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+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+interface nsIEventTarget;
+interface Principal;
+
+/**
+ * Message managers provide a way for chrome-privileged JS code to
+ * communicate with each other, even across process boundaries.
+ *
+ * Message managers are separated into "parent side" and "child side".
+ * These don't always correspond to process boundaries, but can. For
+ * each child-side message manager, there is always exactly one
+ * corresponding parent-side message manager that it sends messages
+ * to. However, for each parent-side message manager, there may be
+ * either one or many child-side managers it can message.
+ *
+ * Message managers that always have exactly one "other side" are of
+ * type MessageSender. Parent-side message managers that have many
+ * "other sides" are of type MessageBroadcaster.
+ *
+ * Child-side message managers can send synchronous messages to their
+ * parent side, but not the other way around.
+ *
+ * There are two realms of message manager hierarchies. One realm
+ * approximately corresponds to DOM elements, the other corresponds to
+ * process boundaries.
+ *
+ * Message managers corresponding to DOM elements
+ * ==============================================
+ *
+ * In this realm of message managers, there are
+ * - "frame message managers" which correspond to frame elements
+ * - "window message managers" which correspond to top-level chrome
+ * windows
+ * - "group message managers" which correspond to named message
+ * managers with a specific window MM as the parent
+ * - the "global message manager", on the parent side. See below.
+ *
+ * The DOM-realm message managers can communicate in the ways shown by
+ * the following diagram. The parent side and child side can
+ * correspond to process boundaries, but don't always.
+ *
+ * Parent side Child side
+ * ------------- ------------
+ * global MMg
+ * |
+ * +-->window MMw1
+ * | |
+ * | +-->frame MMp1_1<------------>frame MMc1_1
+ * | |
+ * | +-->frame MMp1_2<------------>frame MMc1_2
+ * | |
+ * | +-->group MMgr1
+ * | | |
+ * | | +-->frame MMp2_1<------->frame MMc2_1
+ * | | |
+ * | | +-->frame MMp2_2<------->frame MMc2_2
+ * | |
+ * | +-->group MMgr2
+ * | | ...
+ * | |
+ * | ...
+ * |
+ * +-->window MMw2
+ * ...
+ *
+ * For example: a message sent from MMc1_1, from the child side, is
+ * sent only to MMp1_1 on the parent side. However, note that all
+ * message managers in the hierarchy above MMp1_1, in this diagram
+ * MMw1 and MMg, will also notify their message listeners when the
+ * message arrives.
+ *
+ * A message sent from MMc2_1 will be sent to MMp2_1 and also notify
+ * all message managers in the hierarchy above that, including the
+ * group message manager MMgr1.
+
+ * For example: a message broadcast through the global MMg on the
+ * parent side would be broadcast to MMw1, which would transitively
+ * broadcast it to MMp1_1, MM1p_2. The message would next be
+ * broadcast to MMgr1, which would broadcast it to MMp2_1 and MMp2_2.
+ * After that it would broadcast to MMgr2 and then to MMw2, and so
+ * on down the hierarchy.
+ *
+ * ***** PERFORMANCE AND SECURITY WARNING *****
+ * Messages broadcast through the global MM and window or group MMs
+ * can result in messages being dispatched across many OS processes,
+ * and to many processes with different permissions. Great care
+ * should be taken when broadcasting.
+ *
+ * Interfaces
+ * ----------
+ *
+ * The global MMg and window MMw's are message broadcasters implementing
+ * MessageBroadcaster while the frame MMp's are simple message senders (MessageSender).
+ * Their counterparts in the content processes are message senders implementing
+ * ContentFrameMessageManager.
+ *
+ * MessageListenerManager
+ * / \
+ * MessageSender MessageBroadcaster
+ * |
+ * SyncMessageSender (content process/in-process only)
+ * |
+ * ContentFrameMessageManager (content process/in-process only)
+ * |
+ * nsIInProcessContentFrameMessageManager (in-process only)
+ *
+ *
+ * Message managers in the chrome process also implement FrameScriptLoader.
+ *
+ *
+ * Message managers corresponding to process boundaries
+ * ====================================================
+ *
+ * The second realm of message managers is the "process message
+ * managers". With one exception, these always correspond to process
+ * boundaries. The picture looks like
+ *
+ * Parent process Child processes
+ * ---------------- -----------------
+ * global (GPPMM)
+ * |
+ * +-->parent in-process PIPMM<-->child in-process CIPPMM
+ * |
+ * +-->parent (PPMM1)<------------------>child (CPMM1)
+ * |
+ * +-->parent (PPMM2)<------------------>child (CPMM2)
+ * ...
+ *
+ * Note, PIPMM and CIPPMM both run in the parent process.
