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Diffstat (limited to 'ACE/ace/Message_Queue_T.h')
| -rw-r--r-- | ACE/ace/Message_Queue_T.h | 1476 |
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diff --git a/ACE/ace/Message_Queue_T.h b/ACE/ace/Message_Queue_T.h deleted file mode 100644 index 62869da889e..00000000000 --- a/ACE/ace/Message_Queue_T.h +++ /dev/null @@ -1,1476 +0,0 @@ -/* -*- C++ -*- */ - -//============================================================================= -/** - * @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 -#include /**/ "ace/pre.h" - -#include "ace/Message_Queue.h" -#include "ace/Dynamic_Message_Strategy.h" -#include "ace/Synch_Traits.h" -#include "ace/Guard_T.h" - -#if !defined (ACE_LACKS_PRAGMA_ONCE) -# pragma once -#endif /* ACE_LACKS_PRAGMA_ONCE */ - -ACE_BEGIN_VERSIONED_NAMESPACE_DECL - -#if defined (ACE_VXWORKS) -class ACE_Message_Queue_Vx; -#endif /* defined (ACE_VXWORKS) */ - -#if defined (ACE_HAS_WIN32_OVERLAPPED_IO) -class ACE_Message_Queue_NT; -#endif /* ACE_HAS_WIN32_OVERLAPPED_IO*/ - -/** - * @class ACE_Message_Queue - * - * @brief A message queueing facility with parameterized synchronization - * capability. ACE_Message_Queue is modeled after the queueing facilities - * in System V STREAMs. - * - * ACE_Message_Queue is the primary queueing facility for - * messages in the ACE framework. It's one template argument parameterizes - * the queue's synchronization. The argument specifies a synchronization - * strategy. The two main strategies available for ACE_SYNCH_DECL are: - * -# ACE_MT_SYNCH: all operations are thread-safe - * -# ACE_NULL_SYNCH: no synchronization and no locking overhead - * - * All data passing through ACE_Message_Queue is in the form of - * ACE_Message_Block objects. @sa ACE_Message_Block. - */ -template <ACE_SYNCH_DECL> -class ACE_Message_Queue : public ACE_Message_Queue_Base -{ -public: - friend class ACE_Message_Queue_Iterator<ACE_SYNCH_USE>; - friend class ACE_Message_Queue_Reverse_Iterator<ACE_SYNCH_USE>; - - // = Traits - typedef ACE_Message_Queue_Iterator<ACE_SYNCH_USE> - ITERATOR; - typedef ACE_Message_Queue_Reverse_Iterator<ACE_SYNCH_USE> - REVERSE_ITERATOR; - - /** - * @name Initialization methods - */ - //@{ - /** - * Initialize an ACE_Message_Queue. - * - * @param hwm 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. - * @param lwm Low water mark. Determines how many bytes must be in the queue - * before supplier threads are allowed to enqueue additional - * data. By default, the @a hwm equals @a lwm, 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." - * @param ns Notification strategy. Pointer to an object conforming to the - * ACE_Notification_Strategy interface. If set, the object's - * notify(void) method will be called each time data is added to - * this ACE_Message_Queue. @see ACE_Reactor_Notification_Strategy. - */ - ACE_Message_Queue (size_t hwm = ACE_Message_Queue_Base::DEFAULT_HWM, - size_t lwm = ACE_Message_Queue_Base::DEFAULT_LWM, - ACE_Notification_Strategy *ns = 0); - virtual int open (size_t hwm = ACE_Message_Queue_Base::DEFAULT_HWM, - size_t lwm = ACE_Message_Queue_Base::DEFAULT_LWM, - ACE_Notification_Strategy *ns = 0); - //@} - - /// Releases all resources from the message queue and marks it deactivated. - /// @sa flush(). - /// - /// @retval The number of messages released from the queue; -1 on error. - virtual int close (void); - - /// Releases all resources from the message queue and marks it deactivated. - virtual ~ACE_Message_Queue (void); - - /** - * Releases all resources from the message queue but does not mark it - * deactivated. This method holds the queue lock during this operation. - * @sa close(). - * - * @return The number of messages flushed; -1 on error. - */ - virtual int flush (void); - - /** - * Release all resources from the message queue but do not mark it - * as deactivated. - * - * @pre The caller must be holding the queue lock before calling this - * method. - * - * @return The number of messages flushed. - */ - virtual int flush_i (void); - - /** @name Enqueue and dequeue methods - * - * The enqueue and dequeue methods accept a timeout value passed as - * an ACE_Time_Value *. In all cases, if the timeout pointer is 0, - * the caller will block until action is possible. If the timeout pointer - * is non-zero, the call will wait (if needed, subject to water mark - * settings) until the absolute time specified in the referenced - * ACE_Time_Value object is reached. If the time is reached before the - * desired action is possible, the method will return -1 with errno set - * to @c EWOULDBLOCK. Regardless of the timeout setting, however, - * these methods will also fail and return -1 when the queue is closed, - * deactivated, pulsed, or when a signal occurs. - * - * See C++NPv2 Section 6.2 and APG Section 12.3 for a fuller treatment of - * ACE_Message_Queue, enqueueing, dequeueing, and how these operations are - * affected by queue state transitions. - */ - //@{ - /** - * Retrieve a pointer to the first ACE_Message_Block in the queue - * without removing it. - * - * @note Because the block whose pointer is returned is still on the queue, - * another thread may dequeue the referenced block at any time, - * including before the calling thread examines the peeked-at block. - * Be very careful with this method in multithreaded queueing - * situations. - * - * @param first_item Reference to an ACE_Message_Block * that will - * point to the first block on the queue. The block - * remains on the queue until this or another thread - * dequeues it. - * @param timeout The absolute time the caller will wait until - * for a block to be queued. - * - * @retval >0 The number of ACE_Message_Blocks on the queue. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int peek_dequeue_head (ACE_Message_Block *&first_item, - ACE_Time_Value *timeout = 0); - - /** - * Enqueue an ACE_Message_Block into the queue in accordance with - * the ACE_Message_Block's priority (0 is lowest priority). FIFO - * order is maintained when messages of the same priority are - * inserted consecutively. - * - * @param new_item Pointer to an ACE_Message_Block that will be - * added to the queue. The block's @c msg_priority() - * method will be called to obtain the queueing priority. - * @param timeout The absolute time the caller will wait until - * for the block to be queued. - * - * @retval >0 The number of ACE_Message_Blocks on the queue after adding - * the specified block. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int enqueue_prio (ACE_Message_Block *new_item, - ACE_Time_Value *timeout = 0); - - /** - * Enqueue an ACE_Message_Block into the queue in accordance with the - * block's deadline time. FIFO order is maintained when messages of - * the same deadline time are inserted consecutively. - * - * @param new_item Pointer to an ACE_Message_Block that will be - * added to the queue. The block's @c msg_deadline_time() - * method will be called to obtain the relative queueing - * position. - * @param timeout The absolute time the caller will wait until - * for the block to be queued. - * - * @retval >0 The number of ACE_Message_Blocks on the queue after adding - * the specified block. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int enqueue_deadline (ACE_Message_Block *new_item, - ACE_Time_Value *timeout = 0); - - /** - * @deprecated 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. - */ - virtual int enqueue (ACE_Message_Block *new_item, - ACE_Time_Value *timeout = 0); - - /** - * Enqueue one or more ACE_Message_Block objects at the tail of the queue. - * If the @a new_item @c next() pointer is non-zero, it is assumed to be the - * start of a series of ACE_Message_Block objects connected via their - * @c next() pointers. The series of blocks will be added to the queue in - * the same order they are passed in as. - * - * @param new_item Pointer to an ACE_Message_Block that will be - * added to the queue. If the block's @c next() pointer - * is non-zero, all blocks chained from the @c next() - * pointer are enqueued as well. - * @param timeout The absolute time the caller will wait until - * for the block to be queued. - * - * @retval >0 The number of ACE_Message_Blocks on the queue after adding - * the specified block(s). - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int enqueue_tail (ACE_Message_Block *new_item, - ACE_Time_Value *timeout = 0); - - /** - * Enqueue one or more ACE_Message_Block objects at the head of the queue. - * If the @a new_item @c next() pointer is non-zero, it is assumed to be the - * start of a series of ACE_Message_Block objects connected via their - * @c next() pointers. The series of blocks will be added to the queue in - * the same order they are passed in as. - * - * @param new_item Pointer to an ACE_Message_Block that will be - * added to the queue. If the block's @c next() pointer - * is non-zero, all blocks chained from the @c next() - * pointer are enqueued as well. - * @param timeout The absolute time the caller will wait until - * for the block to be queued. - * - * @retval >0 The number of ACE_Message_Blocks on the queue after adding - * the specified block(s). - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int enqueue_head (ACE_Message_Block *new_item, - ACE_Time_Value *timeout = 0); - - /// This method is an alias for the dequeue_head() method. - virtual int dequeue (ACE_Message_Block *&first_item, - ACE_Time_Value *timeout = 0); - - /** - * Dequeue the ACE_Message_Block at the head of the queue and return - * a pointer to the dequeued block. - * - * @param first_item Reference to an ACE_Message_Block * that will - * be set to the address of the dequeued block. - * @param timeout The absolute time the caller will wait until - * for a block to be dequeued. - * - * @retval >=0 The number of ACE_Message_Blocks remaining in the queue. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int dequeue_head (ACE_Message_Block *&first_item, - ACE_Time_Value *timeout = 0); - - /** - * Dequeue the ACE_Message_Block that has the lowest priority (preserves - * FIFO order for messages with the same priority) and return a pointer - * to the dequeued block. - * - * @param first_item Reference to an ACE_Message_Block * that will - * be set to the address of the dequeued block. - * @param timeout The absolute time the caller will wait until - * for a block to be dequeued. - * - * @retval >=0 The number of ACE_Message_Blocks remaining in the queue. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int dequeue_prio (ACE_Message_Block *&first_item, - ACE_Time_Value *timeout = 0); - - /** - * Dequeue the ACE_Message_Block at the tail of the queue and return - * a pointer to the dequeued block. - * - * @param dequeued Reference to an ACE_Message_Block * that will - * be set to the address of the dequeued block. - * @param timeout The absolute time the caller will wait until - * for a block to be dequeued. - * - * @retval >=0 The number of ACE_Message_Blocks remaining in the queue. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int dequeue_tail (ACE_Message_Block *&dequeued, - ACE_Time_Value *timeout = 0); - - /** - * Dequeue the ACE_Message_Block with the earliest deadline time and return - * a pointer to the dequeued block. - * - * @param dequeued Reference to an ACE_Message_Block * that will - * be set to the address of the dequeued block. - * @param timeout The absolute time the caller will wait until - * for a block to be dequeued. - * - * @retval >=0 The number of ACE_Message_Blocks remaining in the queue. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int dequeue_deadline (ACE_Message_Block *&dequeued, - ACE_Time_Value *timeout = 0); - //@} - - /** @name Queue statistics methods - */ - //@{ - - /// True if queue is full, else false. - virtual bool is_full (void); - /// True if queue is empty, else false. - virtual bool is_empty (void); - - /** - * Number of total bytes on the queue, i.e., sum of the message - * block sizes. - */ - virtual size_t message_bytes (void); - - /** - * Number of total length on the queue, i.e., sum of the message - * block lengths. - */ - virtual size_t message_length (void); - - /** - * Number of total messages on the queue. - */ - virtual size_t message_count (void); - - // = 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. - */ - virtual void message_bytes (size_t new_size); - /** - * New value of the number of total length on the queue, i.e., sum - * of the message block lengths. - */ - virtual void message_length (size_t new_length); - - //@} - - - /** @name Water mark (flow control) methods - */ - //@{ - - /** - * Get high watermark. - */ - virtual size_t high_water_mark (void); - /** - * Set the high watermark, which determines how many bytes can be - * stored in a queue before it's considered "full." - */ - virtual void high_water_mark (size_t hwm); - - /** - * Get low watermark. - */ - virtual size_t low_water_mark (void); - /** - * Set the low watermark, which determines how many bytes must be in - * the queue before supplier threads are allowed to enqueue - * additional ACE_Message_Blocks. - */ - virtual void low_water_mark (size_t lwm); - //@} - - /** @name Activation and queue state methods - * See C++NPv2 Section 6.2 and APG Section 12.3 for a fuller treatment of - * queue states and transitions and how the transitions affect message - * enqueueing and dequeueing operations. - */ - //@{ - - /** - * 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 @c 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); - - /** - * Reactivate the queue so that threads can enqueue and dequeue - * messages again. Returns the state of the queue before the call. - */ - virtual int activate (void); - - /** - * Pulse the queue to wake up any waiting threads. Changes the - * queue state to PULSED; future enqueue/dequeue operations proceed - * as in ACTIVATED state. - * - * @return The queue's state before this call. - */ - virtual int pulse (void); - - /// Returns the current state of the queue, which can be one of - /// ACTIVATED, DEACTIVATED, or PULSED. - virtual int state (void); - - /// Returns true if the state of the queue is <DEACTIVATED>, - /// but false if the queue's is <ACTIVATED> or <PULSED>. - virtual int deactivated (void); - //@} - - /** @name Notification strategy methods - */ - //@{ - - /** - * 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); - - /// Get the notification strategy for the <Message_Queue> - virtual ACE_Notification_Strategy *notification_strategy (void); - - /// Set the notification strategy for the <Message_Queue> - virtual void notification_strategy (ACE_Notification_Strategy *s); - //@} - - /// Returns a reference to the lock used by the ACE_Message_Queue. - virtual ACE_SYNCH_MUTEX_T &lock (void); - - /// Dump the state of an object. - virtual void dump (void) const; - - /// Declare the dynamic allocation