xpcom/threads/nsTimerImpl.h

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  17  * The Original Code is mozilla.org code.
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  21  * Portions created by the Initial Developer are Copyright (C) 2001
  22  * the Initial Developer. All Rights Reserved.
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  24  * Contributor(s):
  25  *   Stuart Parmenter <pavlov@netscape.com>
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  40
  41 #ifndef nsTimerImpl_h___
  42 #define nsTimerImpl_h___
  43
  44 //#define FORCE_PR_LOG /* Allow logging in the release build */
  45
  46 #include "nsITimer.h"
  47 #include "nsIEventTarget.h"
  48 #include "nsIObserver.h"
  49
  50 #include "nsCOMPtr.h"
  51
  52 #include "prlog.h"
  53
  54 #if defined(PR_LOGGING)
  55 static PRLogModuleInfo *gTimerLog = PR_NewLogModule("nsTimerImpl");
  56 #define DEBUG_TIMERS 1
  57 #else
  58 #undef DEBUG_TIMERS
  59 #endif
  60
  61 #define NS_TIMER_CLASSNAME "Timer"
  62 #define NS_TIMER_CID \
  63 { /* 5ff24248-1dd2-11b2-8427-fbab44f29bc8 */         \
  64      0x5ff24248,                                     \
  65      0x1dd2,                                         \
  66      0x11b2,                                         \
  67     {0x84, 0x27, 0xfb, 0xab, 0x44, 0xf2, 0x9b, 0xc8} \
  68 }
  69
  70 enum {
  71   CALLBACK_TYPE_UNKNOWN   = 0,
  72   CALLBACK_TYPE_INTERFACE = 1,
  73   CALLBACK_TYPE_FUNC      = 2,
  74   CALLBACK_TYPE_OBSERVER  = 3
  75 };
  76
  77 // Two timer deadlines must differ by less than half the PRIntervalTime domain.
  78 #define DELAY_INTERVAL_LIMIT    PR_BIT(8 * sizeof(PRIntervalTime) - 1)
  79
  80 // Maximum possible delay (XXX rework to use ms rather than interval ticks).
  81 #define DELAY_INTERVAL_MAX      (DELAY_INTERVAL_LIMIT - 1)
  82
  83 // Is interval-time t less than u, even if t has wrapped PRIntervalTime?
  84 #define TIMER_LESS_THAN(t, u)   ((t) - (u) > DELAY_INTERVAL_LIMIT)
  85
  86 class nsTimerImpl : public nsITimer
  87 {
  88 public:
  89
  90   nsTimerImpl();
  91
  92   static NS_HIDDEN_(nsresult) Startup();
  93   static NS_HIDDEN_(void) Shutdown();
  94
  95   friend class TimerThread;
  96
  97   void Fire();
  98   nsresult PostTimerEvent();
  99   void SetDelayInternal(PRUint32 aDelay);
 100
 101   NS_DECL_ISUPPORTS
 102   NS_DECL_NSITIMER
 103
 104   PRInt32 GetGeneration() { return mGeneration; }
 105
 106 private:
 107   ~nsTimerImpl();
 108   nsresult InitCommon(PRUint32 aType, PRUint32 aDelay);
 109
 110   void ReleaseCallback()
 111   {
 112     // if we're the last owner of the callback object, make
 113     // sure that we don't recurse into ReleaseCallback in case
 114     // the callback's destructor calls Cancel() or similar.
 115     PRUint8 cbType = mCallbackType;
 116     mCallbackType = CALLBACK_TYPE_UNKNOWN;
 117
 118     if (cbType == CALLBACK_TYPE_INTERFACE)
 119       NS_RELEASE(mCallback.i);
 120     else if (cbType == CALLBACK_TYPE_OBSERVER)
 121       NS_RELEASE(mCallback.o);
 122   }
 123
 124   nsCOMPtr<nsIEventTarget> mEventTarget;
 125
 126   void *                mClosure;
 127
 128   union CallbackUnion {
 129     nsTimerCallbackFunc c;
 130     nsITimerCallback *  i;
 131     nsIObserver *       o;
 132   } mCallback;
 133
 134   // Some callers expect to be able to access the callback while the
 135   // timer is firing.
 136   nsCOMPtr<nsITimerCallback> mTimerCallbackWhileFiring;
 137
 138   // These members are set by Init (called from NS_NewTimer) and never reset.
 139   PRUint8               mCallbackType;
 140
 141   // These members are set by the initiating thread, when the timer's type is
 142   // changed and during the period where it fires on that thread.
 143   PRUint8               mType;
 144   PRPackedBool          mFiring;
 145
 146
 147   // Use a PRBool (int) here to isolate loads and stores of these two members
 148   // done on various threads under the protection of TimerThread::mLock, from
 149   // loads and stores done on the initiating/type-changing/timer-firing thread
 150   // to the above PRUint8/PRPackedBool members.
 151   PRBool                mArmed;
 152   PRBool                mCanceled;
 153
 154   // The generation number of this timer, re-generated each time the timer is
 155   // initialized so one-shot timers can be canceled and re-initialized by the
 156   // arming thread without any bad race conditions.
 157   PRInt32               mGeneration;
 158
 159   PRUint32              mDelay;
 160   PRIntervalTime        mTimeout;
 161
 162 #ifdef DEBUG_TIMERS
 163   PRIntervalTime        mStart, mStart2;
 164   static double         sDeltaSum;
 165   static double         sDeltaSumSquared;
 166   static double         sDeltaNum;
 167 #endif
 168
 169 };
 170
 171 #endif /* nsTimerImpl_h___ */