NAME
ACE_WFMO_Reactor_Notify - Unblock the ACE_WFMO_Reactor from its event loop, passing it an optional ACE_Event_Handler to dispatch.
SYNOPSIS
#include <ace/WFMO_Reactor.h>
class ACE_WFMO_Reactor_Notify : public ACE_Reactor_Notify
{
public:
ACE_WFMO_Reactor_Notify (void);
virtual int open (
ACE_Reactor_Impl *wfmo_reactor,
ACE_Timer_Queue *timer_queue,
int disable_notify = 0
);
virtual int close (void);
ssize_t notify (
ACE_Event_Handler *event_handler = 0,
ACE_Reactor_Mask mask = ACE_Event_Handler::EXCEPT_MASK,
ACE_Time_Value *timeout = 0
);
virtual int dispatch_notifications (
int &number_of_active_handles,
ACE_Handle_Set &rd_mask
);
virtual ACE_HANDLE get_handle (void) const;
void max_notify_iterations (int);
int max_notify_iterations (void);
virtual void dump (void) const;
private:
ACE_Timer_Queue *timer_queue_;
virtual int handle_signal (
int signum,
siginfo_t * = 0,
ucontext_t * = 0
);
ACE_Auto_Event wakeup_one_thread_;
ACE_Message_Queue<ACE_MT_SYNCH> message_queue_;
int max_notify_iterations_;
};
DESCRIPTION
This implementation is necessary for cases where the ACE_WFMO_Reactor is run in a multi-threaded program. In this case, we need to be able to unblock WaitForMultipleObjects when updates occur other than in the main ACE_WFMO_Reactor thread. To do this, we signal an auto-reset event the ACE_WFMO_Reactor is listening on. If an ACE_Event_Handler and ACE_Reactor_Mask is passed to notify, the appropriate handle_* method is dispatched.
PUBLIC MEMBERS
ACE_WFMO_Reactor_Notify (void);
Constructor
virtual int open (
ACE_Reactor_Impl *wfmo_reactor,
ACE_Timer_Queue *timer_queue,
int disable_notify = 0
);
Initialization. timer_queue is stored to call gettimeofday.
virtual int close (void);
No-op.
ssize_t notify (
ACE_Event_Handler *event_handler = 0,
ACE_Reactor_Mask mask = ACE_Event_Handler::EXCEPT_MASK,
ACE_Time_Value *timeout = 0
);
Special trick to unblock WaitForMultipleObjects when updates occur. All we do is enqueue event_handler and mask onto the ACE_Message_Queue and wakeup the WFMO_Reactor by signaling its ACE_Event handle. The ACE_Time_Value indicates how long to blocking trying to notify the WFMO_Reactor. If timeout == 0, the caller will block until action is possible, else will wait until the relative time specified in timeout elapses).
virtual int dispatch_notifications (
int &number_of_active_handles,
ACE_Handle_Set &rd_mask
);
No-op.
virtual ACE_HANDLE get_handle (void) const;
Returns a handle to the ACE_Auto_Event.
void max_notify_iterations (int);
Set the maximum number of times that the ACE_WFMO_Reactor_Notify::handle_input method will iterate and dispatch the ACE_Event_Handlers that are passed in via the notify queue before breaking out of its ACE_Message_Queue::dequeue loop. By default, this is set to -1, which means "iterate until the queue is empty." Setting this to a value like "1 or 2" will increase "fairness" (and thus prevent starvation) at the expense of slightly higher dispatching overhead.
int max_notify_iterations (void);
Get the maximum number of times that the ACE_WFMO_Reactor_Notify::handle_input method will iterate and dispatch the ACE_Event_Handlers that are passed in via the notify queue before breaking out of its ACE_Message_Queue::dequeue loop.
virtual void dump (void) const;
Dump the state of an object.
PRIVATE MEMBERS
ACE_Timer_Queue *timer_queue_;
Pointer to the wfmo_reactor's timer queue.
virtual int handle_signal (
int signum,
siginfo_t * = 0,
ucontext_t * = 0
);
Called when the notification event waited on by ACE_WFMO_Reactor is signaled. This dequeues all pending ACE_Event_Handlers and dispatches them.
ACE_Auto_Event wakeup_one_thread_;
An auto event is used so that we can signal it to wakeup one thread up (e.g., when the notify method is called).
ACE_Message_Queue<ACE_MT_SYNCH> message_queue_;
int max_notify_iterations_;
Keeps track of the maximum number of times that the ACE_WFMO_Reactor_Notify::handle_input method will iterate and dispatch the ACE_Event_Handlers that are passed in via the notify queue before breaking out of its ACE_Message_Queue::dequeue loop. By default, this is set to -1, which means "iterate until the queue is empty."
AUTHOR
Irfan Pyarali, Tim Harrison, and Doug Schmidt
LIBRARY
ace