hooks. - ACE_ALLOC_HOOK_DECLARE; - -protected: - // = Routines that actually do the enqueueing and dequeueing. - - // These routines assume that locks are held by the corresponding - // 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 deadline time. - virtual int enqueue_deadline_i (ACE_Message_Block *new_item); - - /// 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 head of the queue. - virtual int enqueue_head_i (ACE_Message_Block *new_item); - - /// 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 *> with the lowest - /// priority. - virtual int dequeue_prio_i (ACE_Message_Block *&dequeued); - - /// Dequeue and return the <ACE_Message_Block *> at the tail of the - /// queue. - virtual int dequeue_tail_i (ACE_Message_Block *&first_item); - - /// Dequeue and return the <ACE_Message_Block *> with the lowest - /// deadline time. - virtual int dequeue_deadline_i (ACE_Message_Block *&first_item); - - // = Check the boundary conditions (assumes locks are held). - - /// True if queue is full, else false. - virtual bool is_full_i (void); - - /// True if queue is empty, else false. - virtual bool is_empty_i (void); - - // = Implementation of the public <activate> and <deactivate> methods. - - // These methods assume locks are held. - - /** - * Notifies all waiting threads that the queue has been deactivated - * so they can wakeup and continue other processing. - * No messages are removed from the queue. - * - * @param pulse If 0, the queue's state is changed to DEACTIVATED - * and any other operations called until the queue is - * reactivated will immediately return -1 with - * errno == ESHUTDOWN. - * If not zero, only the waiting threads are notified and - * the queue's state changes to PULSED. - * - * @return The state of the queue before the call. - */ - virtual int deactivate_i (int pulse = 0); - - /// Activate the queue. - virtual int activate_i (void); - - // = 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-empty. - virtual int wait_not_empty_cond (ACE_Guard<ACE_SYNCH_MUTEX_T> &mon, - ACE_Time_Value *timeout); - - /// Inform any threads waiting to enqueue that they can procede. - virtual int signal_enqueue_waiters (void); - - /// Inform any threads waiting to dequeue that they can procede. - virtual int signal_dequeue_waiters (void); - - /// Pointer to head of ACE_Message_Block list. - ACE_Message_Block *head_; - - /// Pointer to tail of ACE_Message_Block list. - ACE_Message_Block *tail_; - - /// Lowest number before unblocking occurs. - size_t low_water_mark_; - - /// Greatest number of bytes before blocking. - size_t high_water_mark_; - - /// Current number of bytes in the queue. - size_t cur_bytes_; - - /// Current length of messages in the queue. - size_t cur_length_; - - /// Current number of messages in the queue. - size_t cur_count_; - - /// The notification strategy used when a new message is enqueued. - ACE_Notification_Strategy *notification_strategy_; - - // = Synchronization primitives for controlling concurrent access. - /// Protect queue from concurrent access. - ACE_SYNCH_MUTEX_T lock_; - - /// 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 full. - ACE_SYNCH_CONDITION_T not_full_cond_; - -private: - - // = Disallow these operations. - ACE_UNIMPLEMENTED_FUNC (void operator= (const ACE_Message_Queue<ACE_SYNCH_USE> &)) - ACE_UNIMPLEMENTED_FUNC (ACE_Message_Queue (const ACE_Message_Queue<ACE_SYNCH_USE> &)) -}; - -// This typedef is used to get around a compiler bug in g++/vxworks. -typedef ACE_Message_Queue<ACE_SYNCH> ACE_DEFAULT_MESSAGE_QUEUE_TYPE; - - -/** - * @class ACE_Message_Queue_Iterator - * - * @brief Iterator for the ACE_Message_Queue. - */ -template <ACE_SYNCH_DECL> -class ACE_Message_Queue_Iterator -{ -public: - // = Initialization method. - ACE_Message_Queue_Iterator (ACE_Message_Queue <ACE_SYNCH_USE> &queue); - - // = Iteration methods. - /// Pass back the @a 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); - - /// Returns 1 when all items have been seen, else 0. - int done (void) const; - - /// 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); - - /// Dump the state of an object. - void dump (void) const; - - /// Declare the dynamic allocation hooks. - ACE_ALLOC_HOOK_DECLARE; - -private: - /// Message_Queue we are iterating over. - ACE_Message_Queue <ACE_SYNCH_USE> &queue_; - - /// Keeps track of how far we've advanced... - ACE_Message_Block *curr_; -}; - -/** - * @class ACE_Message_Queue_Reverse_Iterator - * - * @brief Reverse Iterator for the ACE_Message_Queue. - */ -template <ACE_SYNCH_DECL> -class ACE_Message_Queue_Reverse_Iterator -{ -public: - // = Initialization method. - ACE_Message_Queue_Reverse_Iterator (ACE_Message_Queue <ACE_SYNCH_USE> &queue); - - // = Iteration methods. - /// Pass back the @a 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); - - /// Returns 1 when all items have been seen, else 0. - int done (void) const; - - /// 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); - - /// Dump the state of an