ACE_Select_Reactor_Notify Class Reference

Unblock the ACE_Select_Reactor from its event loop. More...

#include <Select_Reactor_Base.h>

Inheritance diagram for ACE_Select_Reactor_Notify:

[legend]Collaboration diagram for ACE_Select_Reactor_Notify:

[legend]List of all members.

Public Member Functions
	ACE_Select_Reactor_Notify (void)
	Constructor.
virtual	~ACE_Select_Reactor_Notify (void)
	Destructor.
virtual int	open (ACE_Reactor_Impl *, ACE_Timer_Queue *=0, int disable_notify_pipe=ACE_DISABLE_NOTIFY_PIPE_DEFAULT)
	Initialize.
virtual int	close (void)
	Destroy.
virtual int	notify (ACE_Event_Handler *=0, ACE_Reactor_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	notify_handle (void)
virtual int	dispatch_notify (ACE_Notification_Buffer &buffer)
virtual int	read_notify_pipe (ACE_HANDLE handle, ACE_Notification_Buffer &buffer)
virtual int	is_dispatchable (ACE_Notification_Buffer &buffer)
	Verify whether the buffer has dispatchable info or not.
virtual int	handle_input (ACE_HANDLE handle)
virtual void	max_notify_iterations (int)
virtual int	max_notify_iterations (void)
virtual int	purge_pending_notifications (ACE_Event_Handler *sh, ACE_Reactor_Mask mask=ACE_Event_Handler::ALL_EVENTS_MASK)
virtual void	dump (void) const
	Dump the state of an object.
Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.
Protected Attributes
ACE_Select_Reactor_Impl *	select_reactor_
ACE_Pipe	notification_pipe_
int	max_notify_iterations_

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Detailed Description

Unblock the ACE_Select_Reactor from its event loop.

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.

Definition at line 134 of file Select_Reactor_Base.h.

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Constructor & Destructor Documentation

ACE_Select_Reactor_Notify::ACE_Select_Reactor_Notify (  void   )

Constructor. Definition at line 525 of file Select_Reactor_Base.cpp. : max_notify_iterations_ (-1) { }

ACE_Select_Reactor_Notify::~ACE_Select_Reactor_Notify (  void   )  [virtual]

Destructor. Definition at line 530 of file Select_Reactor_Base.cpp. { }

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Member Function Documentation

int ACE_Select_Reactor_Notify::close (  void   )  [virtual]

Destroy. Implements ACE_Reactor_Notify. Definition at line 637 of file Select_Reactor_Base.cpp. References ACE_TRACE, ACE_Pipe::close(), ACE_Notification_Buffer::eh_, notification_pipe_, ACE_Pipe::read_handle(), read_notify_pipe(), and ACE_Event_Handler::remove_reference(). { ACE_TRACE ("ACE_Select_Reactor_Notify::close"); #if defined (ACE_HAS_REACTOR_NOTIFICATION_QUEUE) notification_queue_.reset(); #else if (this->notification_pipe_.read_handle() != ACE_INVALID_HANDLE) { // Please see Bug 2820, if we just close the pipe then we break // the reference counting rules. Basically, all the event // handlers "stored" in the pipe had their reference counts // increased. We need to decrease them before closing the // pipe.... ACE_Notification_Buffer b; for (int r = read_notify_pipe(notification_pipe_.read_handle(), b); r > 0; r = read_notify_pipe(notification_pipe_.read_handle(), b)) { if (b.eh_ == 0) continue; b.eh_->remove_reference(); } } #endif /* ACE_HAS_REACTOR_NOTIFICATION_QUEUE */ return this->notification_pipe_.close (); }

int ACE_Select_Reactor_Notify::dispatch_notifications (  int &  number_of_active_handles, ACE_Handle_Set &  rd_mask )  [virtual]

