зеркало из https://github.com/mozilla/gecko-dev.git
829 строки
28 KiB
JavaScript
829 строки
28 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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"use strict";
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/**
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* This module provides wrappers around standard message managers to
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* simplify bidirectional communication. It currently allows a caller to
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* send a message to a single listener, and receive a reply. If there
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* are no matching listeners, or the message manager disconnects before
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* a reply is received, the caller is returned an error.
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*
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* The listener end may specify filters for the messages it wishes to
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* receive, and the sender end likewise may specify recipient tags to
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* match the filters.
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*
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* The message handler on the listener side may return its response
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* value directly, or may return a promise, the resolution or rejection
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* of which will be returned instead. The sender end likewise receives a
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* promise which resolves or rejects to the listener's response.
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*
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*
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* A basic setup works something like this:
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*
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* A content script adds a message listener to its global
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* nsIContentFrameMessageManager, with an appropriate set of filters:
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*
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* {
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* init(messageManager, window, extensionID) {
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* this.window = window;
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*
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* MessageChannel.addListener(
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* messageManager, "ContentScript:TouchContent",
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* this);
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*
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* this.messageFilterStrict = {
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* innerWindowID: getInnerWindowID(window),
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* extensionID: extensionID,
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* };
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*
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* this.messageFilterPermissive = {
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* outerWindowID: getOuterWindowID(window),
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* };
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* },
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*
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* receiveMessage({ target, messageName, sender, recipient, data }) {
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* if (messageName == "ContentScript:TouchContent") {
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* return new Promise(resolve => {
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* this.touchWindow(data.touchWith, result => {
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* resolve({ touchResult: result });
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* });
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* });
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* }
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* },
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* };
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*
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* A script in the parent process sends a message to the content process
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* via a tab message manager, including recipient tags to match its
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* filter, and an optional sender tag to identify itself:
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*
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* let data = { touchWith: "pencil" };
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* let sender = { extensionID, contextID };
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* let recipient = { innerWindowID: tab.linkedBrowser.innerWindowID, extensionID };
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*
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* MessageChannel.sendMessage(
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* tab.linkedBrowser.messageManager, "ContentScript:TouchContent",
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* data, {recipient, sender}
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* ).then(result => {
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* alert(result.touchResult);
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* });
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*
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* Since the lifetimes of message senders and receivers may not always
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* match, either side of the message channel may cancel pending
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* responses which match its sender or recipient tags.
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*
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* For the above client, this might be done from an
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* inner-window-destroyed observer, when its target scope is destroyed:
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*
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* observe(subject, topic, data) {
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* if (topic == "inner-window-destroyed") {
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* let innerWindowID = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
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*
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* MessageChannel.abortResponses({ innerWindowID });
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* }
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* },
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*
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* From the parent, it may be done when its context is being destroyed:
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*
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* onDestroy() {
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* MessageChannel.abortResponses({
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* extensionID: this.extensionID,
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* contextID: this.contextID,
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* });
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* },
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*
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*/
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this.EXPORTED_SYMBOLS = ["MessageChannel"];
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/* globals MessageChannel */
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const Ci = Components.interfaces;
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const Cc = Components.classes;
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const Cu = Components.utils;
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const Cr = Components.results;
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Cu.import("resource://gre/modules/XPCOMUtils.jsm");
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Cu.import("resource://gre/modules/Services.jsm");
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XPCOMUtils.defineLazyModuleGetter(this, "ExtensionUtils",
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"resource://gre/modules/ExtensionUtils.jsm");
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XPCOMUtils.defineLazyModuleGetter(this, "PromiseUtils",
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"resource://gre/modules/PromiseUtils.jsm");
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XPCOMUtils.defineLazyGetter(this, "MessageManagerProxy",
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() => ExtensionUtils.MessageManagerProxy);
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/**
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* Handles the mapping and dispatching of messages to their registered
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* handlers. There is one broker per message manager and class of
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* messages. Each class of messages is mapped to one native message
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* name, e.g., "MessageChannel:Message", and is dispatched to handlers
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* based on an internal message name, e.g., "Extension:ExecuteScript".
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*/
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class FilteringMessageManager {
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/**
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* @param {string} messageName
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* The name of the native message this broker listens for.
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* @param {function} callback
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* A function which is called for each message after it has been
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* mapped to its handler. The function receives two arguments:
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*
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* result:
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* An object containing either a `handler` or an `error` property.
