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1 /* | |
2 * Copyright (c) 2011 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 // System independant wrapper for spawning threads | |
12 // Note: the spawned thread will loop over the callback function until stopped. | |
13 // Note: The callback function is expected to return every 2 seconds or more | |
14 // often. | |
15 | |
16 #ifndef WEBRTC_SYSTEM_WRAPPERS_INCLUDE_THREAD_WRAPPER_H_ | |
17 #define WEBRTC_SYSTEM_WRAPPERS_INCLUDE_THREAD_WRAPPER_H_ | |
18 | |
19 #if defined(WEBRTC_WIN) | |
20 #include <windows.h> | |
21 #endif | |
22 | |
23 #include "webrtc/base/scoped_ptr.h" | |
24 #include "webrtc/common_types.h" | |
25 #include "webrtc/typedefs.h" | |
26 | |
27 namespace webrtc { | |
28 | |
29 // Callback function that the spawned thread will enter once spawned. | |
30 // A return value of false is interpreted as that the function has no | |
31 // more work to do and that the thread can be released. | |
32 typedef bool(*ThreadRunFunction)(void*); | |
33 | |
34 enum ThreadPriority { | |
35 #ifdef WEBRTC_WIN | |
36 kLowPriority = THREAD_PRIORITY_BELOW_NORMAL, | |
37 kNormalPriority = THREAD_PRIORITY_NORMAL, | |
38 kHighPriority = THREAD_PRIORITY_ABOVE_NORMAL, | |
39 kHighestPriority = THREAD_PRIORITY_HIGHEST, | |
40 kRealtimePriority = THREAD_PRIORITY_TIME_CRITICAL | |
41 #else | |
42 kLowPriority = 1, | |
43 kNormalPriority = 2, | |
44 kHighPriority = 3, | |
45 kHighestPriority = 4, | |
46 kRealtimePriority = 5 | |
47 #endif | |
48 }; | |
49 | |
50 // Represents a simple worker thread. The implementation must be assumed | |
51 // to be single threaded, meaning that all methods of the class, must be | |
52 // called from the same thread, including instantiation. | |
53 // TODO(tommi): There's no need for this to be a virtual interface since there's | |
54 // only ever a single implementation of it. | |
55 class ThreadWrapper { | |
56 public: | |
57 virtual ~ThreadWrapper() {} | |
58 | |
59 // Factory method. Constructor disabled. | |
60 // | |
61 // func Pointer to a, by user, specified callback function. | |
62 // obj Object associated with the thread. Passed in the callback | |
63 // function. | |
64 // prio Thread priority. May require root/admin rights. | |
65 // thread_name NULL terminated thread name, will be visable in the Windows | |
66 // debugger. | |
67 static rtc::scoped_ptr<ThreadWrapper> CreateThread(ThreadRunFunction func, | |
68 void* obj, const char* thread_name); | |
69 | |
70 // Tries to spawns a thread and returns true if that was successful. | |
71 // Additionally, it tries to set thread priority according to the priority | |
72 // from when CreateThread was called. However, failure to set priority will | |
73 // not result in a false return value. | |
74 virtual bool Start() = 0; | |
75 | |
76 // Stops the spawned thread and waits for it to be reclaimed with a timeout | |
77 // of two seconds. Will return false if the thread was not reclaimed. | |
78 // Multiple tries to Stop are allowed (e.g. to wait longer than 2 seconds). | |
79 // It's ok to call Stop() even if the spawned thread has been reclaimed. | |
80 virtual bool Stop() = 0; | |
81 | |
82 // Set the priority of the worker thread. Must be called when thread | |
83 // is running. | |
84 virtual bool SetPriority(ThreadPriority priority) = 0; | |
85 }; | |
86 | |
87 } // namespace webrtc | |
88 | |
89 #endif // WEBRTC_SYSTEM_WRAPPERS_INCLUDE_THREAD_WRAPPER_H_ | |
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