gecko-dev/dom/messages/SystemMessageManager.js

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/* 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";
const Cc = Components.classes;
const Ci = Components.interfaces;
const Cu = Components.utils;
const Cr = Components.results;
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/DOMRequestHelper.jsm");
Cu.import("resource://gre/modules/Services.jsm");
const kSystemMessageInternalReady = "system-message-internal-ready";
XPCOMUtils.defineLazyServiceGetter(this, "cpmm",
"@mozilla.org/childprocessmessagemanager;1",
"nsISyncMessageSender");
function debug(aMsg) {
// dump("-- SystemMessageManager " + Date.now() + " : " + aMsg + "\n");
}
// Implementation of the DOM API for system messages
function SystemMessageManager() {
// If we have a system message handler registered for messages of type
// |type|, this._dispatchers[type] equals {handler, messages, isHandling},
// where
// - |handler| is the message handler that the page registered,
// - |messages| is a list of messages which we've received while
// dispatching messages to the handler, but haven't yet sent, and
// - |isHandling| indicates whether we're currently dispatching messages
// to this handler.
this._dispatchers = {};
// Pending messages for this page, keyed by message type.
this._pendings = {};
// Flag to specify if this process has already registered manifest.
this._registerManifestReady = false;
// Flag to determine this process is a parent or child process.
let appInfo = Cc["@mozilla.org/xre/app-info;1"];
this._isParentProcess =
!appInfo || appInfo.getService(Ci.nsIXULRuntime)
.processType == Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT;
// An oberver to listen to whether the |SystemMessageInternal| is ready.
if (this._isParentProcess) {
Services.obs.addObserver(this, kSystemMessageInternalReady, false);
}
}
SystemMessageManager.prototype = {
__proto__: DOMRequestIpcHelper.prototype,
_dispatchMessage: function sysMessMgr_dispatchMessage(aType, aDispatcher, aMessage) {
if (aDispatcher.isHandling) {
// Queue up the incomming message if we're currently dispatching a
// message; we'll send the message once we finish with the current one.
//
// _dispatchMethod is reentrant because a page can spin up a nested
// event loop from within a system message handler (e.g. via alert()),
// and we can then try to send the page another message while it's
// inside this nested event loop.
aDispatcher.messages.push(aMessage);
return;
}
aDispatcher.isHandling = true;
// We get a json blob, but in some cases we want another kind of object
// to be dispatched.
// To do so, we check if we have a with a contract ID of
// "@mozilla.org/dom/system-messages/wrapper/TYPE;1" component implementing
// nsISystemMessageWrapper.
debug("Dispatching " + JSON.stringify(aMessage) + "\n");
let contractID = "@mozilla.org/dom/system-messages/wrapper/" + aType + ";1";
let wrapped = false;
if (contractID in Cc) {
debug(contractID + " is registered, creating an instance");
let wrapper = Cc[contractID].createInstance(Ci.nsISystemMessagesWrapper);
if (wrapper) {
aMessage = wrapper.wrapMessage(aMessage, this._window);
wrapped = true;
debug("wrapped = " + aMessage);
}
}
aDispatcher.handler
.handleMessage(wrapped ? aMessage
: Cu.cloneInto(aMessage, this._window));
// We need to notify the parent one of the system messages has been handled,
// so the parent can release the CPU wake lock it took on our behalf.
cpmm.sendAsyncMessage("SystemMessageManager:HandleMessagesDone",
{ type: aType,
manifest: this._manifest,
uri: this._uri,
handledCount: 1 });
aDispatcher.isHandling = false;
if (aDispatcher.messages.length > 0) {
this._dispatchMessage(aType, aDispatcher, aDispatcher.messages.shift());
}
},
mozSetMessageHandler: function sysMessMgr_setMessageHandler(aType, aHandler) {
debug("set message handler for [" + aType + "] " + aHandler);
if (this._isInBrowserElement) {
debug("the app loaded in the browser cannot set message handler");
// Don't throw there, but ignore the registration.
return;
}
if (!aType) {
// Just bail out if we have no type.
return;
}
let dispatchers = this._dispatchers;
if (!aHandler) {
// Setting the dispatcher to null means we don't want to handle messages
// for this type anymore.
delete dispatchers[aType];
return;
}
// Last registered handler wins.
dispatchers[aType] = { handler: aHandler, messages: [], isHandling: false };
// Ask for the list of currently pending messages.
cpmm.sendAsyncMessage("SystemMessageManager:GetPendingMessages",
{ type: aType,
uri: this._uri,
manifest: this._manifest });
},
mozHasPendingMessage: function sysMessMgr_hasPendingMessage(aType) {
debug("asking pending message for [" + aType + "]");
if (this._isInBrowserElement) {
debug("the app loaded in the browser cannot ask pending message");
// Don't throw there, but pretend to have no messages available.
return false;
}
// If we have a handler for this type, we can't have any pending message.
if (aType in this._dispatchers) {
return false;
}
return cpmm.sendSyncMessage("SystemMessageManager:HasPendingMessages",
{ type: aType,
uri: this._uri,
manifest: this._manifest })[0];
},
uninit: function sysMessMgr_uninit() {
this._dispatchers = null;
this._pendings = null;
if (this._isParentProcess) {
Services.obs.removeObserver(this, kSystemMessageInternalReady);
}
if (this._isInBrowserElement) {
debug("the app loaded in the browser doesn't need to unregister " +
"the manifest for listening to the system messages");
return;
}
cpmm.sendAsyncMessage("SystemMessageManager:Unregister",
{ manifest: this._manifest,
uri: this._uri,
innerWindowID: this.innerWindowID });
},
// Possible messages:
//
// - SystemMessageManager:Message
// This one will only be received when the child process is alive when
// the message is initially sent.
