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 { 17 kEventSignaled = 1, 18 kEventError = 2, 19 kEventTimeout = 3 20 }; 21 22 #define WEBRTC_EVENT_10_SEC 10000 23 #define WEBRTC_EVENT_INFINITE 0xffffffff 24 25 class EventWrapper 26 { 27 public: 28 // Factory method. Constructor disabled. 29 static EventWrapper* Create(); 30 virtual ~EventWrapper() {} 31 32 // Releases threads who are calling Wait() and has started waiting. Please 33 // note that a thread calling Wait() will not start waiting immediately. 34 // assumptions to the contrary is a very common source of issues in 35 // multithreaded programming. 36 // Set is sticky in the sense that it will release at least one thread 37 // either immediately or some time in the future. 38 virtual bool Set() = 0; 39 40 // Prevents future Wait() calls from finishing without a new Set() call. 41 virtual bool Reset() = 0; 42 43 // Puts the calling thread into a wait state. The thread may be released 44 // by a Set() call depending on if other threads are waiting and if so on 45 // timing. The thread that was released will call Reset() before leaving 46 // preventing more threads from being released. If multiple threads 47 // are waiting for the same Set(), only one (random) thread is guaranteed to 48 // be released. It is possible that multiple (random) threads are released 49 // Depending on timing. 50 virtual EventTypeWrapper Wait(unsigned long maxTime) = 0; 51 52 // Starts a timer that will call a non-sticky version of Set() either once 53 // or periodically. If the timer is periodic it ensures that there is no 54 // drift over time relative to the system clock. 55 virtual bool StartTimer(bool periodic, unsigned long time) = 0; 56 57 virtual bool StopTimer() = 0; 58 59 // Only implemented on Windows 60 // Returns 1 if a key has been pressed since last call to this function. 61 // -1 indicates failure 62 // 0 indicates no key has been pressed since last call 63 // TODO(hellner) this function does not seem to belong here 64 static int KeyPressed(); 65 }; 66 } // namespace webrtc 67 68 #endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_EVENT_WRAPPER_H_ 69
