Files
atom/src/task.coffee
Nathan Sobo 24943dd526 Avoid sending arguments object to child process.
The arguments variable is not a real array, and gets screwed up when
sending it to the child process. This updates it to send an array
instead.

Thanks to @lackac!

Refs atom/terminal#23.
2014-03-19 15:40:35 -06:00

111 lines
3.4 KiB
CoffeeScript

_ = require 'underscore-plus'
child_process = require 'child_process'
{Emitter} = require 'emissary'
# Public: Run a node script in a separate process.
#
# Used by the fuzzy-finder.
#
# ## Events
#
# * task:log - Emitted when console.log is called within the task.
# * task:warn - Emitted when console.warn is called within the task.
# * task:error - Emitted when console.error is called within the task.
# * task:completed - Emitted when the task has succeeded or failed.
#
# ## Requiring in packages
#
# ```coffee
# {Task} = require 'atom'
# ```
module.exports =
class Task
Emitter.includeInto(this)
# Public: A helper method to easily launch and run a task once.
#
# taskPath - The {String} path to the CoffeeScript/JavaScript file which
# exports a single {Function} to execute.
# args - The arguments to pass to the exported function.
@once: (taskPath, args...) ->
task = new Task(taskPath)
task.once 'task:completed', -> task.terminate()
task.start(args...)
task
# Called upon task completion.
#
# It receives the same arguments that were passed to the task.
#
# If subclassed, this is intended to be overridden. However if {::start}
# receives a completion callback, this is overridden.
callback: null
# Public: Creates a task.
#
# taskPath - The {String} path to the CoffeeScript/JavaScript file that
# exports a single {Function} to execute.
constructor: (taskPath) ->
coffeeCacheRequire = "require('#{require.resolve('./coffee-cache')}').register();"
coffeeScriptRequire = "require('#{require.resolve('coffee-script')}').register();"
taskBootstrapRequire = "require('#{require.resolve('./task-bootstrap')}');"
bootstrap = """
#{coffeeScriptRequire}
#{coffeeCacheRequire}
#{taskBootstrapRequire}
"""
bootstrap = bootstrap.replace(/\\/g, "\\\\")
taskPath = require.resolve(taskPath)
taskPath = taskPath.replace(/\\/g, "\\\\")
env = _.extend({}, process.env, {taskPath, userAgent: navigator.userAgent})
args = [bootstrap, '--harmony_collections']
@childProcess = child_process.fork '--eval', args, {env, cwd: __dirname}
@on "task:log", -> console.log(arguments...)
@on "task:warn", -> console.warn(arguments...)
@on "task:error", -> console.error(arguments...)
@on "task:completed", (args...) => @callback?(args...)
@handleEvents()
# Routes messages from the child to the appropriate event.
handleEvents: ->
@childProcess.removeAllListeners()
@childProcess.on 'message', ({event, args}) =>
@emit(event, args...)
# Public: Starts the task.
#
# args - The arguments to pass to the function exported by this task's script.
# callback - An optional {Function} to call when the task completes.
start: (args..., callback) ->
throw new Error("Cannot start terminated process") unless @childProcess?
@handleEvents()
if _.isFunction(callback)
@callback = callback
else
args.push(callback)
@send({event: 'start', args})
# Public: Send message to the task.
#
# message - The message to send to the task.
send: (message) ->
throw new Error("Cannot send message to terminated process") unless @childProcess?
@childProcess.send(message)
# Public: Forcefully stop the running task.
#
# No events are emitted.
terminate: ->
return unless @childProcess?
@childProcess.removeAllListeners()
@childProcess.kill()
@childProcess = null
@off()