//
// - SystemMessageManager:GetPendingMessages:Return
// This one will be received when the starting child process wants to
// retrieve the pending system messages from the parent (i.e. after
// sending SystemMessageManager:GetPendingMessages).
receiveMessage: function sysMessMgr_receiveMessage(aMessage) {
let msg = aMessage.data;
debug("receiveMessage " + aMessage.name + " for [" + msg.type + "] " +
"with manifest = " + msg.manifest + " and uri = " + msg.uri);
// Multiple windows can share the same target (process), the content
// window needs to check if the manifest/page URL is matched. Only
// *one* window should handle the system message.
if (msg.manifest !== this._manifest || msg.uri !== this._uri) {
debug("This page shouldn't handle the messages because its " +
"manifest = " + this._manifest + " and uri = " + this._uri);
return;
}
if (aMessage.name == "SystemMessageManager:Message") {
// Send an acknowledgement to parent to clean up the pending message,
// so a re-launched app won't handle it again, which is redundant.
cpmm.sendAsyncMessage("SystemMessageManager:Message:Return:OK",
{ type: msg.type,
manifest: this._manifest,
uri: this._uri,
msgID: msg.msgID });
}
let messages = (aMessage.name == "SystemMessageManager:Message")
? [msg.msg]
: msg.msgQueue;
// We only dispatch messages when a handler is registered.
let dispatcher = this._dispatchers[msg.type];
if (dispatcher) {
messages.forEach(function(aMsg) {
this._dispatchMessage(msg.type, dispatcher, aMsg);
}, this);
} else {
// We need to notify the parent that all the queued system messages have
// been handled (notice |handledCount: messages.length|), so the parent
// can release the CPU wake lock it took on our behalf.
cpmm.sendAsyncMessage("SystemMessageManager:HandleMessagesDone",
{ type: msg.type,
manifest: this._manifest,
uri: this._uri,
handledCount: messages.length });
}
if (!dispatcher || !dispatcher.isHandling) {
// TODO: Bug 874353 - Remove SystemMessageHandledListener in ContentParent
Services.obs.notifyObservers(/* aSubject */ null,
"handle-system-messages-done",
/* aData */ null);
}
},
// nsIDOMGlobalPropertyInitializer implementation.
init: function sysMessMgr_init(aWindow) {
debug("init");
this.initDOMRequestHelper(aWindow, ["SystemMessageManager:Message",
"SystemMessageManager:GetPendingMessages:Return"]);
let principal = aWindow.document.nodePrincipal;
this._isInBrowserElement = principal.isInBrowserElement;
this._uri = principal.URI.spec;
let appsService = Cc["@mozilla.org/AppsService;1"]
.getService(Ci.nsIAppsService);
this._manifest = appsService.getManifestURLByLocalId(principal.appId);
// Two cases are valid to register the manifest for the current process:
// 1. This is asked by a child process (parent process must be ready).
// 2. Parent process has already constructed the |SystemMessageInternal|.
// Otherwise, delay to do it when the |SystemMessageInternal| is ready.
let readyToRegister = true;
if (this._isParentProcess) {
let ready = cpmm.sendSyncMessage(
"SystemMessageManager:AskReadyToRegister", null);
if (ready.length == 0 || !ready[0]) {
readyToRegister = false;
}
}
if (readyToRegister) {
this._registerManifest();
}
debug("done");
},
observe: function sysMessMgr_observe(aSubject, aTopic, aData) {
if (aTopic === kSystemMessageInternalReady) {
this._registerManifest();
}
// Call the DOMRequestIpcHelper.observe method.
this.__proto__.__proto__.observe.call(this, aSubject, aTopic, aData);
},
_registerManifest: function sysMessMgr_registerManifest() {
if (this._isInBrowserElement) {
debug("the app loaded in the browser doesn't need to register " +
"the manifest for listening to the system messages");
return;
}
if (!this._registerManifestReady) {
cpmm.sendAsyncMessage("SystemMessageManager:Register",
{ manifest: this._manifest,
uri: this._uri,
innerWindowID: this.innerWindowID });
this._registerManifestReady = true;
}
},
classID: Components.ID("{bc076ea0-609b-4d8f-83d7-5af7cbdc3bb2}"),
QueryInterface: XPCOMUtils.generateQI([Ci.nsIDOMNavigatorSystemMessages,
Ci.nsIDOMGlobalPropertyInitializer,
Ci.nsIObserver,
Ci.nsISupportsWeakReference]),
classInfo: XPCOMUtils.generateCI({
classID: Components.ID("{bc076ea0-609b-4d8f-83d7-5af7cbdc3bb2}"),
contractID: "@mozilla.org/system-message-manager;1",
interfaces: [Ci.nsIDOMNavigatorSystemMessages],
flags: Ci.nsIClassInfo.DOM_OBJECT,
classDescription: "System Messages"})
}
this.NSGetFactory = XPCOMUtils.generateNSGetFactory([SystemMessageManager]);