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authorcoryan <coryan@ae88bc3d-4319-0410-8dbf-d08b4c9d3795>2000-11-01 22:17:39 +0000
committercoryan <coryan@ae88bc3d-4319-0410-8dbf-d08b4c9d3795>2000-11-01 22:17:39 +0000
commit53284e215e3d3351a7d7e9c4b68f14b427fb4377 (patch)
tree97236ece363cff48fd287c780db4290da39b02cb /ace/Message_Queue_T.h
parent7b7c52ad2abd228138ba1a948d5e28bf6dc3b880 (diff)
downloadATCD-53284e215e3d3351a7d7e9c4b68f14b427fb4377.tar.gz
ChangeLogTag:Wed Nov 1 14:11:48 2000 Carlos O'Ryan <coryan@uci.edu>
Diffstat (limited to 'ace/Message_Queue_T.h')
-rw-r--r--ace/Message_Queue_T.h687
1 files changed, 364 insertions, 323 deletions
diff --git a/ace/Message_Queue_T.h b/ace/Message_Queue_T.h
index 51db6122ba6..f67a4c9fcb5 100644
--- a/ace/Message_Queue_T.h
+++ b/ace/Message_Queue_T.h
@@ -1,18 +1,15 @@
/* -*- C++ -*- */
-// $Id$
-
-// ============================================================================
-//
-// = LIBRARY
-// ace
-//
-// = FILENAME
-// Message_Queue_T.h
-//
-// = AUTHOR
-// Douglas C. Schmidt <schmidt@cs.wustl.edu>
-//
-// ============================================================================
+
+//=============================================================================
+/**
+ * @file Message_Queue_T.h
+ *
+ * $Id$
+ *
+ * @author Douglas C. Schmidt <schmidt@cs.wustl.edu>
+ */
+//=============================================================================
+
#ifndef ACE_MESSAGE_QUEUE_T_H
#define ACE_MESSAGE_QUEUE_T_H
@@ -32,19 +29,21 @@ class ACE_Message_Queue_Vx;
class ACE_Message_Queue_NT;
#endif /* ACE_WIN32 && ACE_HAS_WINNT4 != 0 */
+/**
+ * @class ACE_Message_Queue
+ *
+ * @brief A threaded message queueing facility, modeled after the
+ * queueing facilities in System V STREAMs.
+ *
+ * An <ACE_Message_Queue> is the central queueing facility for
+ * messages in the ASX framework. If <ACE_SYNCH_DECL> is
+ * <ACE_MT_SYNCH> then all operations are thread-safe.
+ * Otherwise, if it's <ACE_NULL_SYNCH> then there's no locking
+ * overhead.
+ */
template <ACE_SYNCH_DECL>
class ACE_Message_Queue : public ACE_Message_Queue_Base
{
- // = TITLE
- // A threaded message queueing facility, modeled after the
- // queueing facilities in System V STREAMs.
- //
- // = DESCRIPTION
- // An <ACE_Message_Queue> is the central queueing facility for
- // messages in the ASX framework. If <ACE_SYNCH_DECL> is
- // <ACE_MT_SYNCH> then all operations are thread-safe.
- // Otherwise, if it's <ACE_NULL_SYNCH> then there's no locking
- // overhead.
public:
friend class ACE_Message_Queue_Iterator<ACE_SYNCH_USE>;
friend class ACE_Message_Queue_Reverse_Iterator<ACE_SYNCH_USE>;
@@ -56,45 +55,49 @@ public:
REVERSE_ITERATOR;
// = Initialization and termination methods.
+ /**
+ * Initialize an <ACE_Message_Queue>. The <high_water_mark>
+ * determines how many bytes can be stored in a queue before it's
+ * considered "full." Supplier threads must block until the queue
+ * is no longer full. The <low_water_mark> determines how many
+ * bytes must be in the queue before supplier threads are allowed to
+ * enqueue additional <ACE_Message_Block>s. By default, the
+ * <high_water_mark> equals the <low_water_mark>, which means that
+ * suppliers will be able to enqueue new messages as soon as a
+ * consumer removes any message from the queue. Making the
+ * <low_water_mark> smaller than the <high_water_mark> forces
+ * consumers to drain more messages from the queue before suppliers
+ * can enqueue new messages, which can minimize the "silly window
+ * syndrome."
+ */
ACE_Message_Queue (size_t high_water_mark = ACE_Message_Queue_Base::DEFAULT_HWM,
size_t low_water_mark = ACE_Message_Queue_Base::DEFAULT_LWM,
ACE_Notification_Strategy * = 0);
- // Initialize an <ACE_Message_Queue>. The <high_water_mark>
- // determines how many bytes can be stored in a queue before it's
- // considered "full." Supplier threads must block until the queue
- // is no longer full. The <low_water_mark> determines how many
- // bytes must be in the queue before supplier threads are allowed to
- // enqueue additional <ACE_Message_Block>s. By default, the
- // <high_water_mark> equals the <low_water_mark>, which means that
- // suppliers will be able to enqueue new messages as soon as a
- // consumer removes any message from the queue. Making the
- // <low_water_mark> smaller than the <high_water_mark> forces
- // consumers to drain more messages from the queue before suppliers
- // can enqueue new messages, which can minimize the "silly window
- // syndrome."
