atom/src/buffered-process.js at master · torwei/atom · GitHub

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const _ = require('underscore-plus');

const ChildProcess = require('child_process');

const { Emitter } = require('event-kit');

const path = require('path');

// Extended: A wrapper which provides standard error/output line buffering for

// Node's ChildProcess.

// ## Examples

// ```js

// {BufferedProcess} = require('atom')

// const command = 'ps'

// const args = ['-ef']

// const stdout = (output) => console.log(output)

// const exit = (code) => console.log("ps -ef exited with #{code}")

// const process = new BufferedProcess({command, args, stdout, exit})

// ```

module.exports = class BufferedProcess {

Section: Construction

// Public: Runs the given command by spawning a new child process.

// * `options` An {Object} with the following keys:

// * `command` The {String} command to execute.

// * `args` The {Array} of arguments to pass to the command (optional).

// * `options` {Object} (optional) The options {Object} to pass to Node's

// `ChildProcess.spawn` method.

// * `stdout` {Function} (optional) The callback that receives a single

// argument which contains the standard output from the command. The

// callback is called as data is received but it's buffered to ensure only

// complete lines are passed until the source stream closes. After the

// source stream has closed all remaining data is sent in a final call.

// * `data` {String}

// * `stderr` {Function} (optional) The callback that receives a single

// argument which contains the standard error output from the command. The

// callback is called as data is received but it's buffered to ensure only

// complete lines are passed until the source stream closes. After the

// source stream has closed all remaining data is sent in a final call.

// * `data` {String}

// * `exit` {Function} (optional) The callback which receives a single

// argument containing the exit status.

// * `code` {Number}

// * `autoStart` {Boolean} (optional) Whether the command will automatically start

// when this BufferedProcess is created. Defaults to true. When set to false you

// must call the `start` method to start the process.

constructor({

command,

args,

options = {},

stdout,

stderr,

exit,

autoStart = true

} = {}) {

this.emitter = new Emitter();

this.command = command;

this.args = args;

this.options = options;

this.stdout = stdout;

this.stderr = stderr;

this.exit = exit;

if (autoStart === true) {

this.start();

}

this.killed = false;

}

start() {

if (this.started === true) return;

this.started = true;

// Related to joyent/node#2318

if (process.platform === 'win32' && this.options.shell === undefined) {

this.spawnWithEscapedWindowsArgs(this.command, this.args, this.options);

} else {

this.spawn(this.command, this.args, this.options);

}

this.handleEvents(this.stdout, this.stderr, this.exit);

}

// Windows has a bunch of special rules that node still doesn't take care of for you

spawnWithEscapedWindowsArgs(command, args, options) {

let cmdArgs = [];

// Quote all arguments and escapes inner quotes

if (args) {

cmdArgs = args

.filter(arg => arg != null)

.map(arg => {

if (this.isExplorerCommand(command) && /^\/[a-zA-Z]+,.*$/.test(arg)) {

// Don't wrap /root,C:\folder style arguments to explorer calls in

// quotes since they will not be interpreted correctly if they are

return arg;

} else {

// Escape double quotes by putting a backslash in front of them

return `"${arg.toString().replace(/"/g, '\\"')}"`;

}

});

}

// The command itself is quoted if it contains spaces, &, ^, | or # chars

cmdArgs.unshift(

/\s|&|\^|$|$|\||#/.test(command) ? `"${command}"` : command

);

const cmdOptions = _.clone(options);

cmdOptions.windowsVerbatimArguments = true;

this.spawn(

this.getCmdPath(),

['/s', '/d', '/c', `"${cmdArgs.join(' ')}"`],

cmdOptions

);

}

Section: Event Subscription

// Public: Will call your callback when an error will be raised by the process.

// Usually this is due to the command not being available or not on the PATH.

// You can call `handle()` on the object passed to your callback to indicate

// that you have handled this error.

// * `callback` {Function} callback

// * `errorObject` {Object}

// * `error` {Object} the error object

// * `handle` {Function} call this to indicate you have handled the error.

// The error will not be thrown if this function is called.

// Returns a {Disposable}

onWillThrowError(callback) {

return this.emitter.on('will-throw-error', callback);

}

Section: Helper Methods

// Helper method to pass data line by line.

