NAME
ACE_Select_Reactor_Notify - Unblock the ACE_Select_Reactor from its event loop.
SYNOPSIS
#include <ace/Select_Reactor_Base.h>
class ACE_Select_Reactor_Notify : public ACE_Reactor_Notify
{
public:
ACE_Select_Reactor_Notify (void);
~ACE_Select_Reactor_Notify (void);
virtual int open (
ACE_Reactor_Impl *,
ACE_Timer_Queue * = 0,
int disable_notify_pipe = 0
);
virtual int close (void);
virtual ssize_t notify (
ACE_Event_Handler * = 0,
ACE_Reactor_Mask = ACE_Event_Handler::EXCEPT_MASK,
ACE_Time_Value * = 0
);
virtual int dispatch_notifications (
int &number_of_active_handles,
ACE_Handle_Set &rd_mask
);
virtual int handle_input (ACE_HANDLE handle);
virtual void max_notify_iterations (int);
virtual int max_notify_iterations (void);
virtual void dump (void) const;
ACE_ALLOC_HOOK_DECLARE;
private:
ACE_Select_Reactor_Impl *select_reactor_;
ACE_Pipe notification_pipe_;
int max_notify_iterations_;
ACE_Unbounded_Queue <ACE_Notification_Buffer *> alloc_queue_;
ACE_Unbounded_Queue <ACE_Notification_Buffer *> notify_queue_;
ACE_Unbounded_Queue <ACE_Notification_Buffer *> free_queue_;
ACE_SYNCH_MUTEX notify_queue_lock_;
};
DESCRIPTION
This implementation is necessary for cases where the ACE_Select_Reactor is run in a multi-threaded program. In this case, we need to be able to unblock select or poll when updates occur other than in the main ACE_Select_Reactor thread. To do this, we signal an auto-reset event the ACE_Select_Reactor is listening on. If an ACE_Event_Handler and ACE_Select_Reactor_Mask is passed to notify, the appropriate handle_* method is dispatched in the context of the ACE_Select_Reactor thread.
Initialization and termination methods.
virtual int open (
ACE_Reactor_Impl *,
ACE_Timer_Queue * = 0,
int disable_notify_pipe = 0
);
Initialize.
virtual int close (void);
Destroy.
virtual ssize_t notify (
ACE_Event_Handler * = 0,
ACE_Reactor_Mask = ACE_Event_Handler::EXCEPT_MASK,
ACE_Time_Value * = 0
);
Called by a thread when it wants to unblock the ACE_Select_Reactor. This wakeups the ACE_Select_Reactor if currently blocked in select/poll. Pass over both the Event_Handler *and* the mask to allow the caller to dictate which Event_Handler method the ACE_Select_Reactor will invoke. The ACE_Time_Value indicates how long to blocking trying to notify the ACE_Select_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
);
Handles pending threads (if any) that are waiting to unblock the ACE_Select_Reactor.
virtual int handle_input (ACE_HANDLE handle);
Called back by the ACE_Select_Reactor when a thread wants to unblock us.
virtual void max_notify_iterations (int);
Set the maximum number of times that the ACE_Select_Reactor_Notify::handle_input method will iterate and dispatch the ACE_Event_Handlers that are passed in via the notify pipe before breaking out of its recv loop. By default, this is set to -1, which means "iterate until the pipe 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.
virtual int max_notify_iterations (void);
Get the maximum number of times that the ACE_Select_Reactor_Notify::handle_input method will iterate and dispatch the ACE_Event_Handlers that are passed in via the notify pipe before breaking out of its recv loop.
virtual void dump (void) const;
Dump the state of an object.
ACE_ALLOC_HOOK_DECLARE;
Declare the dynamic allocation hooks.
AUTHOR
Doug Schmidt
LIBRARY
ace