Dogcows Code - chaz/openbox/blob - otk/timer.hh

   1 // -*- mode: C++; indent-tabs-mode: nil; c-basic-offset: 2; -*-
   2 #ifndef   __timer_hh
   3 #define   __timer_hh
   4
   5 /*! @file timer.hh
   6   @brief Contains the Timer class, used for timed callbacks.
   7 */
   8
   9 extern "C" {
  10 #include <ctime>
  11 }
  12
  13 #include <queue>
  14 #include <vector>
  15
  16 namespace otk {
  17
  18 //! The Timer class implements timed callbacks.
  19 /*!
  20   The Timer class can be used to have a callback fire after a given time
  21   interval. A created Timer will fire repetitively until it is destroyed.
  22 */
  23 class Timer {
  24 public:
  25   //! Data type of Timer callback
  26   typedef void (*TimeoutHandler)(void *data);
  27
  28 private:
  29   //! Compares two timeval structs
  30   struct TimerCompare {
  31      //! Compares two timeval structs
  32      inline bool operator()(const Timer *a, const Timer *b) const {
  33        return ((&a->_timeout)->tv_sec == (&b->_timeout)->tv_sec) ?
  34          ((&a->_timeout)->tv_usec > (&b->_timeout)->tv_usec) :
  35          ((&a->_timeout)->tv_sec > (&b->_timeout)->tv_sec);
  36      }
  37   };
  38   friend struct TimerCompare; // give access to _timeout for shitty compilers
  39
  40   typedef
  41   std::priority_queue<Timer*, std::vector<Timer*>, TimerCompare> TimerQ;
  42
  43   //! Milliseconds between timer firings
  44   long _delay;
  45   //! Callback for timer expiry
  46   TimeoutHandler _action;
  47   //! Data sent to callback
  48   void *_data;
  49   //! We overload the delete operator to just set this to true
  50   bool _del_me;
  51   //! The time the last fire should've been at
  52   struct timeval _last;
  53   //! When this timer will next trigger
  54   struct timeval _timeout;
  55
  56   //! Queue of pending timers
  57   static TimerQ _q;
  58   //! Time next timer will expire
  59   static timeval _nearest_timeout;
  60   //! Time at start of current processing loop
  61   static timeval _now;
  62
  63   //! Really delete something (not just flag for later)
  64   /*!
  65     @param self Timer to be deleted.
  66   */
  67   static void realDelete(Timer *self);
  68
  69   //! Adds a millisecond delay to a timeval structure
  70   /*!
  71     @param a Amount of time to increment.
  72     @param msec Number of milliseconds to increment by.
  73   */
  74   static void timevalAdd(timeval &a, long msec);
  75
  76 public:
  77   //! Constructs a new running timer and queues it
  78   /*!
  79     @param delay Time in milliseconds between firings
  80     @param cb The function to be called on fire.
  81     @param data Data to be passed to the callback on fire.
  82   */
  83   Timer(long delay, TimeoutHandler cb, void *data);
  84
  85   //! Overloaded delete so we can leave deleted objects in queue for later reap
  86   /*!
  87     @param self Pointer to current instance of Timer.
  88   */
  89   void operator delete(void *self);
  90
  91   //! Dispatches all elligible timers, then optionally waits for X events
  92   /*!
  93     @param wait Whether to wait for X events after processing timers.
  94   */
  95   static void dispatchTimers(bool wait = true);
  96
  97   //! Returns a relative timeval (to pass select) of the next timer
  98   /*!
  99     @param tm Changed to hold the time until next timer.
 100     @return true if there are any timers queued, and the timeout is being
 101             returned in 'tm'. false if there are no timers queued.
 102   */
 103   static bool nearestTimeout(struct timeval &tm);
 104
 105   //! Initializes internal data before use
 106   static void initialize(void);
 107
 108   //! Deletes all waiting timers
 109   static void destroy(void);
 110 };
 111
 112 }
 113
 114 #endif // __timer.hh