xpcom/threads/CondVar.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_CondVar_h
   8 #define mozilla_CondVar_h
   9
  10 #include "mozilla/BlockingResourceBase.h"
  11 #include "mozilla/PlatformConditionVariable.h"
  12 #include "mozilla/Mutex.h"
  13 #include "mozilla/TimeStamp.h"
  14
  15 #if defined(MOZILLA_INTERNAL_API) && !defined(DEBUG)
  16 #  include "GeckoProfiler.h"
  17 #endif  // defined( MOZILLA_INTERNAL_API) && !defined(DEBUG)
  18
  19 namespace mozilla {
  20
  21 /**
  22  * Similarly to OffTheBooksMutex, OffTheBooksCondvar is identical to CondVar,
  23  * except that OffTheBooksCondVar doesn't include leak checking.  Sometimes
  24  * you want to intentionally "leak" a CondVar until shutdown; in these cases,
  25  * OffTheBooksCondVar is for you.
  26  */
  27 class OffTheBooksCondVar : BlockingResourceBase {
  28  public:
  29   /**
  30    * OffTheBooksCondVar
  31    *
  32    * The CALLER owns |aLock|.
  33    *
  34    * @param aLock A Mutex to associate with this condition variable.
  35    * @param aName A name which can reference this monitor
  36    * @returns If failure, nullptr.
  37    *          If success, a valid Monitor* which must be destroyed
  38    *          by Monitor::DestroyMonitor()
  39    **/
  40   OffTheBooksCondVar(OffTheBooksMutex& aLock, const char* aName)
  41       : BlockingResourceBase(aName, eCondVar), mLock(&aLock) {}
  42
  43   /**
  44    * ~OffTheBooksCondVar
  45    * Clean up after this OffTheBooksCondVar, but NOT its associated Mutex.
  46    **/
  47   ~OffTheBooksCondVar() = default;
  48
  49   /**
  50    * Wait
  51    * @see prcvar.h
  52    **/
  53 #ifndef DEBUG
  54   void Wait() {
  55 #  ifdef MOZILLA_INTERNAL_API
  56     AUTO_PROFILER_THREAD_SLEEP;
  57 #  endif  // MOZILLA_INTERNAL_API
  58     mImpl.wait(*mLock);
  59   }
  60
  61   CVStatus Wait(TimeDuration aDuration) {
  62 #  ifdef MOZILLA_INTERNAL_API
  63     AUTO_PROFILER_THREAD_SLEEP;
  64 #  endif  // MOZILLA_INTERNAL_API
  65     return mImpl.wait_for(*mLock, aDuration);
  66   }
  67 #else
  68   // NOTE: debug impl is in BlockingResourceBase.cpp
  69   void Wait();
  70   CVStatus Wait(TimeDuration aDuration);
  71 #endif
  72
  73   /**
  74    * Notify
  75    * @see prcvar.h
  76    **/
  77   void Notify() { mImpl.notify_one(); }
  78
  79   /**
  80    * NotifyAll
  81    * @see prcvar.h
  82    **/
  83   void NotifyAll() { mImpl.notify_all(); }
  84
  85 #ifdef DEBUG
  86   /**
  87    * AssertCurrentThreadOwnsMutex
  88    * @see Mutex::AssertCurrentThreadOwns
  89    **/
  90   void AssertCurrentThreadOwnsMutex() { mLock->AssertCurrentThreadOwns(); }
  91
  92   /**
  93    * AssertNotCurrentThreadOwnsMutex
  94    * @see Mutex::AssertNotCurrentThreadOwns
  95    **/
  96   void AssertNotCurrentThreadOwnsMutex() {
  97     mLock->AssertNotCurrentThreadOwns();
  98   }
  99
 100 #else
 101   void AssertCurrentThreadOwnsMutex() {}
 102   void AssertNotCurrentThreadOwnsMutex() {}
 103
 104 #endif  // ifdef DEBUG
 105
 106  private:
 107   OffTheBooksCondVar();
 108   OffTheBooksCondVar(const OffTheBooksCondVar&) = delete;
 109   OffTheBooksCondVar& operator=(const OffTheBooksCondVar&) = delete;
 110
 111   OffTheBooksMutex* mLock;
 112   detail::ConditionVariableImpl mImpl;
 113 };
 114
 115 /**
 116  * CondVar
 117  * Vanilla condition variable.  Please don't use this unless you have a
 118  * compelling reason --- Monitor provides a simpler API.
 119  */
 120 class CondVar : public OffTheBooksCondVar {
 121  public:
 122   CondVar(OffTheBooksMutex& aLock, const char* aName)
 123       : OffTheBooksCondVar(aLock, aName) {
 124     MOZ_COUNT_CTOR(CondVar);
 125   }
 126
 127   MOZ_COUNTED_DTOR(CondVar)
 128
 129  private:
 130   CondVar();
 131   CondVar(const CondVar&);
 132   CondVar& operator=(const CondVar&);
 133 };
 134
 135 }  // namespace mozilla
 136
 137 #endif  // ifndef mozilla_CondVar_h