+ /**
+ * Initialize an <ACE_Message_Queue>. The <high_water_mark>
+ * determines how many bytes can be stored in a queue before it's
+ * considered "full." Supplier threads must block until the queue
+ * is no longer full. The <low_water_mark> determines how many
+ * bytes must be in the queue before supplier threads are allowed to
+ * enqueue additional <ACE_Message_Block>s. By default, the
+ * <high_water_mark> equals the <low_water_mark>, which means that
+ * suppliers will be able to enqueue new messages as soon as a
+ * consumer removes any message from the queue. Making the
+ * <low_water_mark> smaller than the <high_water_mark> forces
+ * consumers to drain more messages from the queue before suppliers
+ * can enqueue new messages, which can minimize the "silly window
+ * syndrome."
+ */
virtual int open (size_t hwm = ACE_Message_Queue_Base::DEFAULT_HWM,
size_t lwm = ACE_Message_Queue_Base::DEFAULT_LWM,
ACE_Notification_Strategy * = 0);
- // Initialize an <ACE_Message_Queue>. The <high_water_mark>
- // determines how many bytes can be stored in a queue before it's
- // considered "full." Supplier threads must block until the queue
- // is no longer full. The <low_water_mark> determines how many
- // bytes must be in the queue before supplier threads are allowed to
- // enqueue additional <ACE_Message_Block>s. By default, the
- // <high_water_mark> equals the <low_water_mark>, which means that
- // suppliers will be able to enqueue new messages as soon as a
- // consumer removes any message from the queue. Making the
- // <low_water_mark> smaller than the <high_water_mark> forces
- // consumers to drain more messages from the queue before suppliers
- // can enqueue new messages, which can minimize the "silly window
- // syndrome."
+ /// Close down the message queue and release all resources.
virtual int close (void);
- // Close down the message queue and release all resources.
+ /// Close down the message queue and release all resources.
virtual ~ACE_Message_Queue (void);
- // Close down the message queue and release all resources.
// = Enqueue and dequeue methods.
@@ -105,152 +108,178 @@ public:
// when a signal occurs, or if the time specified in timeout
// elapses, (in which case errno = EWOULDBLOCK).
+ /**
+ * Retrieve the first <ACE_Message_Block> without removing it. Note
+ * that <timeout> uses <{absolute}> time rather than <{relative}>
+ * time. If the <timeout> elapses without receiving a message -1 is
+ * returned and <errno> is set to <EWOULDBLOCK>. If the queue is
+ * deactivated -1 is returned and <errno> is set to <ESHUTDOWN>.
+ * Otherwise, returns -1 on failure, else the number of items still
+ * on the queue.
+ */
virtual int peek_dequeue_head (ACE_Message_Block *&first_item,
ACE_Time_Value *timeout = 0);
- // Retrieve the first <ACE_Message_Block> without removing it. Note
- // that <timeout> uses <{absolute}> time rather than <{relative}>
- // time. If the <timeout> elapses without receiving a message -1 is
- // returned and <errno> is set to <EWOULDBLOCK>. If the queue is
- // deactivated -1 is returned and <errno> is set to <ESHUTDOWN>.
- // Otherwise, returns -1 on failure, else the number of items still
- // on the queue.
+ /**
+ * Enqueue an <ACE_Message_Block *> into the <Message_Queue> in
+ * accordance with its <msg_priority> (0 is lowest priority). FIFO
+ * order is maintained when messages of the same priority are
+ * inserted consecutively. Note that <timeout> uses <{absolute}>
+ * time rather than <{relative}> time. If the <timeout> elapses
+ * without receiving a message -1 is returned and <errno> is set to
+ * <EWOULDBLOCK>. If the queue is deactivated -1 is returned and
+ * <errno> is set to <ESHUTDOWN>. Otherwise, returns -1 on failure,
+ * else the number of items still on the queue.
+ */
virtual int enqueue_prio (ACE_Message_Block *new_item,
ACE_Time_Value *timeout = 0);
- // Enqueue an <ACE_Message_Block *> into the <Message_Queue> in
- // accordance with its <msg_priority> (0 is lowest priority). FIFO
- // order is maintained when messages of the same priority are
- // inserted consecutively. Note that <timeout> uses <{absolute}>
- // time rather than <{relative}> time. If the <timeout> elapses
- // without receiving a message -1 is returned and <errno> is set to
- // <EWOULDBLOCK>. If the queue is deactivated -1 is returned and
- // <errno> is set to <ESHUTDOWN>. Otherwise, returns -1 on failure,
- // else the number of items still on the queue.
+ /**
+ * This is an alias for <enqueue_prio>. It's only here for
+ * backwards compatibility and will go away in a subsequent release.
+ * Please use <enqueue_prio> instead. Note that <timeout> uses
+ * <{absolute}> time rather than <{relative}> time.
+ */
virtual int enqueue (ACE_Message_Block *new_item,
ACE_Time_Value *timeout = 0);
- // This is an alias for <enqueue_prio>. It's only here for
- // backwards compatibility and will go away in a subsequent release.
- // Please use <enqueue_prio> instead. Note that <timeout> uses
- // <{absolute}> time rather than <{relative}> time.
+ /**
+ * Enqueue an <ACE_Message_Block *> at the end of the queue. Note
+ * that <timeout> uses <{absolute}> time rather than <{relative}>
+ * time. If the <timeout> elapses without receiving a message -1 is
+ * returned and <errno> is set to <EWOULDBLOCK>. If the queue is
+ * deactivated -1 is returned and <errno> is set to <ESHUTDOWN>.
+ * Otherwise, returns -1 on failure, else the number of items still
+ * on the queue.
