diff options
Diffstat (limited to 'toolkit/components/webextensions/MessageChannel.jsm')
| -rw-r--r-- | toolkit/components/webextensions/MessageChannel.jsm | 797 |
1 files changed, 0 insertions, 797 deletions
diff --git a/toolkit/components/webextensions/MessageChannel.jsm b/toolkit/components/webextensions/MessageChannel.jsm deleted file mode 100644 index c5b326405..000000000 --- a/toolkit/components/webextensions/MessageChannel.jsm +++ /dev/null @@ -1,797 +0,0 @@ -/* 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"; - -/** - * This module provides wrappers around standard message managers to - * simplify bidirectional communication. It currently allows a caller to - * send a message to a single listener, and receive a reply. If there - * are no matching listeners, or the message manager disconnects before - * a reply is received, the caller is returned an error. - * - * The listener end may specify filters for the messages it wishes to - * receive, and the sender end likewise may specify recipient tags to - * match the filters. - * - * The message handler on the listener side may return its response - * value directly, or may return a promise, the resolution or rejection - * of which will be returned instead. The sender end likewise receives a - * promise which resolves or rejects to the listener's response. - * - * - * A basic setup works something like this: - * - * A content script adds a message listener to its global - * nsIContentFrameMessageManager, with an appropriate set of filters: - * - * { - * init(messageManager, window, extensionID) { - * this.window = window; - * - * MessageChannel.addListener( - * messageManager, "ContentScript:TouchContent", - * this); - * - * this.messageFilterStrict = { - * innerWindowID: getInnerWindowID(window), - * extensionID: extensionID, - * }; - * - * this.messageFilterPermissive = { - * outerWindowID: getOuterWindowID(window), - * }; - * }, - * - * receiveMessage({ target, messageName, sender, recipient, data }) { - * if (messageName == "ContentScript:TouchContent") { - * return new Promise(resolve => { - * this.touchWindow(data.touchWith, result => { - * resolve({ touchResult: result }); - * }); - * }); - * } - * }, - * }; - * - * A script in the parent process sends a message to the content process - * via a tab message manager, including recipient tags to match its - * filter, and an optional sender tag to identify itself: - * - * let data = { touchWith: "pencil" }; - * let sender = { extensionID, contextID }; - * let recipient = { innerWindowID: tab.linkedBrowser.innerWindowID, extensionID }; - * - * MessageChannel.sendMessage( - * tab.linkedBrowser.messageManager, "ContentScript:TouchContent", - * data, {recipient, sender} - * ).then(result => { - * alert(result.touchResult); - * }); - * - * Since the lifetimes of message senders and receivers may not always - * match, either side of the message channel may cancel pending - * responses which match its sender or recipient tags. - * - * For the above client, this might be done from an - * inner-window-destroyed observer, when its target scope is destroyed: - * - * observe(subject, topic, data) { - * if (topic == "inner-window-destroyed") { - * let innerWindowID = subject.QueryInterface(Ci.nsISupportsPRUint64).data; - * - * MessageChannel.abortResponses({ innerWindowID }); - * } - * }, - * - * From the parent, it may be done when its context is being destroyed: - * - * onDestroy() { - * MessageChannel.abortResponses({ - * extensionID: this.extensionID, - * contextID: this.contextID, - * }); - * }, - * - */ - -this.EXPORTED_SYMBOLS = ["MessageChannel"]; - -/* globals MessageChannel */ - -const Ci = Components.interfaces; -const Cc = Components.classes; -const Cu = Components.utils; -const Cr = Components.results; - -Cu.import("resource://gre/modules/XPCOMUtils.jsm"); -Cu.import("resource://gre/modules/Services.jsm"); - -XPCOMUtils.defineLazyModuleGetter(this, "ExtensionUtils", - "resource://gre/modules/ExtensionUtils.jsm"); -XPCOMUtils.defineLazyModuleGetter(this, "PromiseUtils", - "resource://gre/modules/PromiseUtils.jsm"); -XPCOMUtils.defineLazyModuleGetter(this, "Task", - "resource://gre/modules/Task.jsm"); - -XPCOMUtils.defineLazyGetter(this, "MessageManagerProxy", - () => ExtensionUtils.MessageManagerProxy); - -/** - * Handles