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 #ifdef    HAVE_UNISTD_H
  22 #  include <sys/types.h>
  23 #  include <unistd.h>
  24 #endif // HAVE_UNISTD_H
  25 }
  26
  27 #include <queue>
  28 #include <vector>
  29
  30 namespace otk {
  31
  32 //! The Timer class implements timed callbacks.
  33 /*!
  34   The Timer class can be used to have a callback fire after a given time
  35   interval. A created Timer will fire repetitively until it is destroyed.
  36 */
  37 class Timer {
  38 public:
  39   //! Data type of Timer callback
  40   typedef void (*TimeoutHandler)(void *data);
  41
  42 private:
  43   //! Compares two timeval structs
  44   struct TimerCompare {
  45      //! Compares two timeval structs
  46      inline bool operator()(const Timer *a, const Timer *b) const {
  47        return timercmp(&a->_timeout, &b->_timeout, >);
  48      }
  49   };
  50
  51   typedef
  52   std::priority_queue<Timer*, std::vector<Timer*>, TimerCompare> TimerQ;
  53
  54   //! Milliseconds between timer firings
  55   long _delay;
  56   //! Callback for timer expiry
  57   TimeoutHandler _action;
  58   //! Data sent to callback
  59   void *_data;
  60   //! We overload the delete operator to just set this to true
  61   bool _del_me;
  62   //! The time the last fire should've been at
  63   struct timeval _last;
  64   //! When this timer will next trigger
  65   struct timeval _timeout;
  66
  67   //! Queue of pending timers
  68   static TimerQ _q;
  69   //! Time next timer will expire
  70   static timeval _nearest_timeout;
  71   //! Time at start of current processing loop
  72   static timeval _now;
  73
  74   //! Really delete something (not just flag for later)
  75   /*!
  76     @param self Timer to be deleted.
  77   */
  78   static void realDelete(Timer *self);
  79
  80   //! Adds a millisecond delay to a timeval structure
  81   /*!
  82     @param a Amount of time to increment.
  83     @param msec Number of milliseconds to increment by.
  84   */
  85   static void timevalAdd(timeval &a, long msec);
  86
  87 public:
  88   //! Constructs a new running timer and queues it
  89   /*!
  90     @param delay Time in milliseconds between firings
  91     @param cb The function to be called on fire.
  92     @param data Data to be passed to the callback on fire.
  93   */
  94   Timer(long delay, TimeoutHandler cb, void *data);
  95
  96   //! Overloaded delete so we can leave deleted objects in queue for later reap
  97   /*!
  98     @param self Pointer to current instance of Timer.
  99   */
 100   void operator delete(void *self);
 101
 102   //! Dispatches all elligible timers, then optionally waits for X events
 103   /*!
 104     @param wait Whether to wait for X events after processing timers.
 105   */
 106   static void dispatchTimers(bool wait = true);
 107
 108   //! Returns a relative timeval (to pass select) of the next timer
 109   /*!
 110     @param tm Changed to hold the time until next timer.
 111     @return true if there are any timers queued, and the timeout is being
 112             returned in 'tm'. false if there are no timers queued.
 113   */
 114   static bool nearestTimeout(struct timeval &tm);
 115
 116   //! Initializes internal data before use
 117   static void initialize(void);
 118
 119   //! Deletes all waiting timers
 120   static void destroy(void);
 121 };
 122
 123 }
 124
 125 #endif // __timer.hh