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
  46   typedef
  47   std::priority_queue<Timer*, std::vector<Timer*>, TimerCompare> TimerQ;
  48
  49   //! Milliseconds between timer firings
  50   long _delay;
  51   //! Callback for timer expiry
  52   TimeoutHandler _action;
  53   //! Data sent to callback
  54   void *_data;
  55   //! We overload the delete operator to just set this to true
  56   bool _del_me;
  57   //! The time the last fire should've been at
  58   struct timeval _last;
  59   //! When this timer will next trigger
  60   struct timeval _timeout;
  61
  62   //! Queue of pending timers
  63   static TimerQ _q;
  64   //! Time next timer will expire
  65   static timeval _nearest_timeout;
  66   //! Time at start of current processing loop
  67   static timeval _now;
  68
  69   //! Really delete something (not just flag for later)
  70   /*!
  71     @param self Timer to be deleted.
  72   */
  73   static void realDelete(Timer *self);
  74
  75   //! Adds a millisecond delay to a timeval structure
  76   /*!
  77     @param a Amount of time to increment.
  78     @param msec Number of milliseconds to increment by.
  79   */
  80   static void timevalAdd(timeval &a, long msec);
  81
  82 public:
  83   //! Constructs a new running timer and queues it
  84   /*!
  85     @param delay Time in milliseconds between firings
  86     @param cb The function to be called on fire.
  87     @param data Data to be passed to the callback on fire.
  88   */
  89   Timer(long delay, TimeoutHandler cb, void *data);
  90
  91   //! Overloaded delete so we can leave deleted objects in queue for later reap
  92   /*!
  93     @param self Pointer to current instance of Timer.
  94   */
  95   void operator delete(void *self);
  96
  97   //! Dispatches all elligible timers, then optionally waits for X events
  98   /*!
  99     @param wait Whether to wait for X events after processing timers.
 100   */
 101   static void dispatchTimers(bool wait = true);
 102
 103   //! Returns a relative timeval (to pass select) of the next timer
 104   /*!
 105     @param tm Changed to hold the time until next timer.
 106     @return true if there are any timers queued, and the timeout is being
 107             returned in 'tm'. false if there are no timers queued.
 108   */
 109   static bool nearestTimeout(struct timeval &tm);
 110
 111   //! Initializes internal data before use
 112   static void initialize(void);
 113
 114   //! Deletes all waiting timers
 115   static void destroy(void);
 116 };
 117
 118 }
 119
 120 #endif // __timer.hh