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 <errno.h>
21 #include <stdint.h>
22 #include <sys/types.h>
23 
24 #include <utils/Looper.h>
25 #include <utils/Timers.h>
26 #include <utils/threads.h>
27 
28 #include <gui/IDisplayEventConnection.h>
29 #include <private/gui/BitTube.h>
30 
31 #include "Barrier.h"
32 
33 #include <functional>
34 
35 namespace android {
36 
37 class EventThread;
38 class SurfaceFlinger;
39 
40 // ---------------------------------------------------------------------------
41 
42 class MessageBase : public MessageHandler {
43 public:
44     MessageBase();
45 
46     // return true if message has a handler
47     virtual bool handler() = 0;
48 
49     // waits for the handler to be processed
wait()50     void wait() const { barrier.wait(); }
51 
52 protected:
53     virtual ~MessageBase();
54 
55 private:
56     virtual void handleMessage(const Message& message);
57 
58     mutable Barrier barrier;
59 };
60 
61 class LambdaMessage : public MessageBase {
62 public:
LambdaMessage(std::function<void ()> handler)63     explicit LambdaMessage(std::function<void()> handler)
64           : MessageBase(), mHandler(std::move(handler)) {}
65 
handler()66     bool handler() override {
67         mHandler();
68         // This return value is no longer checked, so it's always safe to return true
69         return true;
70     }
71 
72 private:
73     const std::function<void()> mHandler;
74 };
75 
76 // ---------------------------------------------------------------------------
77 
78 class MessageQueue {
79 public:
80     enum {
81         INVALIDATE = 0,
82         REFRESH = 1,
83     };
84 
85     virtual ~MessageQueue();
86 
87     virtual void init(const sp<SurfaceFlinger>& flinger) = 0;
88     virtual void setEventThread(EventThread* events) = 0;
89     virtual void waitMessage() = 0;
90     virtual status_t postMessage(const sp<MessageBase>& message, nsecs_t reltime = 0) = 0;
91     virtual void invalidate() = 0;
92     virtual void refresh() = 0;
93 };
94 
95 // ---------------------------------------------------------------------------
96 
97 namespace impl {
98 
99 class MessageQueue final : public android::MessageQueue {
100     class Handler : public MessageHandler {
101         enum { eventMaskInvalidate = 0x1, eventMaskRefresh = 0x2, eventMaskTransaction = 0x4 };
102         MessageQueue& mQueue;
103         int32_t mEventMask;
104 
105     public:
Handler(MessageQueue & queue)106         explicit Handler(MessageQueue& queue) : mQueue(queue), mEventMask(0) {}
107         virtual void handleMessage(const Message& message);
108         void dispatchRefresh();
109         void dispatchInvalidate();
110     };
111 
112     friend class Handler;
113 
114     sp<SurfaceFlinger> mFlinger;
115     sp<Looper> mLooper;
116     android::EventThread* mEventThread;
117     sp<IDisplayEventConnection> mEvents;
118     gui::BitTube mEventTube;
119     sp<Handler> mHandler;
120 
121     static int cb_eventReceiver(int fd, int events, void* data);
122     int eventReceiver(int fd, int events);
123 
124 public:
125     ~MessageQueue() override = default;
126     void init(const sp<SurfaceFlinger>& flinger) override;
127     void setEventThread(android::EventThread* events) override;
128 
129     void waitMessage() override;
130     status_t postMessage(const sp<MessageBase>& message, nsecs_t reltime = 0) override;
131 
132     // sends INVALIDATE message at next VSYNC
133     void invalidate() override;
134     // sends REFRESH message at next VSYNC
135     void refresh() override;
136 };
137 
138 // ---------------------------------------------------------------------------
139 
140 } // namespace impl
141 } // namespace android
142 
143 #endif /* ANDROID_MESSAGE_QUEUE_H */
144