Handles pending threads (if any) that are waiting to unblock the ACE_Select_Reactor. Implements ACE_Reactor_Notify. Definition at line 719 of file Select_Reactor_Base.cpp. References ACE_TRACE, ACE_Handle_Set::clr_bit(), handle_input(), ACE_Handle_Set::is_set(), notification_pipe_, and ACE_Pipe::read_handle(). { ACE_TRACE ("ACE_Select_Reactor_Notify::dispatch_notifications"); ACE_HANDLE const read_handle = this->notification_pipe_.read_handle (); if (read_handle != ACE_INVALID_HANDLE && rd_mask.is_set (read_handle)) { --number_of_active_handles; rd_mask.clr_bit (read_handle); return this->handle_input (read_handle); } else return 0; }

int ACE_Select_Reactor_Notify::dispatch_notify (  ACE_Notification_Buffer &  buffer  )  [virtual]

Handle one of the notify call on the handle. This could be because of a thread trying to unblock the Implements ACE_Reactor_Notify. Definition at line 773 of file Select_Reactor_Base.cpp. References ACE_ERROR, ACE_TEXT, ACE_Notification_Buffer::eh_, ACE_Event_Handler::handle_close(), ACE_Event_Handler::handle_exception(), ACE_Event_Handler::handle_group_qos(), ACE_Event_Handler::handle_input(), ACE_Event_Handler::handle_output(), ACE_Event_Handler::handle_qos(), LM_ERROR, ACE_Notification_Buffer::mask_, ACE_Event_Handler::reference_counting_policy(), ACE_Event_Handler::remove_reference(), and ACE::send(). Referenced by handle_input(). { int result = 0; #if defined (ACE_HAS_REACTOR_NOTIFICATION_QUEUE) // Dispatch one message from the notify queue, and put another in // the pipe if one is available. Remember, the idea is to keep // exactly one message in the pipe at a time. bool more_messages_queued = false; ACE_Notification_Buffer next; result = notification_queue_.pop_next_notification(buffer, more_messages_queued, next); if (result == 0) { return 0; } if (result == -1) { return -1; } if(more_messages_queued) { (void) ACE::send(this->notification_pipe_.write_handle(), (char *)&next, sizeof(ACE_Notification_Buffer)); } #endif /* ACE_HAS_REACTOR_NOTIFICATION_QUEUE */ // If eh == 0 then another thread is unblocking the // <ACE_Select_Reactor> to update the <ACE_Select_Reactor>'s // internal structures. Otherwise, we need to dispatch the // appropriate handle_* method on the <ACE_Event_Handler> pointer // we've been passed. if (buffer.eh_ != 0) { ACE_Event_Handler *event_handler = buffer.eh_; bool const requires_reference_counting = event_handler->reference_counting_policy ().value () == ACE_Event_Handler::Reference_Counting_Policy::ENABLED; switch (buffer.mask_) { case ACE_Event_Handler::READ_MASK: case ACE_Event_Handler::ACCEPT_MASK: result = event_handler->handle_input (ACE_INVALID_HANDLE); break; case ACE_Event_Handler::WRITE_MASK: result = event_handler->handle_output (ACE_INVALID_HANDLE); break; case ACE_Event_Handler::EXCEPT_MASK: result = event_handler->handle_exception (ACE_INVALID_HANDLE); break; case ACE_Event_Handler::QOS_MASK: result = event_handler->handle_qos (ACE_INVALID_HANDLE); break; case ACE_Event_Handler::GROUP_QOS_MASK: result = event_handler->handle_group_qos (ACE_INVALID_HANDLE); break; default: // Should we bail out if we get an invalid mask? ACE_ERROR ((LM_ERROR, ACE_TEXT ("invalid mask = %d\n"), buffer.mask_)); } if (result == -1) event_handler->handle_close (ACE_INVALID_HANDLE, ACE_Event_Handler::EXCEPT_MASK); if (requires_reference_counting) { event_handler->remove_reference (); } } return 1; }

void ACE_Select_Reactor_Notify::dump (  void   )  const [virtual]

