changes

backend/node_modules/mongodb/src/transactions.ts

@@ -0,0 +1,181 @@
+import type { Document } from './bson';
+import { MongoRuntimeError, MongoTransactionError } from './error';
+import type { CommandOperationOptions } from './operations/command';
+import { ReadConcern, type ReadConcernLike } from './read_concern';
+import { ReadPreference, type ReadPreferenceLike } from './read_preference';
+import type { Server } from './sdam/server';
+import { WriteConcern } from './write_concern';
+
+/** @internal */
+export const TxnState = Object.freeze({
+  NO_TRANSACTION: 'NO_TRANSACTION',
+  STARTING_TRANSACTION: 'STARTING_TRANSACTION',
+  TRANSACTION_IN_PROGRESS: 'TRANSACTION_IN_PROGRESS',
+  TRANSACTION_COMMITTED: 'TRANSACTION_COMMITTED',
+  TRANSACTION_COMMITTED_EMPTY: 'TRANSACTION_COMMITTED_EMPTY',
+  TRANSACTION_ABORTED: 'TRANSACTION_ABORTED'
+} as const);
+
+/** @internal */
+export type TxnState = (typeof TxnState)[keyof typeof TxnState];
+
+const stateMachine: { [state in TxnState]: TxnState[] } = {
+  [TxnState.NO_TRANSACTION]: [TxnState.NO_TRANSACTION, TxnState.STARTING_TRANSACTION],
+  [TxnState.STARTING_TRANSACTION]: [
+    TxnState.TRANSACTION_IN_PROGRESS,
+    TxnState.TRANSACTION_COMMITTED,
+    TxnState.TRANSACTION_COMMITTED_EMPTY,
+    TxnState.TRANSACTION_ABORTED
+  ],
+  [TxnState.TRANSACTION_IN_PROGRESS]: [
+    TxnState.TRANSACTION_IN_PROGRESS,
+    TxnState.TRANSACTION_COMMITTED,
+    TxnState.TRANSACTION_ABORTED
+  ],
+  [TxnState.TRANSACTION_COMMITTED]: [
+    TxnState.TRANSACTION_COMMITTED,
+    TxnState.TRANSACTION_COMMITTED_EMPTY,
+    TxnState.STARTING_TRANSACTION,
+    TxnState.NO_TRANSACTION
+  ],
+  [TxnState.TRANSACTION_ABORTED]: [TxnState.STARTING_TRANSACTION, TxnState.NO_TRANSACTION],
+  [TxnState.TRANSACTION_COMMITTED_EMPTY]: [
+    TxnState.TRANSACTION_COMMITTED_EMPTY,
+    TxnState.NO_TRANSACTION
+  ]
+};
+
+const ACTIVE_STATES: Set<TxnState> = new Set([
+  TxnState.STARTING_TRANSACTION,
+  TxnState.TRANSACTION_IN_PROGRESS
+]);
+
+const COMMITTED_STATES: Set<TxnState> = new Set([
+  TxnState.TRANSACTION_COMMITTED,
+  TxnState.TRANSACTION_COMMITTED_EMPTY,
+  TxnState.TRANSACTION_ABORTED
+]);
+
+/**
+ * Configuration options for a transaction.
+ * @public
+ */
+export interface TransactionOptions extends Omit<CommandOperationOptions, 'timeoutMS'> {
+  // TODO(NODE-3344): These options use the proper class forms of these settings, it should accept the basic enum values too
+  /** A default read concern for commands in this transaction */
+  readConcern?: ReadConcernLike;
+  /** A default writeConcern for commands in this transaction */
+  writeConcern?: WriteConcern;
+  /** A default read preference for commands in this transaction */
+  readPreference?: ReadPreferenceLike;
+  /** Specifies the maximum amount of time to allow a commit action on a transaction to run in milliseconds */
+  maxCommitTimeMS?: number;
+}
+
+/**
+ * @internal
+ */
+export class Transaction {
+  state: TxnState;
+  options: TransactionOptions;
+  _pinnedServer?: Server;
+  _recoveryToken?: Document;
+
+  /** Create a transaction */
+  constructor(options?: TransactionOptions) {
+    options = options ?? {};
+    this.state = TxnState.NO_TRANSACTION;
+    this.options = {};
+
+    const writeConcern = WriteConcern.fromOptions(options);
+    if (writeConcern) {
+      if (writeConcern.w === 0) {
+        throw new MongoTransactionError('Transactions do not support unacknowledged write concern');
+      }
+
+      this.options.writeConcern = writeConcern;
+    }
+
+    if (options.readConcern) {
+      this.options.readConcern = ReadConcern.fromOptions(options);
+    }
+
+    if (options.readPreference) {
+      this.options.readPreference = ReadPreference.fromOptions(options);
+    }
+
+    if (options.maxCommitTimeMS) {
+      this.options.maxTimeMS = options.maxCommitTimeMS;
+    }
+
+    // TODO: This isn't technically necessary
+    this._pinnedServer = undefined;
+    this._recoveryToken = undefined;
+  }
+
+  get server(): Server | undefined {
+    return this._pinnedServer;
+  }
+
+  get recoveryToken(): Document | undefined {
+    return this._recoveryToken;
+  }
+
+  get isPinned(): boolean {
+    return !!this.server;
+  }
+
+  /**
+   * @returns Whether the transaction has started
+   */
+  get isStarting(): boolean {
+    return this.state === TxnState.STARTING_TRANSACTION;
+  }
+
+  /**
+   * @returns Whether this session is presently in a transaction
+   */
+  get isActive(): boolean {
+    return ACTIVE_STATES.has(this.state);
+  }
+
+  get isCommitted(): boolean {
+    return COMMITTED_STATES.has(this.state);
+  }
+  /**
+   * Transition the transaction in the state machine
+   * @param nextState - The new state to transition to
+   */
+  transition(nextState: TxnState): void {
+    const nextStates = stateMachine[this.state];
+    if (nextStates && nextStates.includes(nextState)) {
+      this.state = nextState;
+      if (
+        this.state === TxnState.NO_TRANSACTION ||
+        this.state === TxnState.STARTING_TRANSACTION ||
+        this.state === TxnState.TRANSACTION_ABORTED
+      ) {
+        this.unpinServer();
+      }
+      return;
+    }
+
+    throw new MongoRuntimeError(
+      `Attempted illegal state transition from [${this.state}] to [${nextState}]`
+    );
+  }
+
+  pinServer(server: Server): void {
+    if (this.isActive) {
+      this._pinnedServer = server;
+    }
+  }
+
+  unpinServer(): void {
+    this._pinnedServer = undefined;
+  }
+}
+
+export function isTransactionCommand(command: Document): boolean {
+  return !!(command.commitTransaction || command.abortTransaction);
+}