+ */
virtual int enqueue_tail (ACE_Message_Block *new_item,
ACE_Time_Value *timeout = 0);
- // Enqueue an <ACE_Message_Block *> at the end of the queue. Note
- // that <timeout> uses <{absolute}> time rather than <{relative}>
- // time. If the <timeout> elapses without receiving a message -1 is
- // returned and <errno> is set to <EWOULDBLOCK>. If the queue is
- // deactivated -1 is returned and <errno> is set to <ESHUTDOWN>.
- // Otherwise, returns -1 on failure, else the number of items still
- // on the queue.
+ /**
+ * Enqueue an <ACE_Message_Block *> at the head of the queue. Note
+ * that <timeout> uses <{absolute}> time rather than <{relative}>
+ * time. If the <timeout> elapses without receiving a message -1 is
+ * returned and <errno> is set to <EWOULDBLOCK>. If the queue is
+ * deactivated -1 is returned and <errno> is set to <ESHUTDOWN>.
+ * Otherwise, returns -1 on failure, else the number of items still
+ * on the queue.
+ */
virtual int enqueue_head (ACE_Message_Block *new_item,
ACE_Time_Value *timeout = 0);
- // Enqueue an <ACE_Message_Block *> at the head of the queue. Note
- // that <timeout> uses <{absolute}> time rather than <{relative}>
- // time. If the <timeout> elapses without receiving a message -1 is
- // returned and <errno> is set to <EWOULDBLOCK>. If the queue is
- // deactivated -1 is returned and <errno> is set to <ESHUTDOWN>.
- // Otherwise, returns -1 on failure, else the number of items still
- // on the queue.
+ /// This method is an alias for the following <dequeue_head> method.
virtual int dequeue (ACE_Message_Block *&first_item,
ACE_Time_Value *timeout = 0);
- // This method is an alias for the following <dequeue_head> method.
+ /**
+ * Dequeue and return the <ACE_Message_Block *> at the head of the
+ * queue. Note that <timeout> uses <{absolute}> time rather than
+ * <{relative}> time. If the <timeout> elapses without receiving a
+ * message -1 is returned and <errno> is set to <EWOULDBLOCK>. If
+ * the queue is deactivated -1 is returned and <errno> is set to
+ * <ESHUTDOWN>. Otherwise, returns -1 on failure, else the number
+ * of items still on the queue.
+ */
virtual int dequeue_head (ACE_Message_Block *&first_item,
ACE_Time_Value *timeout = 0);
- // Dequeue and return the <ACE_Message_Block *> at the head of the
- // queue. Note that <timeout> uses <{absolute}> time rather than
- // <{relative}> time. If the <timeout> elapses without receiving a
- // message -1 is returned and <errno> is set to <EWOULDBLOCK>. If
- // the queue is deactivated -1 is returned and <errno> is set to
- // <ESHUTDOWN>. Otherwise, returns -1 on failure, else the number
- // of items still on the queue.
// = Check if queue is full/empty.
+ /// True if queue is full, else false.
+ /// True if queue is empty, else false.
virtual int is_full (void);
- // True if queue is full, else false.
virtual int is_empty (void);
- // True if queue is empty, else false.
// = Queue statistic methods.
+ /**
+ * Number of total bytes on the queue, i.e., sum of the message
+ * block sizes.
+ * Number of total length on the queue, i.e., sum of the message
+ * block lengths.
+ * Number of total messages on the queue.
+ */
virtual size_t message_bytes (void);
- // Number of total bytes on the queue, i.e., sum of the message
- // block sizes.
virtual size_t message_length (void);
- // Number of total length on the queue, i.e., sum of the message
- // block lengths.
virtual size_t message_count (void);
- // Number of total messages on the queue.
// = Manual changes to these stats (used when queued message blocks
// change size or lengths).
+ /**
+ * New value of the number of total bytes on the queue, i.e., sum of
+ * the message block sizes.
+ * New value of the number of total length on the queue, i.e., sum
+ * of the message block lengths.
+ */
virtual void message_bytes (size_t new_size);
- // New value of the number of total bytes on the queue, i.e., sum of
- // the message block sizes.
virtual void message_length (size_t new_length);
- // New value of the number of total length on the queue, i.e., sum
- // of the message block lengths.
// = Flow control methods.
+ /**
+ * Get high watermark.
+ * Set the high watermark, which determines how many bytes can be
+ * stored in a queue before it's considered "full."
+ */
virtual size_t high_water_mark (void);
- // Get high watermark.
virtual void high_water_mark (size_t hwm);
- // Set the high watermark, which determines how many bytes can be
- // stored in a queue before it's considered "full."
+ /**
+ * Get low watermark.
+ * Set the low watermark, which determines how many bytes must be in
+ * the queue before supplier threads are allowed to enqueue
+ * additional <ACE_Message_Block>s.
+ */
virtual size_t low_water_mark (void);
- // Get low watermark.
virtual void low_water_mark (size_t lwm);
- // Set the low watermark, which determines how many bytes must be in
- // the queue before supplier threads are allowed to enqueue
- // additional <ACE_Message_Block>s.
// = Activation control methods.
+ /**
+ * Deactivate the queue and wakeup all threads waiting on the queue
+ * so they can continue. No messages are removed from the queue,
+ * however. Any other operations called until the queue is
+ * activated again will immediately return -1 with <errno> ==
+ * ESHUTDOWN. Returns WAS_INACTIVE if queue was inactive before the
+ * call and WAS_ACTIVE if queue was active before the call.