Dump the state of an object. Implements ACE_Reactor_Notify. Definition at line 574 of file Select_Reactor_Base.cpp. References ACE_BEGIN_DUMP, ACE_DEBUG, ACE_END_DUMP, ACE_TEXT, ACE_TRACE, ACE_Pipe::dump(), LM_DEBUG, and notification_pipe_. { #if defined (ACE_HAS_DUMP) ACE_TRACE ("ACE_Select_Reactor_Notify::dump"); ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this)); ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("select_reactor_ = %x"), this->select_reactor_)); this->notification_pipe_.dump (); ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP)); #endif /* ACE_HAS_DUMP */ }

int ACE_Select_Reactor_Notify::handle_input (  ACE_HANDLE  handle  )  [virtual]

Called back by the ACE_Select_Reactor when a thread wants to unblock us. Reimplemented from ACE_Event_Handler. Definition at line 896 of file Select_Reactor_Base.cpp. References ACE_TRACE, dispatch_notify(), max_notify_iterations_, read_notify_pipe(), and ACE_Select_Reactor_Impl::renew(). Referenced by dispatch_notifications(). { ACE_TRACE ("ACE_Select_Reactor_Notify::handle_input"); // Precondition: this->select_reactor_.token_.current_owner () == // ACE_Thread::self (); int number_dispatched = 0; int result = 0; ACE_Notification_Buffer buffer; while ((result = this->read_notify_pipe (handle, buffer)) > 0) { // Dispatch the buffer // NOTE: We count only if we made any dispatches ie. upcalls. if (this->dispatch_notify (buffer) > 0) ++number_dispatched; // Bail out if we've reached the <notify_threshold_>. Note that // by default <notify_threshold_> is -1, so we'll loop until all // the notifications in the pipe have been dispatched. if (number_dispatched == this->max_notify_iterations_) break; } // Reassign number_dispatched to -1 if things have gone seriously // wrong. if (result < 0) number_dispatched = -1; // Enqueue ourselves into the list of waiting threads. When we // reacquire the token we'll be off and running again with ownership // of the token. The postcondition of this call is that // <select_reactor_.token_.current_owner> == <ACE_Thread::self>. this->select_reactor_->renew (); return number_dispatched; }

int ACE_Select_Reactor_Notify::is_dispatchable (  ACE_Notification_Buffer &  buffer  )  [virtual]

Verify whether the buffer has dispatchable info or not. Implements ACE_Reactor_Notify. Definition at line 749 of file Select_Reactor_Base.cpp. References ACE_Notification_Buffer::eh_. { #if defined (ACE_HAS_REACTOR_NOTIFICATION_QUEUE) ACE_UNUSED_ARG(buffer); return 1; #else // If eh == 0 then another thread is unblocking the // <ACE_Select_Reactor> to update the <ACE_Select_Reactor>'s // internal structures. Otherwise, we need to dispatch the // appropriate handle_* method on the <ACE_Event_Handler> // pointer we've been passed. if (buffer.eh_ != 0) { return 1; } else { // has no dispatchable buffer return 0; } #endif /*ACE_HAS_REACTOR_NOTIFICATION_QUEUE */ }

int ACE_Select_Reactor_Notify::max_notify_iterations (  void   )  [virtual]

Get the maximum number of times that the <ACE_Select_Reactor_Notify::handle_input> method will iterate and dispatch the that are passed in via the notify pipe before breaking out of its loop. Implements ACE_Reactor_Notify. Definition at line 545 of file Select_Reactor_Base.cpp. References max_notify_iterations_. { return this->max_notify_iterations_; }

void ACE_Select_Reactor_Notify::max_notify_iterations (  int   )  [virtual]

