michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: const ContentWorker = Object.freeze({
michael@0:   // TODO: Bug 727854 Use same implementation than common JS modules,
michael@0:   // i.e. EventEmitter module
michael@0: 
michael@0:   /**
michael@0:    * Create an EventEmitter instance.
michael@0:    */
michael@0:   createEventEmitter: function createEventEmitter(emit) {
michael@0:     let listeners = Object.create(null);
michael@0:     let eventEmitter = Object.freeze({
michael@0:       emit: emit,
michael@0:       on: function on(name, callback) {
michael@0:         if (typeof callback !== "function")
michael@0:           return this;
michael@0:         if (!(name in listeners))
michael@0:           listeners[name] = [];
michael@0:         listeners[name].push(callback);
michael@0:         return this;
michael@0:       },
michael@0:       once: function once(name, callback) {
michael@0:         eventEmitter.on(name, function onceCallback() {
michael@0:           eventEmitter.removeListener(name, onceCallback);
michael@0:           callback.apply(callback, arguments);
michael@0:         });
michael@0:       },
michael@0:       removeListener: function removeListener(name, callback) {
michael@0:         if (!(name in listeners))
michael@0:           return;
michael@0:         let index = listeners[name].indexOf(callback);
michael@0:         if (index == -1)
michael@0:           return;
michael@0:         listeners[name].splice(index, 1);
michael@0:       }
michael@0:     });
michael@0:     function onEvent(name) {
michael@0:       if (!(name in listeners))
michael@0:         return [];
michael@0:       let args = Array.slice(arguments, 1);
michael@0:       let results = [];
michael@0:       for each (let callback in listeners[name]) {
michael@0:         results.push(callback.apply(null, args));
michael@0:       }
michael@0:       return results;
michael@0:     }
michael@0:     function hasListenerFor(name) {
michael@0:       if (!(name in listeners))
michael@0:         return false;
michael@0:       return listeners[name].length > 0;
michael@0:     }
michael@0:     return {
michael@0:       eventEmitter: eventEmitter,
michael@0:       emit: onEvent,
michael@0:       hasListenerFor: hasListenerFor
michael@0:     };
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Create an EventEmitter instance to communicate with chrome module
michael@0:    * by passing only strings between compartments.
michael@0:    * This function expects `emitToChrome` function, that allows to send
michael@0:    * events to the chrome module. It returns the EventEmitter as `pipe`
michael@0:    * attribute, and, `onChromeEvent` a function that allows chrome module
michael@0:    * to send event into the EventEmitter.
michael@0:    *
michael@0:    *                  pipe.emit --> emitToChrome
michael@0:    *              onChromeEvent --> callback registered through pipe.on
michael@0:    */
michael@0:   createPipe: function createPipe(emitToChrome) {
michael@0:     function onEvent(type, ...args) {
michael@0:       // JSON.stringify is buggy with cross-sandbox values,
michael@0:       // it may return "{}" on functions. Use a replacer to match them correctly.
michael@0:       let replacer = (k, v) =>
michael@0:         typeof(v) === "function"
michael@0:           ? (type === "console" ? Function.toString.call(v) : void(0))
michael@0:           : v;
michael@0: 
michael@0:       let str = JSON.stringify([type, ...args], replacer);
michael@0:       emitToChrome(str);
michael@0:     }
michael@0: 
michael@0:     let { eventEmitter, emit, hasListenerFor } =
michael@0:       ContentWorker.createEventEmitter(onEvent);
michael@0: 
michael@0:     return {
michael@0:       pipe: eventEmitter,
michael@0:       onChromeEvent: function onChromeEvent(array) {
michael@0:         // We either receive a stringified array, or a real array.
