xpcom/threads/TimerThread.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 TimerThread_h___
   8 #define TimerThread_h___
   9
  10 #include "nsIObserver.h"
  11 #include "nsIRunnable.h"
  12 #include "nsIThread.h"
  13
  14 #include "nsTimerImpl.h"
  15 #include "nsThreadUtils.h"
  16
  17 #include "nsTArray.h"
  18
  19 #include "mozilla/Atomics.h"
  20 #include "mozilla/Attributes.h"
  21 #include "mozilla/Monitor.h"
  22 #include "mozilla/UniquePtr.h"
  23
  24 #include <algorithm>
  25
  26 namespace mozilla {
  27 class TimeStamp;
  28 }  // namespace mozilla
  29
  30 class TimerThread final : public mozilla::Runnable, public nsIObserver {
  31  public:
  32   typedef mozilla::Monitor Monitor;
  33   typedef mozilla::TimeStamp TimeStamp;
  34   typedef mozilla::TimeDuration TimeDuration;
  35
  36   TimerThread();
  37   nsresult InitLocks();
  38
  39   NS_DECL_ISUPPORTS_INHERITED
  40   NS_DECL_NSIRUNNABLE
  41   NS_DECL_NSIOBSERVER
  42
  43   nsresult Shutdown();
  44
  45   nsresult AddTimer(nsTimerImpl* aTimer);
  46   nsresult RemoveTimer(nsTimerImpl* aTimer);
  47   TimeStamp FindNextFireTimeForCurrentThread(TimeStamp aDefault,
  48                                              uint32_t aSearchBound);
  49
  50   void DoBeforeSleep();
  51   void DoAfterSleep();
  52
  53   bool IsOnTimerThread() const {
  54     return mThread->SerialEventTarget()->IsOnCurrentThread();
  55   }
  56
  57   uint32_t AllowedEarlyFiringMicroseconds() const;
  58
  59  private:
  60   ~TimerThread();
  61
  62   bool mInitialized;
  63
  64   // These internal helper methods must be called while mMonitor is held.
  65   // AddTimerInternal returns false if the insertion failed.
  66   bool AddTimerInternal(nsTimerImpl* aTimer);
  67   bool RemoveTimerInternal(nsTimerImpl* aTimer);
  68   void RemoveLeadingCanceledTimersInternal();
  69   void RemoveFirstTimerInternal();
  70   nsresult Init();
  71
  72   already_AddRefed<nsTimerImpl> PostTimerEvent(
  73       already_AddRefed<nsTimerImpl> aTimerRef);
  74
  75   nsCOMPtr<nsIThread> mThread;
  76   Monitor mMonitor;
  77
  78   bool mShutdown;
  79   bool mWaiting;
  80   bool mNotified;
  81   bool mSleeping;
  82
  83   class Entry final : public nsTimerImplHolder {
  84     const TimeStamp mTimeout;
  85
  86    public:
  87     Entry(const TimeStamp& aMinTimeout, const TimeStamp& aTimeout,
  88           nsTimerImpl* aTimerImpl)
  89         : nsTimerImplHolder(aTimerImpl),
  90           mTimeout(std::max(aMinTimeout, aTimeout)) {}
  91
  92     nsTimerImpl* Value() const { return mTimerImpl; }
  93
  94     already_AddRefed<nsTimerImpl> Take() {
  95       if (mTimerImpl) {
  96         mTimerImpl->SetHolder(nullptr);
  97       }
  98       return mTimerImpl.forget();
  99     }
 100
 101     static bool UniquePtrLessThan(mozilla::UniquePtr<Entry>& aLeft,
 102                                   mozilla::UniquePtr<Entry>& aRight) {
 103       // This is reversed because std::push_heap() sorts the "largest" to
 104       // the front of the heap.  We want that to be the earliest timer.
 105       return aRight->mTimeout < aLeft->mTimeout;
 106     }
 107
 108     TimeStamp Timeout() const { return mTimeout; }
 109   };
 110
 111   nsTArray<mozilla::UniquePtr<Entry>> mTimers;
 112   uint32_t mAllowedEarlyFiringMicroseconds;
 113 };
 114
 115 #endif /* TimerThread_h___ */