The Tor Browser: addon-sdk/source/lib/sdk/event/utils.js@6474c204b198 (annotated)

addon-sdk/source/lib/sdk/event/utils.js@6474c204b198 (annotated)

addon-sdk/source/lib/sdk/event/utils.js

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 "use strict";
 module.metadata = {
   "stability": "unstable"
 };
 let { emit, on, once, off, EVENT_TYPE_PATTERN } = require("./core");
 // This module provides set of high order function for working with event
 // streams (streams in a NodeJS style that dispatch data, end and error
 // events).
 // Function takes a `target` object and returns set of implicit references
 // (non property references) it keeps. This basically allows defining
 // references between objects without storing the explicitly. See transform for
 // more details.
 let refs = (function() {
   let refSets = new WeakMap();
   return function refs(target) {
     if (!refSets.has(target)) refSets.set(target, new Set());
     return refSets.get(target);
   };
 })();
 function transform(input, f) {
   let output = {};
   // Since event listeners don't prevent `input` to be GC-ed we wanna presrve
   // it until `output` can be GC-ed. There for we add implicit reference which
   // is removed once `input` ends.
   refs(output).add(input);
   const next = data => receive(output, data);
   once(output, "start", () => start(input));
   on(input, "error", error => emit(output, "error", error));
   on(input, "end", function() {
     refs(output).delete(input);
     end(output);
   });
   on(input, "data", data => f(data, next));
   return output;
 }
 // High order event transformation function that takes `input` event channel
 // and returns transformation containing only events on which `p` predicate
 // returns `true`.
 function filter(input, predicate) {
   return transform(input, function(data, next) {
     if (predicate(data))
       next(data);
   });
 }
 exports.filter = filter;
 // High order function that takes `input` and returns input of it's values
 // mapped via given `f` function.
 const map = (input, f) => transform(input, (data, next) => next(f(data)));
 exports.map = map;
 // High order function that takes `input` stream of streams and merges them
 // into single event stream. Like flatten but time based rather than order
 // based.
 function merge(inputs) {
   let output = {};
   let open = 1;
   let state = [];
   output.state = state;
   refs(output).add(inputs);
   function end(input) {
     open = open - 1;
     refs(output).delete(input);
     if (open === 0) emit(output, "end");
   }
   const error = e => emit(output, "error", e);
   function forward(input) {
     state.push(input);
     open = open + 1;
     on(input, "end", () => end(input));
     on(input, "error", error);
     on(input, "data", data => emit(output, "data", data));
   }
   // If `inputs` is an array treat it as a stream.
   if (Array.isArray(inputs)) {
     inputs.forEach(forward);
     end(inputs);
   }
   else {
     on(inputs, "end", () => end(inputs));
     on(inputs, "error", error);
     on(inputs, "data", forward);
   }
   return output;
 }
 exports.merge = merge;
 const expand = (inputs, f) => merge(map(inputs, f));
 exports.expand = expand;
 const pipe = (from, to) => on(from, "*", emit.bind(emit, to));
 exports.pipe = pipe;
 // Shim signal APIs so other modules can be used as is.
 const receive = (input, message) => {
   if (input[receive])
     input[receive](input, message);
   else
     emit(input, "data", message);
   input.value = message;
 };
 receive.toString = () => "@@receive";
 exports.receive = receive;
 exports.send = receive;
 const end = input => {
   if (input[end])
     input[end](input);
   else
     emit(input, "end", input);
 };
 end.toString = () => "@@end";
 exports.end = end;
 const stop = input => {
   if (input[stop])
     input[stop](input);
   else
     emit(input, "stop", input);
 };
 stop.toString = () => "@@stop";
 exports.stop = stop;
 const start = input => {
   if (input[start])
     input[start](input);
   else
     emit(input, "start", input);
 };
 start.toString = () => "@@start";
 exports.start = start;
 const lift = (step, ...inputs) => {
   let args = null;
   let opened = inputs.length;
   let started = false;
   const output = {};
   const init = () => {
     args = [...inputs.map(input => input.value)];
     output.value = step(...args);
   };
   inputs.forEach((input, index) => {
     on(input, "data", data => {
       args[index] = data;
       receive(output, step(...args));
     });
     on(input, "end", () => {
       opened = opened - 1;
       if (opened <= 0)
         end(output);
     });
   });
   once(output, "start", () => {
     inputs.forEach(start);
     init();
   });
   init();
   return output;
 };
 exports.lift = lift;
 const merges = inputs => {
   let opened = inputs.length;
   let output = { value: inputs[0].value };
   inputs.forEach((input, index) => {
     on(input, "data", data => receive(output, data));
     on(input, "end", () => {
       opened = opened - 1;
       if (opened <= 0)
         end(output);
     });
   });
   once(output, "start", () => {
     inputs.forEach(start);
     output.value = inputs[0].value;
   });
   return output;
 };
 exports.merges = merges;
 const foldp = (step, initial, input) => {
   let output = map(input, x => step(output.value, x));
   output.value = initial;
   return output;
 };
 exports.foldp = foldp;
 const keepIf = (p, base, input) => {
   let output = filter(input, p);
   output.value = base;
   return output;
 };
 exports.keepIf = keepIf;
 function Input() {}
 Input.start = input => emit(input, "start", input);
 Input.prototype.start = Input.start;
 Input.end = input => {
   emit(input, "end", input);
   stop(input);
 };
 Input.prototype[end] = Input.end;
 exports.Input = Input;
 const $source = "@@source";
 const $outputs = "@@outputs";
 exports.outputs = $outputs;
 function Reactor(options={}) {
   const {onStep, onStart, onEnd} = options;
   if (onStep)
     this.onStep = onStep;
   if (onStart)
     this.onStart = onStart;
   if (onEnd)
     this.onEnd = onEnd;
 }
 Reactor.prototype.onStep = _ => void(0);
 Reactor.prototype.onStart = _ => void(0);
 Reactor.prototype.onEnd = _ => void(0);
 Reactor.prototype.onNext = function(present, past) {
   this.value = present;
   this.onStep(present, past);
 };
 Reactor.prototype.run = function(input) {
   on(input, "data", message => this.onNext(message, input.value));
   on(input, "end", () => this.onEnd(input.value));
   start(input);
   this.value = input.value;
   this.onStart(input.value);
 };
 exports.Reactor = Reactor;
 /**
  * Takes an object used as options with potential keys like 'onMessage',
  * used to be called `require('sdk/event/core').setListeners` on.
  * This strips all keys that would trigger a listener to be set.
  *
  * @params {Object} object
  * @return {Object}
  */
 function stripListeners (object) {
   return Object.keys(object || {}).reduce((agg, key) => {
     if (!EVENT_TYPE_PATTERN.test(key))
       agg[key] = object[key];
     return agg;
   }, {});
 }
 exports.stripListeners = stripListeners;