michael@0:         // We still allow to pass an array of objects, in WorkerSandbox.emitSync
michael@0:         // in order to allow sending DOM node reference between content script
michael@0:         // and modules (only used for context-menu API)
michael@0:         let args = typeof array == "string" ? JSON.parse(array) : array;
michael@0:         return emit.apply(null, args);
michael@0:       },
michael@0:       hasListenerFor: hasListenerFor
michael@0:     };
michael@0:   },
michael@0: 
michael@0:   injectConsole: function injectConsole(exports, pipe) {
michael@0:     exports.console = Object.freeze({
michael@0:       log: pipe.emit.bind(null, "console", "log"),
michael@0:       info: pipe.emit.bind(null, "console", "info"),
michael@0:       warn: pipe.emit.bind(null, "console", "warn"),
michael@0:       error: pipe.emit.bind(null, "console", "error"),
michael@0:       debug: pipe.emit.bind(null, "console", "debug"),
michael@0:       exception: pipe.emit.bind(null, "console", "exception"),
michael@0:       trace: pipe.emit.bind(null, "console", "trace"),
michael@0:       time: pipe.emit.bind(null, "console", "time"),
michael@0:       timeEnd: pipe.emit.bind(null, "console", "timeEnd")
michael@0:     });
michael@0:   },
michael@0: 
michael@0:   injectTimers: function injectTimers(exports, chromeAPI, pipe, console) {
michael@0:     // wrapped functions from `'timer'` module.
michael@0:     // Wrapper adds `try catch` blocks to the callbacks in order to
michael@0:     // emit `error` event on a symbiont if exception is thrown in
michael@0:     // the Worker global scope.
michael@0:     // @see http://www.w3.org/TR/workers/#workerutils
michael@0: 
michael@0:     // List of all living timeouts/intervals
michael@0:     let _timers = Object.create(null);
michael@0: 
michael@0:     // Keep a reference to original timeout functions
michael@0:     let {
michael@0:       setTimeout: chromeSetTimeout,
michael@0:       setInterval: chromeSetInterval,
michael@0:       clearTimeout: chromeClearTimeout,
michael@0:       clearInterval: chromeClearInterval
michael@0:     } = chromeAPI.timers;
michael@0: 
michael@0:     function registerTimer(timer) {
michael@0:       let registerMethod = null;
michael@0:       if (timer.kind == "timeout")
michael@0:         registerMethod = chromeSetTimeout;
michael@0:       else if (timer.kind == "interval")
michael@0:         registerMethod = chromeSetInterval;
michael@0:       else
michael@0:         throw new Error("Unknown timer kind: " + timer.kind);
michael@0: 
michael@0:       if (typeof timer.fun == 'string') {
michael@0:         let code = timer.fun;
michael@0:         timer.fun = () => chromeAPI.sandbox.evaluate(exports, code);
michael@0:       } else if (typeof timer.fun != 'function') {
michael@0:         throw new Error('Unsupported callback type' + typeof timer.fun);
michael@0:       }
michael@0: 
michael@0:       let id = registerMethod(onFire, timer.delay);
michael@0:       function onFire() {
michael@0:         try {
michael@0:           if (timer.kind == "timeout")
michael@0:             delete _timers[id];
michael@0:           timer.fun.apply(null, timer.args);
michael@0:         } catch(e) {
michael@0:           console.exception(e);
michael@0:           let wrapper = {
michael@0:             instanceOfError: instanceOf(e, Error),
michael@0:             value: e,
michael@0:           };
michael@0:           if (wrapper.instanceOfError) {
michael@0:             wrapper.value = {
michael@0:               message: e.message,
michael@0:               fileName: e.fileName,
michael@0:               lineNumber: e.lineNumber,
michael@0:               stack: e.stack,
michael@0:               name: e.name,
michael@0:             };
michael@0:           }
michael@0:           pipe.emit('error', wrapper);
michael@0:         }
michael@0:       }
michael@0:       _timers[id] = timer;
michael@0:       return id;
michael@0:     }
michael@0: 
michael@0:     // copied from sdk/lang/type.js since modules are not available here
michael@0:     function instanceOf(value, Type) {
michael@0:       var isConstructorNameSame;
michael@0:       var isConstructorSourceSame;
michael@0: 
michael@0:       // If `instanceof` returned `true` we know result right away.