the mapping and dispatching of messages to their registered - * handlers. There is one broker per message manager and class of - * messages. Each class of messages is mapped to one native message - * name, e.g., "MessageChannel:Message", and is dispatched to handlers - * based on an internal message name, e.g., "Extension:ExecuteScript". - */ -class FilteringMessageManager { - /** - * @param {string} messageName - * The name of the native message this broker listens for. - * @param {function} callback - * A function which is called for each message after it has been - * mapped to its handler. The function receives two arguments: - * - * result: - * An object containing either a `handler` or an `error` property. - * If no error occurs, `handler` will be a matching handler that - * was registered by `addHandler`. Otherwise, the `error` property - * will contain an object describing the error. - * - * data: - * An object describing the message, as defined in - * `MessageChannel.addListener`. - * @param {nsIMessageListenerManager} messageManager - */ - constructor(messageName, callback, messageManager) { - this.messageName = messageName; - this.callback = callback; - this.messageManager = messageManager; - - this.messageManager.addMessageListener(this.messageName, this, true); - - this.handlers = new Map(); - } - - /** - * Receives a message from our message manager, maps it to a handler, and - * passes the result to our message callback. - */ - receiveMessage({data, target}) { - let handlers = Array.from(this.getHandlers(data.messageName, data.sender, data.recipient)); - - data.target = target; - this.callback(handlers, data); - } - - /** - * Iterates over all handlers for the given message name. If `recipient` - * is provided, only iterates over handlers whose filters match it. - * - * @param {string|number} messageName - * The message for which to return handlers. - * @param {object} sender - * The sender data on which to filter handlers. - * @param {object} recipient - * The recipient data on which to filter handlers. - */ - * getHandlers(messageName, sender, recipient) { - let handlers = this.handlers.get(messageName) || new Set(); - for (let handler of handlers) { - if (MessageChannel.matchesFilter(handler.messageFilterStrict || {}, recipient) && - MessageChannel.matchesFilter(handler.messageFilterPermissive || {}, recipient, false) && - (!handler.filterMessage || handler.filterMessage(sender, recipient))) { - yield handler; - } - } - } - - /** - * Registers a handler for the given message. - * - * @param {string} messageName - * The internal message name for which to register the handler. - * @param {object} handler - * An opaque handler object. The object may have a - * `messageFilterStrict` and/or a `messageFilterPermissive` - * property and/or a `filterMessage` method on which to filter messages. - * - * Final dispatching is handled by the message callback passed to - * the constructor. - */ - addHandler(messageName, handler) { - if (!this.handlers.has(messageName)) { - this.handlers.set(messageName, new Set()); - } - - this.handlers.get(messageName).add(handler); - } - - /** - * Unregisters a handler for the given message. - * - * @param {string} messageName - * The internal message name for which to unregister the handler. - * @param {object} handler - * The handler object to unregister. - */ - removeHandler(messageName, handler) { - this.handlers.get(messageName).delete(handler); - } -} - -/** - * Manages mappings of message managers to their corresponding message - * brokers. Brokers are lazily created for each message manager the - * first time they are accessed. In the case of content frame message - * managers, they are also automatically destroyed when the frame - * unload event fires. - */ -class FilteringMessageManagerMap extends Map { - // Unfortunately, we can't use a WeakMap for this, because message - // managers do not support preserved wrappers. - - /** - * @param {string} messageName - * The native message name passed to `FilteringMessageManager` constructors. - * @param {function} callback - * The message callback function passed to - * `FilteringMessageManager` constructors. - */ - constructor(messageName, callback) { - super(); - - this.messageName = messageName; - this.callback = callback; - } - - /** - * Returns, and possibly creates, a message broker for the given - * message manager. - * - * @param {nsIMessageListenerManager} target - * The message manager for which to return a broker. - * - * @returns {FilteringMessageManager} - */ - get(target) { - if (this.has(target)) { - return super.get(target); - } - - let broker = new FilteringMessageManager(this.messageName, this.callback, target); - this.set(target, broker); - - if (target instanceof Ci.nsIDOMEventTarget) { - let onUnload = event => { - target.removeEventListener("unload", onUnload); - this.delete(target); - }; - target.addEventListener("unload", onUnload); - } - - return broker; - } -} - -const MESSAGE_MESSAGE = "MessageChannel:Message"; -const MESSAGE_RESPONSE = "MessageChannel:Response"; - -this.MessageChannel = { - init() { - Services.obs.addObserver(this, "message-manager-close", false); - Services.obs.addObserver(this, "message-manager-disconnect", false); - - this.messageManagers = new FilteringMessageManagerMap( - MESSAGE_MESSAGE, this._handleMessage.bind(this)); - - this.responseManagers = new FilteringMessageManagerMap( - MESSAGE_RESPONSE, this._handleResponse.bind(this)); - - /** - * Contains a list of pending responses, either waiting to be - * received or waiting to be sent. @see _addPendingResponse - */ - this.pendingResponses = new Set(); - }, - - RESULT_SUCCESS: 0, - RESULT_DISCONNECTED: 1, - RESULT_NO_HANDLER: 2, - RESULT_MULTIPLE_HANDLERS: 3, - RESULT_ERROR: 4, - RESULT_NO_RESPONSE: 5, - - REASON_DISCONNECTED: { - result: this.RESULT_DISCONNECTED, - message: "Message manager disconnected", - }, - - /** - * Specifies that only a single listener matching the specified - * recipient tag may be listening for the given message, at the other - * end of the target message manager. - * - * If no matching listeners exist, a RESULT_NO_HANDLER error will be - * returned. If multiple matching listeners exist, a - * RESULT_MULTIPLE_HANDLERS error will be returned. - */ - RESPONSE_SINGLE: 0, - - /** - * If multiple message managers matching the specified recipient tag - * are listening for a message, all listeners are notified, but only - * the first response or error is returned. - * - * Only handlers which return a value other than `undefined` are - * considered to have responded. Returning a Promise which evaluates - * to `undefined` is interpreted as an explicit response. - * - * If no matching listeners exist, a RESULT_NO_HANDLER error will be - * returned. If no listeners return a response, a RESULT_NO_RESPONSE - * error will be returned. - */ - RESPONSE_FIRST: 1, - - /** - * If multiple message managers matching the specified recipient tag - * are listening for a message, all listeners are notified, and all - * responses are returned as an array, once all listeners have - * replied. - */ - RESPONSE_ALL: 2, - - /** - * Fire-and-forget: The sender of this message does not expect a reply. - */ - RESPONSE_NONE: 3, - - /** - * Initializes message handlers for the given message managers if needed. - * - * @param {Array<nsIMessageListenerManager>} messageManagers - */ - setupMessageManagers(messageManagers) { - for (let mm of messageManagers) { - // This call initializes a FilteringMessageManager for |mm| if needed. - // The FilteringMessageManager must be created to make sure that senders - // of messages that expect a reply, such as MessageChannel:Message, do - // actually receive a default reply even if there are no explicit message - // handlers. - this.messageManagers.get(mm); - } - }, - - /** - * Returns true if the properties of the `data` object match those in - * the `filter` object. Matching is done on a strict equality basis, - * and the behavior varies depending on the value of the `strict` - * parameter. - * - * @param {object} filter - * The filter object to match against. - * @param {object} data - * The data object being matched. - * @param {boolean} [strict=false] - * If true, all properties in the `filter` object have a - * corresponding property in `data` with the same value. If - * false, properties present in both objects must have the same - * value. - * @returns {boolean} True if the objects match. - */ - matchesFilter(filter, data, strict = true) { - if (strict) { - return Object.keys(filter).every(key => { - return key in data && data[key] === filter[key]; - }); - } - return Object.keys(filter).every(key => { - return !