services/surfaceflinger/MessageQueue.h

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ANDROID_MESSAGE_QUEUE_H
#define ANDROID_MESSAGE_QUEUE_H

#include <stdint.h>
#include <errno.h>
#include <sys/types.h>

#include <utils/threads.h>
#include <utils/Timers.h>
#include <utils/Looper.h>

#include "Barrier.h"

namespace android {

// ---------------------------------------------------------------------------

class MessageBase : public MessageHandler
{
public:
    MessageBase();
    
    // return true if message has a handler
    virtual bool handler() = 0;

    // waits for the handler to be processed
    void wait() const { barrier.wait(); }

protected:
    virtual ~MessageBase();

private:
    virtual void handleMessage(const Message& message);

    mutable Barrier barrier;
};

// ---------------------------------------------------------------------------

class MessageQueue {
    sp<Looper> mLooper;
    volatile int32_t mWorkPending;

public:
    MessageQueue();
    ~MessageQueue();

    void waitMessage();
    status_t postMessage(const sp<MessageBase>& message, nsecs_t reltime=0);
    status_t invalidate();
};

// ---------------------------------------------------------------------------

}; // namespace android

#endif /* ANDROID_MESSAGE_QUEUE_H */