// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_MESSAGE_SERVICE_H_
#define CHROME_BROWSER_EXTENSIONS_EXTENSION_MESSAGE_SERVICE_H_
#pragma once
#include <map>
#include <set>
#include <string>
#include "base/memory/ref_counted.h"
#include "content/common/notification_observer.h"
#include "content/common/notification_registrar.h"
#include "ipc/ipc_message.h"
class GURL;
class Profile;
class TabContents;
// This class manages message and event passing between renderer processes.
// It maintains a list of processes that are listening to events and a set of
// open channels.
//
// Messaging works this way:
// - An extension-owned script context (like a toolstrip or a content script)
// adds an event listener to the "onConnect" event.
// - Another context calls "extension.connect()" to open a channel to the
// extension process, or an extension context calls "tabs.connect(tabId)" to
// open a channel to the content scripts for the given tab. The EMS notifies
// the target process/tab, which then calls the onConnect event in every
// context owned by the connecting extension in that process/tab.
// - Once the channel is established, either side can call postMessage to send
// a message to the opposite side of the channel, which may have multiple
// listeners.
//
// Terminology:
// channel: connection between two ports
// port: an IPC::Message::Sender interface and an optional routing_id (in the
// case that the port is a tab). The Sender is usually either a
// RenderProcessHost or a RenderViewHost.
// TODO(mpcomplete): Remove refcounting and make Profile the sole owner of this
// class. Then we can get rid of ProfileDestroyed().
class ExtensionMessageService
: public base::RefCounted<ExtensionMessageService>,
public NotificationObserver {
public:
// A messaging channel. Note that the opening port can be the same as the
// receiver, if an extension toolstrip wants to talk to its tab (for example).
struct MessageChannel;
struct MessagePort;
// Javascript function name constants.
static const char kDispatchOnConnect[];
static const char kDispatchOnDisconnect[];
static const char kDispatchOnMessage[];
// Allocates a pair of port ids.
// NOTE: this can be called from any thread.
static void AllocatePortIdPair(int* port1, int* port2);
explicit ExtensionMessageService(Profile* profile);
// Notification that our owning profile is going away.
void DestroyingProfile();
// Given an extension's ID, opens a channel between the given renderer "port"
// and every listening context owned by that extension. |channel_name| is
// an optional identifier for use by extension developers.
void OpenChannelToExtension(
int source_process_id, int source_routing_id, int receiver_port_id,
const std::string& source_extension_id,
const std::string& target_extension_id,
const std::string& channel_name);
// Same as above, but opens a channel to the tab with the given ID. Messages
// are restricted to that tab, so if there are multiple tabs in that process,
// only the targeted tab will receive messages.
void OpenChannelToTab(
int source_process_id, int source_routing_id, int receiver_port_id,
int tab_id, const std::string& extension_id,
const std::string& channel_name);
// Given an extension ID, opens a channel between the given
// automation "port" or DevTools service and that extension. the
// channel will be open to the extension process hosting the
// background page and tool strip.
//
// Returns a port ID to be used for posting messages between the
// processes, or -1 if the extension doesn't exist.
int OpenSpecialChannelToExtension(
const std::string& extension_id, const std::string& channel_name,
const std::string& tab_json, IPC::Message::Sender* source);
// Given an extension ID, opens a channel between the given DevTools
// service and the content script for that extension running in the
// designated tab.
//
// Returns a port ID identifying the DevTools end of the channel, to
// be used for posting messages. May return -1 on failure, although
// the code doesn't detect whether the extension actually exists.
int OpenSpecialChannelToTab(
const std::string& extension_id, const std::string& channel_name,
TabContents* target_tab_contents, IPC::Message::Sender* source);
// Closes the message channel associated with the given port, and notifies
// the other side.
void CloseChannel(int port_id);
// Sends a message from a renderer to the given port.
void PostMessageFromRenderer(int port_id, const std::string& message);
private:
friend class base::RefCounted<ExtensionMessageService>;
friend class MockExtensionMessageService;
// A map of channel ID to its channel object.
typedef std::map<int, MessageChannel*> MessageChannelMap;
virtual ~ExtensionMessageService();
// Common among Open(Special)Channel* variants.
bool OpenChannelImpl(
IPC::Message::Sender* source,
const std::string& tab_json,
const MessagePort& receiver, int receiver_port_id,
const std::string& source_extension_id,
const std::string& target_extension_id,
const std::string& channel_name);
void CloseChannelImpl(MessageChannelMap::iterator channel_iter, int port_id,
bool notify_other_port);
// NotificationObserver interface.
virtual void Observe(NotificationType type,
const NotificationSource& source,
const NotificationDetails& details);
// An IPC sender that might be in our list of channels has closed.
void OnSenderClosed(IPC::Message::Sender* sender);
Profile* profile_;
NotificationRegistrar registrar_;
MessageChannelMap channels_;
DISALLOW_COPY_AND_ASSIGN(ExtensionMessageService);
};
#endif // CHROME_BROWSER_EXTENSIONS_EXTENSION_MESSAGE_SERVICE_H_