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/* -*- C++ -*- */
// $Id$
// ============================================================================
//
// = LIBRARY
// ace
//
// = FILENAME
// Timer_Queue.h
//
// = AUTHOR
// Doug Schmidt
//
// ============================================================================
#if !defined (ACE_TIMER_QUEUE_H)
#define ACE_TIMER_QUEUE_H
#include "ace/Event_Handler.h"
#include "ace/Time_Value.h"
#include "ace/Synch.h"
// Forward declaration.
class ACE_Timer_Queue;
// This should be nested within the ACE_Timer_Queue class but some C++
// compilers still don't like this...
class ACE_Export ACE_Timer_Node
// = TITLE
// Maintains the state associated with a Timer entry.
{
// = The use of friends should be replaced with accessors...
friend class ACE_Timer_Queue;
friend class ACE_Timer_List;
friend class ACE_Timer_List_Iterator;
friend class ACE_Timer_Heap;
friend class ACE_Timer_Heap_Iterator;
// = Initialization methods.
ACE_Timer_Node (ACE_Event_Handler *h,
const void *a,
const ACE_Time_Value &t,
const ACE_Time_Value &i,
ACE_Timer_Node *n,
int timer_id);
// Constructor.
ACE_Timer_Node (void);
// Default constructor.
ACE_Event_Handler *handler_;
// Handler to invoke <handle_timeout> on when a timeout occurs.
const void *arg_;
// Argument to pass to <handle_timeout>.
ACE_Time_Value timer_value_;
// Time until the timer expires.
ACE_Time_Value interval_;
// If this is a periodic timer this holds the time until the next
// timeout.
ACE_Timer_Node *next_;
// Pointer to next timer.
int timer_id_;
// Id of this timer (used to cancel timers before they expire).
ACE_ALLOC_HOOK_DECLARE;
// Declare the dynamic allocation hooks.
void dump (void) const;
// Dump the state of an object.
};
class ACE_Export ACE_Timer_Queue_Iterator
// = TITLE
// Generic interfae for iterating over a subclass of
// <ACE_Timer_Queue>.
//
// = DESCRIPTION
// This is a special type of iterator that "advances" by moving
// the head of the timer queue up by one every time.
{
public:
ACE_Timer_Queue_Iterator (void);
virtual ~ACE_Timer_Queue_Iterator (void);
virtual int next (ACE_Timer_Node *&timer_node,
const ACE_Time_Value &cur_time) = 0;
// Pass back the next <timer_node> that hasn't been seen yet, if its
// <time_value_> <= <cur_time>. In addition, moves the timer queue
// forward by one node. Returns 0 when all <timer_nodes> have been
// seen, else 1.
};
class ACE_Export ACE_Timer_Queue
// = TITLE
// Provides an interface to timers.
//
// = DESCRIPTION
// This is an abstract base class that provides hook for
// implementing specialized policies such as <ACE_Timer_List>
// and <ACE_Timer_Heap>.
{
public:
// = Initialization and termination methods.
ACE_Timer_Queue (void);
// Default constructor.
virtual ~ACE_Timer_Queue (void);
// Destructor - make virtual for proper destruction of inherited
// classes.
virtual int is_empty (void) const = 0;
// True if queue is empty, else false.
virtual const ACE_Time_Value &earliest_time (void) const = 0;
// Returns the time of the earlier node in the Timer_Queue.
virtual int schedule (ACE_Event_Handler *event_handler,
const void *arg,
const ACE_Time_Value &delay,
const ACE_Time_Value &interval = ACE_Time_Value::zero) = 0;
// Schedule an <event_handler> that will expire after <delay> amount
// of time. If it expires then <arg> is passed in as the value to
// the <event_handler>'s <handle_timeout> callback method. If
// <interval> is != to <ACE_Time_Value::zero> then it is used to
// reschedule the <event_handler> automatically. This method
// returns a <timer_id> that uniquely identifies the <event_handler>
// in an internal list. This <timer_id> can be used to cancel an
// <event_handler> before it expires. The cancellation ensures that
// <timer_ids> are unique up to values of greater than 2 billion
// timers. As long as timers don't stay around longer than this
// there should be no problems with accidentally deleting the wrong
// timer. Returns -1 on failure (which is guaranteed never to be a
// valid <timer_id>).