+ *
+ * For example: the parent-process PPMM1 sends messages to the
+ * child-process CPMM1.
+ *
+ * For example: CPMM1 sends messages directly to PPMM1. The global GPPMM
+ * will also notify their message listeners when the message arrives.
+ *
+ * For example: messages sent through the global GPPMM will be
+ * dispatched to the listeners of the same-process, CIPPMM, CPMM1,
+ * CPMM2, etc.
+ *
+ * ***** PERFORMANCE AND SECURITY WARNING *****
+ * Messages broadcast through the GPPMM can result in messages
+ * being dispatched across many OS processes, and to many processes
+ * with different permissions. Great care should be taken when
+ * broadcasting.
+ *
+ * Requests sent to parent-process message listeners should usually
+ * have replies scoped to the requesting CPMM. The following pattern
+ * is common
+ *
+ * const ParentProcessListener = {
+ * receiveMessage: function(aMessage) {
+ * switch (aMessage.name) {
+ * case "Foo:Request":
+ * // service request
+ * aMessage.target.sendAsyncMessage("Foo:Response", { data });
+ * }
+ * }
+ * };
+ */
+
+dictionary ReceiveMessageArgument
+{
+ /**
+ * The target of the message. Either an element owning the message manager, or message
+ * manager itself if no element owns it.
+ */
+ required nsISupports target;
+
+ /**
+ * Message name.
+ */
+ required DOMString name;
+
+ required boolean sync;
+
+ /**
+ * Structured clone of the sent message data
+ */
+ any data = null;
+
+ /**
+ * Same as .data, deprecated.
+ */
+ any json = null;
+
+ sequence<MessagePort> ports;
+
+ FrameLoader targetFrameLoader;
+};
+
+[Exposed=Window]
+callback interface MessageListener
+{
+ /**
+ * Each listener is invoked with its own copy of the message
+ * parameter.
+ *
+ * When the listener is called, 'this' value is the target of the message.
+ *
+ * If the message is synchronous, the possible return value is
+ * returned as JSON (will be changed to use structured clones).
+ * When there are multiple listeners to sync messages, each
+ * listener's return value is sent back as an array. |undefined|
+ * return values show up as undefined values in the array.
+ */
+ any receiveMessage(ReceiveMessageArgument argument);
+};
+
+[ChromeOnly, Exposed=Window]
+interface MessageListenerManager
+{
+ // All the methods are pulled in via mixin.
+};
+MessageListenerManager includes MessageListenerManagerMixin;
+
+interface mixin MessageListenerManagerMixin
+{
+ /**
+ * Register |listener| to receive |messageName|. All listener
+ * callbacks for a particular message are invoked when that message
+ * is received.
+ *
+ * The message manager holds a strong ref to |listener|.
+ *
+ * If the same listener registers twice for the same message, the
+ * second registration is ignored.
+ *
+ * Pass true for listenWhenClosed if you want to receive messages
+ * during the short period after a frame has been removed from the
+ * DOM and before its frame script has finished unloading. This
+ * parameter only has an effect for frame message managers in
+ * the main process. Default is false.
+ */
+ [Throws]
+ undefined addMessageListener(DOMString messageName,
+ MessageListener listener,
+ optional boolean listenWhenClosed = false);
+
+ /**
+ * Undo an |addMessageListener| call -- that is, calling this causes us to no
+ * longer invoke |listener| when |messageName| is received.
+ *
+ * removeMessageListener does not remove a message listener added via
+ * addWeakMessageListener; use removeWeakMessageListener for that.
+ */
+ [Throws]
+ undefined removeMessageListener(DOMString messageName,
+ MessageListener listener);
+
+ /**
+ * This is just like addMessageListener, except the message manager holds a
+ * weak ref to |listener|.
+ *
+ * If you have two weak message listeners for the same message, they may be
+ * called in any order.
+ */
+ [Throws]
+ undefined addWeakMessageListener(DOMString messageName,
+ MessageListener listener);
+
+ /**
+ * This undoes an |addWeakMessageListener| call.
+ */
+ [Throws]
+ undefined removeWeakMessageListener(DOMString messageName,
+ MessageListener listener);
+};
+
+/**
+ * Message "senders" have a single "other side" to which messages are
+ * sent. For example, a child-process message manager will send
+ * messages that are only delivered to its one parent-process message
+ * manager.
+ */
+[ChromeOnly, Exposed=Window]
+interface MessageSender : MessageListenerManager
+{
+ // All the methods are pulled in via mixin.
+};
+MessageSender includes MessageSenderMixin;
+
+/**
+ * Anyone including this MUST also incude MessageListenerManagerMixin.
+ */
+interface mixin MessageSenderMixin {
+ /**
+ * Send |messageName| and |obj| to the "other side" of this message
+ * manager. This invokes listeners who registered for
+ * |messageName|.