// * `stream` The Stream to read from.

// * `onLines` The callback to call with each line of data.

// * `onDone` The callback to call when the stream has closed.

bufferStream(stream, onLines, onDone) {

stream.setEncoding('utf8');

let buffered = '';

stream.on('data', data => {

if (this.killed) return;

let bufferedLength = buffered.length;

buffered += data;

let lastNewlineIndex = data.lastIndexOf('\n');

if (lastNewlineIndex !== -1) {

let lineLength = lastNewlineIndex + bufferedLength + 1;

onLines(buffered.substring(0, lineLength));

buffered = buffered.substring(lineLength);

}

});

stream.on('close', () => {

if (this.killed) return;

if (buffered.length > 0) onLines(buffered);

onDone();

});

}

// Kill all child processes of the spawned cmd.exe process on Windows.

// This is required since killing the cmd.exe does not terminate child

// processes.

killOnWindows() {

if (!this.process) return;

const parentPid = this.process.pid;

const cmd = 'wmic';

const args = [

'process',

'where',

`(ParentProcessId=${parentPid})`,

'get',

'processid'

];

let wmicProcess;

try {

wmicProcess = ChildProcess.spawn(cmd, args);

} catch (spawnError) {

this.killProcess();

return;

}

wmicProcess.on('error', () => {}); // ignore errors

let output = '';

wmicProcess.stdout.on('data', data => {

output += data;

});

wmicProcess.stdout.on('close', () => {

for (let pid of output.split(/\s+/)) {

if (!/^\d{1,10}$/.test(pid)) continue;

pid = parseInt(pid, 10);

if (!pid || pid === parentPid) continue;

try {

process.kill(pid);

} catch (error) {}

}

this.killProcess();

});

}

killProcess() {

if (this.process) this.process.kill();

this.process = null;

}

isExplorerCommand(command) {

if (command === 'explorer.exe' || command === 'explorer') {

return true;

} else if (process.env.SystemRoot) {

return (

command === path.join(process.env.SystemRoot, 'explorer.exe') ||

command === path.join(process.env.SystemRoot, 'explorer')

);

} else {

return false;

}

getCmdPath() {

if (process.env.comspec) {

return process.env.comspec;

} else if (process.env.SystemRoot) {

return path.join(process.env.SystemRoot, 'System32', 'cmd.exe');

} else {

return 'cmd.exe';

}

// Public: Terminate the process.

kill() {

if (this.killed) return;

this.killed = true;

if (process.platform === 'win32') {

this.killOnWindows();

} else {

this.killProcess();

}

spawn(command, args, options) {

try {

this.process = ChildProcess.spawn(command, args, options);

} catch (spawnError) {

process.nextTick(() => this.handleError(spawnError));

}

handleEvents(stdout, stderr, exit) {

if (!this.process) return;

const triggerExitCallback = () => {

if (this.killed) return;

if (

stdoutClosed &&

stderrClosed &&

processExited &&

typeof exit === 'function'

) {

exit(exitCode);

}

};

let stdoutClosed = true;

let stderrClosed = true;

let processExited = true;

let exitCode = 0;

if (stdout) {

stdoutClosed = false;

this.bufferStream(this.process.stdout, stdout, () => {

stdoutClosed = true;

triggerExitCallback();

});

}

if (stderr) {

stderrClosed = false;

this.bufferStream(this.process.stderr, stderr, () => {

stderrClosed = true;

triggerExitCallback();

});

}

if (exit) {

processExited = false;

this.process.on('exit', code => {

exitCode = code;

processExited = true;

triggerExitCallback();

});

}

this.process.on('error', error => {

this.handleError(error);

});

}

handleError(error) {

let handled = false;

const handle = () => {

handled = true;

};

this.emitter.emit('will-throw-error', { error, handle });

if (error.code === 'ENOENT' && error.syscall.indexOf('spawn') === 0) {

error = new Error(

`Failed to spawn command \`${this.command}\`. Make sure \`${

this.command

}\` is installed and on your PATH`,

error.path

);

error.name = 'BufferedProcessError';

}

if (!handled) throw error;

}

};

atom/src/buffered-process.js at master · torwei/atom · GitHub

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