1 /*
2  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef WEBRTC_BASE_PLATFORM_THREAD_H_
12 #define WEBRTC_BASE_PLATFORM_THREAD_H_
13 
14 #include <string>
15 
16 #include "webrtc/base/constructormagic.h"
17 #include "webrtc/base/event.h"
18 #include "webrtc/base/platform_thread_types.h"
19 #include "webrtc/base/scoped_ptr.h"
20 #include "webrtc/base/thread_checker.h"
21 
22 namespace rtc {
23 
24 PlatformThreadId CurrentThreadId();
25 PlatformThreadRef CurrentThreadRef();
26 
27 // Compares two thread identifiers for equality.
28 bool IsThreadRefEqual(const PlatformThreadRef& a, const PlatformThreadRef& b);
29 
30 // Sets the current thread name.
31 void SetCurrentThreadName(const char* name);
32 
33 // Callback function that the spawned thread will enter once spawned.
34 // A return value of false is interpreted as that the function has no
35 // more work to do and that the thread can be released.
36 typedef bool (*ThreadRunFunction)(void*);
37 
38 enum ThreadPriority {
39 #ifdef WEBRTC_WIN
40   kLowPriority = THREAD_PRIORITY_BELOW_NORMAL,
41   kNormalPriority = THREAD_PRIORITY_NORMAL,
42   kHighPriority = THREAD_PRIORITY_ABOVE_NORMAL,
43   kHighestPriority = THREAD_PRIORITY_HIGHEST,
44   kRealtimePriority = THREAD_PRIORITY_TIME_CRITICAL
45 #else
46   kLowPriority = 1,
47   kNormalPriority = 2,
48   kHighPriority = 3,
49   kHighestPriority = 4,
50   kRealtimePriority = 5
51 #endif
52 };
53 
54 // Represents a simple worker thread.  The implementation must be assumed
55 // to be single threaded, meaning that all methods of the class, must be
56 // called from the same thread, including instantiation.
57 class PlatformThread {
58  public:
59   PlatformThread(ThreadRunFunction func, void* obj, const char* thread_name);
60   virtual ~PlatformThread();
61 
62   // Spawns a thread and tries to set thread priority according to the priority
63   // from when CreateThread was called.
64   void Start();
65 
66   bool IsRunning() const;
67 
68   // Stops (joins) the spawned thread.
69   void Stop();
70 
71   // Set the priority of the thread. Must be called when thread is running.
72   bool SetPriority(ThreadPriority priority);
73 
74  private:
75   void Run();
76 
77   ThreadRunFunction const run_function_;
78   void* const obj_;
79   // TODO(pbos): Make sure call sites use string literals and update to a const
80   // char* instead of a std::string.
81   const std::string name_;
82   rtc::ThreadChecker thread_checker_;
83 #if defined(WEBRTC_WIN)
84   static DWORD WINAPI StartThread(void* param);
85 
86   bool stop_;
87   HANDLE thread_;
88 #else
89   static void* StartThread(void* param);
90 
91   rtc::Event stop_event_;
92 
93   pthread_t thread_;
94 #endif  // defined(WEBRTC_WIN)
95   RTC_DISALLOW_COPY_AND_ASSIGN(PlatformThread);
96 };
97 
98 }  // namespace rtc
99 
100 #endif  // WEBRTC_BASE_PLATFORM_THREAD_H_
101