1 /*
2  * Copyright (C) 2016 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 AAUDIO_THREAD_H
18 #define AAUDIO_THREAD_H
19 
20 #include <atomic>
21 #include <pthread.h>
22 
23 #include <aaudio/AAudio.h>
24 
25 namespace aaudio {
26 
27 /**
28  * Abstract class similar to Java Runnable.
29  */
30 class Runnable {
31 public:
Runnable()32     Runnable() {};
33     virtual ~Runnable() = default;
34 
35     virtual void run() = 0;
36 };
37 
38 /**
39  * Abstraction for a host dependent thread.
40  * TODO Consider using Android "Thread" class or std::thread instead.
41  */
42 class AAudioThread
43 {
44 public:
45     AAudioThread();
46 
47     explicit AAudioThread(const char *prefix);
48 
49     virtual ~AAudioThread() = default;
50 
51     /**
52      * Start the thread running.
53      */
54     aaudio_result_t start(Runnable *runnable = nullptr);
55 
56     /**
57      * Join the thread.
58      * The caller must somehow tell the thread to exit before calling join().
59      */
60     aaudio_result_t stop();
61 
62     /**
63      * This will get called in the thread.
64      * Override this or pass a Runnable to start().
65      */
run()66     virtual void run() {};
67 
68     void dispatch(); // called internally from 'C' thread wrapper
69 
70 private:
71 
72     void setup(const char *prefix);
73 
74     Runnable    *mRunnable = nullptr;
75     bool         mHasThread = false;
76     pthread_t    mThread; // initialized in constructor
77 
78     static std::atomic<uint32_t> mNextThreadIndex;
79     char         mName[16]; // max length for a pthread_name
80 };
81 
82 } /* namespace aaudio */
83 
84 #endif ///AAUDIO_THREAD_H
85