798 lines
27 KiB
JavaScript
798 lines
27 KiB
JavaScript
/* 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();
|