 0;
+
+// Query flags
+const OPTS_TAILABLE_CURSOR = 2;
+const OPTS_SECONDARY = 4;
+const OPTS_OPLOG_REPLAY = 8;
+const OPTS_NO_CURSOR_TIMEOUT = 16;
+const OPTS_AWAIT_DATA = 32;
+const OPTS_EXHAUST = 64;
+const OPTS_PARTIAL = 128;
+
+// Response flags
+const CURSOR_NOT_FOUND = 1;
+const QUERY_FAILURE = 2;
+const SHARD_CONFIG_STALE = 4;
+const AWAIT_CAPABLE = 8;
+
+/** @internal */
+export type WriteProtocolMessageType = Query | Msg;
+
+/** @internal */
+export interface OpQueryOptions extends CommandOptions {
+  socketTimeoutMS?: number;
+  session?: ClientSession;
+  documentsReturnedIn?: string;
+  numberToSkip?: number;
+  numberToReturn?: number;
+  returnFieldSelector?: Document;
+  pre32Limit?: number;
+  serializeFunctions?: boolean;
+  ignoreUndefined?: boolean;
+  maxBsonSize?: number;
+  checkKeys?: boolean;
+  secondaryOk?: boolean;
+
+  requestId?: number;
+  moreToCome?: boolean;
+  exhaustAllowed?: boolean;
+  readPreference?: ReadPreference;
+}
+
+/**************************************************************
+ * QUERY
+ **************************************************************/
+/** @internal */
+export class Query {
+  ns: string;
+  query: Document;
+  numberToSkip: number;
+  numberToReturn: number;
+  returnFieldSelector?: Document;
+  requestId: number;
+  pre32Limit?: number;
+  serializeFunctions: boolean;
+  ignoreUndefined: boolean;
+  maxBsonSize: number;
+  checkKeys: boolean;
+  batchSize: number;
+  tailable: boolean;
+  secondaryOk: boolean;
+  oplogReplay: boolean;
+  noCursorTimeout: boolean;
+  awaitData: boolean;
+  exhaust: boolean;
+  partial: boolean;
+  documentsReturnedIn?: string;
+
+  constructor(ns: string, query: Document, options: OpQueryOptions) {
+    // Basic options needed to be passed in
+    // TODO(NODE-3483): Replace with MongoCommandError
+    if (ns == null) throw new MongoRuntimeError('Namespace must be specified for query');
+    // TODO(NODE-3483): Replace with MongoCommandError
+    if (query == null) throw new MongoRuntimeError('A query document must be specified for query');
+
+    // Validate that we are not passing 0x00 in the collection name
+    if (ns.indexOf('\x00') !== -1) {
+      // TODO(NODE-3483): Use MongoNamespace static method
+      throw new MongoRuntimeError('Namespace cannot contain a null character');
+    }
+
+    // Basic options
+    this.ns = ns;
+    this.query = query;
+
+    // Additional options
+    this.numberToSkip = options.numberToSkip || 0;
+    this.numberToReturn = options.numberToReturn || 0;
+    this.returnFieldSelector = options.returnFieldSelector || undefined;
+    this.requestId = Query.getRequestId();
+
+    // special case for pre-3.2 find commands, delete ASAP
+    this.pre32Limit = options.pre32Limit;
+
+    // Serialization option
+    this.serializeFunctions =
+      typeof options.serializeFunctions === 'boolean' ? options.serializeFunctions : false;
+    this.ignoreUndefined =
+      typeof options.ignoreUndefined === 'boolean' ? options.ignoreUndefined : false;
+    this.maxBsonSize = options.maxBsonSize || 1024 * 1024 * 16;
+    this.checkKeys = typeof options.checkKeys === 'boolean' ? options.checkKeys : false;
+    this.batchSize = this.numberToReturn;
+
+    // Flags
+    this.tailable = false;
+    this.secondaryOk = typeof options.secondaryOk === 'boolean' ? options.secondaryOk : false;
+    this.oplogReplay = false;
+    this.noCursorTimeout = false;
+    this.awaitData = false;
+    this.exhaust = false;
+    this.partial = false;
+  }
+
+  /** Assign next request Id. */
+  incRequestId(): void {
+    this.requestId = _requestId++;
+  }
+
+  /** Peek next request Id. */
+  nextRequestId(): number {
+    return _requestId + 1;
+  }
+
+  /** Increment then return next request Id. */
+  static getRequestId(): number {
+    return ++_requestId;
+  }
+
+  // Uses a single allocated buffer for the process, avoiding multiple memory allocations
+  toBin(): Buffer[] {
+    const buffers = [];
+    let projection = null;
+
+    // Set up the flags
+    let flags = 0;
+    if (this.tailable) {
+      flags |= OPTS_TAILABLE_CURSOR;
+    }
+
+    if (this.secondaryOk) {
+      flags |= OPTS_SECONDARY;
+    }
+
+    if (this.oplogReplay) {
+      flags |= OPTS_OPLOG_REPLAY;
+    }
+
+    if (this.noCursorTimeout) {
+      flags |= OPTS_NO_CURSOR_TIMEOUT;
+    }
+
+    if (this.awaitData) {
+      flags |= OPTS_AWAIT_DATA;
+    }
+
+    if (this.exhaust) {
+      flags |= OPTS_EXHAUST;
+    }
+
+    if (this.partial) {
+      flags |= OPTS_PARTIAL;
+    }
+
+    // If batchSize is different to this.numberToReturn
+    if (this.batchSize !== this.numberToReturn) this.numberToReturn = this.batchSize;
+
+    // Allocate write protocol header buffer
+    const header = Buffer.alloc(
+      4 * 4 + // Header
+        4 + // Flags
+        Buffer.byteLength(this.ns) +
+        1 + // namespace
+        4 + // numberToSkip
+        4 // numberToReturn
+    );
+
+    // Add header to buffers
+    buffers.push(header);
+
+    // Serialize the query
+    const query = BSON.serialize(this.query, {
+      checkKeys: this.checkKeys,
+      serializeFunctions: this.serializeFunctions,
+      ignoreUndefined: this.ignoreUndefined
+    });
+
+    // Add query document
+    buffers.push(query);
+
+    if (this.returnFieldSelector && Object.keys(this.returnFieldSelector).length > 0) {
+      // Serialize the projection document
+      projection = BSON.serialize(this.returnFieldSelector, {
+        checkKeys: this.checkKeys,
+        serializeFunctions: this.serializeFunctions,
+        ignoreUndefined: this.ignoreUndefined
+      });
+      // Add projection document
+      buffers.push(projection);
+    }
+
+    // Total message size
+    const totalLength = header.length + query.length + (projection ? projection.length : 0);
+
+    // Set up the index
+    let index = 4;
+
+    // Write total document length
+    header[3] = (totalLength >> 24) & 0xff;
+    header[2] = (totalLength >> 16) & 0xff;
+    header[1] = (totalLength >> 8) & 0xff;
+    header[0] = totalLength & 0xff;
+
+    // Write header information requestId
+    header[index + 3] = (this.requestId >> 24) & 0xff;
+    header[index + 2] = (this.requestId >> 16) & 0xff;
+    header[index + 1] = (this.requestId >> 8) & 0xff;
+    header[index] = this.requestId & 0xff;
+    index = index + 4;
+
+    // Write header information responseTo
+    header[index + 3] = (0 >> 24) & 0xff;
+    header[index + 2] = (0 >> 16) & 0xff;
+    header[index + 1] = (0 >> 8) & 0xff;
+    header[index] = 0 & 0xff;
+    index = index + 4;
+
+    // Write header information OP_QUERY
+    header[index + 3] = (OP_QUERY >> 24) & 0xff;
+    header[index + 2] = (OP_QUERY >> 16) & 0xff;
+    header[index + 1] = (OP_QUERY >> 8) & 0xff;
+    header[index] = OP_QUERY & 0xff;
+    index = index + 4;
+
+    // Write header information flags
+    header[index + 3] = (flags >> 24) & 0xff;
+    header[index + 2] = (flags >> 16) & 0xff;
+    header[index + 1] = (flags >> 8) & 0xff;
+    header[index] = flags & 0xff;
+    index = index + 4;
+
+    // Write collection name
+    index = index + header.write(this.ns, index, 'utf8') + 1;
+    header[index - 1] = 0;
+
+    // Write header information flags numberToSkip
+    header[index + 3] = (this.numberToSkip >> 24) & 0xff;
+    header[index + 2] = (this.numberToSkip >> 16) & 0xff;
+    header[index + 1] = (this.numberToSkip >> 8) & 0xff;
+    header[index] = this.numberToSkip & 0xff;
+    index = index + 4;
+
+    // Write header information flags numberToReturn
+    header[index + 3] = (this.numberToReturn >> 24) & 0xff;
+    header[index + 2] = (this.numberToReturn >> 16) & 0xff;
+    header[index + 1] = (this.numberToReturn >> 8) & 0xff;
+    header[index] = this.numberToReturn & 0xff;
+    index = index + 4;
+
+    // Return the buffers
+    return buffers;
+  }
+}
+
+/** @internal */
+export interface MessageHeader {
+  length: number;
+  requestId: number;
+  responseTo: number;
+  opCode: number;
+  fromCompressed?: boolean;
+}
+
+/** @internal */
+export interface OpResponseOptions extends BSONSerializeOptions {
+  raw?: boolean;
+  documentsReturnedIn?: string | null;
+}
+
+/** @internal */
+export class Response {
+  parsed: boolean;
+  raw: Buffer;
+  data: Buffer;
+  opts: OpResponseOptions;
+  length: number;
+  requestId: number;
+  responseTo: number;
+  opCode: number;
+  fromCompressed?: boolean;
+  responseFlags?: number;
+  cursorId?: Long;
+  startingFrom?: number;
+  numberReturned?: number;
+  documents: (Document | Buffer)[] = new Array(0);
+  cursorNotFound?: boolean;
+  queryFailure?: boolean;
+  shardConfigStale?: boolean;
+  awaitCapable?: boolean;
+  promoteLongs: boolean;
+  promoteValues: boolean;
+  promoteBuffers: boolean;
+  bsonRegExp?: boolean;
+  index?: number;
+
+  constructor(
+    message: Buffer,
+    msgHeader: MessageHeader,
+    msgBody: Buffer,
+    opts?: OpResponseOptions
+  ) {
+    this.parsed = false;
+    this.raw = message;
+    this.data = msgBody;
+    this.opts = opts ?? {
+      promoteLongs: true,
+      promoteValues: true,
+      promoteBuffers: false,
+      bsonRegExp: false
+    };
+
+    // Read the message header
+    this.length = msgHeader.length;
+    this.requestId = msgHeader.requestId;
+    this.responseTo = msgHeader.responseTo;
+    this.opCode = msgHeader.opCode;
+    this.fromCompressed = msgHeader.fromCompressed;
+
+    // Flag values
+    this.promoteLongs = typeof this.opts.promoteLongs === 'boolean' ? this.opts.promoteLongs : true;
+    this.promoteValues =
+      typeof this.opts.promoteValues === 'boolean' ? this.opts.promoteValues : true;
+    this.promoteBuffers =
+      typeof this.opts.promoteBuffers === 'boolean' ? this.opts.promoteBuffers : false;
+    this.bsonRegExp = typeof this.opts.bsonRegExp === 'boolean' ? this.opts.bsonRegExp : false;
+  }
+
+  isParsed(): boolean {
+    return this.parsed;
+  }
+
+  parse(options: OpResponseOptions): void {
+    // Don't parse again if not needed
+    if (this.parsed) return;
+    options = options ?? {};
+
+    // Allow the return of raw documents instead of parsing
+    const raw = options.raw || false;
+    const documentsReturnedIn = options.documentsReturnedIn || null;
+    const promoteLongs = options.promoteLongs ?? this.opts.promoteLongs;
+    const promoteValues = options.promoteValues ?? this.opts.promoteValues;
+    const promoteBuffers = options.promoteBuffers ?? this.opts.promoteBuffers;
+    const bsonRegExp = options.bsonRegExp ?? this.opts.bsonRegExp;
+    let bsonSize;
+
+    // Set up the options