+ */
virtual int deactivate (void);
- // Deactivate the queue and wakeup all threads waiting on the queue
- // so they can continue. No messages are removed from the queue,
- // however. Any other operations called until the queue is
- // activated again will immediately return -1 with <errno> ==
- // ESHUTDOWN. Returns WAS_INACTIVE if queue was inactive before the
- // call and WAS_ACTIVE if queue was active before the call.
+ /**
+ * Reactivate the queue so that threads can enqueue and dequeue
+ * messages again. Returns WAS_INACTIVE if queue was inactive
+ * before the call and WAS_ACTIVE if queue was active before the
+ * call.
+ */
virtual int activate (void);
- // Reactivate the queue so that threads can enqueue and dequeue
- // messages again. Returns WAS_INACTIVE if queue was inactive
- // before the call and WAS_ACTIVE if queue was active before the
- // call.
+ /// Returns true if <deactivated_> is enabled.
virtual int deactivated (void);
- // Returns true if <deactivated_> is enabled.
// = Notification hook.
+ /**
+ * This hook is automatically invoked by <enqueue_head>,
+ * <enqueue_tail>, and <enqueue_prio> when a new item is inserted
+ * into the queue. Subclasses can override this method to perform
+ * specific notification strategies (e.g., signaling events for a
+ * <WFMO_Reactor>, notifying a <Reactor>, etc.). In a
+ * multi-threaded application with concurrent consumers, there is no
+ * guarantee that the queue will be still be non-empty by the time
+ * the notification occurs.
+ */
virtual int notify (void);
- // This hook is automatically invoked by <enqueue_head>,
- // <enqueue_tail>, and <enqueue_prio> when a new item is inserted
- // into the queue. Subclasses can override this method to perform
- // specific notification strategies (e.g., signaling events for a
- // <WFMO_Reactor>, notifying a <Reactor>, etc.). In a
- // multi-threaded application with concurrent consumers, there is no
- // guarantee that the queue will be still be non-empty by the time
- // the notification occurs.
// = Get/set the notification strategy for the <Message_Queue>
virtual ACE_Notification_Strategy *notification_strategy (void);
virtual void notification_strategy (ACE_Notification_Strategy *s);
+ /// Returns a reference to the lock used by the <ACE_Message_Queue>.
ACE_SYNCH_MUTEX_T &lock (void);
- // Returns a reference to the lock used by the <ACE_Message_Queue>.
+ /// Dump the state of an object.
virtual void dump (void) const;
- // Dump the state of an object.
+ /// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
- // Declare the dynamic allocation hooks.
protected:
// = Routines that actually do the enqueueing and dequeueing.
@@ -259,102 +288,102 @@ protected:
// public methods. Since they are virtual, you can change the
// queueing mechanism by subclassing from <ACE_Message_Queue>.
+ /// Enqueue an <ACE_Message_Block *> in accordance with its priority.
virtual int enqueue_i (ACE_Message_Block *new_item);
- // Enqueue an <ACE_Message_Block *> in accordance with its priority.
+ /// Enqueue an <ACE_Message_Block *> at the end of the queue.
virtual int enqueue_tail_i (ACE_Message_Block *new_item);
- // Enqueue an <ACE_Message_Block *> at the end of the queue.
+ /// Enqueue an <ACE_Message_Block *> at the head of the queue.
virtual int enqueue_head_i (ACE_Message_Block *new_item);
- // Enqueue an <ACE_Message_Block *> at the head of the queue.
+ /// Dequeue and return the <ACE_Message_Block *> at the head of the
+ /// queue.
virtual int dequeue_head_i (ACE_Message_Block *&first_item);
- // Dequeue and return the <ACE_Message_Block *> at the head of the
- // queue.
// = Check the boundary conditions (assumes locks are held).
+ /// True if queue is full, else false.
virtual int is_full_i (void);
- // True if queue is full, else false.
+ /// True if queue is empty, else false.
virtual int is_empty_i (void);
- // True if queue is empty, else false.
// = Implementation of the public <activate> and <deactivate> methods.
// These methods assume locks are held.
+ /// Deactivate the queue.
virtual int deactivate_i (void);
- // Deactivate the queue.
+ /// Activate the queue.
virtual int activate_i (void);
- // Activate the queue.
// = Helper methods to factor out common #ifdef code.
+ /// Wait for the queue to become non-full.
virtual int wait_not_full_cond (ACE_Guard<ACE_SYNCH_MUTEX_T> &mon,
ACE_Time_Value *timeout);
- // Wait for the queue to become non-full.
+ /// Wait for the queue to become non-empty.
virtual int wait_not_empty_cond (ACE_Guard<ACE_SYNCH_MUTEX_T> &mon,
ACE_Time_Value *timeout);
- // Wait for the queue to become non-empty.
+ /// Inform any threads waiting to enqueue that they can procede.
virtual int signal_enqueue_waiters (void);
- // Inform any threads waiting to enqueue that they can procede.
+ /// Inform any threads waiting to dequeue that they can procede.
virtual int signal_dequeue_waiters (void);
- // Inform any threads waiting to dequeue that they can procede.
+ /// Pointer to head of ACE_Message_Block list.
ACE_Message_Block *head_;
- // Pointer to head of ACE_Message_Block list.
+ /// Pointer to tail of ACE_Message_Block list.
ACE_Message_Block *tail_;
- // Pointer to tail of ACE_Message_Block list.
+ /// Lowest number before unblocking occurs.
size_t low_water_mark_;
- // Lowest number before unblocking occurs.
+ /// Greatest number of bytes before blocking.
size_t high_water_mark_;
- // Greatest number of bytes before blocking.