object. - void dump (void) const; - - /// Declare the dynamic allocation hooks. - ACE_ALLOC_HOOK_DECLARE; - -private: - /// Message_Queue we are iterating over. - ACE_Message_Queue <ACE_SYNCH_USE> &queue_; - - /// Keeps track of how far we've advanced... - ACE_Message_Block *curr_; -}; - -/** - * @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> -{ -public: - // = Initialization and termination methods. - ACE_Dynamic_Message_Queue (ACE_Dynamic_Message_Strategy & message_strategy, - size_t hwm = ACE_Message_Queue_Base::DEFAULT_HWM, - 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); - - /** - * 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); - - /** - * 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); - - /// Dump the state of the queue. - virtual void dump (void) const; - - /** - * 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: 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); - - - /// Declare the dynamic allocation hooks. - ACE_ALLOC_HOOK_DECLARE; - -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 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 ¤t_time, - ACE_Message_Block *&sublist_head, - ACE_Message_Block *&sublist_tail, - ACE_Dynamic_Message_Strategy::Priority_Status status); - - /** - * 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); - - /// Refresh the queue using the strategy - /// specific priority status function. - virtual int refresh_queue (const ACE_Time_Value & current_time); - - /// Refresh the pending queue using the strategy - /// specific priority status function. - virtual int refresh_pending_queue (const ACE_Time_Value & current_time); - - /// Refresh the late queue using the strategy - /// specific priority status function. - virtual int refresh_late_queue (const ACE_Time_Value & current_time); - - /// Pointer to head of the pending messages - ACE_Message_Block *pending_head_; - - /// Pointer to tail of the pending messages - ACE_Message_Block *pending_tail_; - - /// Pointer to head of the late messages - ACE_Message_Block *late_head_; - - /// Pointer to tail of the late messages - ACE_Message_Block *late_tail_; - - /// Pointer to head of the beyond late messages - ACE_Message_Block *beyond_late_head_; - - /// Pointer to tail of the beyond late messages - ACE_Message_Block *beyond_late_tail_; - - /// Pointer to a dynamic priority evaluation function. - ACE_Dynamic_Message_Strategy &message_strategy_; - -private: - // = Disallow public access to these operations. - - ACE_UNIMPLEMENTED_FUNC (void operator= (const ACE_Dynamic_Message_Queue<ACE_SYNCH_USE> &)) - ACE_UNIMPLEMENTED_FUNC (ACE_Dynamic_Message_Queue (const ACE_Dynamic_Message_Queue<ACE_SYNCH_USE> &)) - - // 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); - -}; - -/** - * @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 -{ -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 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, - ACE_Notification_Strategy * = 0, - u_long static_bit_field_mask = 0x3FFUL, // 2^(10) - 1 - 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 - 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, - ACE_Notification_Strategy * = 0, - u_long static_bit_field_mask = 0x3FFUL, // 2^(10) - 1 - 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) - - -#if defined (ACE_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); - -#endif /* defined (ACE_VXWORKS) */ - -#if defined (ACE_HAS_WIN32_OVERLAPPED_IO) - - /// Factory method for a NT message queue. - static ACE_Message_Queue_NT * - create_NT_message_queue (size_t max_threads); - -#endif /* ACE_HAS_WIN32_OVERLAPPED_IO */ -}; - -/** - * @class ACE_Message_Queue_Ex - * - * @brief A threaded message queueing facility, modeled after the - * queueing facilities in System V STREAMs. - * - * ACE_Message_Queue_Ex is a strongly-typed version of the - * ACE_Message_Queue class. Rather than queueing in terms of ACE_Message_Block - * objects, ACE_Message_Queue_Ex has a template argument to specify the - * type of objects that are queued. - * - * The second template argument parameterizes the queue's synchronization. - * The argument specifies a synchronization strategy. The two main - * strategies available for ACE_SYNCH_DECL are: - * -# ACE_MT_SYNCH: all operations are thread-safe - * -# ACE_NULL_SYNCH: no synchronization and no locking overhead - */ -template <class ACE_MESSAGE_TYPE, ACE_SYNCH_DECL> -class ACE_Message_Queue_Ex -{ -public: - - enum - { - /// Default priority value. This is the lowest priority. - DEFAULT_PRIORITY = 0 - }; - -#if 0 - // @@ Iterators are not implemented yet... - - friend class ACE_Message_Queue_Iterator<ACE_SYNCH_USE>; - friend class ACE_Message_Queue_Reverse_Iterator<ACE_SYNCH_USE>; - - // = Traits - typedef ACE_Message_Queue_Iterator<ACE_SYNCH_USE> - ITERATOR; - typedef ACE_Message_Queue_Reverse_Iterator<ACE_SYNCH_USE> - REVERSE_ITERATOR; -#endif /* 0 */ - - /** - * @name Initialization methods - */ - //@{ - /** - * Initialize an