+    const _options: BSONSerializeOptions = {
+      promoteLongs,
+      promoteValues,
+      promoteBuffers,
+      bsonRegExp
+    };
+
+    // Position within OP_REPLY at which documents start
+    // (See https://docs.mongodb.com/manual/reference/mongodb-wire-protocol/#wire-op-reply)
+    this.index = 20;
+
+    // Read the message body
+    this.responseFlags = this.data.readInt32LE(0);
+    this.cursorId = new BSON.Long(this.data.readInt32LE(4), this.data.readInt32LE(8));
+    this.startingFrom = this.data.readInt32LE(12);
+    this.numberReturned = this.data.readInt32LE(16);
+
+    // Preallocate document array
+    this.documents = new Array(this.numberReturned);
+
+    this.cursorNotFound = (this.responseFlags & CURSOR_NOT_FOUND) !== 0;
+    this.queryFailure = (this.responseFlags & QUERY_FAILURE) !== 0;
+    this.shardConfigStale = (this.responseFlags & SHARD_CONFIG_STALE) !== 0;
+    this.awaitCapable = (this.responseFlags & AWAIT_CAPABLE) !== 0;
+
+    // Parse Body
+    for (let i = 0; i < this.numberReturned; i++) {
+      bsonSize =
+        this.data[this.index] |
+        (this.data[this.index + 1] << 8) |
+        (this.data[this.index + 2] << 16) |
+        (this.data[this.index + 3] << 24);
+
+      // If we have raw results specified slice the return document
+      if (raw) {
+        this.documents[i] = this.data.slice(this.index, this.index + bsonSize);
+      } else {
+        this.documents[i] = BSON.deserialize(
+          this.data.slice(this.index, this.index + bsonSize),
+          _options
+        );
+      }
+
+      // Adjust the index
+      this.index = this.index + bsonSize;
+    }
+
+    if (this.documents.length === 1 && documentsReturnedIn != null && raw) {
+      const fieldsAsRaw: Document = {};
+      fieldsAsRaw[documentsReturnedIn] = true;
+      _options.fieldsAsRaw = fieldsAsRaw;
+
+      const doc = BSON.deserialize(this.documents[0] as Buffer, _options);
+      this.documents = [doc];
+    }
+
+    // Set parsed
+    this.parsed = true;
+  }
+}
+
+// Implementation of OP_MSG spec:
+// https://github.com/mongodb/specifications/blob/master/source/message/OP_MSG.rst
+//
+// struct Section {
+//   uint8 payloadType;
+//   union payload {
+//       document  document; // payloadType == 0
+//       struct sequence { // payloadType == 1
+//           int32      size;
+//           cstring    identifier;
+//           document*  documents;
+//       };
+//   };
+// };
+
+// struct OP_MSG {
+//   struct MsgHeader {
+//       int32  messageLength;
+//       int32  requestID;
+//       int32  responseTo;
+//       int32  opCode = 2013;
+//   };
+//   uint32      flagBits;
+//   Section+    sections;
+//   [uint32     checksum;]
+// };
+
+// Msg Flags
+const OPTS_CHECKSUM_PRESENT = 1;
+const OPTS_MORE_TO_COME = 2;
+const OPTS_EXHAUST_ALLOWED = 1 << 16;
+
+/** @internal */
+export interface OpMsgOptions {
+  requestId: number;
+  serializeFunctions: boolean;
+  ignoreUndefined: boolean;
+  checkKeys: boolean;
+  maxBsonSize: number;
+  moreToCome: boolean;
+  exhaustAllowed: boolean;
+  readPreference: ReadPreference;
+}
+
+/** @internal */
+export class Msg {
+  ns: string;
+  command: Document;
+  options: OpQueryOptions;
+  requestId: number;
+  serializeFunctions: boolean;
+  ignoreUndefined: boolean;
+  checkKeys: boolean;
+  maxBsonSize: number;
+  checksumPresent: boolean;
+  moreToCome: boolean;
+  exhaustAllowed: boolean;
+
+  constructor(ns: string, command: Document, options: OpQueryOptions) {
+    // Basic options needed to be passed in
+    if (command == null)
+      throw new MongoInvalidArgumentError('Query document must be specified for query');
+
+    // Basic options
+    this.ns = ns;
+    this.command = command;
+    this.command.$db = databaseNamespace(ns);
+
+    if (options.readPreference && options.readPreference.mode !== ReadPreference.PRIMARY) {
+      this.command.$readPreference = options.readPreference.toJSON();
+    }
+
+    // Ensure empty options
+    this.options = options ?? {};
+
+    // Additional options
+    this.requestId = options.requestId ? options.requestId : Msg.getRequestId();
+
+    // Serialization option
+    this.serializeFunctions =
+      typeof options.serializeFunctions === 'boolean' ? options.serializeFunctions : false;
+    this.ignoreUndefined =
+      typeof options.ignoreUndefined === 'boolean' ? options.ignoreUndefined : false;
+    this.checkKeys = typeof options.checkKeys === 'boolean' ? options.checkKeys : false;
+    this.maxBsonSize = options.maxBsonSize || 1024 * 1024 * 16;
+
+    // flags
+    this.checksumPresent = false;
+    this.moreToCome = options.moreToCome || false;
+    this.exhaustAllowed =
+      typeof options.exhaustAllowed === 'boolean' ? options.exhaustAllowed : false;
+  }
+
+  toBin(): Buffer[] {
+    const buffers: Buffer[] = [];
+    let flags = 0;
+
+    if (this.checksumPresent) {
+      flags |= OPTS_CHECKSUM_PRESENT;
+    }
+
+    if (this.moreToCome) {
+      flags |= OPTS_MORE_TO_COME;
+    }
+
+    if (this.exhaustAllowed) {
+      flags |= OPTS_EXHAUST_ALLOWED;
+    }
+
+    const header = Buffer.alloc(
+      4 * 4 + // Header
+        4 // Flags
+    );
+
+    buffers.push(header);
+
+    let totalLength = header.length;
+    const command = this.command;
+    totalLength += this.makeDocumentSegment(buffers, command);
+
+    header.writeInt32LE(totalLength, 0); // messageLength
+    header.writeInt32LE(this.requestId, 4); // requestID
+    header.writeInt32LE(0, 8); // responseTo
+    header.writeInt32LE(OP_MSG, 12); // opCode
+    header.writeUInt32LE(flags, 16); // flags
+    return buffers;
+  }
+
+  makeDocumentSegment(buffers: Buffer[], document: Document): number {
+    const payloadTypeBuffer = Buffer.alloc(1);
+    payloadTypeBuffer[0] = 0;
+
+    const documentBuffer = this.serializeBson(document);
+    buffers.push(payloadTypeBuffer);
+    buffers.push(documentBuffer);
+
+    return payloadTypeBuffer.length + documentBuffer.length;
+  }
+
+  serializeBson(document: Document): Buffer {
+    return BSON.serialize(document, {
+      checkKeys: this.checkKeys,
+      serializeFunctions: this.serializeFunctions,
+      ignoreUndefined: this.ignoreUndefined
+    });
+  }
+
+  static getRequestId(): number {
+    _requestId = (_requestId + 1) & 0x7fffffff;
+    return _requestId;
+  }
+}
+
+/** @internal */
+export class BinMsg {
+  parsed: boolean;
+  raw: Buffer;
+  data: Buffer;
+  opts: OpResponseOptions;
+  length: number;
+  requestId: number;
+  responseTo: number;
+  opCode: number;
+  fromCompressed?: boolean;
+  responseFlags: number;
+  checksumPresent: boolean;
+  moreToCome: boolean;
+  exhaustAllowed: boolean;
+  promoteLongs: boolean;
+  promoteValues: boolean;
+  promoteBuffers: boolean;
+  bsonRegExp: boolean;
+  documents: (Document | Buffer)[];
+  index?: number;
+
+  constructor(
+    message: Buffer,
+    msgHeader: MessageHeader,
+    msgBody: Buffer,
+    opts?: OpResponseOptions
+  ) {
+    this.parsed = false;
+    this.raw = message;
+    this.data = msgBody;
+    this.opts = opts ?? {
+      promoteLongs: true,
+      promoteValues: true,
+      promoteBuffers: false,
+      bsonRegExp: false
+    };
+
+    // Read the message header
+    this.length = msgHeader.length;
+    this.requestId = msgHeader.requestId;
+    this.responseTo = msgHeader.responseTo;
+    this.opCode = msgHeader.opCode;
+    this.fromCompressed = msgHeader.fromCompressed;
+
+    // Read response flags
+    this.responseFlags = msgBody.readInt32LE(0);
+    this.checksumPresent = (this.responseFlags & OPTS_CHECKSUM_PRESENT) !== 0;
+    this.moreToCome = (this.responseFlags & OPTS_MORE_TO_COME) !== 0;
+    this.exhaustAllowed = (this.responseFlags & OPTS_EXHAUST_ALLOWED) !== 0;
+    this.promoteLongs = typeof this.opts.promoteLongs === 'boolean' ? this.opts.promoteLongs : true;
+    this.promoteValues =
+      typeof this.opts.promoteValues === 'boolean' ? this.opts.promoteValues : true;
+    this.promoteBuffers =
+      typeof this.opts.promoteBuffers === 'boolean' ? this.opts.promoteBuffers : false;
+    this.bsonRegExp = typeof this.opts.bsonRegExp === 'boolean' ? this.opts.bsonRegExp : false;
+
+    this.documents = [];
+  }
+
+  isParsed(): boolean {
+    return this.parsed;
+  }
+
+  parse(options: OpResponseOptions): void {
+    // Don't parse again if not needed
+    if (this.parsed) return;
+    options = options ?? {};
+
+    this.index = 4;
+    // Allow the return of raw documents instead of parsing
+    const raw = options.raw || false;
+    const documentsReturnedIn = options.documentsReturnedIn || null;
+    const promoteLongs = options.promoteLongs ?? this.opts.promoteLongs;
+    const promoteValues = options.promoteValues ?? this.opts.promoteValues;
+    const promoteBuffers = options.promoteBuffers ?? this.opts.promoteBuffers;
+    const bsonRegExp = options.bsonRegExp ?? this.opts.bsonRegExp;
+    const validation = this.parseBsonSerializationOptions(options);
+
+    // Set up the options
+    const bsonOptions: BSONSerializeOptions = {
+      promoteLongs,
+      promoteValues,
+      promoteBuffers,
+      bsonRegExp,
+      validation
+      // Due to the strictness of the BSON libraries validation option we need this cast
+    } as BSONSerializeOptions & { validation: { utf8: { writeErrors: boolean } } };
+
+    while (this.index < this.data.length) {
+      const payloadType = this.data.readUInt8(this.index++);
+      if (payloadType === 0) {
+        const bsonSize = this.data.readUInt32LE(this.index);
+        const bin = this.data.slice(this.index, this.index + bsonSize);
+        this.documents.push(raw ? bin : BSON.deserialize(bin, bsonOptions));
+        this.index += bsonSize;
+      } else if (payloadType === 1) {
+        // It was decided that no driver makes use of payload type 1
+
+        // TODO(NODE-3483): Replace with MongoDeprecationError
+        throw new MongoRuntimeError('OP_MSG Payload Type 1 detected unsupported protocol');
+      }
+    }
+
+    if (this.documents.length === 1 && documentsReturnedIn != null && raw) {
+      const fieldsAsRaw: Document = {};
+      fieldsAsRaw[documentsReturnedIn] = true;
+      bsonOptions.fieldsAsRaw = fieldsAsRaw;
+      const doc = BSON.deserialize(this.documents[0] as Buffer, bsonOptions);
+      this.documents = [doc];
+    }
+
+    this.parsed = true;
+  }
+
+  parseBsonSerializationOptions({ enableUtf8Validation }: BSONSerializeOptions): {
+    utf8: { writeErrors: false } | false;
+  } {
+    if (enableUtf8Validation === false) {
+      return { utf8: false };
+    }
+
+    return { utf8: { writeErrors: false } };
+  }
+}