+ /// Current number of bytes in the queue.
size_t cur_bytes_;
- // Current number of bytes in the queue.
+ /// Current length of messages in the queue.
size_t cur_length_;
- // Current length of messages in the queue.
+ /// Current number of messages in the queue.
size_t cur_count_;
- // Current number of messages in the queue.
+ /// Indicates that the queue is inactive.
int deactivated_;
- // Indicates that the queue is inactive.
+ /// The notification strategy used when a new message is enqueued.
ACE_Notification_Strategy *notification_strategy_;
- // The notification strategy used when a new message is enqueued.
// = Synchronization primitives for controlling concurrent access.
+ /// Protect queue from concurrent access.
ACE_SYNCH_MUTEX_T lock_;
- // Protect queue from concurrent access.
#if defined (ACE_HAS_OPTIMIZED_MESSAGE_QUEUE)
+ /// Used to make threads sleep until the queue is no longer empty.
ACE_SYNCH_SEMAPHORE_T not_empty_cond_;
- // Used to make threads sleep until the queue is no longer empty.
+ /// Used to make threads sleep until the queue is no longer full.
ACE_SYNCH_SEMAPHORE_T not_full_cond_;
- // Used to make threads sleep until the queue is no longer full.
+ /// Number of threads waiting to dequeue a <Message_Block>.
size_t dequeue_waiters_;
- // Number of threads waiting to dequeue a <Message_Block>.
+ /// Number of threads waiting to enqueue a <Message_Block>.
size_t enqueue_waiters_;
- // Number of threads waiting to enqueue a <Message_Block>.
#else
+ /// Used to make threads sleep until the queue is no longer empty.
ACE_SYNCH_CONDITION_T not_empty_cond_;
- // Used to make threads sleep until the queue is no longer empty.
+ /// Used to make threads sleep until the queue is no longer full.
ACE_SYNCH_CONDITION_T not_full_cond_;
- // Used to make threads sleep until the queue is no longer full.
#endif /* ACE_HAS_OPTIMIZED_MESSAGE_QUEUE */
private:
@@ -364,154 +393,152 @@ private:
ACE_UNIMPLEMENTED_FUNC (ACE_Message_Queue (const ACE_Message_Queue<ACE_SYNCH_USE> &))
};
+/**
+ * @class ACE_Message_Queue_Iterator
+ *
+ * @brief Iterator for the <ACE_Message_Queue>.
+ */
template <ACE_SYNCH_DECL>
class ACE_Message_Queue_Iterator
{
- // = TITLE
- // Iterator for the <ACE_Message_Queue>.
public:
// = Initialization method.
ACE_Message_Queue_Iterator (ACE_Message_Queue <ACE_SYNCH_USE> &queue);
// = Iteration methods.
+ /// Pass back the <entry> that hasn't been seen in the queue.
+ /// Returns 0 when all items have been seen, else 1.
int next (ACE_Message_Block *&entry);
- // Pass back the <entry> that hasn't been seen in the queue.
- // Returns 0 when all items have been seen, else 1.
+ /// Returns 1 when all items have been seen, else 0.
int done (void) const;
- // Returns 1 when all items have been seen, else 0.
+ /// Move forward by one element in the queue. Returns 0 when all the
+ /// items in the set have been seen, else 1.
int advance (void);
- // Move forward by one element in the queue. Returns 0 when all the
- // items in the set have been seen, else 1.
+ /// Dump the state of an object.
void dump (void) const;
- // Dump the state of an object.
+ /// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
- // Declare the dynamic allocation hooks.
private:
+ /// Message_Queue we are iterating over.
ACE_Message_Queue <ACE_SYNCH_USE> &queue_;
- // Message_Queue we are iterating over.
+ /// Keeps track of how far we've advanced...
ACE_Message_Block *curr_;
- // Keeps track of how far we've advanced...
};
+/**
+ * @class ACE_Message_Queue_Reverse_Iterator
+ *
+ * @brief Reverse Iterator for the <ACE_Message_Queue>.
+ */
template <ACE_SYNCH_DECL>
class ACE_Message_Queue_Reverse_Iterator
{
- // = TITLE
- // Reverse Iterator for the <ACE_Message_Queue>.
public:
// = Initialization method.
ACE_Message_Queue_Reverse_Iterator (ACE_Message_Queue <ACE_SYNCH_USE> &queue);
// = Iteration methods.
+ /// Pass back the <entry> that hasn't been seen in the queue.
+ /// Returns 0 when all items have been seen, else 1.
int next (ACE_Message_Block *&entry);
- // Pass back the <entry> that hasn't been seen in the queue.
- // Returns 0 when all items have been seen, else 1.
+ /// Returns 1 when all items have been seen, else 0.
int done (void) const;
- // Returns 1 when all items have been seen, else 0.
+ /// Move forward by one element in the queue. Returns 0 when all the
+ /// items in the set have been seen, else 1.
int advance (void);
- // Move forward by one element in the queue. Returns 0 when all the
- // items in the set have been seen, else 1.
+ /// Dump the state of an object.
void dump (void) const;
- // Dump the state of an object.
+ /// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
- // Declare the dynamic allocation hooks.
private:
+ /// Message_Queue we are iterating over.
ACE_Message_Queue <ACE_SYNCH_USE> &queue_;
- // Message_Queue we are iterating over.
+ /// Keeps track of how far we've advanced...
ACE_Message_Block *curr_;
- // Keeps track of how far we've advanced...