+ *
+ * See ReceiveMessageArgument for the format of the data delivered to listeners.
+ * @throws NS_ERROR_NOT_INITIALIZED if the sender is not initialized. For
+ * example, we will throw NS_ERROR_NOT_INITIALIZED if we try to send
+ * a message to a cross-process frame but the other process has not
+ * yet been set up.
+ * @throws NS_ERROR_FAILURE when the message receiver cannot be found. For
+ * example, we will throw NS_ERROR_FAILURE if we try to send a message
+ * to a cross-process frame whose process has crashed.
+ */
+ [Throws]
+ undefined sendAsyncMessage(optional DOMString? messageName = null,
+ optional any obj,
+ optional any transfers);
+
+ /**
+ * For remote browsers there is always a corresponding process message
+ * manager. The intention of this attribute is to link leaf level frame
+ * message managers on the parent side with the corresponding process
+ * message managers (if there is one). For any other cases this property
+ * is null.
+ */
+ [Throws]
+ readonly attribute MessageSender? processMessageManager;
+
+ /**
+ * For remote browsers, this contains the remoteType of the content child.
+ * Otherwise, it is empty.
+ */
+ [Throws]
+ readonly attribute UTF8String remoteType;
+};
+
+[ChromeOnly, Exposed=Window]
+interface SyncMessageSender : MessageSender
+{
+ // All the methods are pulled in via mixin.
+};
+SyncMessageSender includes SyncMessageSenderMixin;
+
+/**
+ * Anyone including this MUST also incude MessageSenderMixin.
+ */
+interface mixin SyncMessageSenderMixin
+{
+ /**
+ * Like |sendAsyncMessage()|, except blocks the sender until all
+ * listeners of the message have been invoked. Returns an array
+ * containing return values from each listener invoked.
+ */
+ [Throws]
+ sequence<any> sendSyncMessage(optional DOMString? messageName = null,
+ optional any obj);
+};
+
+/**
+ * ChildProcessMessageManager is used in a child process to communicate with the parent
+ * process.
+ */
+[ChromeOnly, Exposed=Window]
+interface ChildProcessMessageManager : SyncMessageSender
+{
+};
+
+/**
+ * Mixin for message manager globals. Anyone including this MUST also
+ * include SyncMessageSenderMixin.
+ */
+interface mixin MessageManagerGlobal
+{
+ /**
+ * Print a string to stdout.
+ */
+ undefined dump(DOMString str);
+
+ /**
+ * Ascii base64 data to binary data and vice versa
+ */
+ [Throws]
+ DOMString atob(DOMString asciiString);
+ [Throws]
+ DOMString btoa(DOMString base64Data);
+};
+
+interface mixin FrameScriptLoader
+{
+ /**
+ * Load a script in the (remote) frame. |url| must be the absolute URL.
+ * data: URLs are also supported. For example data:,dump("foo\n");
+ * If allowDelayedLoad is true, script will be loaded when the
+ * remote frame becomes available. Otherwise the script will be loaded
+ * only if the frame is already available.
+ */
+ [Throws]
+ undefined loadFrameScript(DOMString url, boolean allowDelayedLoad,
+ optional boolean runInGlobalScope = false);
+
+ /**
+ * Removes |url| from the list of scripts which support delayed load.
+ */
+ undefined removeDelayedFrameScript(DOMString url);
+
+ /**
+ * Returns all delayed scripts that will be loaded once a (remote)
+ * frame becomes available. The return value is a list of pairs
+ * [<URL>, <WasLoadedInGlobalScope>].
+ */
+ [Throws]
+ sequence<sequence<any>> getDelayedFrameScripts();
+};
+
+interface mixin ProcessScriptLoader
+{
+ /**
+ * Load a script in the (possibly remote) process. |url| must be the absolute
+ * URL. data: URLs are also supported. For example data:,dump("foo\n");
+ * If allowDelayedLoad is true, script will be loaded when the
+ * remote frame becomes available. Otherwise the script will be loaded
+ * only if the frame is already available.
+ */
+ [Throws]
+ undefined loadProcessScript(DOMString url, boolean allowDelayedLoad);
+
+ /**
+ * Removes |url| from the list of scripts which support delayed load.
+ */
+ undefined removeDelayedProcessScript(DOMString url);
+
+ /**
+ * Returns all delayed scripts that will be loaded once a (remote)
+ * frame becomes available. The return value is a list of pairs
+ * [<URL>, <WasLoadedInGlobalScope>].
+ */
+ [Throws]
+ sequence<sequence<any>> getDelayedProcessScripts();
+};
+
+/**
+ * Anyone including GlobalProcessScriptLoader MUST also include ProcessScriptLoader.