node_modules/mongodb/src/cmap/connect.ts

@@ -0,0 +1,523 @@
+import type { Socket, SocketConnectOpts } from 'net';
+import * as net from 'net';
+import { SocksClient } from 'socks';
+import type { ConnectionOptions as TLSConnectionOpts, TLSSocket } from 'tls';
+import * as tls from 'tls';
+
+import type { Document } from '../bson';
+import { Int32 } from '../bson';
+import { LEGACY_HELLO_COMMAND } from '../constants';
+import {
+  MongoCompatibilityError,
+  MongoError,
+  MongoErrorLabel,
+  MongoInvalidArgumentError,
+  MongoNetworkError,
+  MongoNetworkTimeoutError,
+  MongoRuntimeError,
+  MongoServerError,
+  needsRetryableWriteLabel
+} from '../error';
+import { Callback, ClientMetadata, HostAddress, makeClientMetadata, ns } from '../utils';
+import { AuthContext, AuthProvider } from './auth/auth_provider';
+import { GSSAPI } from './auth/gssapi';
+import { MongoCR } from './auth/mongocr';
+import { MongoDBAWS } from './auth/mongodb_aws';
+import { Plain } from './auth/plain';
+import { AuthMechanism } from './auth/providers';
+import { ScramSHA1, ScramSHA256 } from './auth/scram';
+import { X509 } from './auth/x509';
+import { Connection, ConnectionOptions, CryptoConnection } from './connection';
+import {
+  MAX_SUPPORTED_SERVER_VERSION,
+  MAX_SUPPORTED_WIRE_VERSION,
+  MIN_SUPPORTED_SERVER_VERSION,
+  MIN_SUPPORTED_WIRE_VERSION
+} from './wire_protocol/constants';
+
+const AUTH_PROVIDERS = new Map<AuthMechanism | string, AuthProvider>([
+  [AuthMechanism.MONGODB_AWS, new MongoDBAWS()],
+  [AuthMechanism.MONGODB_CR, new MongoCR()],
+  [AuthMechanism.MONGODB_GSSAPI, new GSSAPI()],
+  [AuthMechanism.MONGODB_PLAIN, new Plain()],
+  [AuthMechanism.MONGODB_SCRAM_SHA1, new ScramSHA1()],
+  [AuthMechanism.MONGODB_SCRAM_SHA256, new ScramSHA256()],
+  [AuthMechanism.MONGODB_X509, new X509()]
+]);
+
+/** @public */
+export type Stream = Socket | TLSSocket;
+
+export function connect(options: ConnectionOptions, callback: Callback<Connection>): void {
+  makeConnection({ ...options, existingSocket: undefined }, (err, socket) => {
+    if (err || !socket) {
+      return callback(err);
+    }
+
+    let ConnectionType = options.connectionType ?? Connection;
+    if (options.autoEncrypter) {
+      ConnectionType = CryptoConnection;
+    }
+    performInitialHandshake(new ConnectionType(socket, options), options, callback);
+  });
+}
+
+function checkSupportedServer(hello: Document, options: ConnectionOptions) {
+  const serverVersionHighEnough =
+    hello &&
+    (typeof hello.maxWireVersion === 'number' || hello.maxWireVersion instanceof Int32) &&
+    hello.maxWireVersion >= MIN_SUPPORTED_WIRE_VERSION;
+  const serverVersionLowEnough =
+    hello &&
+    (typeof hello.minWireVersion === 'number' || hello.minWireVersion instanceof Int32) &&
+    hello.minWireVersion <= MAX_SUPPORTED_WIRE_VERSION;
+
+  if (serverVersionHighEnough) {
+    if (serverVersionLowEnough) {
+      return null;
+    }
+
+    const message = `Server at ${options.hostAddress} reports minimum wire version ${JSON.stringify(
+      hello.minWireVersion
+    )}, but this version of the Node.js Driver requires at most ${MAX_SUPPORTED_WIRE_VERSION} (MongoDB ${MAX_SUPPORTED_SERVER_VERSION})`;
+    return new MongoCompatibilityError(message);
+  }
+
+  const message = `Server at ${options.hostAddress} reports maximum wire version ${
+    JSON.stringify(hello.maxWireVersion) ?? 0
+  }, but this version of the Node.js Driver requires at least ${MIN_SUPPORTED_WIRE_VERSION} (MongoDB ${MIN_SUPPORTED_SERVER_VERSION})`;
+  return new MongoCompatibilityError(message);
+}
+
+function performInitialHandshake(
+  conn: Connection,
+  options: ConnectionOptions,
+  _callback: Callback
+) {
+  const callback: Callback<Document> = function (err, ret) {
+    if (err && conn) {
+      conn.destroy();
+    }
+    _callback(err, ret);
+  };
+
+  const credentials = options.credentials;
+  if (credentials) {
+    if (
+      !(credentials.mechanism === AuthMechanism.MONGODB_DEFAULT) &&
+      !AUTH_PROVIDERS.get(credentials.mechanism)
+    ) {
+      callback(
+        new MongoInvalidArgumentError(`AuthMechanism '${credentials.mechanism}' not supported`)
+      );
+      return;
+    }
+  }
+
+  const authContext = new AuthContext(conn, credentials, options);
+  prepareHandshakeDocument(authContext, (err, handshakeDoc) => {
+    if (err || !handshakeDoc) {
+      return callback(err);
+    }
+
+    const handshakeOptions: Document = Object.assign({}, options);
+    if (typeof options.connectTimeoutMS === 'number') {
+      // The handshake technically is a monitoring check, so its socket timeout should be connectTimeoutMS
+      handshakeOptions.socketTimeoutMS = options.connectTimeoutMS;
+    }
+
+    const start = new Date().getTime();
+    conn.command(ns('admin.$cmd'), handshakeDoc, handshakeOptions, (err, response) => {
+      if (err) {
+        callback(err);
+        return;
+      }
+
+      if (response?.ok === 0) {
+        callback(new MongoServerError(response));
+        return;
+      }
+
+      if (!('isWritablePrimary' in response)) {
+        // Provide hello-style response document.
+        response.isWritablePrimary = response[LEGACY_HELLO_COMMAND];
+      }
+
+      if (response.helloOk) {
+        conn.helloOk = true;
+      }
+
+      const supportedServerErr = checkSupportedServer(response, options);
+      if (supportedServerErr) {
+        callback(supportedServerErr);
+        return;
+      }
+
+      if (options.loadBalanced) {
+        if (!response.serviceId) {
+          return callback(
+            new MongoCompatibilityError(
+              'Driver attempted to initialize in load balancing mode, ' +
+                'but the server does not support this mode.'
+            )
+          );
+        }
+      }
+
+      // NOTE: This is metadata attached to the connection while porting away from
+      //       handshake being done in the `Server` class. Likely, it should be
+      //       relocated, or at very least restructured.
+      conn.hello = response;
+      conn.lastHelloMS = new Date().getTime() - start;
+
+      if (!response.arbiterOnly && credentials) {
+        // store the response on auth context
+        authContext.response = response;
+
+        const resolvedCredentials = credentials.resolveAuthMechanism(response);
+        const provider = AUTH_PROVIDERS.get(resolvedCredentials.mechanism);
+        if (!provider) {
+          return callback(
+            new MongoInvalidArgumentError(
+              `No AuthProvider for ${resolvedCredentials.mechanism} defined.`
+            )
+          );
+        }
+        provider.auth(authContext, err => {
+          if (err) {
+            if (err instanceof MongoError) {
+              err.addErrorLabel(MongoErrorLabel.HandshakeError);
+              if (needsRetryableWriteLabel(err, response.maxWireVersion)) {
+                err.addErrorLabel(MongoErrorLabel.RetryableWriteError);
+              }
+            }
+            return callback(err);
+          }
+          callback(undefined, conn);
+        });
+
+        return;
+      }
+
+      callback(undefined, conn);
+    });
+  });
+}
+
+export interface HandshakeDocument extends Document {
+  /**
+   * @deprecated Use hello instead
+   */
+  ismaster?: boolean;
+  hello?: boolean;
+  helloOk?: boolean;
+  client: ClientMetadata;
+  compression: string[];
+  saslSupportedMechs?: string;
+  loadBalanced?: boolean;
+}
+
+/**
+ * @internal
+ *
+ * This function is only exposed for testing purposes.
+ */
+export function prepareHandshakeDocument(
+  authContext: AuthContext,
+  callback: Callback<HandshakeDocument>
+) {
+  const options = authContext.options;
+  const compressors = options.compressors ? options.compressors : [];
+  const { serverApi } = authContext.connection;
+
+  const handshakeDoc: HandshakeDocument = {
+    [serverApi?.version ? 'hello' : LEGACY_HELLO_COMMAND]: true,
+    helloOk: true,
+    client: options.metadata || makeClientMetadata(options),
+    compression: compressors
+  };
+
+  if (options.loadBalanced === true) {
+    handshakeDoc.loadBalanced = true;
+  }
+
+  const credentials = authContext.credentials;
+  if (credentials) {
+    if (credentials.mechanism === AuthMechanism.MONGODB_DEFAULT && credentials.username) {
+      handshakeDoc.saslSupportedMechs = `${credentials.source}.${credentials.username}`;
+
+      const provider = AUTH_PROVIDERS.get(AuthMechanism.MONGODB_SCRAM_SHA256);
+      if (!provider) {
+        // This auth mechanism is always present.
+        return callback(
+          new MongoInvalidArgumentError(
+            `No AuthProvider for ${AuthMechanism.MONGODB_SCRAM_SHA256} defined.`
+          )
+        );
+      }
+      return provider.prepare(handshakeDoc, authContext, callback);
+    }
+    const provider = AUTH_PROVIDERS.get(credentials.mechanism);
+    if (!provider) {
+      return callback(
+        new MongoInvalidArgumentError(`No AuthProvider for ${credentials.mechanism} defined.`)
+      );
+    }
+    return provider.prepare(handshakeDoc, authContext, callback);
+  }
+  callback(undefined, handshakeDoc);
+}
+
+/** @public */
+export const LEGAL_TLS_SOCKET_OPTIONS = [
+  'ALPNProtocols',
+  'ca',
+  'cert',
+  'checkServerIdentity',
+  'ciphers',
+  'crl',
+  'ecdhCurve',
+  'key',
+  'minDHSize',
+  'passphrase',
+  'pfx',
+  'rejectUnauthorized',
+  'secureContext',
+  'secureProtocol',
+  'servername',
+  'session'
+] as const;
+
+/** @public */
+export const LEGAL_TCP_SOCKET_OPTIONS = [
+  'family',
+  'hints',
+  'localAddress',
+  'localPort',
+  'lookup'
+] as const;
+
+function parseConnectOptions(options: ConnectionOptions): SocketConnectOpts {
+  const hostAddress = options.hostAddress;
+  if (!hostAddress) throw new MongoInvalidArgumentError('Option "hostAddress" is required');
+
+  const result: Partial<net.TcpNetConnectOpts & net.IpcNetConnectOpts> = {};
+  for (const name of LEGAL_TCP_SOCKET_OPTIONS) {
+    if (options[name] != null) {
+      (result as Document)[name] = options[name];
+    }
+  }
+
+  if (typeof hostAddress.socketPath === 'string') {
+    result.path = hostAddress.socketPath;
+    return result as net.IpcNetConnectOpts;
+  } else if (typeof hostAddress.host === 'string') {
+    result.host = hostAddress.host;
+    result.port = hostAddress.port;
+    return result as net.TcpNetConnectOpts;
+  } else {
+    // This should never happen since we set up HostAddresses
+    // But if we don't throw here the socket could hang until timeout
+    // TODO(NODE-3483)
+    throw new MongoRuntimeError(`Unexpected HostAddress ${JSON.stringify(hostAddress)}`);
+  }
+}
+
+type MakeConnectionOptions = ConnectionOptions & { existingSocket?: Stream };
+
+function parseSslOptions(options: MakeConnectionOptions): TLSConnectionOpts {
+  const result: TLSConnectionOpts = parseConnectOptions(options);
+  // Merge in valid SSL options
+  for (const name of LEGAL_TLS_SOCKET_OPTIONS) {
+    if (options[name] != null) {
+      (result as Document)[name] = options[name];
+    }
+  }
+
+  if (options.existingSocket) {
+    result.socket = options.existingSocket;
+  }
+
+  // Set default sni servername to be the same as host
+  if (result.servername == null && result.host && !net.isIP(result.host)) {
+    result.servername = result.host;
+  }
+
+  return result;
+}
+
+const SOCKET_ERROR_EVENT_LIST = ['error', 'close', 'timeout', 'parseError'] as const;
+type ErrorHandlerEventName = typeof SOCKET_ERROR_EVENT_LIST[number] | 'cancel';
+const SOCKET_ERROR_EVENTS = new Set(SOCKET_ERROR_EVENT_LIST);
+
+function makeConnection(options: MakeConnectionOptions, _callback: Callback<Stream>) {
+  const useTLS = options.tls ?? false;
+  const keepAlive = options.keepAlive ?? true;
+  const socketTimeoutMS = options.socketTimeoutMS ?? Reflect.get(options, 'socketTimeout') ?? 0;
+  const noDelay = options.noDelay ?? true;
+  const connectTimeoutMS = options.connectTimeoutMS ?? 30000;
+  const rejectUnauthorized = options.rejectUnauthorized ?? true;
+  const keepAliveInitialDelay =
+    ((options.keepAliveInitialDelay ?? 120000) > socketTimeoutMS
+      ? Math.round(socketTimeoutMS / 2)
+      : options.keepAliveInitialDelay) ?? 120000;
+  const existingSocket = options.existingSocket;
+
+  let socket: Stream;
+  const callback: Callback<Stream> = function (err, ret) {
+    if (err && socket) {
+      socket.destroy();
+    }
+
+    _callback(err, ret);
+  };
+
+  if (options.proxyHost != null) {
+    // Currently, only Socks5 is supported.
+    return makeSocks5Connection(
+      {
+        ...options,
+        connectTimeoutMS // Should always be present for Socks5
+      },
+      callback
+    );
+  }
+
+  if (useTLS) {
+    const tlsSocket = tls.connect(parseSslOptions(options));
+    if (typeof tlsSocket.disableRenegotiation === 'function') {
+      tlsSocket.disableRenegotiation();
+    }
+    socket = tlsSocket;
+  } else if (existingSocket) {
+    // In the TLS case, parseSslOptions() sets options.socket to existingSocket,
+    // so we only need to handle the non-TLS case here (where existingSocket
+    // gives us all we need out of the box).
+    socket = existingSocket;
+  } else {
+    socket = net.createConnection(parseConnectOptions(options));
+  }
+
+  socket.setKeepAlive(keepAlive, keepAliveInitialDelay);
+  socket.setTimeout(connectTimeoutMS);
+  socket.setNoDelay(noDelay);
+
+  const connectEvent = useTLS ? 'secureConnect' : 'connect';
+  let cancellationHandler: (err: Error) => void;
+  function errorHandler(eventName: ErrorHandlerEventName) {
+    return (err: Error) => {
+      SOCKET_ERROR_EVENTS.forEach(event => socket.removeAllListeners(event));
+      if (cancellationHandler && options.cancellationToken) {
+        options.cancellationToken.removeListener('cancel', cancellationHandler);
+      }
+
+      socket.removeListener(connectEvent, connectHandler);
+      callback(connectionFailureError(eventName, err));
+    };
+  }
+
+  function connectHandler() {
+    SOCKET_ERROR_EVENTS.forEach(event => socket.removeAllListeners(event));
+    if (cancellationHandler && options.cancellationToken) {
+      options.cancellationToken.removeListener('cancel', cancellationHandler);
+    }
+
+    if ('authorizationError' in socket) {
+      if (socket.authorizationError && rejectUnauthorized) {
+        return callback(socket.authorizationError);
+      }
+    }
+
+    socket.setTimeout(socketTimeoutMS);
+    callback(undefined, socket);
+  }
+
+  SOCKET_ERROR_EVENTS.forEach(event => socket.once(event, errorHandler(event)));
+  if (options.cancellationToken) {
+    cancellationHandler = errorHandler('cancel');
+    options.cancellationToken.once('cancel', cancellationHandler);
+  }
+
+  if (existingSocket) {
+    process.nextTick(connectHandler);
+  } else {
+    socket.once(connectEvent, connectHandler);
+  }
+}
+
+function makeSocks5Connection(options: MakeConnectionOptions, callback: Callback<Stream>) {
+  const hostAddress = HostAddress.fromHostPort(
+    options.proxyHost ?? '', // proxyHost is guaranteed to set here
+    options.proxyPort ?? 1080
+  );
+
+  // First, connect to the proxy server itself:
+  makeConnection(
+    {
+      ...options,
+      hostAddress,
+      tls: false,
+      proxyHost: undefined
+    },
+    (err, rawSocket) => {
+      if (err) {
+        return callback(err);
+      }
+
+      const destination = parseConnectOptions(options) as net.TcpNetConnectOpts;
+      if (typeof destination.host !== 'string' || typeof destination.port !== 'number') {
+        return callback(
+          new MongoInvalidArgumentError('Can only make Socks5 connections to TCP hosts')
+        );
+      }
+
+      // Then, establish the Socks5 proxy connection:
+      SocksClient.createConnection({
+        existing_socket: rawSocket,
+        timeout: options.connectTimeoutMS,
+        command: 'connect',
+        destination: {
+          host: destination.host,
+          port: destination.port
+        },
+        proxy: {
+          // host and port are ignored because we pass existing_socket
+          host: 'iLoveJavaScript',
+          port: 0,
+          type: 5,
+          userId: options.proxyUsername || undefined,
+          password: options.proxyPassword || undefined
+        }
+      }).then(
+        ({ socket }) => {
+          // Finally, now treat the resulting duplex stream as the
+          // socket over which we send and receive wire protocol messages:
+          makeConnection(
+            {
+              ...options,
+              existingSocket: socket,
+              proxyHost: undefined
+            },
+            callback
+          );
+        },
+        error => callback(connectionFailureError('error', error))
+      );
+    }
+  );
+}
+
+function connectionFailureError(type: ErrorHandlerEventName, err: Error) {
+  switch (type) {
+    case 'error':
+      return new MongoNetworkError(err);
+    case 'timeout':
+      return new MongoNetworkTimeoutError('connection timed out');
+    case 'close':
+      return new MongoNetworkError('connection closed');
+    case 'cancel':
+      return new MongoNetworkError('connection establishment was cancelled');
+    default:
+      return new MongoNetworkError('unknown network error');
+  }
+}