};
+/**
+ * @class ACE_Dynamic_Message_Queue
+ *
+ * @brief A derived class which adapts the <ACE_Message_Queue>
+ * class in order to maintain dynamic priorities for enqueued
+ * <ACE_Message_Blocks> and manage the queue order according
+ * to these dynamic priorities.
+ *
+ * The messages in the queue are managed so as to preserve
+ * a logical ordering with minimal overhead per enqueue and
+ * dequeue operation. For this reason, the actual order of
+ * messages in the linked list of the queue may differ from
+ * their priority order. As time passes, a message may change
+ * from pending status to late status, and eventually to beyond
+ * late status. To minimize reordering overhead under this
+ * design force, three separate boundaries are maintained
+ * within the linked list of messages. Messages are dequeued
+ * preferentially from the head of the pending portion, then
+ * the head of the late portion, and finally from the head
+ * of the beyond late portion. In this way, only the boundaries
+ * need to be maintained (which can be done efficiently, as
+ * aging messages maintain the same linked list order as they
+ * progress from one status to the next), with no reordering
+ * of the messages themselves, while providing correct priority
+ * ordered dequeueing semantics.
+ * Head and tail enqueue methods inherited from ACE_Message_Queue
+ * are made private to prevent out-of-order messages from confusing
+ * management of the various portions of the queue. Messages in
+ * the pending portion of the queue whose priority becomes late
+ * (according to the specific dynamic strategy) advance into
+ * the late portion of the queue. Messages in the late portion
+ * of the queue whose priority becomes later than can be represented
+ * advance to the beyond_late portion of the queue. These behaviors
+ * support a limited schedule overrun, with pending messages prioritized
+ * ahead of late messages, and late messages ahead of beyond late
+ * messages. These behaviors can be modified in derived classes by
+ * providing alternative definitions for the appropriate virtual methods.
+ * When filled with messages, the queue's linked list should look like:
+ * H T
+ * | |
+ * B - B - B - B - L - L - L - P - P - P - P - P
+ * | | | | | |
+ * BH BT LH LT PH PT
+ * Where the symbols are as follows:
+ * H = Head of the entire list
+ * T = Tail of the entire list
+ * B = Beyond late message
+ * BH = Beyond late messages Head
+ * BT = Beyond late messages Tail
+ * L = Late message
+ * LH = Late messages Head
+ * LT = Late messages Tail
+ * P = Pending message
+ * PH = Pending messages Head
+ * PT = Pending messages Tail
+ * Caveat: the virtual methods enqueue_tail, enqueue_head,
+ * and peek_dequeue_head have semantics for the static
+ * message queues that cannot be guaranteed for dynamic
+ * message queues. The peek_dequeue_head method just
+ * calls the base class method, while the two enqueue
+ * methods call the priority enqueue method. The
+ * order of messages in the dynamic queue is a function
+ * of message deadlines and how long they are in the
+ * queues. You can manipulate these in some cases to
+ * ensure the correct semantics, but that is not a
+ * very stable or portable approach (discouraged).
+ */
template <ACE_SYNCH_DECL>
class ACE_Dynamic_Message_Queue : public ACE_Message_Queue<ACE_SYNCH_USE>
{
- // = TITLE
- // A derived class which adapts the <ACE_Message_Queue>
- // class in order to maintain dynamic priorities for enqueued
- // <ACE_Message_Blocks> and manage the queue order according
- // to these dynamic priorities.
- //
- // = DESCRIPTION
- //
- // The messages in the queue are managed so as to preserve
- // a logical ordering with minimal overhead per enqueue and
- // dequeue operation. For this reason, the actual order of
- // messages in the linked list of the queue may differ from
- // their priority order. As time passes, a message may change
- // from pending status to late status, and eventually to beyond
- // late status. To minimize reordering overhead under this
- // design force, three separate boundaries are maintained
- // within the linked list of messages. Messages are dequeued
- // preferentially from the head of the pending portion, then
- // the head of the late portion, and finally from the head
- // of the beyond late portion. In this way, only the boundaries
- // need to be maintained (which can be done efficiently, as
- // aging messages maintain the same linked list order as they
- // progress from one status to the next), with no reordering
- // of the messages themselves, while providing correct priority
- // ordered dequeueing semantics.
- //
- // Head and tail enqueue methods inherited from ACE_Message_Queue
- // are made private to prevent out-of-order messages from confusing
- // management of the various portions of the queue. Messages in
- // the pending portion of the queue whose priority becomes late
- // (according to the specific dynamic strategy) advance into
- // the late portion of the queue. Messages in the late portion
- // of the queue whose priority becomes later than can be represented
- // advance to the beyond_late portion of the queue. These behaviors
- // support a limited schedule overrun, with pending messages prioritized
- // ahead of late messages, and late messages ahead of beyond late
- // messages. These behaviors can be modified in derived classes by
- // providing alternative definitions for the appropriate virtual methods.
- //
- // When filled with messages, the queue's linked list should look like:
- //
- // H T
- // | |
- //
- // B - B - B - B - L - L - L - P - P - P - P - P
- //
- // | | | | | |
- // BH BT LH LT PH PT
- //
- // Where the symbols are as follows:
- //
- // H = Head of the entire list
- // T = Tail of the entire list
- // B = Beyond late message
- // BH = Beyond late messages Head
- // BT = Beyond late messages Tail
- // L = Late message
- // LH = Late messages Head
- // LT = Late messages Tail
- // P = Pending message
- // PH = Pending messages Head
- // PT = Pending messages Tail
- //
- // Caveat: the virtual methods enqueue_tail, enqueue_head,
- // and peek_dequeue_head have semantics for the static
- // message queues that cannot be guaranteed for dynamic
- // message queues. The peek_dequeue_head method just
- // calls the base class method, while the two enqueue
- // methods call the priority enqueue method. The
- // order of messages in the dynamic queue is a function
- // of message deadlines and how long they are in the
- // queues. You can manipulate these in some cases to
- // ensure the correct semantics, but that is not a
- // very stable or portable approach (discouraged).
