services/surfaceflinger/EventThread.h

/*
 * Copyright (C) 2011 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_SURFACE_FLINGER_EVENT_THREAD_H
#define ANDROID_SURFACE_FLINGER_EVENT_THREAD_H

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

#include <gui/DisplayEventReceiver.h>
#include <gui/IDisplayEventConnection.h>

#include <utils/Errors.h>
#include <utils/threads.h>
#include <utils/SortedVector.h>

#include "DisplayHardware/DisplayHardware.h"

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

namespace android {

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

class SurfaceFlinger;

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

class EventThread : public Thread, public DisplayHardware::VSyncHandler {
    class Connection : public BnDisplayEventConnection {
    public:
        Connection(const sp<EventThread>& eventThread);
        status_t postEvent(const DisplayEventReceiver::Event& event);

        // count >= 1 : continuous event. count is the vsync rate
        // count == 0 : one-shot event that has not fired
        // count ==-1 : one-shot event that fired this round / disabled
        // count ==-2 : one-shot event that fired the round before
        int32_t count;

    private:
        virtual ~Connection();
        virtual void onFirstRef();
        virtual sp<BitTube> getDataChannel() const;
        virtual void setVsyncRate(uint32_t count);
        virtual void requestNextVsync();    // asynchronous
        sp<EventThread> const mEventThread;
        sp<BitTube> const mChannel;
    };

public:

    EventThread(const sp<SurfaceFlinger>& flinger);

    sp<Connection> createEventConnection() const;
    status_t registerDisplayEventConnection(const sp<Connection>& connection);
    status_t unregisterDisplayEventConnection(const wp<Connection>& connection);

    void setVsyncRate(uint32_t count, const sp<Connection>& connection);
    void requestNextVsync(const sp<Connection>& connection);

    nsecs_t getLastVSyncTimestamp() const;
    nsecs_t getVSyncPeriod() const;

    void dump(String8& result, char* buffer, size_t SIZE) const;

private:
    virtual bool        threadLoop();
    virtual status_t    readyToRun();
    virtual void        onFirstRef();
    virtual void        onVSyncReceived(int, nsecs_t timestamp);

    void removeDisplayEventConnection(const wp<Connection>& connection);
    void enableVSync();
    void disableVSync();

    // constants
    sp<SurfaceFlinger> mFlinger;
    DisplayHardware& mHw;

    mutable Mutex mLock;
    mutable Condition mCondition;

    // protected by mLock
    SortedVector< wp<Connection> > mDisplayEventConnections;
    nsecs_t mLastVSyncTimestamp;
    nsecs_t mVSyncTimestamp;

    // main thread only
    size_t mDeliveredEvents;

    // for debugging
    bool mDebugVsyncEnabled;
};

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

}; // namespace android

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

#endif /* ANDROID_SURFACE_FLINGER_EVENT_THREAD_H */