1 // Copyright (C) 2021 The Android Open Source Project
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //      http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #pragma once
16 
17 #include <atomic>
18 #include <mutex>
19 
20 // clang-format off
21 #include PATH(android/hardware/audio/FILE_VERSION/IStreamOut.h)
22 // clang-format on
23 
24 #include <android-base/thread_annotations.h>
25 #include <fmq/EventFlag.h>
26 #include <fmq/MessageQueue.h>
27 #include <hidl/MQDescriptor.h>
28 #include <inttypes.h>
29 #include <utils/Thread.h>
30 
31 #include "AidlTypes.h"
32 
33 using android::sp;
34 using android::Thread;
35 using android::hardware::EventFlag;
36 using android::hardware::kSynchronizedReadWrite;
37 using android::hardware::MessageQueue;
38 using namespace android::hardware::audio::common::CPP_VERSION;
39 using namespace android::hardware::audio::CPP_VERSION;
40 
41 namespace audio_proxy::service {
42 
43 class BusOutputStream;
44 
45 class WriteThread : public Thread {
46  public:
47   using CommandMQ =
48       MessageQueue<IStreamOut::WriteCommand, kSynchronizedReadWrite>;
49   using DataMQ = MessageQueue<uint8_t, kSynchronizedReadWrite>;
50   using StatusMQ =
51       MessageQueue<IStreamOut::WriteStatus, kSynchronizedReadWrite>;
52 
53   // WriteThread's lifespan never exceeds StreamOut's lifespan.
54   WriteThread(std::shared_ptr<BusOutputStream> stream, CommandMQ* commandMQ,
55               DataMQ* dataMQ, StatusMQ* statusMQ, EventFlag* eventFlag,
56               uint32_t latencyMs);
57 
58   ~WriteThread() override;
59 
60   void stop();
61 
62   void updateOutputStream(std::shared_ptr<BusOutputStream> stream);
63 
64   std::pair<uint64_t, TimeSpec> getPresentationPosition();
65 
66  private:
67   bool threadLoop() override;
68 
69   // The following function is called on the thread and it will modify the
70   // variables which may be read from another thread.
71   IStreamOut::WriteStatus doWrite(BusOutputStream* stream);
72 
73   // The following function is called on the thread and only read variable
74   // that is written on the same thread, so there's no need to lock the
75   // resources.
76   IStreamOut::WriteStatus doGetPresentationPosition() const
77       NO_THREAD_SAFETY_ANALYSIS;
78 
79   IStreamOut::WriteStatus doGetLatency() const;
80 
81   // Write 0 buffer to {@param stream} for latest presentation info.
82   void queryPresentationPosition(BusOutputStream* stream);
83 
84   // Update presentation position info after writing to {@param stream}. Caller
85   // should validate the {@param status}.
86   void updatePresentationPosition(const AidlWriteStatus& status,
87                                   BusOutputStream* stream);
88 
89   std::atomic<bool> mStop = false;
90 
91   std::mutex mStreamLock;
92   std::shared_ptr<BusOutputStream> mStream GUARDED_BY(mStreamLock);
93 
94   CommandMQ* const mCommandMQ;
95   DataMQ* const mDataMQ;
96   StatusMQ* const mStatusMQ;
97   EventFlag* const mEventFlag;
98 
99   // Latency in ms, used in HIDL API getLatency.
100   const uint32_t mLatencyMs;
101 
102   // Count for consecutive FMQ command that is not WRITE.
103   int64_t mNonWriteCommandCount = 0;
104 
105   // Presentation position information.
106   std::mutex mPositionLock;
107   uint64_t mPresentationFramesOffset GUARDED_BY(mPositionLock) = 0;
108   uint64_t mPresentationFrames GUARDED_BY(mPositionLock) = 0;
109   TimeSpec mPresentationTimestamp GUARDED_BY(mPositionLock) = {0, 0};
110   uint64_t mTotalWrittenFrames GUARDED_BY(mPositionLock) = 0;
111 };
112 
113 }  // namespace audio_proxy::service