node_modules/mongodb/src/cmap/connection.ts

@@ -0,0 +1,752 @@
+import { clearTimeout, setTimeout } from 'timers';
+
+import type { BSONSerializeOptions, Document, ObjectId } from '../bson';
+import {
+  CLOSE,
+  CLUSTER_TIME_RECEIVED,
+  COMMAND_FAILED,
+  COMMAND_STARTED,
+  COMMAND_SUCCEEDED,
+  MESSAGE,
+  PINNED,
+  UNPINNED
+} from '../constants';
+import type { AutoEncrypter } from '../deps';
+import {
+  MongoCompatibilityError,
+  MongoMissingDependencyError,
+  MongoNetworkError,
+  MongoNetworkTimeoutError,
+  MongoServerError,
+  MongoWriteConcernError
+} from '../error';
+import type { ServerApi, SupportedNodeConnectionOptions } from '../mongo_client';
+import { CancellationToken, TypedEventEmitter } from '../mongo_types';
+import type { ReadPreference, ReadPreferenceLike } from '../read_preference';
+import { applySession, ClientSession, updateSessionFromResponse } from '../sessions';
+import {
+  calculateDurationInMs,
+  Callback,
+  ClientMetadata,
+  HostAddress,
+  maxWireVersion,
+  MongoDBNamespace,
+  now,
+  uuidV4
+} from '../utils';
+import type { WriteConcern } from '../write_concern';
+import type { MongoCredentials } from './auth/mongo_credentials';
+import {
+  CommandFailedEvent,
+  CommandStartedEvent,
+  CommandSucceededEvent
+} from './command_monitoring_events';
+import { BinMsg, Msg, Query, Response, WriteProtocolMessageType } from './commands';
+import type { Stream } from './connect';
+import { MessageStream, OperationDescription } from './message_stream';
+import { StreamDescription, StreamDescriptionOptions } from './stream_description';
+import { getReadPreference, isSharded } from './wire_protocol/shared';
+
+/** @internal */
+const kStream = Symbol('stream');
+/** @internal */
+const kQueue = Symbol('queue');
+/** @internal */
+const kMessageStream = Symbol('messageStream');
+/** @internal */
+const kGeneration = Symbol('generation');
+/** @internal */
+const kLastUseTime = Symbol('lastUseTime');
+/** @internal */
+const kClusterTime = Symbol('clusterTime');
+/** @internal */
+const kDescription = Symbol('description');
+/** @internal */
+const kHello = Symbol('hello');
+/** @internal */
+const kAutoEncrypter = Symbol('autoEncrypter');
+/** @internal */
+const kDelayedTimeoutId = Symbol('delayedTimeoutId');
+
+/** @internal */
+export interface QueryOptions extends BSONSerializeOptions {
+  readPreference: ReadPreference;
+  documentsReturnedIn?: string;
+  batchSize?: number;
+  limit?: number;
+  skip?: number;
+  projection?: Document;
+  tailable?: boolean;
+  awaitData?: boolean;
+  noCursorTimeout?: boolean;
+  /** @deprecated use `noCursorTimeout` instead */
+  timeout?: boolean;
+  partial?: boolean;
+  oplogReplay?: boolean;
+}
+
+/** @internal */
+export interface CommandOptions extends BSONSerializeOptions {
+  command?: boolean;
+  secondaryOk?: boolean;
+  /** Specify read preference if command supports it */
+  readPreference?: ReadPreferenceLike;
+  raw?: boolean;
+  monitoring?: boolean;
+  socketTimeoutMS?: number;
+  /** Session to use for the operation */
+  session?: ClientSession;
+  documentsReturnedIn?: string;
+  noResponse?: boolean;
+  omitReadPreference?: boolean;
+
+  // TODO(NODE-2802): Currently the CommandOptions take a property willRetryWrite which is a hint
+  // from executeOperation that the txnNum should be applied to this command.
+  // Applying a session to a command should happen as part of command construction,
+  // most likely in the CommandOperation#executeCommand method, where we have access to
+  // the details we need to determine if a txnNum should also be applied.
+  willRetryWrite?: boolean;
+
+  writeConcern?: WriteConcern;
+}
+
+/** @internal */
+export interface GetMoreOptions extends CommandOptions {
+  batchSize?: number;
+  maxTimeMS?: number;
+  maxAwaitTimeMS?: number;
+  /**
+   * Comment to apply to the operation.
+   *
+   * In server versions pre-4.4, 'comment' must be string.  A server
+   * error will be thrown if any other type is provided.
+   *
+   * In server versions 4.4 and above, 'comment' can be any valid BSON type.
+   */
+  comment?: unknown;
+}
+
+/** @public */
+export interface ProxyOptions {
+  proxyHost?: string;
+  proxyPort?: number;
+  proxyUsername?: string;
+  proxyPassword?: string;
+}
+
+/** @public */
+export interface ConnectionOptions
+  extends SupportedNodeConnectionOptions,
+    StreamDescriptionOptions,
+    ProxyOptions {
+  // Internal creation info
+  id: number | '<monitor>';
+  generation: number;
+  hostAddress: HostAddress;
+  // Settings
+  autoEncrypter?: AutoEncrypter;
+  serverApi?: ServerApi;
+  monitorCommands: boolean;
+  /** @internal */
+  connectionType?: typeof Connection;
+  credentials?: MongoCredentials;
+  connectTimeoutMS?: number;
+  tls: boolean;
+  keepAlive?: boolean;
+  keepAliveInitialDelay?: number;
+  noDelay?: boolean;
+  socketTimeoutMS?: number;
+  cancellationToken?: CancellationToken;
+
+  metadata: ClientMetadata;
+}
+
+/** @public */
+export interface DestroyOptions {
+  /** Force the destruction. */
+  force?: boolean;
+}
+
+/** @public */
+export type ConnectionEvents = {
+  commandStarted(event: CommandStartedEvent): void;
+  commandSucceeded(event: CommandSucceededEvent): void;
+  commandFailed(event: CommandFailedEvent): void;
+  clusterTimeReceived(clusterTime: Document): void;
+  close(): void;
+  message(message: any): void;
+  pinned(pinType: string): void;
+  unpinned(pinType: string): void;
+};
+
+/** @internal */
+export class Connection extends TypedEventEmitter<ConnectionEvents> {
+  id: number | '<monitor>';
+  address: string;
+  socketTimeoutMS: number;
+  monitorCommands: boolean;
+  closed: boolean;
+  destroyed: boolean;
+  lastHelloMS?: number;
+  serverApi?: ServerApi;
+  helloOk?: boolean;
+
+  /**@internal */
+  [kDelayedTimeoutId]: NodeJS.Timeout | null;
+  /** @internal */
+  [kDescription]: StreamDescription;
+  /** @internal */
+  [kGeneration]: number;
+  /** @internal */
+  [kLastUseTime]: number;
+  /** @internal */
+  [kQueue]: Map<number, OperationDescription>;
+  /** @internal */
+  [kMessageStream]: MessageStream;
+  /** @internal */
+  [kStream]: Stream;
+  /** @internal */
+  [kHello]: Document | null;
+  /** @internal */
+  [kClusterTime]: Document | null;
+
+  /** @event */
+  static readonly COMMAND_STARTED = COMMAND_STARTED;
+  /** @event */
+  static readonly COMMAND_SUCCEEDED = COMMAND_SUCCEEDED;
+  /** @event */
+  static readonly COMMAND_FAILED = COMMAND_FAILED;
+  /** @event */
+  static readonly CLUSTER_TIME_RECEIVED = CLUSTER_TIME_RECEIVED;
+  /** @event */
+  static readonly CLOSE = CLOSE;
+  /** @event */
+  static readonly MESSAGE = MESSAGE;
+  /** @event */
+  static readonly PINNED = PINNED;
+  /** @event */
+  static readonly UNPINNED = UNPINNED;
+
+  constructor(stream: Stream, options: ConnectionOptions) {
+    super();
+    this.id = options.id;
+    this.address = streamIdentifier(stream, options);
+    this.socketTimeoutMS = options.socketTimeoutMS ?? 0;
+    this.monitorCommands = options.monitorCommands;
+    this.serverApi = options.serverApi;
+    this.closed = false;
+    this.destroyed = false;
+    this[kHello] = null;
+    this[kClusterTime] = null;
+
+    this[kDescription] = new StreamDescription(this.address, options);
+    this[kGeneration] = options.generation;
+    this[kLastUseTime] = now();
+
+    // setup parser stream and message handling
+    this[kQueue] = new Map();
+    this[kMessageStream] = new MessageStream({
+      ...options,
+      maxBsonMessageSize: this.hello?.maxBsonMessageSize
+    });
+    this[kStream] = stream;
+
+    this[kDelayedTimeoutId] = null;
+
+    this[kMessageStream].on('message', message => this.onMessage(message));
+    this[kMessageStream].on('error', error => this.onError(error));
+    this[kStream].on('close', () => this.onClose());
+    this[kStream].on('timeout', () => this.onTimeout());
+    this[kStream].on('error', () => {
+      /* ignore errors, listen to `close` instead */
+    });
+
+    // hook the message stream up to the passed in stream
+    this[kStream].pipe(this[kMessageStream]);
+    this[kMessageStream].pipe(this[kStream]);
+  }
+
+  get description(): StreamDescription {
+    return this[kDescription];
+  }
+
+  get hello(): Document | null {
+    return this[kHello];
+  }
+
+  // the `connect` method stores the result of the handshake hello on the connection
+  set hello(response: Document | null) {
+    this[kDescription].receiveResponse(response);
+    this[kDescription] = Object.freeze(this[kDescription]);
+
+    // TODO: remove this, and only use the `StreamDescription` in the future
+    this[kHello] = response;
+  }
+
+  // Set the whether the message stream is for a monitoring connection.
+  set isMonitoringConnection(value: boolean) {
+    this[kMessageStream].isMonitoringConnection = value;
+  }
+
+  get isMonitoringConnection(): boolean {
+    return this[kMessageStream].isMonitoringConnection;
+  }
+
+  get serviceId(): ObjectId | undefined {
+    return this.hello?.serviceId;
+  }
+
+  get loadBalanced(): boolean {
+    return this.description.loadBalanced;
+  }
+
+  get generation(): number {
+    return this[kGeneration] || 0;
+  }
+
+  set generation(generation: number) {
+    this[kGeneration] = generation;
+  }
+
+  get idleTime(): number {
+    return calculateDurationInMs(this[kLastUseTime]);
+  }
+
+  get clusterTime(): Document | null {
+    return this[kClusterTime];
+  }
+
+  get stream(): Stream {
+    return this[kStream];
+  }
+
+  markAvailable(): void {
+    this[kLastUseTime] = now();
+  }
+
+  onError(error: Error) {
+    if (this.closed) {
+      return;
+    }
+
+    this[kStream].destroy(error);
+
+    this.closed = true;
+
+    for (const op of this[kQueue].values()) {
+      op.cb(error);
+    }
+
+    this[kQueue].clear();
+    this.emit(Connection.CLOSE);
+  }
+
+  onClose() {
+    if (this.closed) {
+      return;
+    }
+
+    this.closed = true;
+
+    const message = `connection ${this.id} to ${this.address} closed`;
+    for (const op of this[kQueue].values()) {
+      op.cb(new MongoNetworkError(message));
+    }
+
+    this[kQueue].clear();
+    this.emit(Connection.CLOSE);
+  }
+
+  onTimeout() {
+    if (this.closed) {
+      return;
+    }
+
+    this[kDelayedTimeoutId] = setTimeout(() => {
+      this[kStream].destroy();
+
+      this.closed = true;
+
+      const message = `connection ${this.id} to ${this.address} timed out`;
+      const beforeHandshake = this.hello == null;
+      for (const op of this[kQueue].values()) {
+        op.cb(new MongoNetworkTimeoutError(message, { beforeHandshake }));
+      }
+
+      this[kQueue].clear();
+      this.emit(Connection.CLOSE);
+    }, 1).unref(); // No need for this timer to hold the event loop open
+  }
+
+  onMessage(message: BinMsg | Response) {
+    const delayedTimeoutId = this[kDelayedTimeoutId];
+    if (delayedTimeoutId != null) {
+      clearTimeout(delayedTimeoutId);
+      this[kDelayedTimeoutId] = null;
+    }
+
+    // always emit the message, in case we are streaming
+    this.emit('message', message);
+    const operationDescription = this[kQueue].get(message.responseTo);
+    if (!operationDescription) {
+      return;
+    }
+
+    const callback = operationDescription.cb;
+
+    // SERVER-45775: For exhaust responses we should be able to use the same requestId to
+    // track response, however the server currently synthetically produces remote requests
+    // making the `responseTo` change on each response
+    this[kQueue].delete(message.responseTo);
+    if ('moreToCome' in message && message.moreToCome) {
+      // requeue the callback for next synthetic request
+      this[kQueue].set(message.requestId, operationDescription);
+    } else if (operationDescription.socketTimeoutOverride) {
+      this[kStream].setTimeout(this.socketTimeoutMS);
+    }
+
+    try {
+      // Pass in the entire description because it has BSON parsing options
+      message.parse(operationDescription);
+    } catch (err) {
+      // If this error is generated by our own code, it will already have the correct class applied
+      // if it is not, then it is coming from a catastrophic data parse failure or the BSON library
+      // in either case, it should not be wrapped
+      callback(err);
+      return;
+    }
+
+    if (message.documents[0]) {
+      const document: Document = message.documents[0];
+      const session = operationDescription.session;
+      if (session) {
+        updateSessionFromResponse(session, document);
+      }
+
+      if (document.$clusterTime) {
+        this[kClusterTime] = document.$clusterTime;
+        this.emit(Connection.CLUSTER_TIME_RECEIVED, document.$clusterTime);
+      }
+
+      if (operationDescription.command) {
+        if (document.writeConcernError) {
+          callback(new MongoWriteConcernError(document.writeConcernError, document));
+          return;
+        }
+
+        if (document.ok === 0 || document.$err || document.errmsg || document.code) {
+          callback(new MongoServerError(document));
+          return;
+        }
+      } else {
+        // Pre 3.2 support
+        if (document.ok === 0 || document.$err || document.errmsg) {
+          callback(new MongoServerError(document));
+          return;
+        }
+      }
+    }
+
+    callback(undefined, message.documents[0]);
+  }
+
+  destroy(options?: DestroyOptions, callback?: Callback): void {
+    if (typeof options === 'function') {
+      callback = options;
+      options = { force: false };
+    }
+
+    this.removeAllListeners(Connection.PINNED);
+    this.removeAllListeners(Connection.UNPINNED);
+
+    options = Object.assign({ force: false }, options);
+    if (this[kStream] == null || this.destroyed) {
+      this.destroyed = true;
+      if (typeof callback === 'function') {
+        callback();
+      }
+
+      return;
+    }
+
+    if (options.force) {
+      this[kStream].destroy();
+      this.destroyed = true;
+      if (typeof callback === 'function') {
+        callback();
+      }
+
+      return;
+    }
+
+    this[kStream].end(() => {
+      this.destroyed = true;
+      if (typeof callback === 'function') {
+        callback();
+      }
+    });
+  }
+
+  command(
+    ns: MongoDBNamespace,
+    cmd: Document,
+    options: CommandOptions | undefined,
+    callback: Callback
+  ): void {
+    const readPreference = getReadPreference(cmd, options);
+    const shouldUseOpMsg = supportsOpMsg(this);
+    const session = options?.session;
+
+    let clusterTime = this.clusterTime;
+    let finalCmd = Object.assign({}, cmd);
+
+    if (this.serverApi) {
+      const { version, strict, deprecationErrors } = this.serverApi;
+      finalCmd.apiVersion = version;
+      if (strict != null) finalCmd.apiStrict = strict;
+      if (deprecationErrors != null) finalCmd.apiDeprecationErrors = deprecationErrors;
+    }
+
+    if (hasSessionSupport(this) && session) {
+      if (
+        session.clusterTime &&
+        clusterTime &&
+        session.clusterTime.clusterTime.greaterThan(clusterTime.clusterTime)
+      ) {
+        clusterTime = session.clusterTime;
+      }
+
+      const err = applySession(session, finalCmd, options);
+      if (err) {
+        return callback(err);
+      }
+    }
+
+    // if we have a known cluster time, gossip it
+    if (clusterTime) {
+      finalCmd.$clusterTime = clusterTime;
+    }
+
+    if (isSharded(this) && !shouldUseOpMsg && readPreference && readPreference.mode !== 'primary') {
+      finalCmd = {
+        $query: finalCmd,
+        $readPreference: readPreference.toJSON()
+      };
+    }
+
+    const commandOptions: Document = Object.assign(
+      {
+        command: true,
+        numberToSkip: 0,
+        numberToReturn: -1,
+        checkKeys: false,
+        // This value is not overridable
+        secondaryOk: readPreference.secondaryOk()
+      },
+      options
+    );
+
+    const cmdNs = `${ns.db}.$cmd`;
+    const message = shouldUseOpMsg
+      ? new Msg(cmdNs, finalCmd, commandOptions)
+      : new Query(cmdNs, finalCmd, commandOptions);
+
+    try {
+      write(this, message, commandOptions, callback);
+    } catch (err) {
+      callback(err);
+    }
+  }
+}
+
+/** @internal */
+export class CryptoConnection extends Connection {
+  /** @internal */
+  [kAutoEncrypter]?: AutoEncrypter;
+
+  constructor(stream: Stream, options: ConnectionOptions) {
+    super(stream, options);
+    this[kAutoEncrypter] = options.autoEncrypter;
+  }
+
+  /** @internal @override */
+  override command(
+    ns: MongoDBNamespace,
+    cmd: Document,
+    options: CommandOptions,
+    callback: Callback
+  ): void {
+    const autoEncrypter = this[kAutoEncrypter];
+    if (!autoEncrypter) {
+      return callback(new MongoMissingDependencyError('No AutoEncrypter available for encryption'));
+    }
+
+    const serverWireVersion = maxWireVersion(this);
+    if (serverWireVersion === 0) {
+      // This means the initial handshake hasn't happened yet
+      return super.command(ns, cmd, options, callback);
+    }
+
+    if (serverWireVersion < 8) {
+      callback(
+        new MongoCompatibilityError('Auto-encryption requires a minimum MongoDB version of 4.2')
+      );
+      return;
+    }
+
+    // Save sort or indexKeys based on the command being run
+    // the encrypt API serializes our JS objects to BSON to pass to the native code layer
+    // and then deserializes the encrypted result, the protocol level components
+    // of the command (ex. sort) are then converted to JS objects potentially losing
+    // import key order information. These fields are never encrypted so we can save the values
+    // from before the encryption and replace them after encryption has been performed
+    const sort: Map<string, number> | null = cmd.find || cmd.findAndModify ? cmd.sort : null;
+    const indexKeys: Map<string, number>[] | null = cmd.createIndexes
+      ? cmd.indexes.map((index: { key: Map<string, number> }) => index.key)
+      : null;
+
+    autoEncrypter.encrypt(ns.toString(), cmd, options, (err, encrypted) => {
+      if (err || encrypted == null) {
+        callback(err, null);
+        return;
+      }
+
+      // Replace the saved values
+      if (sort != null && (cmd.find || cmd.findAndModify)) {
+        encrypted.sort = sort;
+      }
+      if (indexKeys != null && cmd.createIndexes) {
+        for (const [offset, index] of indexKeys.entries()) {
+          encrypted.indexes[offset].key = index;
+        }
+      }
+
+      super.command(ns, encrypted, options, (err, response) => {
+        if (err || response == null) {
+          callback(err, response);
+          return;
+        }
+
+        autoEncrypter.decrypt(response, options, callback);
+      });
+    });
+  }
+}
+
+/** @internal */
+export function hasSessionSupport(conn: Connection): boolean {
+  const description = conn.description;
+  return description.logicalSessionTimeoutMinutes != null || !!description.loadBalanced;
+}
+
+function supportsOpMsg(conn: Connection) {
+  const description = conn.description;
+  if (description == null) {
+    return false;
+  }
+
+  return maxWireVersion(conn) >= 6 && !description.__nodejs_mock_server__;
+}
+
+function streamIdentifier(stream: Stream, options: ConnectionOptions): string {
+  if (options.proxyHost) {
+    // If proxy options are specified, the properties of `stream` itself
+    // will not accurately reflect what endpoint this is connected to.
+    return options.hostAddress.toString();
+  }
+
+  if (typeof stream.address === 'function') {
+    return `${stream.remoteAddress}:${stream.remotePort}`;
+  }
+
+  return uuidV4().toString('hex');
+}
+
+function write(
+  conn: Connection,
+  command: WriteProtocolMessageType,
+  options: CommandOptions,
+  callback: Callback
+) {
+  options = options ?? {};
+  const operationDescription: OperationDescription = {
+    requestId: command.requestId,
+    cb: callback,
+    session: options.session,
+    noResponse: typeof options.noResponse === 'boolean' ? options.noResponse : false,
+    documentsReturnedIn: options.documentsReturnedIn,
+    command: !!options.command,
+
+    // for BSON parsing
+    promoteLongs: typeof options.promoteLongs === 'boolean' ? options.promoteLongs : true,
+    promoteValues: typeof options.promoteValues === 'boolean' ? options.promoteValues : true,
+    promoteBuffers: typeof options.promoteBuffers === 'boolean' ? options.promoteBuffers : false,
+    bsonRegExp: typeof options.bsonRegExp === 'boolean' ? options.bsonRegExp : false,
+    enableUtf8Validation:
+      typeof options.enableUtf8Validation === 'boolean' ? options.enableUtf8Validation : true,
+    raw: typeof options.raw === 'boolean' ? options.raw : false,
+    started: 0
+  };
+
+  if (conn[kDescription] && conn[kDescription].compressor) {
+    operationDescription.agreedCompressor = conn[kDescription].compressor;
+
+    if (conn[kDescription].zlibCompressionLevel) {
+      operationDescription.zlibCompressionLevel = conn[kDescription].zlibCompressionLevel;
+    }
+  }
+
+  if (typeof options.socketTimeoutMS === 'number') {
+    operationDescription.socketTimeoutOverride = true;
+    conn[kStream].setTimeout(options.socketTimeoutMS);
+  }
+
+  // if command monitoring is enabled we need to modify the callback here
+  if (conn.monitorCommands) {
+    conn.emit(Connection.COMMAND_STARTED, new CommandStartedEvent(conn, command));
+
+    operationDescription.started = now();
+    operationDescription.cb = (err, reply) => {
+      if (err) {
+        conn.emit(
+          Connection.COMMAND_FAILED,
+          new CommandFailedEvent(conn, command, err, operationDescription.started)
+        );
+      } else {
+        if (reply && (reply.ok === 0 || reply.$err)) {
+          conn.emit(
+            Connection.COMMAND_FAILED,
+            new CommandFailedEvent(conn, command, reply, operationDescription.started)
+          );
+        } else {
+          conn.emit(
+            Connection.COMMAND_SUCCEEDED,
+            new CommandSucceededEvent(conn, command, reply, operationDescription.started)
+          );
+        }
+      }
+
+      if (typeof callback === 'function') {
+        callback(err, reply);
+      }
+    };
+  }
+
+  if (!operationDescription.noResponse) {
+    conn[kQueue].set(operationDescription.requestId, operationDescription);
+  }
+
+  try {
+    conn[kMessageStream].writeCommand(command, operationDescription);
+  } catch (e) {
+    if (!operationDescription.noResponse) {
+      conn[kQueue].delete(operationDescription.requestId);
+      operationDescription.cb(e);
+      return;
+    }
+  }
+
+  if (operationDescription.noResponse) {
+    operationDescription.cb();
+  }
+}

