The Tor Browser: browser/devtools/shared/observable-object.js@6474c204b198 (annotated)

browser/devtools/shared/observable-object.js@6474c204b198 (annotated)

browser/devtools/shared/observable-object.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/. */
 /**
  * ObservableObject
  *
  * An observable object is a JSON-like object that throws
  * events when its direct properties or properties of any
  * contained objects, are getting accessed or set.
  *
  * Inherits from EventEmitter.
  *
  * Properties:
  * ⬩ object: JSON-like object
  *
  * Events:
  * ⬩ "get" / path (array of property names)
  * ⬩ "set" / path / new value
  *
  * Example:
  *
  *   let emitter = new ObservableObject({ x: { y: [10] } });
  *   emitter.on("set", console.log);
  *   emitter.on("get", console.log);
  *   let obj = emitter.object;
  *   obj.x.y[0] = 50;
  *
  */
 "use strict";
 const EventEmitter = require("devtools/toolkit/event-emitter");
 function ObservableObject(object = {}) {
   EventEmitter.decorate(this);
   let handler = new Handler(this);
   this.object = new Proxy(object, handler);
   handler._wrappers.set(this.object, object);
   handler._paths.set(object, []);
 }
 module.exports = ObservableObject;
 function isObject(x) {
   if (typeof x === "object")
     return x !== null;
   return typeof x === "function";
 }
 function Handler(emitter) {
   this._emitter = emitter;
   this._wrappers = new WeakMap();
   this._values = new WeakMap();
   this._paths = new WeakMap();
 }
 Handler.prototype = {
   wrap: function(target, key, value) {
     let path;
     if (!isObject(value)) {
       path = this._paths.get(target).concat(key);
     } else if (this._wrappers.has(value)) {
       path = this._paths.get(value);
     } else if (this._paths.has(value)) {
       path = this._paths.get(value);
       value = this._values.get(value);
     } else {
       path = this._paths.get(target).concat(key);
       this._paths.set(value, path);
       let wrapper = new Proxy(value, this);
       this._wrappers.set(wrapper, value);
       this._values.set(value, wrapper);
       value = wrapper;
     }
     return [value, path];
   },
   unwrap: function(target, key, value) {
     if (!isObject(value) || !this._wrappers.has(value)) {
       return [value, this._paths.get(target).concat(key)];
     }
     return [this._wrappers.get(value), this._paths.get(target).concat(key)];
   },
   get: function(target, key) {
     let value = target[key];
     let [wrapped, path] = this.wrap(target, key, value);
     this._emitter.emit("get", path, value);
     return wrapped;
   },
   set: function(target, key, value) {
     let [wrapped, path] = this.unwrap(target, key, value);
     target[key] = value;
     this._emitter.emit("set", path, value);
   },
   getOwnPropertyDescriptor: function(target, key) {
     let desc = Object.getOwnPropertyDescriptor(target, key);
     if (desc) {
       if ("value" in desc) {
         let [wrapped, path] = this.wrap(target, key, desc.value);
         desc.value = wrapped;
         this._emitter.emit("get", path, desc.value);
       } else {
         if ("get" in desc) {
           [desc.get] = this.wrap(target, "get "+key, desc.get);
         }
         if ("set" in desc) {
           [desc.set] = this.wrap(target, "set "+key, desc.set);
         }
       }
     }
     return desc;
   },
   defineProperty: function(target, key, desc) {
     if ("value" in desc) {
       let [unwrapped, path] = this.unwrap(target, key, desc.value);
       desc.value = unwrapped;
       Object.defineProperty(target, key, desc);
       this._emitter.emit("set", path, desc.value);
     } else {
       if ("get" in desc) {
         [desc.get] = this.unwrap(target, "get "+key, desc.get);
       }
       if ("set" in desc) {
         [desc.set] = this.unwrap(target, "set "+key, desc.set);
       }
       Object.defineProperty(target, key, desc);
     }
   }
 };