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/* -*- C++ -*- */
// ============================================================================
//
// = LIBRARY
// ace
//
// = FILENAME
// Timer_Wheel.h
//
// = AUTHOR
// Darrell Brunsch <brunsch@cs.wustl.edu>
//
// ============================================================================
#if !defined (ACE_TIMER_WHEEL_T_H)
#define ACE_TIMER_WHEEL_T_H
#include "ace/Timer_Queue_T.h"
// Forward declaration
template <class TYPE, class FUNCTOR, class LOCK>
class ACE_Timer_Wheel_T;
template <class TYPE, class FUNCTOR, class LOCK>
class ACE_Timer_Wheel_Iterator_T : public ACE_Timer_Queue_Iterator_T <TYPE, FUNCTOR, LOCK>
// = TITLE
// Iterates over an <ACE_Timer_Wheel>.
//
// = DESCRIPTION
// This is a generic iterator that can be used to visit every
// node of a timer queue. Be aware that it doesn't transverse
// in the order of timeout values.
{
public:
ACE_Timer_Wheel_Iterator_T (ACE_Timer_Wheel_T<TYPE, FUNCTOR, LOCK> &);
// Constructor
virtual void first (void);
// Positions the iterator at the earliest node in the Timer Queue
virtual void next (void);
// Positions the iterator at the next node in the Timer Queue
virtual int isdone (void);
// Returns true when there are no more nodes in the sequence
virtual ACE_Timer_Node_T<TYPE> *item (void);
// Returns the node at the current position in the sequence
protected:
ACE_Timer_Wheel_T<TYPE, FUNCTOR, LOCK> &timer_wheel_;
// Pointer to the <ACE_Timer_List> that we are iterating over.
size_t pos_;
// Current position in the timing wheel
ACE_Timer_Node_T<TYPE> *list_item_;
// Pointer to the position in the the <pos_>th list
};
template <class TYPE, class FUNCTOR, class LOCK>
class ACE_Timer_Wheel_T : public ACE_Timer_Queue_T<TYPE, FUNCTOR, LOCK>
// = TITLE
// Provides a Timing Wheel version of Timer Queue
//
// = 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)
//
{
public:
typedef ACE_Timer_Wheel_Iterator_T<TYPE, FUNCTOR, LOCK> WHEEL_ITERATOR;
// Type of iterator
friend class ACE_Timer_Wheel_Iterator_T<TYPE, FUNCTOR, LOCK>;
// Iterator is a friend
typedef ACE_Timer_Queue_T<TYPE, FUNCTOR, LOCK> INHERITED;
// Type inherited from
// = 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.
// 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. 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 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, 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.
private:
virtual void reschedule (ACE_Timer_Node_T<TYPE> *);
// Reschedule an "interval" node
ACE_Timer_Node_T<TYPE> **wheel_;
// Timing Wheel.
size_t wheel_size_;
// Size of the timing wheel.
size_t resolution_;
// Resolution (in microsoconds) of the timing wheel.
size_t earliest_pos_;
// Index of the list with the earliest time
long size_;
// Keeps track of the size of the queue
ACE_Timer_Wheel_Iterator_T<TYPE, FUNCTOR, LOCK> iterator_;
// Iterator used to expire timers.
ACE_Timer_Node_T<TYPE> *freelist_;
// Pointer to the freelist of <ACE_Timer_Node_T<TYPE>>.
// = Don't allow these operations for now.
ACE_Timer_Wheel_T (const ACE_Timer_Wheel_T<TYPE, FUNCTOR, LOCK> &);
void operator= (const ACE_Timer_Wheel_T<TYPE, FUNCTOR, LOCK> &);
};
#if defined (ACE_TEMPLATES_REQUIRE_SOURCE)
#include "ace/Timer_Wheel_T.cpp"
#endif /* ACE_TEMPLATES_REQUIRE_SOURCE */
#if defined (ACE_TEMPLATES_REQUIRE_PRAGMA)
#pragma implementation ("Timer_Wheel_T.cpp")
#endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */
#endif /* ACE_TIMER_WHEEL_T_H */
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