Set the maximum number of times that the <ACE_Select_Reactor_Notify::handle_input> method will iterate and dispatch the that are passed in via the notify pipe before breaking out of its 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. Implements ACE_Reactor_Notify. Definition at line 535 of file Select_Reactor_Base.cpp. References max_notify_iterations_. { // Must always be > 0 or < 0 to optimize the loop exit condition. if (iterations == 0) iterations = 1; this->max_notify_iterations_ = iterations; }

int ACE_Select_Reactor_Notify::notify (  ACE_Event_Handler *  = 0, ACE_Reactor_Mask  = ACE_Event_Handler::EXCEPT_MASK, ACE_Time_Value *  timeout = 0 )  [virtual]

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). Implements ACE_Reactor_Notify. Definition at line 666 of file Select_Reactor_Base.cpp. References ACE_Reactor_Mask, ACE_TRACE, ACE_Event_Handler::add_reference(), ACE_Event_Handler_var::release(), ACE::send(), and ssize_t. { ACE_TRACE ("ACE_Select_Reactor_Notify::notify"); // Just consider this method a "no-op" if there's no // <ACE_Select_Reactor> configured. if (this->select_reactor_ == 0) return 0; ACE_Event_Handler_var safe_handler (event_handler); if (event_handler) event_handler->add_reference (); ACE_Notification_Buffer buffer (event_handler, mask); #if defined (ACE_HAS_REACTOR_NOTIFICATION_QUEUE) int notification_required = notification_queue_.push_new_notification(buffer); if (notification_required == -1) { return -1; } if (notification_required == 0) { // No failures, the handler is now owned by the notification queue safe_handler.release (); return 0; } #endif /* ACE_HAS_REACTOR_NOTIFICATION_QUEUE */ ssize_t const n = ACE::send (this->notification_pipe_.write_handle (), (char *) &buffer, sizeof buffer, timeout); if (n == -1) return -1; // No failures. safe_handler.release (); return 0; }

ACE_HANDLE ACE_Select_Reactor_Notify::notify_handle (  void   )  [virtual]

Returns the ACE_HANDLE of the notify pipe on which the reactor is listening for notifications so that other threads can unblock the Select_Reactor Implements ACE_Reactor_Notify. Definition at line 740 of file Select_Reactor_Base.cpp. References ACE_TRACE, notification_pipe_, and ACE_Pipe::read_handle(). { ACE_TRACE ("ACE_Select_Reactor_Notify::notify_handle"); return this->notification_pipe_.read_handle (); }

int ACE_Select_Reactor_Notify::open (  ACE_Reactor_Impl *  , ACE_Timer_Queue *  = 0, int  disable_notify_pipe = ACE_DISABLE_NOTIFY_PIPE_DEFAULT )  [virtual]

Initialize. Implements ACE_Reactor_Notify. Definition at line 587 of file Select_Reactor_Base.cpp. References ACE_NONBLOCK, ACE_Timer_Queue, ACE_TRACE, ACE_OS::fcntl(), notification_pipe_, ACE_Pipe::open(), ACE_Pipe::read_handle(), ACE_Reactor_Impl::register_handler(), and ACE::set_flags(). { ACE_TRACE ("ACE_Select_Reactor_Notify::open"); if (disable_notify_pipe == 0) { this->select_reactor_ = dynamic_cast<ACE_Select_Reactor_Impl *> (r); if (select_reactor_ == 0) { errno = EINVAL; return -1; } if (this->notification_pipe_.open () == -1) return -1; #if defined (F_SETFD) ACE_OS::fcntl (this->notification_pipe_.read_handle (), F_SETFD, 1); ACE_OS::fcntl (this->notification_pipe_.write_handle (), F_SETFD, 1); #endif /* F_SETFD */ #if defined (ACE_HAS_REACTOR_NOTIFICATION_QUEUE) if (notification_queue_.open() == -1) { return -1; } #endif /* ACE_HAS_REACTOR_NOTIFICATION_QUEUE */ // There seems to be a Win32 bug with this... Set this into // non-blocking mode. if (ACE::set_flags (this->notification_pipe_.read_handle (), ACE_NONBLOCK) == -1) return -1; else return this->select_reactor_->register_handler (this->notification_pipe_.read_handle (), this, ACE_Event_Handler::READ_MASK); } else { this->select_reactor_ = 0; return 0; } }

int ACE_Select_Reactor_Notify::purge_pending_notifications (  ACE_Event_Handler *  sh, ACE_Reactor_Mask  mask = ACE_Event_Handler::ALL_EVENTS_MASK )  [virtual]

