NAME
ACE_Timer_Wheel_T - Provides a Timing Wheel version of Timer Queue
SYNOPSIS
#include <ace/Timer_Wheel.h>
template<class TYPE, class FUNCTOR, class ACE_LOCK>
class ACE_Timer_Wheel_T :
public ACE_Timer_Queue_T<TYPE, FUNCTOR, ACE_LOCK>
{
public:
typedef ACE_Timer_Wheel_Iterator_T<TYPE, FUNCTOR, ACE_LOCK> WHEEL_ITERATOR;
friend class ACE_Timer_Wheel_Iterator_T<TYPE, FUNCTOR, ACE_LOCK>;
typedef ACE_Timer_Queue_T<TYPE, FUNCTOR, ACE_LOCK> INHERITED;
ACE_Timer_Wheel_T (
size_t wheelsize,
size_t resolution,
size_t prealloc = 0,
FUNCTOR *upcall_functor = 0,
ACE_Free_List<ACE_Timer_Node_T <TYPE> > *freelist = 0
);
ACE_Timer_Wheel_T (
FUNCTOR *upcall_functor = 0,
ACE_Free_List<ACE_Timer_Node_T <TYPE> > *freelist = 0
);
virtual ~ACE_Timer_Wheel_T (void);
virtual int is_empty (void) const;
virtual const ACE_Time_Value &earliest_time (void) const;
virtual long schedule (
const TYPE &type,
const void *act,
const ACE_Time_Value &delay,
const ACE_Time_Value &interval = ACE_Time_Value::zero
);
virtual int reset_interval (
long timer_id,
const ACE_Time_Value &interval
);
virtual int cancel (
const TYPE &type,
int dont_call_handle_close = 1
);
virtual int cancel (
long timer_id,
const void **act = 0,
int dont_call_handle_close = 1
);
virtual int expire (void);
int expire (const ACE_Time_Value &);
virtual ACE_Timer_Queue_Iterator_T<TYPE, FUNCTOR, ACE_LOCK> &iter (
void
);
virtual ACE_Timer_Node_T<TYPE> *remove_first (void);
virtual void dump (void) const;
virtual ACE_Timer_Node_T<TYPE> *get_first (void);
private:
virtual void reschedule (ACE_Timer_Node_T<TYPE> *);
ACE_Timer_Node_T<TYPE> **wheel_;
size_t wheel_size_;
size_t resolution_;
size_t earliest_pos_;
long size_;
WHEEL_ITERATOR *iterator_;
ACE_Timer_Node_T<TYPE> *freelist_;
inline ACE_UNIMPLEMENTED_FUNC (
ACE_Timer_Wheel_T (const ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK> &)
);
};
DESCRIPTION
This implementation uses a hash table of ordered doubly- linked lists of absolute times. The other enhancements to Timer List include using the pointer to the node as the timer id (to speed up removing), adding a free list and the ability to preallocate nodes. Timer Wheel is based on the timing wheel implementation used in Adam M. Costello and George Varghese's paper "Redesigning the BSD Callout and Timer Facilities" (http://dworkin.wustl.edu/~varghese/PAPERS/newbsd.ps.Z)
Initialization and termination methods
ACE_Timer_Wheel_T (
size_t wheelsize,
size_t resolution,
size_t prealloc = 0,
FUNCTOR *upcall_functor = 0,
ACE_Free_List<ACE_Timer_Node_T <TYPE> > *freelist = 0
);
Constructor that takes in wheelsize - size of the timing wheel, resolution - resolution of time values the hashing function uses, and upcall_functor - a functor that will be used instead of creating a default functor. Also, when the freelist is created, prealloc nodes will be allocated. This can also take in a upcall functor and freelist (if 0, then defaults will be created)
ACE_Timer_Wheel_T (
FUNCTOR *upcall_functor = 0,
ACE_Free_List<ACE_Timer_Node_T <TYPE> > *freelist = 0
);
Default constructor. upcall_functor is the instance of the FUNCTOR to be used by the queue. If upcall_functor is 0, Timer Queue will create a default FUNCTOR. freelist the freelist of timer nodes. If 0, then a default freelist will be created. The defaults will be used for size and resolution and no preallocation (ACE_DEFAULT_TIMER_WHEEL_SIZE, ACE_DEFAULT_TIMER_WHEEL_RESOLUTION)
virtual ~ACE_Timer_Wheel_T (void);
Destructor
virtual int is_empty (void) const;
True if queue is empty, else false.
virtual const ACE_Time_Value &earliest_time (void) const;
Returns the time of the earlier node in the ACE_Timer_Wheel.
virtual long schedule (
const TYPE &type,
const void *act,
const ACE_Time_Value &delay,
const ACE_Time_Value &interval = ACE_Time_Value::zero
);
Schedule type that will expire after delay amount of time, which is specified in absolute time. If it expires then act is passed in as the value to the functor. If interval is != to ACE_Time_Value::zero then it is used to reschedule the type automatically, using relative time to the current gettimeofday. This method returns a timer_id that uniquely identifies the the timer. This timer_id can be used to cancel the timer before it expires. Returns -1 on failure.
virtual int reset_interval (
long timer_id,
const ACE_Time_Value &interval
);
Resets the interval of the timer represented by timer_id to interval, which is specified in relative time to the current gettimeofday. If interval is equal to ACE_Time_Value::zero, the timer will become a non-rescheduling timer. Returns 0 if successful, -1 if not.
virtual int cancel (const TYPE &type, int dont_call_handle_close = 1);
Cancel all timer associated with type. If dont_call is 0 then the functor will be invoked. Returns number of timers cancelled.
virtual int cancel (
long timer_id,
const void **act = 0,
int dont_call_handle_close = 1
);
Cancel the single timer that matches the timer_id value (which was returned from the schedule method). If act is non-NULL then it will be set to point to the ``magic cookie'' argument passed in when the timer was registered. This makes it possible to free up the memory and avoid memory leaks. If dont_call is 0 then the functor will be invoked. Returns 1 if cancellation succeeded and 0 if the timer_id wasn't found.
virtual int expire (void);
Run the functor for all timers whose values are = ACE_OS::gettimeofday. Also accounts for timer_skew. Returns the number of timers canceled.
int expire (const ACE_Time_Value &);
Run the functor for all timers whose values are = cur_time. This does not account for timer_skew. Returns the number of timers canceled.
virtual ACE_Timer_Queue_Iterator_T<TYPE, FUNCTOR, ACE_LOCK> &iter (
void
);
Returns a pointer to this ACE_Timer_Queue_T's iterator.
virtual ACE_Timer_Node_T<TYPE> *remove_first (void);
Removes the earliest node from the queue and returns it
virtual void dump (void) const;
Dump the state of an object.
virtual ACE_Timer_Node_T<TYPE> *get_first (void);
Reads the earliest node from the queue and returns it.
Don't allow these operations for now.
inline ACE_UNIMPLEMENTED_FUNC (
ACE_Timer_Wheel_T (const ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK> &)
);
AUTHOR
Darrell Brunsch [email protected]
LIBRARY
ace