michael@0:       var isInstanceOf = value instanceof Type;
michael@0: 
michael@0:       // If `instanceof` returned `false` we do ducktype check since `Type` may be
michael@0:       // from a different sandbox. If a constructor of the `value` or a constructor
michael@0:       // of the value's prototype has same name and source we assume that it's an
michael@0:       // instance of the Type.
michael@0:       if (!isInstanceOf && value) {
michael@0:         isConstructorNameSame = value.constructor.name === Type.name;
michael@0:         isConstructorSourceSame = String(value.constructor) == String(Type);
michael@0:         isInstanceOf = (isConstructorNameSame && isConstructorSourceSame) ||
michael@0:                         instanceOf(Object.getPrototypeOf(value), Type);
michael@0:       }
michael@0:       return isInstanceOf;
michael@0:     }
michael@0: 
michael@0:     function unregisterTimer(id) {
michael@0:       if (!(id in _timers))
michael@0:         return;
michael@0:       let { kind } = _timers[id];
michael@0:       delete _timers[id];
michael@0:       if (kind == "timeout")
michael@0:         chromeClearTimeout(id);
michael@0:       else if (kind == "interval")
michael@0:         chromeClearInterval(id);
michael@0:       else
michael@0:         throw new Error("Unknown timer kind: " + kind);
michael@0:     }
michael@0: 
michael@0:     function disableAllTimers() {
michael@0:       Object.keys(_timers).forEach(unregisterTimer);
michael@0:     }
michael@0: 
michael@0:     exports.setTimeout = function ContentScriptSetTimeout(callback, delay) {
michael@0:       return registerTimer({
michael@0:         kind: "timeout",
michael@0:         fun: callback,
michael@0:         delay: delay,
michael@0:         args: Array.slice(arguments, 2)
michael@0:       });
michael@0:     };
michael@0:     exports.clearTimeout = function ContentScriptClearTimeout(id) {
michael@0:       unregisterTimer(id);
michael@0:     };
michael@0: 
michael@0:     exports.setInterval = function ContentScriptSetInterval(callback, delay) {
michael@0:       return registerTimer({
michael@0:         kind: "interval",
michael@0:         fun: callback,
michael@0:         delay: delay,
michael@0:         args: Array.slice(arguments, 2)
michael@0:       });
michael@0:     };
michael@0:     exports.clearInterval = function ContentScriptClearInterval(id) {
michael@0:       unregisterTimer(id);
michael@0:     };
michael@0: 
michael@0:     // On page-hide, save a list of all existing timers before disabling them,
michael@0:     // in order to be able to restore them on page-show.
michael@0:     // These events are fired when the page goes in/out of bfcache.
michael@0:     // https://developer.mozilla.org/En/Working_with_BFCache
michael@0:     let frozenTimers = [];
michael@0:     pipe.on("pageshow", function onPageShow() {
michael@0:       frozenTimers.forEach(registerTimer);
michael@0:     });
michael@0:     pipe.on("pagehide", function onPageHide() {
michael@0:       frozenTimers = [];
michael@0:       for (let id in _timers)
michael@0:         frozenTimers.push(_timers[id]);
michael@0:       disableAllTimers();
michael@0:       // Some other pagehide listeners may register some timers that won't be
michael@0:       // frozen as this particular pagehide listener is called first.
michael@0:       // So freeze these timers on next cycle.