- //
public:
// = Initialization and termination methods.
ACE_Dynamic_Message_Queue (ACE_Dynamic_Message_Strategy & message_strategy,
@@ -519,102 +546,114 @@ public:
size_t lwm = ACE_Message_Queue_Base::DEFAULT_LWM,
ACE_Notification_Strategy * = 0);
+ /// Close down the message queue and release all resources.
virtual ~ACE_Dynamic_Message_Queue (void);
- // Close down the message queue and release all resources.
+ /**
+ * Detach all messages with status given in the passed flags from
+ * the queue and return them by setting passed head and tail pointers
+ * to the linked list they comprise. This method is intended primarily
+ * as a means of periodically harvesting messages that have missed
+ * their deadlines, but is available in its most general form. All
+ * messages are returned in priority order, from head to tail, as of
+ * the time this method was called.
+ */
virtual int remove_messages (ACE_Message_Block *&list_head,
ACE_Message_Block *&list_tail,
u_int status_flags);
- // Detach all messages with status given in the passed flags from
- // the queue and return them by setting passed head and tail pointers
- // to the linked list they comprise. This method is intended primarily
- // as a means of periodically harvesting messages that have missed
- // their deadlines, but is available in its most general form. All
- // messages are returned in priority order, from head to tail, as of
- // the time this method was called.
+ /**
+ * Dequeue and return the <ACE_Message_Block *> at the head of the
+ * queue. Returns -1 on failure, else the number of items still on
+ * the queue.
+ */
virtual int dequeue_head (ACE_Message_Block *&first_item,
ACE_Time_Value *timeout = 0);
- // Dequeue and return the <ACE_Message_Block *> at the head of the
- // queue. Returns -1 on failure, else the number of items still on
- // the queue.
+ /// Dump the state of the queue.
virtual void dump (void) const;
- // Dump the state of the queue.
+ /**
+ * just call priority enqueue method: tail enqueue semantics for dynamic
+ * message queues are unstable: the message may or may not be where
+ * it was placed after the queue is refreshed prior to the next
+ * enqueue or dequeue operation.
+ */
virtual int enqueue_tail (ACE_Message_Block *new_item,
ACE_Time_Value *timeout = 0);
- // just call priority enqueue method: tail enqueue semantics for dynamic
- // message queues are unstable: the message may or may not be where
- // it was placed after the queue is refreshed prior to the next
- // enqueue or dequeue operation.
+ /**
+ * just call priority enqueue method: head enqueue semantics for dynamic
+ * message queues are unstable: the message may or may not be where
+ * it was placed after the queue is refreshed prior to the next
+ * enqueue or dequeue operation.
+ */
virtual int enqueue_head (ACE_Message_Block *new_item,
ACE_Time_Value *timeout = 0);
- // just call priority enqueue method: head enqueue semantics for dynamic
- // message queues are unstable: the message may or may not be where
- // it was placed after the queue is refreshed prior to the next
- // enqueue or dequeue operation.
+ /// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
- // Declare the dynamic allocation hooks.
protected:
+ /**
+ * Enqueue an <ACE_Message_Block *> in accordance with its priority.
+ * priority may be *dynamic* or *static* or a combination or *both*
+ * It calls the priority evaluation function passed into the Dynamic
+ * Message Queue constructor to update the priorities of all
+ * enqueued messages.
+ */
virtual int enqueue_i (ACE_Message_Block *new_item);
- // Enqueue an <ACE_Message_Block *> in accordance with its priority.
- // priority may be *dynamic* or *static* or a combination or *both*
- // It calls the priority evaluation function passed into the Dynamic
- // Message Queue constructor to update the priorities of all
- // enqueued messages.
+ /// enqueue a message in priority order within a given priority status sublist
virtual int sublist_enqueue_i (ACE_Message_Block *new_item,
const ACE_Time_Value &current_time,
ACE_Message_Block *&sublist_head,
ACE_Message_Block *&sublist_tail,
ACE_Dynamic_Message_Strategy::Priority_Status status);
- // enqueue a message in priority order within a given priority status sublist
+ /**
+ * Dequeue and return the <ACE_Message_Block *> at the head of the
+ * logical queue. Attempts first to dequeue from the pending
+ * portion of the queue, or if that is empty from the late portion,
+ * or if that is empty from the beyond late portion, or if that is
+ * empty just sets the passed pointer to zero and returns -1.
+ */
virtual int dequeue_head_i (ACE_Message_Block *&first_item);
- // Dequeue and return the <ACE_Message_Block *> at the head of the
- // logical queue. Attempts first to dequeue from the pending
- // portion of the queue, or if that is empty from the late portion,
- // or if that is empty from the beyond late portion, or if that is
- // empty just sets the passed pointer to zero and returns -1.
+ /// Refresh the queue using the strategy
+ /// specific priority status function.
virtual int refresh_queue (const ACE_Time_Value & current_time);
- // Refresh the queue using the strategy
- // specific priority status function.