ACE_Message_Queue_Ex. - * - * @param high_water_mark 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. - * @param low_water_mark Low water mark. Determines how many bytes must be in - * the queue before supplier threads are allowed to enqueue additional - * data. By default, the @a hwm equals @a lwm, 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." - * @param ns Notification strategy. Pointer to an object conforming to the - * ACE_Notification_Strategy interface. If set, the object's - * notify(void) method will be called each time data is added to - * this ACE_Message_Queue. @see ACE_Reactor_Notification_Strategy. - */ - ACE_Message_Queue_Ex (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 * ns = 0); - 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); - //@} - - /// Releases all resources from the message queue and marks it deactivated. - /// @sa flush(). - /// - /// @retval The number of messages released from the queue; -1 on error. - virtual int close (void); - - /// Releases all resources from the message queue and marks it deactivated. - virtual ~ACE_Message_Queue_Ex (void); - - /** - * Releases all resources from the message queue but does not mark it - * deactivated. This method holds the queue lock during this operation. - * @sa close(). - * - * @return The number of messages flushed; -1 on error. - */ - virtual int flush (void); - - /** - * Release all resources from the message queue but do not mark it - * as deactivated. - * - * @pre The caller must be holding the queue lock before calling this - * method. - * - * @return The number of messages flushed. - */ - virtual int flush_i (void); - - /** @name Enqueue and dequeue methods - * - * The enqueue and dequeue methods accept a timeout value passed as - * an ACE_Time_Value *. In all cases, if the timeout pointer is 0, - * the caller will block until action is possible. If the timeout pointer - * is non-zero, the call will wait (if needed, subject to water mark - * settings) until the absolute time specified in the referenced - * ACE_Time_Value object is reached. If the time is reached before the - * desired action is possible, the method will return -1 with errno set - * to @c EWOULDBLOCK. Regardless of the timeout setting, however, - * these methods will also fail and return -1 when the queue is closed, - * deactivated, pulsed, or when a signal occurs. - * - * The time parameters are handled the same as in ACE_Message_Queue, so - * you can see C++NPv2 Section 6.2 and APG Section 12.3 for a fuller - * treatment of ACE_Message_Queue, enqueueing, dequeueing, and how these - * operations are affected by queue state transitions. - */ - //@{ - /** - * Retrieve a pointer to the first item in the queue without removing it. - * - * @note Because the item whose pointer is returned is still on the queue, - * another thread may dequeue that item at any time, - * including before the calling thread examines the peeked-at item. - * Be very careful with this method in multithreaded queueing - * situations. - * - * @param first_item Reference to an ACE_MESSAGE_TYPE * that will - * point to the first item on the queue. The item - * remains on the queue until this or another thread - * dequeues it. - * @param timeout The absolute time the caller will wait until - * for an item to be queued. - * - * @retval >0 The number of items on the queue. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int peek_dequeue_head (ACE_MESSAGE_TYPE *&first_item, - ACE_Time_Value *timeout = 0); - - /** - * Enqueue an ACE_MESSAGE TYPE into the queue in accordance with - * the specified priority (0 is lowest priority). FIFO - * order is maintained when items of the same priority are - * inserted consecutively. - * - * @param new_item Pointer to an item that will be added to the queue. - * @param timeout The absolute time the caller will wait until - * for the block to be queued. - * @param priority The priority to use when enqueueing the item. - * - * @retval >0 The number of items on the queue after adding - * the specified item. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int enqueue_prio (ACE_MESSAGE_TYPE *new_item, - ACE_Time_Value *timeout = 0, - unsigned long priority = DEFAULT_PRIORITY); - - /** - * This method acts just like enqueue_tail(). There's no deadline - * time associated with items. - */ - virtual int enqueue_deadline (ACE_MESSAGE_TYPE *new_item, - ACE_Time_Value *timeout = 0); - - /** - * @deprecated 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. - */ - virtual int enqueue (ACE_MESSAGE_TYPE *new_item, - ACE_Time_Value *timeout = 0); - - /** - * Enqueue an item at the tail of the queue. - * - * @param new_item Pointer to an item that will be added to the queue. - * @param timeout The absolute time the caller will wait until - * for the item to be queued. - * - * @retval >0 The number of items on the queue after adding - * the specified item. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int enqueue_tail (ACE_MESSAGE_TYPE *new_item, - ACE_Time_Value *timeout = 0); - - /** - * Enqueue an item at the head of the queue. - * - * @param new_item Pointer to an item that will be added to the queue. - * @param timeout The absolute time the caller will wait until - * for the item to be queued. - * - * @retval >0 The number of items on the queue after adding - * the specified item. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int enqueue_head (ACE_MESSAGE_TYPE *new_item, - ACE_Time_Value *timeout = 0); - - /// This method is an alias for the following <dequeue_head> method. - virtual int dequeue (ACE_MESSAGE_TYPE *&first_item, - ACE_Time_Value *timeout = 0); - - /** - * Dequeue the item at the head of the queue and return a pointer to it. - * - * @param first_item Reference to an ACE_MESSAGE_TYPE * that will - * be set to the address of the dequeued item. - * @param timeout The absolute time the caller will wait until - * for an item to be dequeued. - * - * @retval >=0 The number of items remaining in the queue. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int dequeue_head (ACE_MESSAGE_TYPE *&first_item, - ACE_Time_Value *timeout = 0); - - /** - * Dequeue the item that has the lowest priority (preserves - * FIFO order for items with the same priority) and return a pointer - * to it. - * - * @param dequeued Reference to an ACE_MESSAGE_TYPE * that will - * be set to the address of the dequeued item. - * @param timeout The absolute time the caller will wait until - * for an item to be dequeued. - * - * @retval >=0 The number of items remaining in the queue. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int dequeue_prio (ACE_MESSAGE_TYPE *&dequeued, - ACE_Time_Value *timeout = 0); - - /** - * Dequeue the item at the tail of the queue and return a pointer to it. - * - * @param dequeued Reference to an ACE_MESSAGE_TYPE * that will - * be set to the address of the dequeued item. - * @param timeout The absolute time the caller will wait until - * for an item to be dequeued. - * - * @retval >=0 The number of items remaining in the queue. - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int dequeue_tail (ACE_MESSAGE_TYPE *&dequeued, - ACE_Time_Value *timeout = 0); - - /** - * Because there's deadline associated with enqueue_deadline(), this - * method will behave just as dequeue_head(). - */ - virtual int dequeue_deadline (ACE_MESSAGE_TYPE *&dequeued, - ACE_Time_Value *timeout = 0); - //@} - - /** @name Queue statistics methods - */ - //@{ - - /// True if queue is full, else false. - virtual bool is_full (void); - - /// True if queue is empty, else false. - virtual bool is_empty (void); - - /** - * Number of total bytes on the queue, i.e., sum of the message - * block sizes. - */ - virtual size_t message_bytes (void); - /** - * Number of total length on the queue, i.e., sum of the message - * block lengths. - */ - virtual size_t message_length (void); - /** - * Number of total messages on the queue. - */ - virtual size_t message_count (void); - - // = 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. - */ - virtual void message_bytes (size_t new_size); - /** - * New value of the number of total length on the queue, i.e., sum - * of the message block lengths. - */ - virtual void message_length (size_t new_length); - - //@} - - /** @name Water mark (flow control) methods - */ - //@{ - - /** - * Get high watermark. - */ - virtual size_t high_water_mark (void); - /** - * Set the high watermark, which determines how many bytes can be - * stored in a queue before it's considered "full." - */ - virtual void high_water_mark (size_t hwm); - - /** - * Get low watermark. - */ - virtual size_t low_water_mark (void); - /** - * Set the low watermark, which determines how many bytes must be in - * the queue before supplier threads are allowed to enqueue - * additional <ACE_MESSAGE_TYPE>s. - */ - virtual void low_water_mark (size_t lwm); - //@} - - /** @name Activation and queue state methods - * See C++NPv2 Section 6.2 and APG Section 12.3 for a fuller treatment of - * queue states and transitions and how the transitions affect message - * enqueueing and dequeueing operations. - */ - //@{ - - /** - * 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 @c 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); - - /** - * Reactivate the queue so that threads can enqueue and dequeue - * messages again. Returns the state of the queue before the call. - */ - virtual int activate (void); - - /** - * Pulse the queue to wake up any waiting threads. Changes the - * queue state to PULSED; future enqueue/dequeue operations proceed - * as in ACTIVATED state. - * - * @retval The queue's state before this call. - */ - virtual int pulse (void); - - /// Returns the current state of the queue, which can be one of - /// ACTIVATED, DEACTIVATED, or PULSED. - virtual int state (void); - - /// Returns true if the state of the queue is DEACTIVATED, - /// but false if the queue's state is ACTIVATED or PULSED. - virtual int