1 // The MIT License (MIT)
2 //
3 // 	Copyright (c) 2015 Sergey Makeev, Vadim Slyusarev
4 //
5 // 	Permission is hereby granted, free of charge, to any person obtaining a copy
6 // 	of this software and associated documentation files (the "Software"), to deal
7 // 	in the Software without restriction, including without limitation the rights
8 // 	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 // 	copies of the Software, and to permit persons to whom the Software is
10 // 	furnished to do so, subject to the following conditions:
11 //
12 //  The above copyright notice and this permission notice shall be included in
13 // 	all copies or substantial portions of the Software.
14 //
15 // 	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 // 	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 // 	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 // 	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 // 	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 // 	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
21 // 	THE SOFTWARE.
22 
23 #pragma once
24 
25 #include <sys/time.h>
26 #include <sched.h>
27 #include <errno.h>
28 
29 
30 namespace MT
31 {
32 	//
33 	//
34 	//
35 	class Event
36 	{
37 		static const int NOT_SIGNALED = 0;
38 		static const int SIGNALED = 1;
39 
40 		uint32 numOfWaitingThreads;
41 
42 		pthread_mutex_t	mutex;
43 		pthread_cond_t	condition;
44 		AtomicInt val;
45 		EventReset::Type resetType;
46 		bool isInitialized;
47 
48 	private:
49 
50 		Event(const Event&) {}
51 		void operator=(const Event&) {}
52 
53 		void AutoResetIfNeed()
54 		{
55 			if (resetType == EventReset::MANUAL)
56 			{
57 				return;
58 			}
59 			Reset();
60 		}
61 
62 	public:
63 
64 		Event()
65 			: numOfWaitingThreads(0)
66 			, isInitialized(false)
67 		{
68 		}
69 
70 		Event(EventReset::Type resetType, bool initialState)
71 			: numOfWaitingThreads(0)
72 			, isInitialized(false)
73 		{
74 			Create(resetType, initialState);
75 		}
76 
77 		~Event()
78 		{
79 			if (isInitialized)
80 			{
81 				pthread_cond_destroy( &condition );
82 				pthread_mutex_destroy( &mutex );
83 			}
84 		}
85 
86 		void Create(EventReset::Type _resetType, bool initialState)
87 		{
88 			MT_ASSERT (!isInitialized, "Event already initialized");
89 
90 			resetType = _resetType;
91 
92 			pthread_mutex_init( &mutex, nullptr );
93 			pthread_cond_init( &condition, nullptr );
94 			val.Set(initialState ? SIGNALED : NOT_SIGNALED);
95 
96 			isInitialized = true;
97 			numOfWaitingThreads = 0;
98 		}
99 
100 		void Signal()
101 		{
102 			MT_ASSERT (isInitialized, "Event not initialized");
103 
104 			pthread_mutex_lock( &mutex );
105 
106 			val.Set(SIGNALED);
107 
108 			if (numOfWaitingThreads)
109 			{
110 				if (resetType == EventReset::MANUAL)
111 				{
112 					pthread_cond_broadcast( &condition );
113 				} else
114 				{
115 					pthread_cond_signal( &condition );
116 				}
117 			}
118 
119 			pthread_mutex_unlock( &mutex );
120 		}
121 
122 		void Reset()
123 		{
124 			MT_ASSERT (isInitialized, "Event not initialized");
125 			val.Set(NOT_SIGNALED);
126 		}
127 
128 		bool Wait(uint32 milliseconds)
129 		{
130 			MT_ASSERT (isInitialized, "Event not initialized");
131 
132 			pthread_mutex_lock( &mutex );
133 
134 			// early exit if event already signaled
135 			if ( val.Get() != NOT_SIGNALED )
136 			{
137 				AutoResetIfNeed();
138 				pthread_mutex_unlock( &mutex );
139 				return true;
140 			}
141 
142 			numOfWaitingThreads++;
143 
144 			//convert milliseconds to posix time
145 			struct timeval tv;
146 			gettimeofday( &tv, nullptr );
147 			struct timespec tm;
148 			tm.tv_sec = tv.tv_sec + milliseconds / 1000;
149 			uint64 nanosec = (uint64)tv.tv_usec * 1000 + (uint64)milliseconds * 1000000;
150 			if (nanosec >= 1000000000)
151 			{
152 				tm.tv_sec += (long)(nanosec / 1000000000);
153 				nanosec = nanosec % 1000000000;
154 			}
155 			tm.tv_nsec = (long)nanosec;
156 
157 			int ret = 0;
158 			while(true)
159 			{
160 				ret = pthread_cond_timedwait( &condition, &mutex, &tm );
161 
162 				MT_ASSERT(ret == 0 || ret == ETIMEDOUT || ret == EINTR, "Unexpected return value");
163 
164 				if (ret != EINTR)
165 				{
166 					break;
167 				}
168 			}
169 
170 			numOfWaitingThreads--;
171 
172 			AutoResetIfNeed();
173 
174 			pthread_mutex_unlock( &mutex );
175 
176 			//return true if val in SIGNALED state instead of ret == 0 ?
177 			return ret == 0;
178 		}
179 
180 	};
181 
182 }
183 
184 
185