+ /// Refresh the pending queue using the strategy
+ /// specific priority status function.
virtual int refresh_pending_queue (const ACE_Time_Value & current_time);
- // Refresh the pending queue using the strategy
- // specific priority status function.
+ /// Refresh the late queue using the strategy
+ /// specific priority status function.
virtual int refresh_late_queue (const ACE_Time_Value & current_time);
- // Refresh the late queue using the strategy
- // specific priority status function.
+ /// Pointer to head of the pending messages
ACE_Message_Block *pending_head_;
- // Pointer to head of the pending messages
+ /// Pointer to tail of the pending messages
ACE_Message_Block *pending_tail_;
- // Pointer to tail of the pending messages
+ /// Pointer to head of the late messages
ACE_Message_Block *late_head_;
- // Pointer to head of the late messages
+ /// Pointer to tail of the late messages
ACE_Message_Block *late_tail_;
- // Pointer to tail of the late messages
+ /// Pointer to head of the beyond late messages
ACE_Message_Block *beyond_late_head_;
- // Pointer to head of the beyond late messages
+ /// Pointer to tail of the beyond late messages
ACE_Message_Block *beyond_late_tail_;
- // Pointer to tail of the beyond late messages
+ /// Pointer to a dynamic priority evaluation function.
ACE_Dynamic_Message_Strategy &message_strategy_;
- // Pointer to a dynamic priority evaluation function.
private:
// = Disallow public access to these operations.
@@ -625,35 +664,38 @@ private:
// provide definitions for these (just call base class method),
// but make them private so they're not accessible outside the class
+ /// private method to hide public base class method: just calls base class method
virtual int peek_dequeue_head (ACE_Message_Block *&first_item,
ACE_Time_Value *timeout = 0);
- // private method to hide public base class method: just calls base class method
};
+/**
+ * @class ACE_Message_Queue_Factory
+ *
+ * @brief ACE_Message_Queue_Factory is a static factory class template which
+ * provides a separate factory method for each of the major kinds of
+ * priority based message dispatching: static, earliest deadline first
+ * (EDF), and minimum laxity first (MLF).
+ *
+ * The ACE_Dynamic_Message_Queue class assumes responsibility for
+ * releasing the resources of the strategy with which it was
+ * constructed: the user of a message queue constructed by
+ * any of these factory methods is only responsible for
+ * ensuring destruction of the message queue itself.
+ */
template <ACE_SYNCH_DECL>
class ACE_Message_Queue_Factory
{
- // = TITLE
- // ACE_Message_Queue_Factory is a static factory class template which
- // provides a separate factory method for each of the major kinds of
- // priority based message dispatching: static, earliest deadline first
- // (EDF), and minimum laxity first (MLF).
- //
- // = DESCRIPTION
- // The ACE_Dynamic_Message_Queue class assumes responsibility for
- // releasing the resources of the strategy with which it was
- // constructed: the user of a message queue constructed by
- // any of these factory methods is only responsible for
- // ensuring destruction of the message queue itself.
public:
+ /// factory method for a statically prioritized ACE_Message_Queue
static ACE_Message_Queue<ACE_SYNCH_USE> *
create_static_message_queue (size_t hwm = ACE_Message_Queue_Base::DEFAULT_HWM,
size_t lwm = ACE_Message_Queue_Base::DEFAULT_LWM,
ACE_Notification_Strategy * = 0);
- // factory method for a statically prioritized ACE_Message_Queue
+ /// factory method for a dynamically prioritized (by time to deadline) ACE_Dynamic_Message_Queue
static ACE_Dynamic_Message_Queue<ACE_SYNCH_USE> *
create_deadline_message_queue (size_t hwm = ACE_Message_Queue_Base::DEFAULT_HWM,
size_t lwm = ACE_Message_Queue_Base::DEFAULT_LWM,
@@ -662,8 +704,8 @@ public:
u_long static_bit_field_shift = 10, // 10 low order bits
u_long dynamic_priority_max = 0x3FFFFFUL, // 2^(22)-1
u_long dynamic_priority_offset = 0x200000UL); // 2^(22-1)
- // factory method for a dynamically prioritized (by time to deadline) ACE_Dynamic_Message_Queue
+ /// factory method for a dynamically prioritized (by laxity) ACE_Dynamic_Message_Queue
static ACE_Dynamic_Message_Queue<ACE_SYNCH_USE> *
create_laxity_message_queue (size_t hwm = ACE_Message_Queue_Base::DEFAULT_HWM,
size_t lwm = ACE_Message_Queue_Base::DEFAULT_LWM,
@@ -672,23 +714,22 @@ public:
u_long static_bit_field_shift = 10, // 10 low order bits
u_long dynamic_priority_max = 0x3FFFFFUL, // 2^(22)-1
u_long dynamic_priority_offset = 0x200000UL); // 2^(22-1)
- // factory method for a dynamically prioritized (by laxity) ACE_Dynamic_Message_Queue
#if defined (VXWORKS)
+ /// factory method for a wrapped VxWorks message queue
static ACE_Message_Queue_Vx *
create_Vx_message_queue (size_t max_messages, size_t max_message_length,
ACE_Notification_Strategy *ns = 0);
- // factory method for a wrapped VxWorks message queue
#endif /* defined (VXWORKS) */
#if defined (ACE_WIN32) && (ACE_HAS_WINNT4 != 0)
+ /// factory method for a NT message queue.
static ACE_Message_Queue_NT *
create_NT_message_queue (size_t max_threads);
- // factory method for a NT message queue.
#endif /* ACE_WIN32 && ACE_HAS_WINNT4 != 0 */
};