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      1 /*
      2  * Copyright (C) 2009 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ANDROID_MESSAGE_QUEUE_H
     18 #define ANDROID_MESSAGE_QUEUE_H
     19 
     20 #include <stdint.h>
     21 #include <errno.h>
     22 #include <sys/types.h>
     23 
     24 #include <utils/threads.h>
     25 #include <utils/Timers.h>
     26 #include <utils/Looper.h>
     27 
     28 #include <private/gui/BitTube.h>
     29 #include <gui/DisplayEventReceiver.h>
     30 
     31 #include "Barrier.h"
     32 
     33 #include <functional>
     34 
     35 namespace android {
     36 
     37 class IDisplayEventConnection;
     38 class EventThread;
     39 class SurfaceFlinger;
     40 
     41 // ---------------------------------------------------------------------------
     42 
     43 class MessageBase : public MessageHandler
     44 {
     45 public:
     46     MessageBase();
     47 
     48     // return true if message has a handler
     49     virtual bool handler() = 0;
     50 
     51     // waits for the handler to be processed
     52     void wait() const { barrier.wait(); }
     53 
     54 protected:
     55     virtual ~MessageBase();
     56 
     57 private:
     58     virtual void handleMessage(const Message& message);
     59 
     60     mutable Barrier barrier;
     61 };
     62 
     63 class LambdaMessage : public MessageBase {
     64 public:
     65     explicit LambdaMessage(std::function<void()> handler)
     66           : MessageBase(), mHandler(std::move(handler)) {}
     67 
     68     bool handler() override {
     69         mHandler();
     70         // This return value is no longer checked, so it's always safe to return true
     71         return true;
     72     }
     73 
     74 private:
     75     const std::function<void()> mHandler;
     76 };
     77 
     78 // ---------------------------------------------------------------------------
     79 
     80 class MessageQueue {
     81     class Handler : public MessageHandler {
     82         enum {
     83             eventMaskInvalidate     = 0x1,
     84             eventMaskRefresh        = 0x2,
     85             eventMaskTransaction    = 0x4
     86         };
     87         MessageQueue& mQueue;
     88         int32_t mEventMask;
     89     public:
     90         explicit Handler(MessageQueue& queue) : mQueue(queue), mEventMask(0) { }
     91         virtual void handleMessage(const Message& message);
     92         void dispatchRefresh();
     93         void dispatchInvalidate();
     94     };
     95 
     96     friend class Handler;
     97 
     98     sp<SurfaceFlinger> mFlinger;
     99     sp<Looper> mLooper;
    100     sp<EventThread> mEventThread;
    101     sp<IDisplayEventConnection> mEvents;
    102     gui::BitTube mEventTube;
    103     sp<Handler> mHandler;
    104 
    105 
    106     static int cb_eventReceiver(int fd, int events, void* data);
    107     int eventReceiver(int fd, int events);
    108 
    109 public:
    110     enum {
    111         INVALIDATE  = 0,
    112         REFRESH     = 1,
    113     };
    114 
    115     MessageQueue();
    116     ~MessageQueue();
    117     void init(const sp<SurfaceFlinger>& flinger);
    118     void setEventThread(const sp<EventThread>& events);
    119 
    120     void waitMessage();
    121     status_t postMessage(const sp<MessageBase>& message, nsecs_t reltime=0);
    122 
    123     // sends INVALIDATE message at next VSYNC
    124     void invalidate();
    125     // sends REFRESH message at next VSYNC
    126     void refresh();
    127 };
    128 
    129 // ---------------------------------------------------------------------------
    130 
    131 }; // namespace android
    132 
    133 #endif /* ANDROID_MESSAGE_QUEUE_H */
    134