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| 1 | +/** |
| 2 | + * @license |
| 3 | + * Copyright Google LLC All Rights Reserved. |
| 4 | + * |
| 5 | + * Use of this source code is governed by an MIT-style license that can be |
| 6 | + * found in the LICENSE file at https://angular.dev/license |
| 7 | + */ |
| 8 | + |
| 9 | +/** |
| 10 | + * @fileoverview |
| 11 | + * This file defines an abstraction layer for operating-system or file-system operations, such as |
| 12 | + * command execution. This allows for easier testing by enabling the injection of mock or |
| 13 | + * test-specific implementations. |
| 14 | + */ |
| 15 | + |
| 16 | +import { existsSync as nodeExistsSync } from 'fs'; |
| 17 | +import { spawn } from 'node:child_process'; |
| 18 | +import { Stats } from 'node:fs'; |
| 19 | +import { stat } from 'node:fs/promises'; |
| 20 | + |
| 21 | +/** |
| 22 | + * An error thrown when a command fails to execute. |
| 23 | + */ |
| 24 | +export class CommandError extends Error { |
| 25 | + constructor( |
| 26 | + message: string, |
| 27 | + public readonly stdout: string, |
| 28 | + public readonly stderr: string, |
| 29 | + public readonly code: number | null, |
| 30 | + ) { |
| 31 | + super(message); |
| 32 | + } |
| 33 | +} |
| 34 | + |
| 35 | +/** |
| 36 | + * An abstraction layer for operating-system or file-system operations. |
| 37 | + */ |
| 38 | +export interface Host { |
| 39 | + /** |
| 40 | + * Gets the stats of a file or directory. |
| 41 | + * @param path The path to the file or directory. |
| 42 | + * @returns A promise that resolves to the stats. |
| 43 | + */ |
| 44 | + stat(path: string): Promise<Stats>; |
| 45 | + |
| 46 | + /** |
| 47 | + * Checks if a path exists on the file system. |
| 48 | + * @param path The path to check. |
| 49 | + * @returns A boolean indicating whether the path exists. |
| 50 | + */ |
| 51 | + existsSync(path: string): boolean; |
| 52 | + |
| 53 | + /** |
| 54 | + * Spawns a child process and returns a promise that resolves with the process's |
| 55 | + * output or rejects with a structured error. |
| 56 | + * @param command The command to run. |
| 57 | + * @param args The arguments to pass to the command. |
| 58 | + * @param options Options for the child process. |
| 59 | + * @returns A promise that resolves with the standard output and standard error of the command. |
| 60 | + */ |
| 61 | + runCommand( |
| 62 | + command: string, |
| 63 | + args: readonly string[], |
| 64 | + options?: { |
| 65 | + timeout?: number; |
| 66 | + stdio?: 'pipe' | 'ignore'; |
| 67 | + cwd?: string; |
| 68 | + env?: Record<string, string>; |
| 69 | + }, |
| 70 | + ): Promise<{ stdout: string; stderr: string }>; |
| 71 | +} |
| 72 | + |
| 73 | +/** |
| 74 | + * A concrete implementation of the `Host` interface that runs on a local workspace. |
| 75 | + */ |
| 76 | +export const LocalWorkspaceHost: Host = { |
| 77 | + stat, |
| 78 | + existsSync: nodeExistsSync, |
| 79 | + runCommand: async ( |
| 80 | + command: string, |
| 81 | + args: readonly string[], |
| 82 | + options: { |
| 83 | + timeout?: number; |
| 84 | + stdio?: 'pipe' | 'ignore'; |
| 85 | + cwd?: string; |
| 86 | + env?: Record<string, string>; |
| 87 | + } = {}, |
| 88 | + ): Promise<{ stdout: string; stderr: string }> => { |
| 89 | + const signal = options.timeout ? AbortSignal.timeout(options.timeout) : undefined; |
| 90 | + |
| 91 | + return new Promise((resolve, reject) => { |
| 92 | + const childProcess = spawn(command, args, { |
| 93 | + shell: false, |
| 94 | + stdio: options.stdio ?? 'pipe', |
| 95 | + signal, |
| 96 | + cwd: options.cwd, |
| 97 | + env: { |
| 98 | + ...process.env, |
| 99 | + ...options.env, |
| 100 | + }, |
| 101 | + }); |
| 102 | + |
| 103 | + let stdout = ''; |
| 104 | + childProcess.stdout?.on('data', (data) => (stdout += data.toString())); |
| 105 | + |
| 106 | + let stderr = ''; |
| 107 | + childProcess.stderr?.on('data', (data) => (stderr += data.toString())); |
| 108 | + |
| 109 | + childProcess.on('close', (code) => { |
| 110 | + if (code === 0) { |
| 111 | + resolve({ stdout, stderr }); |
| 112 | + } else { |
| 113 | + const message = `Process exited with code ${code}.`; |
| 114 | + reject(new CommandError(message, stdout, stderr, code)); |
| 115 | + } |
| 116 | + }); |
| 117 | + |
| 118 | + childProcess.on('error', (err) => { |
| 119 | + if (err.name === 'AbortError') { |
| 120 | + const message = `Process timed out.`; |
| 121 | + reject(new CommandError(message, stdout, stderr, null)); |
| 122 | + |
| 123 | + return; |
| 124 | + } |
| 125 | + const message = `Process failed with error: ${err.message}`; |
| 126 | + reject(new CommandError(message, stdout, stderr, null)); |
| 127 | + }); |
| 128 | + }); |
| 129 | + }, |
| 130 | +}; |
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