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* If no error occurs, `handler` will be a matching handler that
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* was registered by `addHandler`. Otherwise, the `error` property
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* will contain an object describing the error.
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*
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* data:
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* An object describing the message, as defined in
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* `MessageChannel.addListener`.
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* @param {nsIMessageListenerManager} messageManager
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*/
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constructor(messageName, callback, messageManager) {
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this.messageName = messageName;
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this.callback = callback;
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this.messageManager = messageManager;
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this.messageManager.addMessageListener(this.messageName, this, true);
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this.handlers = new Map();
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}
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/**
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* Receives a message from our message manager, maps it to a handler, and
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* passes the result to our message callback.
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*/
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receiveMessage({data, target}) {
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let handlers = Array.from(this.getHandlers(data.messageName, data.sender || null, data.recipient));
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data.target = target;
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this.callback(handlers, data);
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}
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/**
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* Iterates over all handlers for the given message name. If `recipient`
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* is provided, only iterates over handlers whose filters match it.
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*
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* @param {string|number} messageName
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* The message for which to return handlers.
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* @param {object} sender
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* The sender data on which to filter handlers.
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* @param {object} recipient
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* The recipient data on which to filter handlers.
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*/
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* getHandlers(messageName, sender, recipient) {
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let handlers = this.handlers.get(messageName) || new Set();
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for (let handler of handlers) {
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if (MessageChannel.matchesFilter(handler.messageFilterStrict || {}, recipient) &&
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MessageChannel.matchesFilter(handler.messageFilterPermissive || {}, recipient, false) &&
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(!handler.filterMessage || handler.filterMessage(sender, recipient))) {
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yield handler;
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}
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}
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}
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/**
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* Registers a handler for the given message.
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*
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* @param {string} messageName
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* The internal message name for which to register the handler.
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* @param {object} handler
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* An opaque handler object. The object may have a
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* `messageFilterStrict` and/or a `messageFilterPermissive`
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* property and/or a `filterMessage` method on which to filter messages.
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*
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* Final dispatching is handled by the message callback passed to
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* the constructor.
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*/
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addHandler(messageName, handler) {
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if (!this.handlers.has(messageName)) {
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this.handlers.set(messageName, new Set());
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}
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this.handlers.get(messageName).add(handler);
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}
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/**
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* Unregisters a handler for the given message.
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*
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* @param {string} messageName
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* The internal message name for which to unregister the handler.
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* @param {object} handler
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* The handler object to unregister.
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*/
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removeHandler(messageName, handler) {
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if (this.handlers.has(messageName)) {
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this.handlers.get(messageName).delete(handler);
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}
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}
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}
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/**
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* Manages mappings of message managers to their corresponding message
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* brokers. Brokers are lazily created for each message manager the
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* first time they are accessed. In the case of content frame message
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* managers, they are also automatically destroyed when the frame
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* unload event fires.
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*/
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class FilteringMessageManagerMap extends Map {
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// Unfortunately, we can't use a WeakMap for this, because message
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// managers do not support preserved wrappers.
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/**
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* @param {string} messageName
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* The native message name passed to `FilteringMessageManager` constructors.
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* @param {function} callback
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* The message callback function passed to
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* `FilteringMessageManager` constructors.
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*/
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constructor(messageName, callback) {
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super();
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this.messageName = messageName;
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this.callback = callback;
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}
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/**
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* Returns, and possibly creates, a message broker for the given
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* message manager.
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*
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* @param {nsIMessageListenerManager} target
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* The message manager for which to return a broker.
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*
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* @returns {FilteringMessageManager}
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*/
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get(target) {
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if (this.has(target)) {
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return super.get(target);
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}
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let broker = new FilteringMessageManager(this.messageName, this.callback, target);
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this.set(target, broker);
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if (target instanceof Ci.nsIDOMEventTarget) {
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let onUnload = event => {
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target.removeEventListener("unload", onUnload);
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this.delete(target);
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};
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target.addEventListener("unload", onUnload);
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}
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return broker;
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}
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}
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const MESSAGE_MESSAGE = "MessageChannel:Message";
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const MESSAGE_RESPONSE = "MessageChannel:Response";
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this.MessageChannel = {
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init() {
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Services.obs.addObserver(this, "message-manager-close");
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Services.obs.addObserver(this, "message-manager-disconnect");
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this.messageManagers = new FilteringMessageManagerMap(
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MESSAGE_MESSAGE, this._handleMessage.bind(this));
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this.responseManagers = new FilteringMessageManagerMap(
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MESSAGE_RESPONSE, this._handleResponse.bind(this));
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/**
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* Contains a list of pending responses, either waiting to be
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* received or waiting to be sent. @see _addPendingResponse
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*/
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this.pendingResponses = new Set();
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/**
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* Contains the message name of a limited number of aborted response
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* handlers, the responses for which will be ignored.
