1 /**
2  * Copyright (C) 2022 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 IIMS_MEDIA_THREAD
18 #define IIMS_MEDIA_THREAD
19 
20 #include <mutex>
21 
22 #define MAX_EVENTHANDLER_NAME 256
23 
24 // Thread priority value used with SCH_FIFO scheduling policy to set Real-Time priority.
25 #define THREAD_PRIORITY_REALTIME 2
26 
27 /**
28  * @class IImsMediaThread
29  * @brief Base class of thread
30  *        - Child class should implement run() method.
31  *        - Call StartThread() method to start thread.
32  */
33 class IImsMediaThread
34 {
35 public:
36     IImsMediaThread();
37     virtual ~IImsMediaThread();
38 
39     /**
40      * @brief Starts the new thread execution and detaches from the calling thread.
41      *
42      * @param name Optional param. If passed, used to set name for the thread.
43      *               Helpful for debugging.
44      */
45     bool StartThread(const char* name = nullptr);
46 
47     /**
48      * @brief Sets given thread priority for a given thread. Used to set realtime thread priority
49      * for time critical thread in the audio graph.
50      *
51      * @param pid Id of the current process
52      * @param tid Id of the thread whose priority should be modified.
53      * @param priority Thread priority value used with SCH_FIFO scheduling policy.
54      *                 THREAD_PRIORITY_REALTIME can be used to set realtime priority.
55      */
56     static void SetThreadPriority(pid_t pid, pid_t tid, int priority);
57 
58     /**
59      * @brief Sets the stopped flag and the thread's run method should read and return.
60      * Method is asynchronous and returns immediately without waiting for the thread's run
61      * method to return.
62      */
63     void StopThread();
64 
65     /**
66      * @brief Used to check if the thread is running.
67      */
68     bool IsThreadStopped();
69 
70     /**
71      * @brief Should be implemented by the derived call. Called by new thread when StartThread is
72      * invoked.
73      */
74     virtual void* run() = 0;
75 
76 private:
77     std::mutex mThreadMutex;
78     bool mThreadStopped;
79 };
80 
81 #endif