node_modules/mongodb/src/cmap/connection_pool.ts

@@ -0,0 +1,747 @@
+import Denque = require('denque');
+import { clearTimeout, setTimeout } from 'timers';
+
+import type { ObjectId } from '../bson';
+import {
+  APM_EVENTS,
+  CONNECTION_CHECK_OUT_FAILED,
+  CONNECTION_CHECK_OUT_STARTED,
+  CONNECTION_CHECKED_IN,
+  CONNECTION_CHECKED_OUT,
+  CONNECTION_CLOSED,
+  CONNECTION_CREATED,
+  CONNECTION_POOL_CLEARED,
+  CONNECTION_POOL_CLOSED,
+  CONNECTION_POOL_CREATED,
+  CONNECTION_READY
+} from '../constants';
+import { MongoError, MongoInvalidArgumentError, MongoRuntimeError } from '../error';
+import { Logger } from '../logger';
+import { CancellationToken, TypedEventEmitter } from '../mongo_types';
+import { Callback, eachAsync, makeCounter } from '../utils';
+import { connect } from './connect';
+import { Connection, ConnectionEvents, ConnectionOptions } from './connection';
+import {
+  ConnectionCheckedInEvent,
+  ConnectionCheckedOutEvent,
+  ConnectionCheckOutFailedEvent,
+  ConnectionCheckOutStartedEvent,
+  ConnectionClosedEvent,
+  ConnectionCreatedEvent,
+  ConnectionPoolClearedEvent,
+  ConnectionPoolClosedEvent,
+  ConnectionPoolCreatedEvent,
+  ConnectionReadyEvent
+} from './connection_pool_events';
+import { PoolClosedError, WaitQueueTimeoutError } from './errors';
+import { ConnectionPoolMetrics } from './metrics';
+
+/** @internal */
+const kLogger = Symbol('logger');
+/** @internal */
+const kConnections = Symbol('connections');
+/** @internal */
+const kPending = Symbol('pending');
+/** @internal */
+const kCheckedOut = Symbol('checkedOut');
+/** @internal */
+const kMinPoolSizeTimer = Symbol('minPoolSizeTimer');
+/** @internal */
+const kGeneration = Symbol('generation');
+/** @internal */
+const kServiceGenerations = Symbol('serviceGenerations');
+/** @internal */
+const kConnectionCounter = Symbol('connectionCounter');
+/** @internal */
+const kCancellationToken = Symbol('cancellationToken');
+/** @internal */
+const kWaitQueue = Symbol('waitQueue');
+/** @internal */
+const kCancelled = Symbol('cancelled');
+/** @internal */
+const kMetrics = Symbol('metrics');
+/** @internal */
+const kProcessingWaitQueue = Symbol('processingWaitQueue');
+/** @internal */
+const kPoolState = Symbol('poolState');
+
+/** @public */
+export interface ConnectionPoolOptions extends Omit<ConnectionOptions, 'id' | 'generation'> {
+  /** The maximum number of connections that may be associated with a pool at a given time. This includes in use and available connections. */
+  maxPoolSize: number;
+  /** The minimum number of connections that MUST exist at any moment in a single connection pool. */
+  minPoolSize: number;
+  /** The maximum number of connections that may be in the process of being established concurrently by the connection pool. */
+  maxConnecting: number;
+  /** The maximum amount of time a connection should remain idle in the connection pool before being marked idle. */
+  maxIdleTimeMS: number;
+  /** The maximum amount of time operation execution should wait for a connection to become available. The default is 0 which means there is no limit. */
+  waitQueueTimeoutMS: number;
+  /** If we are in load balancer mode. */
+  loadBalanced: boolean;
+}
+
+/** @internal */
+export interface WaitQueueMember {
+  callback: Callback<Connection>;
+  timer?: NodeJS.Timeout;
+  [kCancelled]?: boolean;
+}
+
+/** @internal */
+export const PoolState = Object.freeze({
+  paused: 'paused',
+  ready: 'ready',
+  closed: 'closed'
+} as const);
+
+/** @public */
+export interface CloseOptions {
+  force?: boolean;
+}
+
+/** @public */
+export type ConnectionPoolEvents = {
+  connectionPoolCreated(event: ConnectionPoolCreatedEvent): void;
+  connectionPoolClosed(event: ConnectionPoolClosedEvent): void;
+  connectionPoolCleared(event: ConnectionPoolClearedEvent): void;
+  connectionCreated(event: ConnectionCreatedEvent): void;
+  connectionReady(event: ConnectionReadyEvent): void;
+  connectionClosed(event: ConnectionClosedEvent): void;
+  connectionCheckOutStarted(event: ConnectionCheckOutStartedEvent): void;
+  connectionCheckOutFailed(event: ConnectionCheckOutFailedEvent): void;
+  connectionCheckedOut(event: ConnectionCheckedOutEvent): void;
+  connectionCheckedIn(event: ConnectionCheckedInEvent): void;
+} & Omit<ConnectionEvents, 'close' | 'message'>;
+
+/**
+ * A pool of connections which dynamically resizes, and emit events related to pool activity
+ * @internal
+ */
+export class ConnectionPool extends TypedEventEmitter<ConnectionPoolEvents> {
+  options: Readonly<ConnectionPoolOptions>;
+  /** @internal */
+  [kPoolState]: typeof PoolState[keyof typeof PoolState];
+  /** @internal */
+  [kLogger]: Logger;
+  /** @internal */
+  [kConnections]: Denque<Connection>;
+  /** @internal */
+  [kPending]: number;
+  /** @internal */
+  [kCheckedOut]: number;
+  /** @internal */
+  [kMinPoolSizeTimer]?: NodeJS.Timeout;
+  /**
+   * An integer representing the SDAM generation of the pool
+   * @internal
+   */
+  [kGeneration]: number;
+  /** A map of generations to service ids
+   * @internal
+   */
+  [kServiceGenerations]: Map<string, number>;
+  /** @internal */
+  [kConnectionCounter]: Generator<number>;
+  /** @internal */
+  [kCancellationToken]: CancellationToken;
+  /** @internal */
+  [kWaitQueue]: Denque<WaitQueueMember>;
+  /** @internal */
+  [kMetrics]: ConnectionPoolMetrics;
+  /** @internal */
+  [kProcessingWaitQueue]: boolean;
+
+  /**
+   * Emitted when the connection pool is created.
+   * @event
+   */
+  static readonly CONNECTION_POOL_CREATED = CONNECTION_POOL_CREATED;
+  /**
+   * Emitted once when the connection pool is closed
+   * @event
+   */
+  static readonly CONNECTION_POOL_CLOSED = CONNECTION_POOL_CLOSED;
+  /**
+   * Emitted each time the connection pool is cleared and it's generation incremented
+   * @event
+   */
+  static readonly CONNECTION_POOL_CLEARED = CONNECTION_POOL_CLEARED;
+  /**
+   * Emitted when a connection is created.
+   * @event
+   */
+  static readonly CONNECTION_CREATED = CONNECTION_CREATED;
+  /**
+   * Emitted when a connection becomes established, and is ready to use
+   * @event
+   */
+  static readonly CONNECTION_READY = CONNECTION_READY;
+  /**
+   * Emitted when a connection is closed
+   * @event
+   */
+  static readonly CONNECTION_CLOSED = CONNECTION_CLOSED;
+  /**
+   * Emitted when an attempt to check out a connection begins
+   * @event
+   */
+  static readonly CONNECTION_CHECK_OUT_STARTED = CONNECTION_CHECK_OUT_STARTED;
+  /**
+   * Emitted when an attempt to check out a connection fails
+   * @event
+   */
+  static readonly CONNECTION_CHECK_OUT_FAILED = CONNECTION_CHECK_OUT_FAILED;
+  /**
+   * Emitted each time a connection is successfully checked out of the connection pool
+   * @event
+   */
+  static readonly CONNECTION_CHECKED_OUT = CONNECTION_CHECKED_OUT;
+  /**
+   * Emitted each time a connection is successfully checked into the connection pool
+   * @event
+   */
+  static readonly CONNECTION_CHECKED_IN = CONNECTION_CHECKED_IN;
+
+  /** @internal */
+  constructor(options: ConnectionPoolOptions) {
+    super();
+
+    this.options = Object.freeze({
+      ...options,
+      connectionType: Connection,
+      maxPoolSize: options.maxPoolSize ?? 100,
+      minPoolSize: options.minPoolSize ?? 0,
+      maxConnecting: options.maxConnecting ?? 2,
+      maxIdleTimeMS: options.maxIdleTimeMS ?? 0,
+      waitQueueTimeoutMS: options.waitQueueTimeoutMS ?? 0,
+      autoEncrypter: options.autoEncrypter,
+      metadata: options.metadata
+    });
+
+    if (this.options.minPoolSize > this.options.maxPoolSize) {
+      throw new MongoInvalidArgumentError(
+        'Connection pool minimum size must not be greater than maximum pool size'
+      );
+    }
+
+    this[kPoolState] = PoolState.paused;
+    this[kLogger] = new Logger('ConnectionPool');
+    this[kConnections] = new Denque();
+    this[kPending] = 0;
+    this[kCheckedOut] = 0;
+    this[kMinPoolSizeTimer] = undefined;
+    this[kGeneration] = 0;
+    this[kServiceGenerations] = new Map();
+    this[kConnectionCounter] = makeCounter(1);
+    this[kCancellationToken] = new CancellationToken();
+    this[kCancellationToken].setMaxListeners(Infinity);
+    this[kWaitQueue] = new Denque();
+    this[kMetrics] = new ConnectionPoolMetrics();
+    this[kProcessingWaitQueue] = false;
+
+    process.nextTick(() => {
+      this.emit(ConnectionPool.CONNECTION_POOL_CREATED, new ConnectionPoolCreatedEvent(this));
+      this.ensureMinPoolSize();
+    });
+  }
+
+  /** The address of the endpoint the pool is connected to */
+  get address(): string {
+    return this.options.hostAddress.toString();
+  }
+
+  /**
+   * Check if the pool has been closed
+   *
+   * TODO(NODE-3263): We can remove this property once shell no longer needs it
+   */
+  get closed(): boolean {
+    return this[kPoolState] === PoolState.closed;
+  }
+
+  /** An integer representing the SDAM generation of the pool */
+  get generation(): number {
+    return this[kGeneration];
+  }
+
+  /** An integer expressing how many total connections (available + pending + in use) the pool currently has */
+  get totalConnectionCount(): number {
+    return (
+      this.availableConnectionCount + this.pendingConnectionCount + this.currentCheckedOutCount
+    );
+  }
+
+  /** An integer expressing how many connections are currently available in the pool. */
+  get availableConnectionCount(): number {
+    return this[kConnections].length;
+  }
+
+  get pendingConnectionCount(): number {
+    return this[kPending];
+  }
+
+  get currentCheckedOutCount(): number {
+    return this[kCheckedOut];
+  }
+
+  get waitQueueSize(): number {
+    return this[kWaitQueue].length;
+  }
+
+  get loadBalanced(): boolean {
+    return this.options.loadBalanced;
+  }
+
+  get serviceGenerations(): Map<string, number> {
+    return this[kServiceGenerations];
+  }
+
+  /**
+   * Get the metrics information for the pool when a wait queue timeout occurs.
+   */
+  private waitQueueErrorMetrics(): string {
+    return this[kMetrics].info(this.options.maxPoolSize);
+  }
+
+  /**
+   * Set the pool state to "ready"
+   */
+  ready(): void {
+    this[kPoolState] = PoolState.ready;
+  }
+
+  /**
+   * Check a connection out of this pool. The connection will continue to be tracked, but no reference to it
+   * will be held by the pool. This means that if a connection is checked out it MUST be checked back in or
+   * explicitly destroyed by the new owner.
+   */
+  checkOut(callback: Callback<Connection>): void {
+    this.emit(
+      ConnectionPool.CONNECTION_CHECK_OUT_STARTED,
+      new ConnectionCheckOutStartedEvent(this)
+    );
+
+    if (this.closed) {
+      this.emit(
+        ConnectionPool.CONNECTION_CHECK_OUT_FAILED,
+        new ConnectionCheckOutFailedEvent(this, 'poolClosed')
+      );
+      callback(new PoolClosedError(this));
+      return;
+    }
+
+    const waitQueueMember: WaitQueueMember = { callback };
+    const waitQueueTimeoutMS = this.options.waitQueueTimeoutMS;
+    if (waitQueueTimeoutMS) {
+      waitQueueMember.timer = setTimeout(() => {
+        waitQueueMember[kCancelled] = true;
+        waitQueueMember.timer = undefined;
+
+        this.emit(
+          ConnectionPool.CONNECTION_CHECK_OUT_FAILED,
+          new ConnectionCheckOutFailedEvent(this, 'timeout')
+        );
+        waitQueueMember.callback(
+          new WaitQueueTimeoutError(
+            this.loadBalanced
+              ? this.waitQueueErrorMetrics()
+              : 'Timed out while checking out a connection from connection pool',
+            this.address
+          )
+        );
+      }, waitQueueTimeoutMS);
+    }
+
+    this[kWaitQueue].push(waitQueueMember);
+    process.nextTick(() => this.processWaitQueue());
+  }
+
+  /**
+   * Check a connection into the pool.
+   *
+   * @param connection - The connection to check in
+   */
+  checkIn(connection: Connection): void {
+    const poolClosed = this.closed;
+    const stale = this.connectionIsStale(connection);
+    const willDestroy = !!(poolClosed || stale || connection.closed);
+