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*/
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this.abortedResponses = new ExtensionUtils.LimitedSet(30);
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},
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RESULT_SUCCESS: 0,
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RESULT_DISCONNECTED: 1,
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RESULT_NO_HANDLER: 2,
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RESULT_MULTIPLE_HANDLERS: 3,
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RESULT_ERROR: 4,
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RESULT_NO_RESPONSE: 5,
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REASON_DISCONNECTED: {
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result: 1, // this.RESULT_DISCONNECTED
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message: "Message manager disconnected",
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},
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/**
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* Specifies that only a single listener matching the specified
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* recipient tag may be listening for the given message, at the other
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* end of the target message manager.
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*
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* If no matching listeners exist, a RESULT_NO_HANDLER error will be
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* returned. If multiple matching listeners exist, a
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* RESULT_MULTIPLE_HANDLERS error will be returned.
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*/
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RESPONSE_SINGLE: 0,
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/**
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* If multiple message managers matching the specified recipient tag
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* are listening for a message, all listeners are notified, but only
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* the first response or error is returned.
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*
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* Only handlers which return a value other than `undefined` are
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* considered to have responded. Returning a Promise which evaluates
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* to `undefined` is interpreted as an explicit response.
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*
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* If no matching listeners exist, a RESULT_NO_HANDLER error will be
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* returned. If no listeners return a response, a RESULT_NO_RESPONSE
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* error will be returned.
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*/
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RESPONSE_FIRST: 1,
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/**
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* If multiple message managers matching the specified recipient tag
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* are listening for a message, all listeners are notified, and all
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* responses are returned as an array, once all listeners have
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* replied.
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*/
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RESPONSE_ALL: 2,
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/**
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* Fire-and-forget: The sender of this message does not expect a reply.
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*/
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RESPONSE_NONE: 3,
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/**
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* Initializes message handlers for the given message managers if needed.
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*
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* @param {Array<nsIMessageListenerManager>} messageManagers
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*/
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setupMessageManagers(messageManagers) {
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for (let mm of messageManagers) {
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// This call initializes a FilteringMessageManager for |mm| if needed.
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// The FilteringMessageManager must be created to make sure that senders
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// of messages that expect a reply, such as MessageChannel:Message, do
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// actually receive a default reply even if there are no explicit message
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// handlers.
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this.messageManagers.get(mm);
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}
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},
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/**
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* Returns true if the properties of the `data` object match those in
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* the `filter` object. Matching is done on a strict equality basis,
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* and the behavior varies depending on the value of the `strict`
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* parameter.
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*
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* @param {object} filter
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* The filter object to match against.
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* @param {object} data
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* The data object being matched.
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* @param {boolean} [strict=true]
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* If true, all properties in the `filter` object have a
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* corresponding property in `data` with the same value. If
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* false, properties present in both objects must have the same
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* value.
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* @returns {boolean} True if the objects match.
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*/
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matchesFilter(filter, data, strict = true) {
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if (strict) {
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return Object.keys(filter).every(key => {
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return key in data && data[key] === filter[key];
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});
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}
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return Object.keys(filter).every(key => {
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return !(key in data) || data[key] === filter[key];
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});
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},
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/**
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* Adds a message listener to the given message manager.
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*
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* @param {nsIMessageListenerManager|Array<nsIMessageListenerManager>} targets
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* The message managers on which to listen.
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* @param {string|number} messageName
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* The name of the message to listen for.
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* @param {MessageReceiver} handler
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* The handler to dispatch to. Must be an object with the following
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* properties:
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*
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* receiveMessage:
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* A method which is called for each message received by the
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* listener. The method takes one argument, an object, with the
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* following properties:
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*
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* messageName:
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* The internal message name, as passed to `sendMessage`.
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*
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* target:
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* The message manager which received this message.
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*
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* channelId:
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* The internal ID of the transaction, used to map responses to
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* the original sender.