deactivated (void); - //@} - - /** @name Notification strategy methods - */ - //@{ - - /** - * 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); - - /// Get the notification strategy for the <Message_Queue> - virtual ACE_Notification_Strategy *notification_strategy (void); - - /// Set the notification strategy for the <Message_Queue> - virtual void notification_strategy (ACE_Notification_Strategy *s); - //@} - - /// Returns a reference to the lock used by the ACE_Message_Queue_Ex. - virtual ACE_SYNCH_MUTEX_T &lock (void); - - /// Dump the state of an object. - virtual void dump (void) const; - - /// Declare the dynamic allocation hooks. - ACE_ALLOC_HOOK_DECLARE; - -protected: - /// Implement this via an ACE_Message_Queue. - ACE_Message_Queue<ACE_SYNCH_USE> queue_; -}; - -/** - * @class ACE_Message_Queue_Ex_N - * - * @brief A threaded message queueing facility, modeled after the - * queueing facilities in System V STREAMs which can enqueue - * multiple messages in one call. - * - * As ACE_Message_Queue_Ex, ACE_Message_Queue_Ex_N is a strongly-typed - * version of the ACE_Message_Queue. If @c ACE_SYNCH_DECL is @c ACE_MT_SYNCH - * then all operations are thread-safe. Otherwise, if it's @c ACE_NULL_SYNCH - * then there's no locking overhead. - * - * The @c ACE_MESSAGE_TYPE messages that are sent to this - * queue can be chained. Messages are expected to have a - * @c next method that returns the next message in the chain; - * ACE_Message_Queue_Ex_N uses this method to run through - * all the incoming messages and enqueue them in one call. - */ -template <class ACE_MESSAGE_TYPE, ACE_SYNCH_DECL> -class ACE_Message_Queue_Ex_N : public ACE_Message_Queue_Ex<ACE_MESSAGE_TYPE, ACE_SYNCH_USE> -{ -public: - // = Initialization and termination methods. - - /** - * Initialize an ACE_Message_Queue_Ex_N. The @a 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 @a low_water_mark determines how many - * bytes must be in the queue before supplier threads are allowed to - * enqueue additional messages. By default, the @a high_water_mark - * equals the @a 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 @a low_water_mark smaller than the - * @a 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_Ex_N (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 * ns = 0); - - /// Close down the message queue and release all resources. - virtual ~ACE_Message_Queue_Ex_N (void); - - /** - * Enqueue one or more @c ACE_MESSAGE_TYPE objects at the head of the queue. - * If the @a new_item @c next() pointer is non-zero, it is assumed to be the - * start of a series of @c ACE_MESSAGE_TYPE objects connected via their - * @c next() pointers. The series of blocks will be added to the queue in - * the same order they are passed in as. - * - * @param new_item Pointer to an @c ACE_MESSAGE_TYPE that will be - * added to the queue. If the block's @c next() pointer - * is non-zero, all blocks chained from the @c next() - * pointer are enqueued as well. - * @param tv The absolute time the caller will wait until - * for the block to be queued. - * - * @retval >0 The number of @c ACE_MESSAGE_TYPE objects on the queue after - * adding the specified block(s). - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int enqueue_head (ACE_MESSAGE_TYPE *new_item, ACE_Time_Value *tv = 0); - - /** - * Enqueue one or more @c ACE_MESSAGE_TYPE objects at the tail of the queue. - * If the @a new_item @c next() pointer is non-zero, it is assumed to be the - * start of a series of @c ACE_MESSAGE_TYPE objects connected via their - * @c next() pointers. The series of blocks will be added to the queue in - * the same order they are passed in as. - * - * @param new_item Pointer to an @c ACE_MESSAGE_TYPE that will be - * added to the queue. If the block's @c next() pointer - * is non-zero, all blocks chained from the @c next() - * pointer are enqueued as well. - * @param tv The absolute time the caller will wait until - * for the block to be queued. - * - * @retval >0 The number of @c ACE_MESSAGE_TYPE objects on the queue after - * adding the specified block(s). - * @retval -1 On failure. errno holds the reason. Common errno values are: - * - EWOULDBLOCK: the timeout elapsed - * - ESHUTDOWN: the queue was deactivated or pulsed - */ - virtual int enqueue_tail (ACE_MESSAGE_TYPE *new_item, ACE_Time_Value *tv = 0); - - /// Declare the dynamic allocation hooks. - ACE_ALLOC_HOOK_DECLARE; - -protected: - /** - * An helper method that wraps the incoming chain messages - * with ACE_Message_Blocks. - */ - ACE_Message_Block *wrap_with_mbs_i (ACE_MESSAGE_TYPE *new_item); -}; - -ACE_END_VERSIONED_NAMESPACE_DECL - -#if defined (ACE_TEMPLATES_REQUIRE_SOURCE) -#include "ace/Message_Queue_T.cpp" -#endif /* ACE_TEMPLATES_REQUIRE_SOURCE */ - -#if defined (ACE_TEMPLATES_REQUIRE_PRAGMA) -#pragma implementation ("Message_Queue_T.cpp") -#endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */ - -#include /**/ "ace/post.h" -#endif /* ACE_MESSAGE_QUEUE_T_H */ |