virtual int cancel (ACE_Event_Handler *event_handler,
int dont_call_handle_close = 1) = 0;
// Cancel all <event_handlers> that match the address of
// <event_handler>. If <dont_call_handle_close> is 0 then the
// <handle_close> method of <event_handler> will be invoked.
// Returns number of handler's cancelled.
virtual int cancel (int timer_id,
const void **arg = 0,
int dont_call_handle_close = 1) = 0;
// Cancel the single <ACE_Event_Handler> that matches the <timer_id>
// value (which was returned from the <schedule> method). If arg is
// non-NULL then it will be set to point to the ``magic cookie''
// argument passed in when the <Event_Handler> was registered. This
// makes it possible to free up the memory and avoid memory leaks.
// If <dont_call_handle_close> is 0 then the <handle_close> method
// of <event_handler> will be invoked. Returns 1 if cancellation
// succeeded and 0 if the <timer_id> wasn't found.
virtual int expire (const ACE_Time_Value ¤t_time);
// Run the <handle_timeout> method for all Timers whose values are
// <= <cur_time>. This does not account for <timer_skew>. Returns
// the number of <Event_Handler>s for which <handle_timeout> was
// called.
virtual int expire (void);
// Run the <handle_timeout> method for all Timers whose values are
// <= <ACE_OS::gettimeofday>. Also accounts for <timer_skew>.
// Returns the number of <Event_Handler>s for which <handle_timeout>
// was called.
virtual ACE_Time_Value gettimeofday (void);
// Returns the current time of day. This allows different
// implementations of the timer queue to use special high resolution
// timers.
void gettimeofday (ACE_Time_Value (*gettimeofday)(void));
// Allows applications to control how the timer queue gets the time
// of day.
virtual ACE_Time_Value *calculate_timeout (ACE_Time_Value *max);
// Determine the next event to timeout. Returns <max> if there are
// no pending timers or if all pending timers are longer than max.
// = Set/get the timer skew for the Timer_Queue.
void timer_skew (const ACE_Time_Value &skew);
const ACE_Time_Value &timer_skew (void) const;
virtual void dump (void) const;
// Dump the state of an object.
ACE_ALLOC_HOOK_DECLARE;
// Declare the dynamic allocation hooks.
protected:
virtual void reschedule (ACE_Timer_Node *) = 0;
// Reschedule an "interval" <ACE_Timer_Node>.
virtual ACE_Timer_Queue_Iterator &iter (void) = 0;
// Returns a pointer to this <ACE_Timer_Queue>'s iterator.
virtual ACE_Timer_Node *alloc_node (void) = 0;
// Factory method that allocates a new node.
virtual void free_node (ACE_Timer_Node *) = 0;
// Factory method that frees a previously allocated node.
#if defined (ACE_MT_SAFE)
ACE_Recursive_Thread_Mutex lock_;
// Synchronization variable for the MT_SAFE ACE_Reactor
#endif /* ACE_MT_SAFE */
ACE_Time_Value (*gettimeofday_)(void);
// Pointer to function that returns the current time of day.
private:
ACE_Time_Value timeout_;
// Returned by <calculate_timeout>.
ACE_Time_Value timer_skew_;
// Adjusts for timer skew in various clocks.
// = Don't allow these operations for now.
ACE_Timer_Queue (const ACE_Timer_Queue &);
void operator= (const ACE_Timer_Queue &);
};
#if defined (__ACE_INLINE__)
#include "ace/Timer_Queue.i"
#endif /* __ACE_INLINE__ */
#endif /* ACE_TIMER_QUEUE_H */
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