opusdev/vector-similarity-api

1/*!2 * on-finished3 * Copyright(c) 2013 Jonathan Ong4 * Copyright(c) 2014 Douglas Christopher Wilson5 * MIT Licensed6 */7 8'use strict'9 10/**11 * Module exports.12 * @public13 */14 15module.exports = onFinished16module.exports.isFinished = isFinished17 18/**19 * Module dependencies.20 * @private21 */22 23var asyncHooks = tryRequireAsyncHooks()24var first = require('ee-first')25 26/**27 * Variables.28 * @private29 */30 31/* istanbul ignore next */32var defer = typeof setImmediate === 'function'33  ? setImmediate34  : function (fn) { process.nextTick(fn.bind.apply(fn, arguments)) }35 36/**37 * Invoke callback when the response has finished, useful for38 * cleaning up resources afterwards.39 *40 * @param {object} msg41 * @param {function} listener42 * @return {object}43 * @public44 */45 46function onFinished (msg, listener) {47  if (isFinished(msg) !== false) {48    defer(listener, null, msg)49    return msg50  }51 52  // attach the listener to the message53  attachListener(msg, wrap(listener))54 55  return msg56}57 58/**59 * Determine if message is already finished.60 *61 * @param {object} msg62 * @return {boolean}63 * @public64 */65 66function isFinished (msg) {67  var socket = msg.socket68 69  if (typeof msg.finished === 'boolean') {70    // OutgoingMessage71    return Boolean(msg.finished || (socket && !socket.writable))72  }73 74  if (typeof msg.complete === 'boolean') {75    // IncomingMessage76    return Boolean(msg.upgrade || !socket || !socket.readable || (msg.complete && !msg.readable))77  }78 79  // don't know80  return undefined81}82 83/**84 * Attach a finished listener to the message.85 *86 * @param {object} msg87 * @param {function} callback88 * @private89 */90 91function attachFinishedListener (msg, callback) {92  var eeMsg93  var eeSocket94  var finished = false95 96  function onFinish (error) {97    eeMsg.cancel()98    eeSocket.cancel()99 100    finished = true101    callback(error)102  }103 104  // finished on first message event105  eeMsg = eeSocket = first([[msg, 'end', 'finish']], onFinish)106 107  function onSocket (socket) {108    // remove listener109    msg.removeListener('socket', onSocket)110 111    if (finished) return112    if (eeMsg !== eeSocket) return113 114    // finished on first socket event115    eeSocket = first([[socket, 'error', 'close']], onFinish)116  }117 118  if (msg.socket) {119    // socket already assigned120    onSocket(msg.socket)121    return122  }123 124  // wait for socket to be assigned125  msg.on('socket', onSocket)126 127  if (msg.socket === undefined) {128    // istanbul ignore next: node.js 0.8 patch129    patchAssignSocket(msg, onSocket)130  }131}132 133/**134 * Attach the listener to the message.135 *136 * @param {object} msg137 * @return {function}138 * @private139 */140 141function attachListener (msg, listener) {142  var attached = msg.__onFinished143 144  // create a private single listener with queue145  if (!attached || !attached.queue) {146    attached = msg.__onFinished = createListener(msg)147    attachFinishedListener(msg, attached)148  }149 150  attached.queue.push(listener)151}152 153/**154 * Create listener on message.155 *156 * @param {object} msg157 * @return {function}158 * @private159 */160 161function createListener (msg) {162  function listener (err) {163    if (msg.__onFinished === listener) msg.__onFinished = null164    if (!listener.queue) return165 166    var queue = listener.queue167    listener.queue = null168 169    for (var i = 0; i < queue.length; i++) {170      queue[i](err, msg)171    }172  }173 174  listener.queue = []175 176  return listener177}178 179/**180 * Patch ServerResponse.prototype.assignSocket for node.js 0.8.181 *182 * @param {ServerResponse} res183 * @param {function} callback184 * @private185 */186 187// istanbul ignore next: node.js 0.8 patch188function patchAssignSocket (res, callback) {189  var assignSocket = res.assignSocket190 191  if (typeof assignSocket !== 'function') return192 193  // res.on('socket', callback) is broken in 0.8194  res.assignSocket = function _assignSocket (socket) {195    assignSocket.call(this, socket)196    callback(socket)197  }198}199 200/**201 * Try to require async_hooks202 * @private203 */204 205function tryRequireAsyncHooks () {206  try {207    return require('async_hooks')208  } catch (e) {209    return {}210  }211}212 213/**214 * Wrap function with async resource, if possible.215 * AsyncResource.bind static method backported.216 * @private217 */218 219function wrap (fn) {220  var res221 222  // create anonymous resource223  if (asyncHooks.AsyncResource) {224    res = new asyncHooks.AsyncResource(fn.name || 'bound-anonymous-fn')225  }226 227  // incompatible node.js228  if (!res || !res.runInAsyncScope) {229    return fn230  }231 232  // return bound function233  return res.runInAsyncScope.bind(res, fn, null)234}235