// Copyright (c) 2012 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 IPC_IPC_FORWARDING_MESSAGE_FILTER_H_
#define IPC_IPC_FORWARDING_MESSAGE_FILTER_H_
#include <map>
#include <set>
#include "base/bind.h"
#include "base/callback_forward.h"
#include "base/synchronization/lock.h"
#include "base/task_runner.h"
#include "ipc/ipc_channel_proxy.h"
namespace IPC {
// This class can be used to intercept routed messages and
// deliver them to a different task runner than they would otherwise
// be sent. Messages are filtered based on type. To route these messages,
// add a MessageRouter to the handler.
//
// The user of this class implements ForwardingMessageFilter::Client,
// which will receive the intercepted messages, on the specified target thread.
class IPC_EXPORT ForwardingMessageFilter : public ChannelProxy::MessageFilter {
public:
// The handler is invoked on the thread associated with
// |target_task_runner| with messages that were intercepted by this filter.
typedef base::Callback<void(const Message&)> Handler;
// This filter will intercept |message_ids_to_filter| and post
// them to the provided |target_task_runner|, where they will be given
// to |handler|.
//
// The caller must ensure that |handler| outlives the lifetime of the filter.
ForwardingMessageFilter(
const uint32* message_ids_to_filter,
size_t num_message_ids_to_filter,
base::TaskRunner* target_task_runner);
// Define the message routes to be filtered.
void AddRoute(int routing_id, const Handler& handler);
void RemoveRoute(int routing_id);
// ChannelProxy::MessageFilter methods:
virtual bool OnMessageReceived(const Message& message) OVERRIDE;
private:
friend class ChannelProxy::MessageFilter;
virtual ~ForwardingMessageFilter();
std::set<int> message_ids_to_filter_;
// The handler_ only gets Run on the thread corresponding to
// target_task_runner_.
scoped_refptr<base::TaskRunner> target_task_runner_;
// Protects access to routes_.
base::Lock handlers_lock_;
// Indicates the routing_ids for which messages should be filtered.
std::map<int, Handler> handlers_;
DISALLOW_COPY_AND_ASSIGN(ForwardingMessageFilter);
};
} // namespace IPC
#endif // IPC_IPC_FORWARDING_MESSAGE_FILTER_H_