+    if (!willDestroy) {
+      connection.markAvailable();
+      this[kConnections].unshift(connection);
+    }
+
+    this[kCheckedOut]--;
+    this.emit(ConnectionPool.CONNECTION_CHECKED_IN, new ConnectionCheckedInEvent(this, connection));
+
+    if (willDestroy) {
+      const reason = connection.closed ? 'error' : poolClosed ? 'poolClosed' : 'stale';
+      this.destroyConnection(connection, reason);
+    }
+
+    process.nextTick(() => this.processWaitQueue());
+  }
+
+  /**
+   * Clear the pool
+   *
+   * Pool reset is handled by incrementing the pool's generation count. Any existing connection of a
+   * previous generation will eventually be pruned during subsequent checkouts.
+   */
+  clear(serviceId?: ObjectId): void {
+    if (this.loadBalanced && serviceId) {
+      const sid = serviceId.toHexString();
+      const generation = this.serviceGenerations.get(sid);
+      // Only need to worry if the generation exists, since it should
+      // always be there but typescript needs the check.
+      if (generation == null) {
+        // TODO(NODE-3483)
+        throw new MongoRuntimeError('Service generations are required in load balancer mode.');
+      } else {
+        // Increment the generation for the service id.
+        this.serviceGenerations.set(sid, generation + 1);
+      }
+    } else {
+      this[kGeneration] += 1;
+    }
+
+    this.emit(
+      ConnectionPool.CONNECTION_POOL_CLEARED,
+      new ConnectionPoolClearedEvent(this, serviceId)
+    );
+  }
+
+  /** Close the pool */
+  close(callback: Callback<void>): void;
+  close(options: CloseOptions, callback: Callback<void>): void;
+  close(_options?: CloseOptions | Callback<void>, _cb?: Callback<void>): void {
+    let options = _options as CloseOptions;
+    const callback = (_cb ?? _options) as Callback<void>;
+    if (typeof options === 'function') {
+      options = {};
+    }
+
+    options = Object.assign({ force: false }, options);
+    if (this.closed) {
+      return callback();
+    }
+
+    // immediately cancel any in-flight connections
+    this[kCancellationToken].emit('cancel');
+
+    // drain the wait queue
+    while (this.waitQueueSize) {
+      const waitQueueMember = this[kWaitQueue].pop();
+      if (waitQueueMember) {
+        if (waitQueueMember.timer) {
+          clearTimeout(waitQueueMember.timer);
+        }
+        if (!waitQueueMember[kCancelled]) {
+          // TODO(NODE-3483): Replace with MongoConnectionPoolClosedError
+          waitQueueMember.callback(new MongoRuntimeError('Connection pool closed'));
+        }
+      }
+    }
+
+    // clear the min pool size timer
+    const minPoolSizeTimer = this[kMinPoolSizeTimer];
+    if (minPoolSizeTimer) {
+      clearTimeout(minPoolSizeTimer);
+    }
+
+    // end the connection counter
+    if (typeof this[kConnectionCounter].return === 'function') {
+      this[kConnectionCounter].return(undefined);
+    }
+
+    // mark the pool as closed immediately
+    this[kPoolState] = PoolState.closed;
+    eachAsync<Connection>(
+      this[kConnections].toArray(),
+      (conn, cb) => {
+        this.emit(
+          ConnectionPool.CONNECTION_CLOSED,
+          new ConnectionClosedEvent(this, conn, 'poolClosed')
+        );
+        conn.destroy(options, cb);
+      },
+      err => {
+        this[kConnections].clear();
+        this.emit(ConnectionPool.CONNECTION_POOL_CLOSED, new ConnectionPoolClosedEvent(this));
+        callback(err);
+      }
+    );
+  }
+
+  /**
+   * Runs a lambda with an implicitly checked out connection, checking that connection back in when the lambda
+   * has completed by calling back.
+   *
+   * NOTE: please note the required signature of `fn`
+   *
+   * @remarks When in load balancer mode, connections can be pinned to cursors or transactions.
+   *   In these cases we pass the connection in to this method to ensure it is used and a new
+   *   connection is not checked out.
+   *
+   * @param conn - A pinned connection for use in load balancing mode.
+   * @param fn - A function which operates on a managed connection
+   * @param callback - The original callback
+   */
+  withConnection(
+    conn: Connection | undefined,
+    fn: WithConnectionCallback,
+    callback?: Callback<Connection>
+  ): void {
+    if (conn) {
+      // use the provided connection, and do _not_ check it in after execution
+      fn(undefined, conn, (fnErr, result) => {
+        if (typeof callback === 'function') {
+          if (fnErr) {
+            callback(fnErr);
+          } else {
+            callback(undefined, result);
+          }
+        }
+      });
+
+      return;
+    }
+
+    this.checkOut((err, conn) => {
+      // don't callback with `err` here, we might want to act upon it inside `fn`
+      fn(err as MongoError, conn, (fnErr, result) => {
+        if (typeof callback === 'function') {
+          if (fnErr) {
+            callback(fnErr);
+          } else {
+            callback(undefined, result);
+          }
+        }
+
+        if (conn) {
+          this.checkIn(conn);
+        }
+      });
+    });
+  }
+
+  private destroyConnection(connection: Connection, reason: string) {
+    this.emit(
+      ConnectionPool.CONNECTION_CLOSED,
+      new ConnectionClosedEvent(this, connection, reason)
+    );
+
+    // destroy the connection
+    process.nextTick(() => connection.destroy());
+  }
+
+  private connectionIsStale(connection: Connection) {
+    const serviceId = connection.serviceId;
+    if (this.loadBalanced && serviceId) {
+      const sid = serviceId.toHexString();
+      const generation = this.serviceGenerations.get(sid);
+      return connection.generation !== generation;
+    }
+
+    return connection.generation !== this[kGeneration];
+  }
+
+  private connectionIsIdle(connection: Connection) {
+    return !!(this.options.maxIdleTimeMS && connection.idleTime > this.options.maxIdleTimeMS);
+  }
+
+  private connectionIsPerished(connection: Connection) {
+    const isStale = this.connectionIsStale(connection);
+    const isIdle = this.connectionIsIdle(connection);
+    if (!isStale && !isIdle && !connection.closed) {
+      return false;
+    }
+    const reason = connection.closed ? 'error' : isStale ? 'stale' : 'idle';
+    this.destroyConnection(connection, reason);
+    return true;
+  }
+
+  private createConnection(callback: Callback<Connection>) {
+    const connectOptions: ConnectionOptions = {
+      ...this.options,
+      id: this[kConnectionCounter].next().value,
+      generation: this[kGeneration],
+      cancellationToken: this[kCancellationToken]
+    };
+
+    this[kPending]++;
+    // This is our version of a "virtual" no-I/O connection as the spec requires
+    this.emit(
+      ConnectionPool.CONNECTION_CREATED,
+      new ConnectionCreatedEvent(this, { id: connectOptions.id })
+    );
+
+    connect(connectOptions, (err, connection) => {
+      if (err || !connection) {
+        this[kLogger].debug(`connection attempt failed with error [${JSON.stringify(err)}]`);
+        callback(err);
+        return;
+      }
+
+      // The pool might have closed since we started trying to create a connection
+      if (this.closed) {
+        this[kPending]--;
+        connection.destroy({ force: true });
+        return;
+      }
+
+      // forward all events from the connection to the pool
+      for (const event of [...APM_EVENTS, Connection.CLUSTER_TIME_RECEIVED]) {
+        connection.on(event, (e: any) => this.emit(event, e));
+      }
+
+      if (this.loadBalanced) {
+        connection.on(Connection.PINNED, pinType => this[kMetrics].markPinned(pinType));
+        connection.on(Connection.UNPINNED, pinType => this[kMetrics].markUnpinned(pinType));
+
+        const serviceId = connection.serviceId;
+        if (serviceId) {
+          let generation;
+          const sid = serviceId.toHexString();
+          if ((generation = this.serviceGenerations.get(sid))) {
+            connection.generation = generation;
+          } else {
+            this.serviceGenerations.set(sid, 0);
+            connection.generation = 0;
+          }
+        }
+      }
+
+      connection.markAvailable();
+      this.emit(ConnectionPool.CONNECTION_READY, new ConnectionReadyEvent(this, connection));
+
+      callback(undefined, connection);
+      return;
+    });
+  }
+
+  private ensureMinPoolSize() {
+    const minPoolSize = this.options.minPoolSize;
+    if (this.closed || minPoolSize === 0) {
+      return;
+    }
+
+    if (
+      this.totalConnectionCount < minPoolSize &&
+      this.pendingConnectionCount < this.options.maxConnecting
+    ) {
+      // NOTE: ensureMinPoolSize should not try to get all the pending
+      // connection permits because that potentially delays the availability of
+      // the connection to a checkout request
+      this.createConnection((err, connection) => {
+        this[kPending]--;
+        if (!err && connection) {
+          this[kConnections].push(connection);
+          process.nextTick(() => this.processWaitQueue());
+        }
+        this[kMinPoolSizeTimer] = setTimeout(() => this.ensureMinPoolSize(), 10);
+      });
+    } else {
+      this[kMinPoolSizeTimer] = setTimeout(() => this.ensureMinPoolSize(), 100);
+    }
+  }
+
+  private processWaitQueue() {
+    if (this.closed || this[kProcessingWaitQueue]) {
+      return;
+    }
+
+    this[kProcessingWaitQueue] = true;
+
+    while (this.waitQueueSize) {
+      const waitQueueMember = this[kWaitQueue].peekFront();
+      if (!waitQueueMember) {
+        this[kWaitQueue].shift();
+        continue;
+      }
+
+      if (waitQueueMember[kCancelled]) {
+        this[kWaitQueue].shift();
+        continue;
+      }
+
+      if (!this.availableConnectionCount) {
+        break;
+      }
+
+      const connection = this[kConnections].shift();
+      if (!connection) {
+        break;
+      }
+
+      if (!this.connectionIsPerished(connection)) {
+        this[kCheckedOut]++;
+        this.emit(
+          ConnectionPool.CONNECTION_CHECKED_OUT,
+          new ConnectionCheckedOutEvent(this, connection)
+        );
+        if (waitQueueMember.timer) {
+          clearTimeout(waitQueueMember.timer);
+        }
+
+        this[kWaitQueue].shift();
+        waitQueueMember.callback(undefined, connection);
+      }
+    }
+
+    const { maxPoolSize, maxConnecting } = this.options;
+    while (
+      this.waitQueueSize > 0 &&
+      this.pendingConnectionCount < maxConnecting &&
+      (maxPoolSize === 0 || this.totalConnectionCount < maxPoolSize)
+    ) {
+      const waitQueueMember = this[kWaitQueue].shift();
+      if (!waitQueueMember || waitQueueMember[kCancelled]) {
+        continue;
+      }
+      this.createConnection((err, connection) => {
+        this[kPending]--;
+        if (waitQueueMember[kCancelled]) {
+          if (!err && connection) {
+            this[kConnections].push(connection);
+          }
+        } else {
+          if (err) {
+            this.emit(
+              ConnectionPool.CONNECTION_CHECK_OUT_FAILED,
+              new ConnectionCheckOutFailedEvent(this, err)
+            );
+          } else if (connection) {
+            this[kCheckedOut]++;
+            this.emit(
+              ConnectionPool.CONNECTION_CHECKED_OUT,
+              new ConnectionCheckedOutEvent(this, connection)
+            );
+          }
+
+          if (waitQueueMember.timer) {
+            clearTimeout(waitQueueMember.timer);
+          }
+          waitQueueMember.callback(err, connection);
+        }
+        process.nextTick(() => this.processWaitQueue());
+      });
+    }
+    this[kProcessingWaitQueue] = false;
+  }
+}
+
+/**
+ * A callback provided to `withConnection`
+ * @internal
+ *
+ * @param error - An error instance representing the error during the execution.
+ * @param connection - The managed connection which was checked out of the pool.
+ * @param callback - A function to call back after connection management is complete
+ */
+export type WithConnectionCallback = (
+  error: MongoError | undefined,
+  connection: Connection | undefined,
+  callback: Callback<Connection>
+) => void;