+ */
+interface mixin GlobalProcessScriptLoader
+{
+ /**
+ * Allows the parent process to set the initial process data for
+ * new, not-yet-created child processes. This attribute should only
+ * be used by the global parent process message manager. When a new
+ * process is created, it gets a copy of this data (via structured
+ * cloning). It can access the data via the initialProcessData
+ * attribute of its childprocessmessagemanager.
+ *
+ * This value will always be a JS object if it's not null or undefined. Different
+ * users are expected to set properties on this object. The property name should be
+ * unique enough that other Gecko consumers won't accidentally choose it.
+ */
+ [Throws]
+ readonly attribute any initialProcessData;
+
+ readonly attribute MozWritableSharedMap sharedData;
+};
+
+[ChromeOnly, Exposed=Window]
+interface ContentFrameMessageManager : EventTarget
+{
+ /**
+ * The current top level window in the frame or null.
+ */
+ [Throws]
+ readonly attribute WindowProxy? content;
+
+ /**
+ * The top level docshell or null.
+ */
+ [Throws]
+ readonly attribute nsIDocShell? docShell;
+
+ /**
+ * Returns the SchedulerEventTarget corresponding to the TabGroup
+ * for this frame.
+ */
+ readonly attribute nsIEventTarget? tabEventTarget;
+
+};
+ContentFrameMessageManager includes MessageManagerGlobal;
+ContentFrameMessageManager includes SyncMessageSenderMixin;
+ContentFrameMessageManager includes MessageSenderMixin;
+ContentFrameMessageManager includes MessageListenerManagerMixin;
+
+[ChromeOnly, Exposed=Window]
+interface ContentProcessMessageManager
+{
+ /**
+ * Read out a copy of the object that was initialized in the parent
+ * process via ProcessScriptLoader.initialProcessData.
+ */
+ [Throws]
+ readonly attribute any initialProcessData;
+
+ readonly attribute MozSharedMap? sharedData;
+};
+ContentProcessMessageManager includes MessageManagerGlobal;
+ContentProcessMessageManager includes SyncMessageSenderMixin;
+ContentProcessMessageManager includes MessageSenderMixin;
+ContentProcessMessageManager includes MessageListenerManagerMixin;
+
+/**
+ * Message "broadcasters" don't have a single "other side" that they send messages to, but
+ * rather a set of subordinate message managers. For example, broadcasting a message
+ * through a window message manager will broadcast the message to all frame message
+ * managers within its window.
+ */
+[ChromeOnly, Exposed=Window]
+interface MessageBroadcaster : MessageListenerManager
+{
+ /**
+ * Like |sendAsyncMessage()|, but also broadcasts this message to
+ * all "child" message managers of this message manager. See long
+ * comment above for details.
+ *
+ * WARNING: broadcasting messages can be very expensive and leak
+ * sensitive data. Use with extreme caution.
+ */
+ [Throws]
+ undefined broadcastAsyncMessage(optional DOMString? messageName = null,
+ optional any obj);
+
+ /**
+ * Number of subordinate message managers.
+ */
+ readonly attribute unsigned long childCount;
+
+ /**
+ * Return a single subordinate message manager.
+ */
+ MessageListenerManager? getChildAt(unsigned long aIndex);
+
+ /**
+ * Some processes are kept alive after their last tab/window are closed for testing
+ * (see dom.ipc.keepProcessesAlive). This function releases those.
+ */
+ undefined releaseCachedProcesses();
+};
+
+/**
+ * ChromeMessageBroadcaster is used for window and group message managers.
+ */
+[ChromeOnly, Exposed=Window]
+interface ChromeMessageBroadcaster : MessageBroadcaster
+{
+};
+ChromeMessageBroadcaster includes FrameScriptLoader;
+
+/**
+ * ParentProcessMessageManager is used in a parent process to communicate with all the
+ * child processes.
+ */
+[ChromeOnly, Exposed=Window]
+interface ParentProcessMessageManager : MessageBroadcaster
+{
+};
+ParentProcessMessageManager includes ProcessScriptLoader;
+ParentProcessMessageManager includes GlobalProcessScriptLoader;
+
+[ChromeOnly, Exposed=Window]
+interface ChromeMessageSender : MessageSender
+{
+};
+ChromeMessageSender includes FrameScriptLoader;
+
+/**
+ * ProcessMessageManager is used in a parent process to communicate with a child process
+ * (or with the process itself in a single-process scenario).
+ */
+[ChromeOnly, Exposed=Window]
+interface ProcessMessageManager : MessageSender
+{
+ // PID of the process being communicated with.
+ readonly attribute long osPid;
+
+ // Whether this is message manager for the current process.
+ readonly attribute boolean isInProcess;
+};
+ProcessMessageManager includes ProcessScriptLoader;