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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
wait()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:
LambdaMessage(std::function<void ()> handler)65     explicit LambdaMessage(std::function<void()> handler)
66           : MessageBase(), mHandler(std::move(handler)) {}
67 
handler()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:
Handler(MessageQueue & queue)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