(key in data) || data[key] === filter[key]; - }); - }, - - /** - * Adds a message listener to the given message manager. - * - * @param {nsIMessageListenerManager|Array<nsIMessageListenerManager>} targets - * The message managers on which to listen. - * @param {string|number} messageName - * The name of the message to listen for. - * @param {MessageReceiver} handler - * The handler to dispatch to. Must be an object with the following - * properties: - * - * receiveMessage: - * A method which is called for each message received by the - * listener. The method takes one argument, an object, with the - * following properties: - * - * messageName: - * The internal message name, as passed to `sendMessage`. - * - * target: - * The message manager which received this message. - * - * channelId: - * The internal ID of the transaction, used to map responses to - * the original sender. - * - * sender: - * An object describing the sender, as passed to `sendMessage`. - * - * recipient: - * An object describing the recipient, as passed to - * `sendMessage`. - * - * data: - * The contents of the message, as passed to `sendMessage`. - * - * The method may return any structured-clone-compatible - * object, which will be returned as a response to the message - * sender. It may also instead return a `Promise`, the - * resolution or rejection value of which will likewise be - * returned to the message sender. - * - * messageFilterStrict: - * An object containing arbitrary properties on which to filter - * received messages. Messages will only be dispatched to this - * object if the `recipient` object passed to `sendMessage` - * matches this filter, as determined by `matchesFilter` with - * `strict=true`. - * - * messageFilterPermissive: - * An object containing arbitrary properties on which to filter - * received messages. Messages will only be dispatched to this - * object if the `recipient` object passed to `sendMessage` - * matches this filter, as determined by `matchesFilter` with - * `strict=false`. - * - * filterMessage: - * An optional function that prevents the handler from handling a - * message by returning `false`. See `getHandlers` for the parameters. - */ - addListener(targets, messageName, handler) { - for (let target of [].concat(targets)) { - this.messageManagers.get(target).addHandler(messageName, handler); - } - }, - - /** - * Removes a message listener from the given message manager. - * - * @param {nsIMessageListenerManager|Array<nsIMessageListenerManager>} targets - * The message managers on which to stop listening. - * @param {string|number} messageName - * The name of the message to stop listening for. - * @param {MessageReceiver} handler - * The handler to stop dispatching to. - */ - removeListener(targets, messageName, handler) { - for (let target of [].concat(targets)) { - if (this.messageManagers.has(target)) { - this.messageManagers.get(target).removeHandler(messageName, handler); - } - } - }, - - /** - * Sends a message via the given message manager. Returns a promise which - * resolves or rejects with the return value of the message receiver. - * - * The promise also rejects if there is no matching listener, or the other - * side of the message manager disconnects before the response is received. - * - * @param {nsIMessageSender} target - * The message manager on which to send the message. - * @param {string} messageName - * The name of the message to send, as passed to `addListener`. - * @param {object} data - * A structured-clone-compatible object to send to the message - * recipient. - * @param {object} [options] - * An object containing any of the following properties: - * @param {object} [options.recipient] - * A structured-clone-compatible object to identify the message - * recipient. The object must match the `messageFilterStrict` and - * `messageFilterPermissive` filters defined by recipients in order - * for the message to be received. - * @param {object} [options.sender] - * A structured-clone-compatible object to