michael@0:       chromeSetTimeout(function () {
michael@0:         for (let id in _timers)
michael@0:           frozenTimers.push(_timers[id]);
michael@0:         disableAllTimers();
michael@0:       }, 0);
michael@0:     });
michael@0: 
michael@0:     // Unregister all timers when the page is destroyed
michael@0:     // (i.e. when it is removed from bfcache)
michael@0:     pipe.on("detach", function clearTimeouts() {
michael@0:       disableAllTimers();
michael@0:       _timers = {};
michael@0:       frozenTimers = [];
michael@0:     });
michael@0:   },
michael@0: 
michael@0:   injectMessageAPI: function injectMessageAPI(exports, pipe, console) {
michael@0: 
michael@0:     let { eventEmitter: port, emit : portEmit } =
michael@0:       ContentWorker.createEventEmitter(pipe.emit.bind(null, "event"));
michael@0:     pipe.on("event", portEmit);
michael@0: 
michael@0:     let self = {
michael@0:       port: port,
michael@0:       postMessage: pipe.emit.bind(null, "message"),
michael@0:       on: pipe.on.bind(null),
michael@0:       once: pipe.once.bind(null),
michael@0:       removeListener: pipe.removeListener.bind(null),
michael@0:     };
michael@0:     Object.defineProperty(exports, "self", {
michael@0:       value: self
michael@0:     });
michael@0: 
michael@0:     exports.on = function deprecatedOn() {
michael@0:       console.error("DEPRECATED: The global `on()` function in content " +
michael@0:                     "scripts is deprecated in favor of the `self.on()` " +
michael@0:                     "function, which works the same. Replace calls to `on()` " +
michael@0:                     "with calls to `self.on()`" +
michael@0:                     "For more info on `self.on`, see " +
michael@0:                     "<https://addons.mozilla.org/en-US/developers/docs/sdk/latest/dev-guide/addon-development/web-content.html>.");
michael@0:       return self.on.apply(null, arguments);
michael@0:     };
michael@0: 
michael@0:     // Deprecated use of `onMessage` from globals
michael@0:     let onMessage = null;
michael@0:     Object.defineProperty(exports, "onMessage", {
michael@0:       get: function () onMessage,
michael@0:       set: function (v) {
michael@0:         if (onMessage)
michael@0:           self.removeListener("message", onMessage);
michael@0:         console.error("DEPRECATED: The global `onMessage` function in content" +
michael@0:                       "scripts is deprecated in favor of the `self.on()` " +
michael@0:                       "function. Replace `onMessage = function (data){}` " +
michael@0:                       "definitions with calls to `self.on('message', " +
michael@0:                       "function (data){})`. " +
michael@0:                       "For more info on `self.on`, see " +
michael@0:                       "<https://addons.mozilla.org/en-US/developers/docs/sdk/latest/dev-guide/addon-development/web-content.html>.");
michael@0:         onMessage = v;
michael@0:         if (typeof onMessage == "function")
michael@0:           self.on("message", onMessage);
michael@0:       }
michael@0:     });
michael@0:   },
michael@0: 
michael@0:   injectOptions: function (exports, options) {
michael@0:     Object.defineProperty( exports.self, "options", { value: JSON.parse( options ) });
michael@0:   },
michael@0: 
michael@0:   inject: function (exports, chromeAPI, emitToChrome, options) {
michael@0:     let { pipe, onChromeEvent, hasListenerFor } =
michael@0:       ContentWorker.createPipe(emitToChrome);
michael@0: 
michael@0:     ContentWorker.injectConsole(exports, pipe);
michael@0:     ContentWorker.injectTimers(exports, chromeAPI, pipe, exports.console);
michael@0:     ContentWorker.injectMessageAPI(exports, pipe, exports.console);
michael@0:     if ( options !== undefined ) {
michael@0:       ContentWorker.injectOptions(exports, options);
michael@0:     }
michael@0: 
michael@0:     Object.freeze( exports.self );
michael@0: 
michael@0:     return {
michael@0:       emitToContent: onChromeEvent,
michael@0:       hasListenerFor: hasListenerFor
michael@0:     };
michael@0:   }
michael@0: });