From 99aa8c60282c7b8072eb35eb9ac815702f5bf586 Mon Sep 17 00:00:00 2001
From: "William R. Otte" <wotte@dre.vanderbilt.edu>
Date: Tue, 4 Mar 2008 14:51:23 +0000
Subject: undoing accidental deletion

---
 ACE/ace/Notification_Queue.h | 156 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 156 insertions(+)
 create mode 100644 ACE/ace/Notification_Queue.h

(limited to 'ACE/ace/Notification_Queue.h')

diff --git a/ACE/ace/Notification_Queue.h b/ACE/ace/Notification_Queue.h
new file mode 100644
index 00000000000..d4cf815aada
--- /dev/null
+++ b/ACE/ace/Notification_Queue.h
@@ -0,0 +1,156 @@
+#ifndef ACE_NOTIFICATION_QUEUE_H
+#define ACE_NOTIFICATION_QUEUE_H
+
+#include /**/ "ace/pre.h"
+
+/**
+ *  @file Notification_Queue.h
+ *
+ *  $Id$
+ *
+ *  @author Carlos O'Ryan <coryan@atdesk.com>
+ */
+#include "ace/Copy_Disabled.h"
+#include "ace/Event_Handler.h"
+#include "ace/Intrusive_List.h"
+#include "ace/Intrusive_List_Node.h"
+#include "ace/Unbounded_Queue.h"
+
+ACE_BEGIN_VERSIONED_NAMESPACE_DECL
+
+/**
+ * @class ACE_Notification_Queue_Node
+ *
+ * @brief Helper class
+ */
+class ACE_Export ACE_Notification_Queue_Node
+  : public ACE_Intrusive_List_Node<ACE_Notification_Queue_Node>
+{
+public:
+  /**
+   * @brief Constructor
+   */
+  ACE_Notification_Queue_Node();
+
+  /**
+   * @brief Modifier change the contained buffer
+   */
+  void set(ACE_Notification_Buffer const & rhs);
+
+  /**
+   * @brief Accessor, fetch the contained buffer
+   */
+  ACE_Notification_Buffer const & get() const;
+
+  /**
+   * @brief Checks if the event handler matches the purge condition
+   */
+  bool matches_for_purging(ACE_Event_Handler * eh) const;
+
+  /**
+   * @brief Return true if clearing the mask would leave no
+   * notifications to deliver.
+   */
+  bool mask_disables_all_notifications(ACE_Reactor_Mask mask);
+
+  /**
+   * @brief Clear the notifications specified by @c mask
+   */
+  void clear_mask(ACE_Reactor_Mask mask);
+
+private:
+  ACE_Notification_Buffer contents_;
+};
+
+/**
+ * @class ACE_Notification_Queue
+ *
+ * @brief Implements a user-space queue to send Reactor notifications.
+ *
+ * The ACE_Reactor uses a pipe to send wake up the thread running the
+ * event loop from other threads.  This pipe can be limited in size
+ * under some operating systems.  For some applications, this limit
+ * presents a problem.  A user-space notification queue is used to
+ * overcome those limitations.  The queue tries to use as few
+ * resources on the pipe as possible, while keeping all the data in
+ * user space.
+ *
+ * This code was refactored from Select_Reactor_Base.
+ */
+class ACE_Export ACE_Notification_Queue : private ACE_Copy_Disabled
+{
+public:
+  ACE_Notification_Queue();
+  ~ACE_Notification_Queue();
+
+  /**
+   * @brief Pre-allocate resources in the queue
+   */
+  int open();
+
+  /**
+   * @brief Release all resources in the queue
+   */
+  void reset();
+
+  /**
+   * @brief Remove all elements in the queue matching @c eh and @c mask
+   *
+   * I suggest reading the documentation in ACE_Reactor to find a more
+   * detailed description.  This is just a helper function.
+   */
+  int purge_pending_notifications(ACE_Event_Handler * eh,
+                                  ACE_Reactor_Mask mask);
+
+  /**
+   * @brief Add a new notification to the queue
+   *
+   * @return -1 on failure, 1 if a new message should be sent through
+   * the pipe and 0 otherwise.
+   */
+  int push_new_notification(ACE_Notification_Buffer const & buffer);
+
+  /**
+   * @brief Extract the next notification from the queue
+   *
+   * @return -1 on failure, 1 if a message was popped, 0 otherwise
+   */
+  int pop_next_notification(
+      ACE_Notification_Buffer & current,
+      bool & more_messages_queued,
+      ACE_Notification_Buffer & next);
+
+private:
+  /**
+   * @brief Allocate more memory for the queue
+   */
+  int allocate_more_buffers();
+
+private:
+  /// Keeps track of allocated arrays of type
+  /// ACE_Notification_Buffer.  The idea is to amortize allocation
+  /// costs by allocating multiple ACE_Notification_Buffer objects at
+  /// a time.
+  ACE_Unbounded_Queue <ACE_Notification_Queue_Node*> alloc_queue_;
+
+  typedef ACE_Intrusive_List<ACE_Notification_Queue_Node> Buffer_List;
+
+  /// Keeps track of all pending notifications.
+  Buffer_List notify_queue_;
+
+  /// Keeps track of all free buffers.
+  Buffer_List free_queue_;
+
+  /// Synchronization for handling of queues.
+  ACE_SYNCH_MUTEX notify_queue_lock_;
+};
+
+ACE_END_VERSIONED_NAMESPACE_DECL
+
+#if defined (__ACE_INLINE__)
+#include "ace/Notification_Queue.inl"
+#endif /* __ACE_INLINE__ */
+
+#include /**/ "ace/post.h"
+
+#endif /* ACE_NOTIFICATION_QUEUE_H */
-- 
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