Purge any notifications pending in this reactor for the specified ACE_Event_Handler object. If eh == 0, all notifications for all handlers are removed (but not any notifications posted just to wake up the reactor itself). Returns the number of notifications purged. Returns -1 on error. Implements ACE_Reactor_Notify. Definition at line 557 of file Select_Reactor_Base.cpp. References ACE_NOTSUP_RETURN, ACE_Reactor_Mask, and ACE_TRACE. { ACE_TRACE ("ACE_Select_Reactor_Notify::purge_pending_notifications"); #if defined (ACE_HAS_REACTOR_NOTIFICATION_QUEUE) return notification_queue_.purge_pending_notifications(eh, mask); #else /* defined (ACE_HAS_REACTOR_NOTIFICATION_QUEUE) */ ACE_UNUSED_ARG (eh); ACE_UNUSED_ARG (mask); ACE_NOTSUP_RETURN (-1); #endif /* defined (ACE_HAS_REACTOR_NOTIFICATION_QUEUE) */ }

int ACE_Select_Reactor_Notify::read_notify_pipe (  ACE_HANDLE  handle, ACE_Notification_Buffer &  buffer )  [virtual]

Read one of the notify call on the handle into the buffer. This could be because of a thread trying to unblock the Implements ACE_Reactor_Notify. Definition at line 859 of file Select_Reactor_Base.cpp. References ACE_TRACE, EWOULDBLOCK, ACE::recv(), and ssize_t. Referenced by close(), and handle_input(). { ACE_TRACE ("ACE_Select_Reactor_Notify::read_notify_pipe"); ssize_t const n = ACE::recv (handle, (char *) &buffer, sizeof buffer); if (n > 0) { // Check to see if we've got a short read. if (n != sizeof buffer) { ssize_t const remainder = sizeof buffer - n; // If so, try to recover by reading the remainder. If this // doesn't work we're in big trouble since the input stream // won't be aligned correctly. I'm not sure quite what to // do at this point. It's probably best just to return -1. if (ACE::recv (handle, ((char *) &buffer) + n, remainder) != remainder) return -1; } return 1; } // Return -1 if things have gone seriously wrong. if (n <= 0 && (errno != EWOULDBLOCK && errno != EAGAIN)) return -1; return 0; }

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Member Data Documentation

ACE_Select_Reactor_Notify::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks. Definition at line 229 of file Select_Reactor_Base.h.

int ACE_Select_Reactor_Notify::max_notify_iterations_ [protected]

Keeps track of the maximum number of times that the <ACE_Select_Reactor_Notify::handle_input> method will iterate and dispatch the that are passed in via the notify pipe before breaking out of its loop. By default, this is set to -1, which means "iterate until the pipe is empty." Definition at line 253 of file Select_Reactor_Base.h. Referenced by handle_input(), and max_notify_iterations().

ACE_Pipe ACE_Select_Reactor_Notify::notification_pipe_ [protected]

Contains the ACE_HANDLE the ACE_Select_Reactor is listening on, as well as the ACE_HANDLE that threads wanting the attention of the ACE_Select_Reactor will write to. Definition at line 244 of file Select_Reactor_Base.h. Referenced by close(), dispatch_notifications(), dump(), notify_handle(), and open().

ACE_Select_Reactor_Impl* ACE_Select_Reactor_Notify::select_reactor_ [protected]

Keep a back pointer to the ACE_Select_Reactor. If this value if NULL then the ACE_Select_Reactor has been initialized with . Definition at line 237 of file Select_Reactor_Base.h.

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The documentation for this class was generated from the following files:

• Select_Reactor_Base.h
• Select_Reactor_Base.cpp

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