2 * Copyright (C) 2005-2011 Team XBMC
5 * This Program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2, or (at your option)
10 * This Program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with XBMC; see the file COPYING. If not, see
17 * <http://www.gnu.org/licenses/>.
25 #include "threads/Condition.h"
26 #include "threads/SingleLock.h"
28 // forward declare the CEventGroup
36 * This is an Event class built from a ConditionVariable. The Event adds the state
37 * that the condition is gating as well as the mutex/lock.
39 * This Event can be 'interruptible' (even though there is only a single place
40 * in the code that uses this behavior).
42 * This class manages 'spurious returns' from the condition variable.
44 class CEvent : public XbmcThreads::NonCopyable
47 volatile bool signaled;
48 unsigned int numWaits;
50 CCriticalSection groupListMutex; // lock for the groups list
51 std::vector<XbmcThreads::CEventGroup*> * groups;
54 * To satisfy the TightConditionVariable requirements and allow the
55 * predicate being monitored to include both the signaled and interrupted
58 XbmcThreads::ConditionVariable actualCv;
59 XbmcThreads::TightConditionVariable<volatile bool&> condVar;
60 CCriticalSection mutex;
62 friend class XbmcThreads::CEventGroup;
64 void addGroup(XbmcThreads::CEventGroup* group);
65 void removeGroup(XbmcThreads::CEventGroup* group);
67 // helper for the two wait methods
68 inline bool prepReturn() { bool ret = signaled; if (!manualReset && numWaits == 0) signaled = false; return ret; }
71 inline CEvent(bool manual = false, bool signaled_ = false) :
72 manualReset(manual), signaled(signaled_), numWaits(0), groups(NULL), condVar(actualCv,signaled) {}
74 inline void Reset() { CSingleLock lock(mutex); signaled = false; }
78 * This will wait up to 'milliSeconds' milliseconds for the Event
79 * to be triggered. The method will return 'true' if the Event
80 * was triggered. Otherwise it will return false.
82 inline bool WaitMSec(unsigned int milliSeconds)
83 { CSingleLock lock(mutex); numWaits++; condVar.wait(mutex,milliSeconds); numWaits--; return prepReturn(); }
86 * This will wait for the Event to be triggered. The method will return
87 * 'true' if the Event was triggered. If it was either interrupted
88 * it will return false. Otherwise it will return false.
91 { CSingleLock lock(mutex); numWaits++; condVar.wait(mutex); numWaits--; return prepReturn(); }
94 * This is mostly for testing. It allows a thread to make sure there are
95 * the right amount of other threads waiting.
97 inline int getNumWaits() { CSingleLock lock(mutex); return numWaits; }
101 namespace XbmcThreads
104 * CEventGroup is a means of grouping CEvents to wait on them together.
105 * It is equivalent to WaitOnMultipleObject that returns when "any" Event
106 * in the group signaled.
108 class CEventGroup : public NonCopyable
110 std::vector<CEvent*> events;
112 XbmcThreads::ConditionVariable actualCv;
113 XbmcThreads::TightConditionVariable<CEvent*&> condVar;
114 CCriticalSection mutex;
116 unsigned int numWaits;
118 // This is ONLY called from CEvent::Set.
119 inline void Set(CEvent* child) { CSingleLock l(mutex); signaled = child; condVar.notifyAll(); }
121 friend class ::CEvent;
126 * Create a CEventGroup from a number of CEvents. num is the number
127 * of Events that follow. E.g.:
129 * CEventGroup g(3, event1, event2, event3);
131 CEventGroup(int num, CEvent* v1, ...);
134 * Create a CEventGroup from a number of CEvents. The parameters
135 * should form a NULL terminated list of CEvent*'s
137 * CEventGroup g(event1, event2, event3, NULL);
139 CEventGroup(CEvent* v1, ...);
143 * This will block until any one of the CEvents in the group are
144 * signaled at which point a pointer to that CEvents will be
150 * This will block until any one of the CEvents in the group are
151 * signaled or the timeout is reachec. If an event is signaled then
152 * it will return a pointer to that CEvent, otherwise it will return
155 CEvent* wait(unsigned int milliseconds);
158 * This is mostly for testing. It allows a thread to make sure there are
159 * the right amount of other threads waiting.
161 inline int getNumWaits() { CSingleLock lock(mutex); return numWaits; }