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*
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* sender:
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* An object describing the sender, as passed to `sendMessage`.
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*
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* recipient:
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* An object describing the recipient, as passed to
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* `sendMessage`.
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*
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* data:
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* The contents of the message, as passed to `sendMessage`.
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*
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* The method may return any structured-clone-compatible
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* object, which will be returned as a response to the message
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* sender. It may also instead return a `Promise`, the
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* resolution or rejection value of which will likewise be
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* returned to the message sender.
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*
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* messageFilterStrict:
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* An object containing arbitrary properties on which to filter
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* received messages. Messages will only be dispatched to this
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* object if the `recipient` object passed to `sendMessage`
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* matches this filter, as determined by `matchesFilter` with
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* `strict=true`.
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*
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* messageFilterPermissive:
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* An object containing arbitrary properties on which to filter
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* received messages. Messages will only be dispatched to this
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* object if the `recipient` object passed to `sendMessage`
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* matches this filter, as determined by `matchesFilter` with
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* `strict=false`.
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*
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* filterMessage:
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* An optional function that prevents the handler from handling a
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* message by returning `false`. See `getHandlers` for the parameters.
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*/
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addListener(targets, messageName, handler) {
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if (!Array.isArray(targets)) {
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targets = [targets];
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}
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for (let target of targets) {
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this.messageManagers.get(target).addHandler(messageName, handler);
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}
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},
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/**
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* Removes a message listener from the given message manager.
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*
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* @param {nsIMessageListenerManager|Array<nsIMessageListenerManager>} targets
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* The message managers on which to stop listening.
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* @param {string|number} messageName
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* The name of the message to stop listening for.
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* @param {MessageReceiver} handler
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* The handler to stop dispatching to.
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*/
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removeListener(targets, messageName, handler) {
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if (!Array.isArray(targets)) {
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targets = [targets];
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}
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for (let target of targets) {
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if (this.messageManagers.has(target)) {
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this.messageManagers.get(target).removeHandler(messageName, handler);
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}
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}
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},
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/**
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* Sends a message via the given message manager. Returns a promise which
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* resolves or rejects with the return value of the message receiver.
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*
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* The promise also rejects if there is no matching listener, or the other
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* side of the message manager disconnects before the response is received.
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*
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* @param {nsIMessageSender} target
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* The message manager on which to send the message.
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* @param {string} messageName
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* The name of the message to send, as passed to `addListener`.
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* @param {object} data
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* A structured-clone-compatible object to send to the message
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* recipient.
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* @param {object} [options]
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* An object containing any of the following properties:
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* @param {object} [options.recipient]
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* A structured-clone-compatible object to identify the message
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* recipient. The object must match the `messageFilterStrict` and
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* `messageFilterPermissive` filters defined by recipients in order
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* for the message to be received.
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* @param {object} [options.sender]
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* A structured-clone-compatible object to identify the message
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* sender. This object may also be used to avoid delivering the
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* message to the sender, and as a filter to prematurely
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* abort responses when the sender is being destroyed.
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* @see `abortResponses`.
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* @param {integer} [options.responseType=RESPONSE_SINGLE]
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* Specifies the type of response expected. See the `RESPONSE_*`
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* contents for details.
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* @returns {Promise}
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*/
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sendMessage(target, messageName, data, options = {}) {
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let sender = options.sender || {};
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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;
|
|
deferred.channelId = channelId;
|
|
|
|
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,
|
|
channelId: data.channelId,
|
|
};
|
|
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 => {
|
|
if (target.isDisconnected) {
|
|
// Target is disconnected. We can't send an error response, so
|
|
// don't even try.
|
|
if (error.result !== this.RESULT_DISCONNECTED &&
|
|
error.result !== this.RESULT_NO_RESPONSE) {
|
|
Cu.reportError(Cu.getClassName(error, false) === "Object" ? error.message : error);
|
|
}
|
|
return;
|
|
}
|
|
|
|
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) {
|
|
if (this.abortedResponses.has(data.messageName)) {
|
|
this.abortedResponses.delete(data.messageName);
|
|
Services.console.logStringMessage(`Ignoring response to aborted listener for ${data.messageName}`);
|
|
} else {
|
|
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)) {
|
|
this.abortedResponses.add(response.channelId);
|
|
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)) {
|
|
this.abortedResponses.add(response.channelId);
|
|
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();
|