node_modules/mongodb/src/cmap/connection_pool_events.ts

@@ -0,0 +1,179 @@
+import type { ObjectId } from '../bson';
+import type { AnyError } from '../error';
+import type { Connection } from './connection';
+import type { ConnectionPool, ConnectionPoolOptions } from './connection_pool';
+
+/**
+ * The base export class for all monitoring events published from the connection pool
+ * @public
+ * @category Event
+ */
+export class ConnectionPoolMonitoringEvent {
+  /** A timestamp when the event was created  */
+  time: Date;
+  /** The address (host/port pair) of the pool */
+  address: string;
+
+  /** @internal */
+  constructor(pool: ConnectionPool) {
+    this.time = new Date();
+    this.address = pool.address;
+  }
+}
+
+/**
+ * An event published when a connection pool is created
+ * @public
+ * @category Event
+ */
+export class ConnectionPoolCreatedEvent extends ConnectionPoolMonitoringEvent {
+  /** The options used to create this connection pool */
+  options?: ConnectionPoolOptions;
+
+  /** @internal */
+  constructor(pool: ConnectionPool) {
+    super(pool);
+    this.options = pool.options;
+  }
+}
+
+/**
+ * An event published when a connection pool is closed
+ * @public
+ * @category Event
+ */
+export class ConnectionPoolClosedEvent extends ConnectionPoolMonitoringEvent {
+  /** @internal */
+  constructor(pool: ConnectionPool) {
+    super(pool);
+  }
+}
+
+/**
+ * An event published when a connection pool creates a new connection
+ * @public
+ * @category Event
+ */
+export class ConnectionCreatedEvent extends ConnectionPoolMonitoringEvent {
+  /** A monotonically increasing, per-pool id for the newly created connection */
+  connectionId: number | '<monitor>';
+
+  /** @internal */
+  constructor(pool: ConnectionPool, connection: { id: number | '<monitor>' }) {
+    super(pool);
+    this.connectionId = connection.id;
+  }
+}
+
+/**
+ * An event published when a connection is ready for use
+ * @public
+ * @category Event
+ */
+export class ConnectionReadyEvent extends ConnectionPoolMonitoringEvent {
+  /** The id of the connection */
+  connectionId: number | '<monitor>';
+
+  /** @internal */
+  constructor(pool: ConnectionPool, connection: Connection) {
+    super(pool);
+    this.connectionId = connection.id;
+  }
+}
+
+/**
+ * An event published when a connection is closed
+ * @public
+ * @category Event
+ */
+export class ConnectionClosedEvent extends ConnectionPoolMonitoringEvent {
+  /** The id of the connection */
+  connectionId: number | '<monitor>';
+  /** The reason the connection was closed */
+  reason: string;
+  serviceId?: ObjectId;
+
+  /** @internal */
+  constructor(pool: ConnectionPool, connection: Connection, reason: string) {
+    super(pool);
+    this.connectionId = connection.id;
+    this.reason = reason || 'unknown';
+    this.serviceId = connection.serviceId;
+  }
+}
+
+/**
+ * An event published when a request to check a connection out begins
+ * @public
+ * @category Event
+ */
+export class ConnectionCheckOutStartedEvent extends ConnectionPoolMonitoringEvent {
+  /** @internal */
+  constructor(pool: ConnectionPool) {
+    super(pool);
+  }
+}
+
+/**
+ * An event published when a request to check a connection out fails
+ * @public
+ * @category Event
+ */
+export class ConnectionCheckOutFailedEvent extends ConnectionPoolMonitoringEvent {
+  /** The reason the attempt to check out failed */
+  reason: AnyError | string;
+
+  /** @internal */
+  constructor(pool: ConnectionPool, reason: AnyError | string) {
+    super(pool);
+    this.reason = reason;
+  }
+}
+
+/**
+ * An event published when a connection is checked out of the connection pool
+ * @public
+ * @category Event
+ */
+export class ConnectionCheckedOutEvent extends ConnectionPoolMonitoringEvent {
+  /** The id of the connection */
+  connectionId: number | '<monitor>';
+
+  /** @internal */
+  constructor(pool: ConnectionPool, connection: Connection) {
+    super(pool);
+    this.connectionId = connection.id;
+  }
+}
+
+/**
+ * An event published when a connection is checked into the connection pool
+ * @public
+ * @category Event
+ */
+export class ConnectionCheckedInEvent extends ConnectionPoolMonitoringEvent {
+  /** The id of the connection */
+  connectionId: number | '<monitor>';
+
+  /** @internal */
+  constructor(pool: ConnectionPool, connection: Connection) {
+    super(pool);
+    this.connectionId = connection.id;
+  }
+}
+
+/**
+ * An event published when a connection pool is cleared
+ * @public
+ * @category Event
+ */
+export class ConnectionPoolClearedEvent extends ConnectionPoolMonitoringEvent {
+  /** @internal */
+  serviceId?: ObjectId;
+
+  /** @internal */
+  constructor(pool: ConnectionPool, serviceId?: ObjectId) {
+    super(pool);
+    this.serviceId = serviceId;
+  }
+}

node_modules/mongodb/src/cmap/errors.ts

@@ -0,0 +1,38 @@
+import { MongoDriverError } from '../error';
+import type { ConnectionPool } from './connection_pool';
+
+/**
+ * An error indicating a connection pool is closed
+ * @category Error
+ */
+export class PoolClosedError extends MongoDriverError {
+  /** The address of the connection pool */
+  address: string;
+
+  constructor(pool: ConnectionPool) {
+    super('Attempted to check out a connection from closed connection pool');
+    this.address = pool.address;
+  }
+
+  override get name(): string {
+    return 'MongoPoolClosedError';
+  }
+}
+
+/**
+ * An error thrown when a request to check out a connection times out
+ * @category Error
+ */
+export class WaitQueueTimeoutError extends MongoDriverError {
+  /** The address of the connection pool */
+  address: string;
+
+  constructor(message: string, address: string) {
+    super(message);
+    this.address = address;
+  }
+
+  override get name(): string {
+    return 'MongoWaitQueueTimeoutError';
+  }
+}

node_modules/mongodb/src/cmap/message_stream.ts

@@ -0,0 +1,242 @@
+import { Duplex, DuplexOptions } from 'stream';
+
+import type { BSONSerializeOptions, Document } from '../bson';
+import { MongoDecompressionError, MongoParseError } from '../error';
+import type { ClientSession } from '../sessions';
+import { BufferPool, Callback } from '../utils';
+import { BinMsg, MessageHeader, Msg, Response, WriteProtocolMessageType } from './commands';
+import {
+  compress,
+  Compressor,
+  CompressorName,
+  decompress,
+  uncompressibleCommands
+} from './wire_protocol/compression';
+import { OP_COMPRESSED, OP_MSG } from './wire_protocol/constants';
+
+const MESSAGE_HEADER_SIZE = 16;
+const COMPRESSION_DETAILS_SIZE = 9; // originalOpcode + uncompressedSize, compressorID
+
+const kDefaultMaxBsonMessageSize = 1024 * 1024 * 16 * 4;
+/** @internal */
+const kBuffer = Symbol('buffer');
+
+/** @internal */
+export interface MessageStreamOptions extends DuplexOptions {
+  maxBsonMessageSize?: number;
+}
+
+/** @internal */
+export interface OperationDescription extends BSONSerializeOptions {
+  started: number;
+  cb: Callback<Document>;
+  command: boolean;
+  documentsReturnedIn?: string;
+  noResponse: boolean;
+  raw: boolean;
+  requestId: number;
+  session?: ClientSession;
+  socketTimeoutOverride?: boolean;
+  agreedCompressor?: CompressorName;
+  zlibCompressionLevel?: number;
+  $clusterTime?: Document;
+}
+
+/**
+ * A duplex stream that is capable of reading and writing raw wire protocol messages, with
+ * support for optional compression
+ * @internal
+ */
+export class MessageStream extends Duplex {
+  /** @internal */
+  maxBsonMessageSize: number;
+  /** @internal */
+  [kBuffer]: BufferPool;
+  /** @internal */
+  isMonitoringConnection = false;
+
+  constructor(options: MessageStreamOptions = {}) {
+    super(options);
+    this.maxBsonMessageSize = options.maxBsonMessageSize || kDefaultMaxBsonMessageSize;
+    this[kBuffer] = new BufferPool();
+  }
+
+  get buffer(): BufferPool {
+    return this[kBuffer];
+  }
+
+  override _write(chunk: Buffer, _: unknown, callback: Callback<Buffer>): void {
+    this[kBuffer].append(chunk);
+    processIncomingData(this, callback);
+  }
+
+  override _read(/* size */): void {
+    // NOTE: This implementation is empty because we explicitly push data to be read
+    //       when `writeMessage` is called.
+    return;
+  }
+
+  writeCommand(
+    command: WriteProtocolMessageType,
+    operationDescription: OperationDescription
+  ): void {
+    // TODO: agreed compressor should live in `StreamDescription`
+    const compressorName: CompressorName =
+      operationDescription && operationDescription.agreedCompressor
+        ? operationDescription.agreedCompressor
+        : 'none';
+    if (compressorName === 'none' || !canCompress(command)) {
+      const data = command.toBin();
+      this.push(Array.isArray(data) ? Buffer.concat(data) : data);
+      return;
+    }
+    // otherwise, compress the message
+    const concatenatedOriginalCommandBuffer = Buffer.concat(command.toBin());
+    const messageToBeCompressed = concatenatedOriginalCommandBuffer.slice(MESSAGE_HEADER_SIZE);
+
+    // Extract information needed for OP_COMPRESSED from the uncompressed message
+    const originalCommandOpCode = concatenatedOriginalCommandBuffer.readInt32LE(12);
+
+    // Compress the message body
+    compress({ options: operationDescription }, messageToBeCompressed, (err, compressedMessage) => {
+      if (err || !compressedMessage) {
+        operationDescription.cb(err);
+        return;
+      }
+
+      // Create the msgHeader of OP_COMPRESSED
+      const msgHeader = Buffer.alloc(MESSAGE_HEADER_SIZE);
+      msgHeader.writeInt32LE(
+        MESSAGE_HEADER_SIZE + COMPRESSION_DETAILS_SIZE + compressedMessage.length,
+        0
+      ); // messageLength
+      msgHeader.writeInt32LE(command.requestId, 4); // requestID
+      msgHeader.writeInt32LE(0, 8); // responseTo (zero)
+      msgHeader.writeInt32LE(OP_COMPRESSED, 12); // opCode
+
+      // Create the compression details of OP_COMPRESSED
+      const compressionDetails = Buffer.alloc(COMPRESSION_DETAILS_SIZE);
+      compressionDetails.writeInt32LE(originalCommandOpCode, 0); // originalOpcode
+      compressionDetails.writeInt32LE(messageToBeCompressed.length, 4); // Size of the uncompressed compressedMessage, excluding the MsgHeader
+      compressionDetails.writeUInt8(Compressor[compressorName], 8); // compressorID
+      this.push(Buffer.concat([msgHeader, compressionDetails, compressedMessage]));
+    });
+  }
+}
+
+// Return whether a command contains an uncompressible command term
+// Will return true if command contains no uncompressible command terms
+function canCompress(command: WriteProtocolMessageType) {
+  const commandDoc = command instanceof Msg ? command.command : command.query;
+  const commandName = Object.keys(commandDoc)[0];
+  return !uncompressibleCommands.has(commandName);
+}
+
+function processIncomingData(stream: MessageStream, callback: Callback<Buffer>) {
+  const buffer = stream[kBuffer];
+  if (buffer.length < 4) {
+    callback();
+    return;
+  }
+
+  const sizeOfMessage = buffer.peek(4).readInt32LE();
+  if (sizeOfMessage < 0) {
+    callback(new MongoParseError(`Invalid message size: ${sizeOfMessage}`));
+    return;
+  }
+
+  if (sizeOfMessage > stream.maxBsonMessageSize) {
+    callback(
+      new MongoParseError(
+        `Invalid message size: ${sizeOfMessage}, max allowed: ${stream.maxBsonMessageSize}`
+      )
+    );
+    return;
+  }
+
+  if (sizeOfMessage > buffer.length) {
+    callback();
+    return;
+  }
+
+  const message = buffer.read(sizeOfMessage);
+  const messageHeader: MessageHeader = {
+    length: message.readInt32LE(0),
+    requestId: message.readInt32LE(4),
+    responseTo: message.readInt32LE(8),
+    opCode: message.readInt32LE(12)
+  };
+
+  const monitorHasAnotherHello = () => {
+    if (stream.isMonitoringConnection) {
+      // Can we read the next message size?
+      if (buffer.length >= 4) {
+        const sizeOfMessage = buffer.peek(4).readInt32LE();
+        if (sizeOfMessage <= buffer.length) {
+          return true;
+        }
+      }
+    }
+    return false;
+  };
+
+  let ResponseType = messageHeader.opCode === OP_MSG ? BinMsg : Response;
+  if (messageHeader.opCode !== OP_COMPRESSED) {
+    const messageBody = message.slice(MESSAGE_HEADER_SIZE);
+
+    // If we are a monitoring connection message stream and
+    // there is more in the buffer that can be read, skip processing since we
+    // want the last hello command response that is in the buffer.
+    if (monitorHasAnotherHello()) {
+      processIncomingData(stream, callback);
+    } else {
+      stream.emit('message', new ResponseType(message, messageHeader, messageBody));
+
+      if (buffer.length >= 4) {
+        processIncomingData(stream, callback);
+      } else {
+        callback();
+      }
+    }
+
+    return;
+  }
+
+  messageHeader.fromCompressed = true;
+  messageHeader.opCode = message.readInt32LE(MESSAGE_HEADER_SIZE);
+  messageHeader.length = message.readInt32LE(MESSAGE_HEADER_SIZE + 4);
+  const compressorID: Compressor = message[MESSAGE_HEADER_SIZE + 8] as Compressor;
+  const compressedBuffer = message.slice(MESSAGE_HEADER_SIZE + 9);
+
+  // recalculate based on wrapped opcode
+  ResponseType = messageHeader.opCode === OP_MSG ? BinMsg : Response;
+  decompress(compressorID, compressedBuffer, (err, messageBody) => {
+    if (err || !messageBody) {
+      callback(err);
+      return;
+    }
+
+    if (messageBody.length !== messageHeader.length) {
+      callback(
+        new MongoDecompressionError('Message body and message header must be the same length')
+      );
+
+      return;
+    }
+
+    // If we are a monitoring connection message stream and
+    // there is more in the buffer that can be read, skip processing since we
+    // want the last hello command response that is in the buffer.
+    if (monitorHasAnotherHello()) {
+      processIncomingData(stream, callback);
+    } else {
+      stream.emit('message', new ResponseType(message, messageHeader, messageBody));
+
+      if (buffer.length >= 4) {
+        processIncomingData(stream, callback);
+      } else {
+        callback();
+      }
+    }
+  });
+}