identify the message - * sender. This object may also be used to avoid delivering the - * message to the sender, and as a filter to prematurely - * abort responses when the sender is being destroyed. - * @see `abortResponses`. - * @param {integer} [options.responseType=RESPONSE_SINGLE] - * Specifies the type of response expected. See the `RESPONSE_*` - * contents for details. - * @returns {Promise} - */ - sendMessage(target, messageName, data, options = {}) { - let sender = options.sender || {}; - let recipient = options.recipient || {}; - let responseType = options.responseType || this.RESPONSE_SINGLE; - - let channelId = ExtensionUtils.getUniqueId(); - let message = {messageName, channelId, sender, recipient, data, responseType}; - - if (responseType == this.RESPONSE_NONE) { - try { - target.sendAsyncMessage(MESSAGE_MESSAGE, message); - } catch (e) { - // Caller is not expecting a reply, so dump the error to the console. - Cu.reportError(e); - return Promise.reject(e); - } - return Promise.resolve(); // Not expecting any reply. - } - - let deferred = PromiseUtils.defer(); - deferred.sender = recipient; - deferred.messageManager = target; - - this._addPendingResponse(deferred); - - // The channel ID is used as the message name when routing responses. - // Add a message listener to the response broker, and remove it once - // we've gotten (or canceled) a response. - let broker = this.responseManagers.get(target); - broker.addHandler(channelId, deferred); - - let cleanup = () => { - broker.removeHandler(channelId, deferred); - }; - deferred.promise.then(cleanup, cleanup); - - try { - target.sendAsyncMessage(MESSAGE_MESSAGE, message); - } catch (e) { - deferred.reject(e); - } - return deferred.promise; - }, - - _callHandlers(handlers, data) { - let responseType = data.responseType; - - // At least one handler is required for all response types but - // RESPONSE_ALL. - if (handlers.length == 0 && responseType != this.RESPONSE_ALL) { - return Promise.reject({result: MessageChannel.RESULT_NO_HANDLER, - message: "No matching message handler"}); - } - - if (responseType == this.RESPONSE_SINGLE) { - if (handlers.length > 1) { - return Promise.reject({result: MessageChannel.RESULT_MULTIPLE_HANDLERS, - message: `Multiple matching handlers for ${data.messageName}`}); - } - - // Note: We use `new Promise` rather than `Promise.resolve` here - // so that errors from the handler are trapped and converted into - // rejected promises. - return new Promise(resolve => { - resolve(handlers[0].receiveMessage(data)); - }); - } - - let responses = handlers.map(handler => { - try { - return handler.receiveMessage(data); - } catch (e) { - return Promise.reject(e); - } - }); - responses = responses.filter(response => response !== undefined); - - switch (responseType) { - case this.RESPONSE_FIRST: - if (responses.length == 0) { - return Promise.reject({result: MessageChannel.RESULT_NO_RESPONSE, - message: "No handler returned a response"}); - } - - return Promise.race(responses); - - case this.RESPONSE_ALL: - return Promise.all(responses); - } - return Promise.reject({message: "Invalid response type"}); - }, - - /** - * Handles dispatching message callbacks from the message brokers to their - * appropriate `MessageReceivers`, and routing the responses back to the - * original senders. - * - * Each handler object is a `MessageReceiver` object as passed to - * `addListener`. - * - * @param {Array<MessageHandler>} handlers - * @param {object} data - * @param {nsIMessageSender|{messageManager:nsIMessageSender}} data.target - */ - _handleMessage(handlers, data) { - if (data.responseType == this.RESPONSE_NONE) { - handlers.forEach(handler => { - // The sender expects no reply, so dump any errors to the console. - new Promise(resolve => { - resolve(handler.receiveMessage(data)); - }).catch(e => { - Cu.reportError(e.stack ? `${e}\n${e.stack}` : e.message || e); - }); - }); - // Note: Unhandled messages are silently dropped. - return; - } - - let target = new MessageManagerProxy(data.target); - - let deferred = { - sender: data.sender, - messageManager: target, - }; - deferred.promise = new Promise((resolve, reject) => { - deferred.reject = reject; - - this._callHandlers(handlers, data).then(resolve, reject); - }).then( - value => { - let response = { - result: this.RESULT_SUCCESS, - messageName: data.channelId, - recipient: {}, - value, - }; - - target.sendAsyncMessage(MESSAGE_RESPONSE, response); - }, - error => { - let response = { - result: this.RESULT_ERROR, - messageName: data.channelId, - recipient: {}, - error: {}, - }; - - if (error && typeof(error) == "object") { - if (error.result) { - response.result = error.result; - } - // Error objects are not structured-clonable, so just copy - // over the important properties. - for (let key of ["fileName", "filename", "lineNumber", - "columnNumber", "message", "stack", "result"]) { - if (key in error) { - response.error[key] = error[key]; - } - } - } - - target.sendAsyncMessage(MESSAGE_RESPONSE, response); - }).catch(e => { - Cu.reportError(e); - }).then(() => { - target.dispose(); - }); - - this._addPendingResponse(deferred); - }, - - /** - * Handles message callbacks from the response brokers. - * - * Each handler object is a deferred object created by `sendMessage`, and - * should be resolved or rejected based on the contents of the response. - * - * @param {Array<MessageHandler>} handlers - * @param {object} data - * @param {nsIMessageSender|{messageManager:nsIMessageSender}} data.target - */ - _handleResponse(handlers, data) { - // If we have an error at this point, we have handler to report it to, - // so just log it. - if (handlers.length == 0) { - Cu.reportError(`No matching message response handler for ${data.messageName}`); - } else if (handlers.length > 1) { - Cu.reportError(`Multiple matching response handlers for ${data.messageName}`); - } else if (data.result === this.RESULT_SUCCESS) { - handlers[0].resolve(data.value); - } else { - handlers[0].reject(data.error); - } - }, - - /** - * Adds a pending response to the the `pendingResponses` list. - * - * The response object must be a deferred promise with the following - * properties: - * - * promise: - * The promise object which resolves or rejects when the response - * is no longer pending. - * - * reject: - * A function which, when called, causes the `promise` object to be - * rejected. - * - * sender: - * A sender object, as passed to `sendMessage. - * - * messageManager: - * The message manager the response will be sent or received on. - * - * When the promise resolves or rejects, it will be removed from the - * list. - * - * These values are used to clear pending responses when execution - * contexts are destroyed. - * - * @param {Deferred} deferred - */ - _addPendingResponse(deferred) { - let cleanup = () => { - this.pendingResponses.delete(deferred); - }; - this.pendingResponses.add(deferred); - deferred.promise.then(cleanup, cleanup); - }, - - /** - * Aborts any pending message responses to senders matching the given - * filter. - * - * @param {object} sender - * The object on which to filter senders, as determined by - * `matchesFilter`. - * @param {object} [reason] - * An optional object describing the reason the response was aborted. - * Will be passed to the promise rejection handler of all aborted - * responses. - */ - abortResponses(sender, reason = this.REASON_DISCONNECTED) { - for (let response of this.pendingResponses) { - if (this.matchesFilter(sender, response.sender)) { - response.reject(reason); - } - } - }, - - /** - * Aborts any pending message responses to the broker for the given - * message manager. - * - * @param {nsIMessageListenerManager} target - * The message manager for which to abort brokers. - * @param {object} reason - * An object describing the reason the responses were aborted. - * Will be passed to the promise rejection handler of all aborted - * responses. - */ - abortMessageManager(target, reason) { - for (let response of this.pendingResponses) { - if (MessageManagerProxy.matches(response.messageManager, target)) { - response.reject(reason); - } - } - }, - - observe(subject, topic, data) { - switch (topic) { - case "message-manager-close": - case "message-manager-disconnect": - try { - if (this.responseManagers.has(subject)) { - this.abortMessageManager(subject, this.REASON_DISCONNECTED); - } - } finally { - this.responseManagers.delete(subject); - this.messageManagers.delete(subject); - } - break; - } - }, -}; - -MessageChannel.init(); |