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 #ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_EVENT_WRAPPER_H_ 12 #define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_EVENT_WRAPPER_H_ 13 14 namespace webrtc { 15 enum EventTypeWrapper { 16 kEventSignaled = 1, 17 kEventError = 2, 18 kEventTimeout = 3 19 }; 20 21 #define WEBRTC_EVENT_10_SEC 10000 22 #define WEBRTC_EVENT_INFINITE 0xffffffff 23 24 class EventWrapper { 25 public: 26 // Factory method. Constructor disabled. 27 static EventWrapper* Create(); 28 virtual ~EventWrapper() {} 29 30 // Releases threads who are calling Wait() and has started waiting. Please 31 // note that a thread calling Wait() will not start waiting immediately. 32 // assumptions to the contrary is a very common source of issues in 33 // multithreaded programming. 34 // Set is sticky in the sense that it will release at least one thread 35 // either immediately or some time in the future. 36 virtual bool Set() = 0; 37 38 // Prevents future Wait() calls from finishing without a new Set() call. 39 virtual bool Reset() = 0; 40 41 // Puts the calling thread into a wait state. The thread may be released 42 // by a Set() call depending on if other threads are waiting and if so on 43 // timing. The thread that was released will call Reset() before leaving 44 // preventing more threads from being released. If multiple threads 45 // are waiting for the same Set(), only one (random) thread is guaranteed to 46 // be released. It is possible that multiple (random) threads are released 47 // Depending on timing. 48 virtual EventTypeWrapper Wait(unsigned long max_time) = 0; 49 50 // Starts a timer that will call a non-sticky version of Set() either once 51 // or periodically. If the timer is periodic it ensures that there is no 52 // drift over time relative to the system clock. 53 virtual bool StartTimer(bool periodic, unsigned long time) = 0; 54 55 virtual bool StopTimer() = 0; 56 57 }; 58 } // namespace webrtc 59 60 #endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_EVENT_WRAPPER_H_ 61