node_modules/mongodb/src/cmap/metrics.ts

@@ -0,0 +1,58 @@
+/** @internal */
+export class ConnectionPoolMetrics {
+  static readonly TXN = 'txn' as const;
+  static readonly CURSOR = 'cursor' as const;
+  static readonly OTHER = 'other' as const;
+
+  txnConnections = 0;
+  cursorConnections = 0;
+  otherConnections = 0;
+
+  /**
+   * Mark a connection as pinned for a specific operation.
+   */
+  markPinned(pinType: string): void {
+    if (pinType === ConnectionPoolMetrics.TXN) {
+      this.txnConnections += 1;
+    } else if (pinType === ConnectionPoolMetrics.CURSOR) {
+      this.cursorConnections += 1;
+    } else {
+      this.otherConnections += 1;
+    }
+  }
+
+  /**
+   * Unmark a connection as pinned for an operation.
+   */
+  markUnpinned(pinType: string): void {
+    if (pinType === ConnectionPoolMetrics.TXN) {
+      this.txnConnections -= 1;
+    } else if (pinType === ConnectionPoolMetrics.CURSOR) {
+      this.cursorConnections -= 1;
+    } else {
+      this.otherConnections -= 1;
+    }
+  }
+
+  /**
+   * Return information about the cmap metrics as a string.
+   */
+  info(maxPoolSize: number): string {
+    return (
+      'Timed out while checking out a connection from connection pool: ' +
+      `maxPoolSize: ${maxPoolSize}, ` +
+      `connections in use by cursors: ${this.cursorConnections}, ` +
+      `connections in use by transactions: ${this.txnConnections}, ` +
+      `connections in use by other operations: ${this.otherConnections}`
+    );
+  }
+
+  /**
+   * Reset the metrics to the initial values.
+   */
+  reset(): void {
+    this.txnConnections = 0;
+    this.cursorConnections = 0;
+    this.otherConnections = 0;
+  }
+}

node_modules/mongodb/src/cmap/stream_description.ts

@@ -0,0 +1,76 @@
+import type { Document } from '../bson';
+import { ServerType } from '../sdam/common';
+import { parseServerType } from '../sdam/server_description';
+import type { CompressorName } from './wire_protocol/compression';
+
+const RESPONSE_FIELDS = [
+  'minWireVersion',
+  'maxWireVersion',
+  'maxBsonObjectSize',
+  'maxMessageSizeBytes',
+  'maxWriteBatchSize',
+  'logicalSessionTimeoutMinutes'
+] as const;
+
+/** @public */
+export interface StreamDescriptionOptions {
+  compressors?: CompressorName[];
+  logicalSessionTimeoutMinutes?: number;
+  loadBalanced: boolean;
+}
+
+/** @public */
+export class StreamDescription {
+  address: string;
+  type: string;
+  minWireVersion?: number;
+  maxWireVersion?: number;
+  maxBsonObjectSize: number;
+  maxMessageSizeBytes: number;
+  maxWriteBatchSize: number;
+  compressors: CompressorName[];
+  compressor?: CompressorName;
+  logicalSessionTimeoutMinutes?: number;
+  loadBalanced: boolean;
+
+  __nodejs_mock_server__?: boolean;
+
+  zlibCompressionLevel?: number;
+
+  constructor(address: string, options?: StreamDescriptionOptions) {
+    this.address = address;
+    this.type = ServerType.Unknown;
+    this.minWireVersion = undefined;
+    this.maxWireVersion = undefined;
+    this.maxBsonObjectSize = 16777216;
+    this.maxMessageSizeBytes = 48000000;
+    this.maxWriteBatchSize = 100000;
+    this.logicalSessionTimeoutMinutes = options?.logicalSessionTimeoutMinutes;
+    this.loadBalanced = !!options?.loadBalanced;
+    this.compressors =
+      options && options.compressors && Array.isArray(options.compressors)
+        ? options.compressors
+        : [];
+  }
+
+  receiveResponse(response: Document | null): void {
+    if (response == null) {
+      return;
+    }
+    this.type = parseServerType(response);
+    for (const field of RESPONSE_FIELDS) {
+      if (response[field] != null) {
+        this[field] = response[field];
+      }
+
+      // testing case
+      if ('__nodejs_mock_server__' in response) {
+        this.__nodejs_mock_server__ = response['__nodejs_mock_server__'];
+      }
+    }
+
+    if (response.compression) {
+      this.compressor = this.compressors.filter(c => response.compression?.includes(c))[0];
+    }
+  }
+}

node_modules/mongodb/src/cmap/wire_protocol/compression.ts

@@ -0,0 +1,130 @@
+import * as zlib from 'zlib';
+
+import { LEGACY_HELLO_COMMAND } from '../../constants';
+import { PKG_VERSION, Snappy, ZStandard } from '../../deps';
+import { MongoDecompressionError, MongoInvalidArgumentError } from '../../error';
+import type { Callback } from '../../utils';
+import type { OperationDescription } from '../message_stream';
+
+/** @public */
+export const Compressor = Object.freeze({
+  none: 0,
+  snappy: 1,
+  zlib: 2,
+  zstd: 3
+} as const);
+
+/** @public */
+export type Compressor = typeof Compressor[CompressorName];
+
+/** @public */
+export type CompressorName = keyof typeof Compressor;
+
+export const uncompressibleCommands = new Set([
+  LEGACY_HELLO_COMMAND,
+  'saslStart',
+  'saslContinue',
+  'getnonce',
+  'authenticate',
+  'createUser',
+  'updateUser',
+  'copydbSaslStart',
+  'copydbgetnonce',
+  'copydb'
+]);
+
+const MAX_COMPRESSOR_ID = 3;
+const ZSTD_COMPRESSION_LEVEL = 3;
+
+// Facilitate compressing a message using an agreed compressor
+export function compress(
+  self: { options: OperationDescription & zlib.ZlibOptions },
+  dataToBeCompressed: Buffer,
+  callback: Callback<Buffer>
+): void {
+  const zlibOptions = {} as zlib.ZlibOptions;
+  switch (self.options.agreedCompressor) {
+    case 'snappy': {
+      if ('kModuleError' in Snappy) {
+        return callback(Snappy['kModuleError']);
+      }
+
+      if (Snappy[PKG_VERSION].major <= 6) {
+        Snappy.compress(dataToBeCompressed, callback);
+      } else {
+        Snappy.compress(dataToBeCompressed).then(
+          buffer => callback(undefined, buffer),
+          error => callback(error)
+        );
+      }
+      break;
+    }
+    case 'zlib':
+      // Determine zlibCompressionLevel
+      if (self.options.zlibCompressionLevel) {
+        zlibOptions.level = self.options.zlibCompressionLevel;
+      }
+      zlib.deflate(dataToBeCompressed, zlibOptions, callback as zlib.CompressCallback);
+      break;
+    case 'zstd':
+      if ('kModuleError' in ZStandard) {
+        return callback(ZStandard['kModuleError']);
+      }
+      ZStandard.compress(dataToBeCompressed, ZSTD_COMPRESSION_LEVEL).then(
+        buffer => callback(undefined, buffer),
+        error => callback(error)
+      );
+      break;
+    default:
+      throw new MongoInvalidArgumentError(
+        `Unknown compressor ${self.options.agreedCompressor} failed to compress`
+      );
+  }
+}
+
+// Decompress a message using the given compressor
+export function decompress(
+  compressorID: Compressor,
+  compressedData: Buffer,
+  callback: Callback<Buffer>
+): void {
+  if (compressorID < 0 || compressorID > MAX_COMPRESSOR_ID) {
+    throw new MongoDecompressionError(
+      `Server sent message compressed using an unsupported compressor. (Received compressor ID ${compressorID})`
+    );
+  }
+
+  switch (compressorID) {
+    case Compressor.snappy: {
+      if ('kModuleError' in Snappy) {
+        return callback(Snappy['kModuleError']);
+      }
+
+      if (Snappy[PKG_VERSION].major <= 6) {
+        Snappy.uncompress(compressedData, { asBuffer: true }, callback);
+      } else {
+        Snappy.uncompress(compressedData, { asBuffer: true }).then(
+          buffer => callback(undefined, buffer),
+          error => callback(error)
+        );
+      }
+      break;
+    }
+    case Compressor.zstd: {
+      if ('kModuleError' in ZStandard) {
+        return callback(ZStandard['kModuleError']);
+      }
+
+      ZStandard.decompress(compressedData).then(
+        buffer => callback(undefined, buffer),
+        error => callback(error)
+      );
+      break;
+    }
+    case Compressor.zlib:
+      zlib.inflate(compressedData, callback as zlib.CompressCallback);
+      break;
+    default:
+      callback(undefined, compressedData);
+  }
+}

node_modules/mongodb/src/cmap/wire_protocol/constants.ts

@@ -0,0 +1,11 @@
+export const MIN_SUPPORTED_SERVER_VERSION = '3.6';
+export const MAX_SUPPORTED_SERVER_VERSION = '6.0';
+export const MIN_SUPPORTED_WIRE_VERSION = 6;
+export const MAX_SUPPORTED_WIRE_VERSION = 17;
+export const OP_REPLY = 1;
+export const OP_UPDATE = 2001;
+export const OP_INSERT = 2002;
+export const OP_QUERY = 2004;
+export const OP_DELETE = 2006;
+export const OP_COMPRESSED = 2012;
+export const OP_MSG = 2013;

node_modules/mongodb/src/cmap/wire_protocol/shared.ts

@@ -0,0 +1,76 @@
+import type { Document } from '../../bson';
+import { MongoInvalidArgumentError } from '../../error';
+import type { ReadPreferenceLike } from '../../read_preference';
+import { ReadPreference } from '../../read_preference';
+import { ServerType } from '../../sdam/common';
+import type { Server } from '../../sdam/server';
+import type { ServerDescription } from '../../sdam/server_description';
+import type { Topology } from '../../sdam/topology';
+import { TopologyDescription } from '../../sdam/topology_description';
+import type { OpQueryOptions } from '../commands';
+import type { CommandOptions, Connection } from '../connection';
+
+export interface ReadPreferenceOption {
+  readPreference?: ReadPreferenceLike;
+}
+
+export function getReadPreference(cmd: Document, options?: ReadPreferenceOption): ReadPreference {
+  // Default to command version of the readPreference
+  let readPreference = cmd.readPreference || ReadPreference.primary;
+  // If we have an option readPreference override the command one
+  if (options?.readPreference) {
+    readPreference = options.readPreference;
+  }
+
+  if (typeof readPreference === 'string') {
+    readPreference = ReadPreference.fromString(readPreference);
+  }
+
+  if (!(readPreference instanceof ReadPreference)) {
+    throw new MongoInvalidArgumentError(
+      'Option "readPreference" must be a ReadPreference instance'
+    );
+  }
+
+  return readPreference;
+}
+
+export function applyCommonQueryOptions(
+  queryOptions: OpQueryOptions,
+  options: CommandOptions
+): CommandOptions {
+  Object.assign(queryOptions, {
+    raw: typeof options.raw === 'boolean' ? options.raw : false,
+    promoteLongs: typeof options.promoteLongs === 'boolean' ? options.promoteLongs : true,
+    promoteValues: typeof options.promoteValues === 'boolean' ? options.promoteValues : true,
+    promoteBuffers: typeof options.promoteBuffers === 'boolean' ? options.promoteBuffers : false,
+    bsonRegExp: typeof options.bsonRegExp === 'boolean' ? options.bsonRegExp : false,
+    enableUtf8Validation:
+      typeof options.enableUtf8Validation === 'boolean' ? options.enableUtf8Validation : true
+  });
+
+  if (options.session) {
+    queryOptions.session = options.session;
+  }
+
+  return queryOptions;
+}
+
+export function isSharded(topologyOrServer?: Topology | Server | Connection): boolean {
+  if (topologyOrServer == null) {
+    return false;
+  }
+
+  if (topologyOrServer.description && topologyOrServer.description.type === ServerType.Mongos) {
+    return true;
+  }
+
+  // NOTE: This is incredibly inefficient, and should be removed once command construction
+  //       happens based on `Server` not `Topology`.
+  if (topologyOrServer.description && topologyOrServer.description instanceof TopologyDescription) {
+    const servers: ServerDescription[] = Array.from(topologyOrServer.description.servers.values());
+    return servers.some((server: ServerDescription) => server.type === ServerType.Mongos);
+  }
+
+  return false;
+}