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 #ifdef    TIME_WITH_SYS_TIME
  11 #  include <sys/time.h>
  12 #  include <time.h>
  13 #else // !TIME_WITH_SYS_TIME
  14 #  ifdef    HAVE_SYS_TIME_H
  15 #    include <sys/time.h>
  16 #  else // !HAVE_SYS_TIME_H
  17 #    include <time.h>
  18 #  endif // HAVE_SYS_TIME_H
  19 #endif // TIME_WITH_SYS_TIME
  20 }
  21
  22 #include <queue>
  23 #include <vector>
  24
  25 namespace otk {
  26
  27 //! The Timer class implements timed callbacks.
  28 /*!
  29   The Timer class can be used to have a callback fire after a given time
  30   interval. A created Timer will fire repetitively until it is destroyed.
  31 */
  32 class Timer {
  33 public:
  34   //! Data type of Timer callback
  35   typedef void (*TimeoutHandler)(void *data);
  36
  37 private:
  38   //! Compares two timeval structs
  39   struct TimerCompare {
  40      //! Compares two timeval structs
  41      inline bool operator()(const Timer *a, const Timer *b) const {
  42        return timercmp(&a->_timeout, &b->_timeout, >);
  43      }
  44   };
  45   friend struct TimerCompare; // give access to _timeout for shitty compilers
  46
  47   typedef
  48   std::priority_queue<Timer*, std::vector<Timer*>, TimerCompare> TimerQ;
  49
  50   //! Milliseconds between timer firings
  51   long _delay;
  52   //! Callback for timer expiry
  53   TimeoutHandler _action;
  54   //! Data sent to callback
  55   void *_data;
  56   //! We overload the delete operator to just set this to true
  57   bool _del_me;
  58   //! The time the last fire should've been at
  59   struct timeval _last;
  60   //! When this timer will next trigger
  61   struct timeval _timeout;
  62
  63   //! Queue of pending timers
  64   static TimerQ _q;
  65   //! Time next timer will expire
  66   static timeval _nearest_timeout;
  67   //! Time at start of current processing loop
  68   static timeval _now;
  69
  70   //! Really delete something (not just flag for later)
  71   /*!
  72     @param self Timer to be deleted.
  73   */
  74   static void realDelete(Timer *self);
  75
  76   //! Adds a millisecond delay to a timeval structure
  77   /*!
  78     @param a Amount of time to increment.
  79     @param msec Number of milliseconds to increment by.
  80   */
  81   static void timevalAdd(timeval &a, long msec);
  82
  83 public:
  84   //! Constructs a new running timer and queues it
  85   /*!
  86     @param delay Time in milliseconds between firings
  87     @param cb The function to be called on fire.
  88     @param data Data to be passed to the callback on fire.
  89   */
  90   Timer(long delay, TimeoutHandler cb, void *data);
  91
  92   //! Overloaded delete so we can leave deleted objects in queue for later reap
  93   /*!
  94     @param self Pointer to current instance of Timer.
  95   */
  96   void operator delete(void *self);
  97
  98   //! Dispatches all elligible timers, then optionally waits for X events
  99   /*!
 100     @param wait Whether to wait for X events after processing timers.
 101   */
 102   static void dispatchTimers(bool wait = true);
 103
 104   //! Returns a relative timeval (to pass select) of the next timer
 105   /*!
 106     @param tm Changed to hold the time until next timer.
 107     @return true if there are any timers queued, and the timeout is being
 108             returned in 'tm'. false if there are no timers queued.
 109   */
 110   static bool nearestTimeout(struct timeval &tm);
 111
 112   //! Initializes internal data before use
 113   static void initialize(void);
 114
 115   //! Deletes all waiting timers
 116   static void destroy(void);
 117 };
 118
 119 }
 120
 121 #endif // __timer.hh