1 // Copyright (c) 2016 Marshall A. Greenblatt. All rights reserved. 2 // 3 // Redistribution and use in source and binary forms, with or without 4 // modification, are permitted provided that the following conditions are 5 // met: 6 // 7 // * Redistributions of source code must retain the above copyright 8 // notice, this list of conditions and the following disclaimer. 9 // * Redistributions in binary form must reproduce the above 10 // copyright notice, this list of conditions and the following disclaimer 11 // in the documentation and/or other materials provided with the 12 // distribution. 13 // * Neither the name of Google Inc. nor the name Chromium Embedded 14 // Framework nor the names of its contributors may be used to endorse 15 // or promote products derived from this software without specific prior 16 // written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 // 30 // --------------------------------------------------------------------------- 31 // 32 // The contents of this file must follow a specific format in order to 33 // support the CEF translator tool. See the translator.README.txt file in the 34 // tools directory for more information. 35 // 36 37 #ifndef CEF_INCLUDE_CEF_WAITABLE_EVENT_H_ 38 #define CEF_INCLUDE_CEF_WAITABLE_EVENT_H_ 39 #pragma once 40 41 #include "include/cef_base.h" 42 43 /// 44 // WaitableEvent is a thread synchronization tool that allows one thread to wait 45 // for another thread to finish some work. This is equivalent to using a 46 // Lock+ConditionVariable to protect a simple boolean value. However, using 47 // WaitableEvent in conjunction with a Lock to wait for a more complex state 48 // change (e.g., for an item to be added to a queue) is not recommended. In that 49 // case consider using a ConditionVariable instead of a WaitableEvent. It is 50 // safe to create and/or signal a WaitableEvent from any thread. Blocking on a 51 // WaitableEvent by calling the *Wait() methods is not allowed on the browser 52 // process UI or IO threads. 53 /// 54 /*--cef(source=library)--*/ 55 class CefWaitableEvent : public CefBaseRefCounted { 56 public: 57 /// 58 // Create a new waitable event. If |automatic_reset| is true then the event 59 // state is automatically reset to un-signaled after a single waiting thread 60 // has been released; otherwise, the state remains signaled until Reset() is 61 // called manually. If |initially_signaled| is true then the event will start 62 // in the signaled state. 63 /// 64 /*--cef()--*/ 65 static CefRefPtr<CefWaitableEvent> CreateWaitableEvent( 66 bool automatic_reset, 67 bool initially_signaled); 68 69 /// 70 // Put the event in the un-signaled state. 71 /// 72 /*--cef()--*/ 73 virtual void Reset() = 0; 74 75 /// 76 // Put the event in the signaled state. This causes any thread blocked on Wait 77 // to be woken up. 78 /// 79 /*--cef()--*/ 80 virtual void Signal() = 0; 81 82 /// 83 // Returns true if the event is in the signaled state, else false. If the 84 // event was created with |automatic_reset| set to true then calling this 85 // method will also cause a reset. 86 /// 87 /*--cef()--*/ 88 virtual bool IsSignaled() = 0; 89 90 /// 91 // Wait indefinitely for the event to be signaled. This method will not return 92 // until after the call to Signal() has completed. This method cannot be 93 // called on the browser process UI or IO threads. 94 /// 95 /*--cef()--*/ 96 virtual void Wait() = 0; 97 98 /// 99 // Wait up to |max_ms| milliseconds for the event to be signaled. Returns true 100 // if the event was signaled. A return value of false does not necessarily 101 // mean that |max_ms| was exceeded. This method will not return until after 102 // the call to Signal() has completed. This method cannot be called on the 103 // browser process UI or IO threads. 104 /// 105 /*--cef()--*/ 106 virtual bool TimedWait(int64 max_ms) = 0; 107 }; 108 109 #endif // CEF_INCLUDE_CEF_WAITABLE_EVENT_H_ 110