/*!
* on-finished
* Copyright(c) 2013 Jonathan Ong
* Copyright(c) 2014 Douglas Christopher Wilson
* MIT Licensed
*/
'use strict'
/**
* Module exports.
* @public
*/
module.exports = onFinished
module.exports.isFinished = isFinished
/**
* Module dependencies.
* @private
*/
var asyncHooks = tryRequireAsyncHooks()
var first = require('ee-first')
/**
* Variables.
* @private
*/
/* istanbul ignore next */
var defer = typeof setImmediate === 'function'
? setImmediate
: function (fn) { process.nextTick(fn.bind.apply(fn, arguments)) }
/**
* Invoke callback when the response has finished, useful for
* cleaning up resources afterwards.
*
* @param {object} msg
* @param {function} listener
* @return {object}
* @public
*/
function onFinished (msg, listener) {
if (isFinished(msg) !== false) {
defer(listener, null, msg)
return msg
}
// attach the listener to the message
attachListener(msg, wrap(listener))
return msg
}
/**
* Determine if message is already finished.
*
* @param {object} msg
* @return {boolean}
* @public
*/
function isFinished (msg) {
var socket = msg.socket
if (typeof msg.finished === 'boolean') {
// OutgoingMessage
return Boolean(msg.finished || (socket && !socket.writable))
}
if (typeof msg.complete === 'boolean') {
// IncomingMessage
return Boolean(msg.upgrade || !socket || !socket.readable || (msg.complete && !msg.readable))
}
// don't know
return undefined
}
/**
* Attach a finished listener to the message.
*
* @param {object} msg
* @param {function} callback
* @private
*/
function attachFinishedListener (msg, callback) {
var eeMsg
var eeSocket
var finished = false
function onFinish (error) {
eeMsg.cancel()
eeSocket.cancel()
finished = true
callback(error)
}
// finished on first message event
eeMsg = eeSocket = first([[msg, 'end', 'finish']], onFinish)
function onSocket (socket) {
// remove listener
msg.removeListener('socket', onSocket)
if (finished) return
if (eeMsg !== eeSocket) return
// finished on first socket event
eeSocket = first([[socket, 'error', 'close']], onFinish)
}
if (msg.socket) {
// socket already assigned
onSocket(msg.socket)
return
}
// wait for socket to be assigned
msg.on('socket', onSocket)
if (msg.socket === undefined) {
// istanbul ignore next: node.js 0.8 patch
patchAssignSocket(msg, onSocket)
}
}
/**
* Attach the listener to the message.
*
* @param {object} msg
* @return {function}
* @private
*/
function attachListener (msg, listener) {
var attached = msg.__onFinished
// create a private single listener with queue
if (!attached || !attached.queue) {
attached = msg.__onFinished = createListener(msg)
attachFinishedListener(msg, attached)
}
attached.queue.push(listener)
}
/**
* Create listener on message.
*
* @param {object} msg
* @return {function}
* @private
*/
function createListener (msg) {
function listener (err) {
if (msg.__onFinished === listener) msg.__onFinished = null
if (!listener.queue) return
var queue = listener.queue
listener.queue = null
for (var i = 0; i < queue.length; i++) {
queue[i](err, msg)
}
}
listener.queue = []
return listener
}
/**
* Patch ServerResponse.prototype.assignSocket for node.js 0.8.
*
* @param {ServerResponse} res
* @param {function} callback
* @private
*/
// istanbul ignore next: node.js 0.8 patch
function patchAssignSocket (res, callback) {
var assignSocket = res.assignSocket
if (typeof assignSocket !== 'function') return
// res.on('socket', callback) is broken in 0.8
res.assignSocket = function _assignSocket (socket) {
assignSocket.call(this, socket)
callback(socket)
}
}
/**
* Try to require async_hooks
* @private
*/
function tryRequireAsyncHooks () {
try {
return require('async_hooks')
} catch (e) {
return {}
}
}
/**
* Wrap function with async resource, if possible.
* AsyncResource.bind static method backported.
* @private
*/
function wrap (fn) {
var res
// create anonymous resource
if (asyncHooks.AsyncResource) {
res = new asyncHooks.AsyncResource(fn.name || 'bound-anonymous-fn')
}
// incompatible node.js
if (!res || !res.runInAsyncScope) {
return fn
}
// return bound function
return res.runInAsyncScope.bind(res, fn, null)
}