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/* -*- C++ -*- */
// $Id$
// ============================================================================
//
// = LIBRARY
// ace
//
// = FILENAME
// Message_Queue.h
//
// = AUTHOR
// Doug Schmidt
//
// ============================================================================
#ifndef ACE_MESSAGE_QUEUE_H
#define ACE_MESSAGE_QUEUE_H
#include "ace/Message_Block.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
#include "ace/IO_Cntl_Msg.h"
// Forward decls.
class ACE_Notification_Strategy;
template <ACE_SYNCH_DECL> class ACE_Message_Queue_Iterator;
template <ACE_SYNCH_DECL> class ACE_Message_Queue_Reverse_Iterator;
class ACE_Export ACE_Message_Queue_Base
{
// = TITLE
// Workaround HP/C++ compiler bug with enums in templates.
//
// = DESCRIPTION
// The ever lamest HP/C++ compiler seems to fail if enums are
// defined inside a template, hence we have to move them into a
// base class.
public:
// = Default high and low water marks.
enum
{
DEFAULT_HWM = 16 * 1024,
// Default high watermark (16 K).
DEFAULT_LWM = 16 * 1024,
// Default low watermark (same as high water mark).
WAS_ACTIVE = 1,
// Message queue was active before activate() or deactivate().
WAS_INACTIVE = 2
// Message queue was inactive before activate() or deactivate().
};
};
// Include the templates here.
#include "ace/Message_Queue_T.h"
#if defined (VXWORKS)
# include /**/ <msgQLib.h>
class ACE_Message_Queue_Vx : public ACE_Message_Queue<ACE_NULL_SYNCH>
{
// = TITLE
// Wrapper for VxWorks message queues.
//
// = DESCRIPTION
// Specialization of ACE_Message_Queue to simply wrap VxWorks
// MsgQ. It does not use any synchronization, because it relies
// on the native MsgQ implementation to take care of that. The
// only system calls that it uses are VxWorks msgQLib calls, so
// it is suitable for use in iterrupt service routines.
//
// NOTE: *Many* ACE_Message_Queue features are not supported with
// this specialization, including:
// * The two size arguments to the constructor and open () are
// interpreted differently. The first is interpreted as the
// maximum number of bytes in a message. The second is
// interpreted as the maximum number of messages that can be
// queued.
// * dequeue_head () *requires* that the ACE_Message_Block
// pointer argument point to an ACE_Message_Block that was
// allocated by the caller. It must be big enough to support
// the received message, without using continutation. The
// pointer argument is not modified.
// * Message priority. MSG_Q_FIFO is hard-coded.
// * enqueue method timeouts.
// * peek_dequeue_head ().
// * ACE_Message_Queue_Iterators.
// * The ability to change low and high water marks after creation.
// * Message_Block chains. The continuation field of ACE_Message_Block
// * is ignored; only the first block of a fragment chain is
// * recognized.
public:
// = Initialization and termination methods.
ACE_Message_Queue_Vx (size_t max_messages,
size_t max_message_length,
ACE_Notification_Strategy * = 0);
// Create a message queue with all the defaults.
virtual int open (size_t max_messages,
size_t max_message_length,
ACE_Notification_Strategy * = 0);
// Create a message queue with all the defaults.
virtual int close (void);
// Close down the message queue and release all resources.
virtual ~ACE_Message_Queue_Vx (void);
// Close down the message queue and release all resources.
// = Queue statistic methods.
virtual size_t message_bytes (void);
// Number of total bytes on the queue.
virtual size_t message_count (void);
// Number of total messages on the queue.
// = Flow control routines
virtual size_t high_water_mark (void);
// Get high watermark.
virtual void high_water_mark (size_t hwm);
// Set high watermark.
virtual size_t low_water_mark (void);
// Get low watermark.
virtual void low_water_mark (size_t lwm);
// Set low watermark.
// = Activation control methods.
void dump (void) const;
// Dump the state of an object.
ACE_ALLOC_HOOK_DECLARE;
// Declare the dynamic allocation hooks.
protected:
virtual int enqueue_i (ACE_Message_Block *new_item);
// Enqueue an <ACE_Message_Block *> in accordance with its priority.
virtual int enqueue_tail_i (ACE_Message_Block *new_item);
// Enqueue an <ACE_Message_Block *> at the end of the queue.
virtual int enqueue_head_i (ACE_Message_Block *new_item);
// Enqueue an <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).
virtual int is_full_i (void);
// True if queue is full, else false.
virtual int is_empty_i (void);
// True if queue is empty, else false.
// = Implementation of the public activate() and deactivate() methods above (assumes locks are held).
virtual int deactivate_i (void);
// Deactivate the queue.
virtual int activate_i (void);
// Activate the queue.
// = Helper methods to factor out common #ifdef code.
virtual int wait_not_full_cond (ACE_Guard<ACE_Null_Mutex> &mon,
ACE_Time_Value *tv);
// Wait for the queue to become non-full.
virtual int wait_not_empty_cond (ACE_Guard<ACE_Null_Mutex> &mon,
ACE_Time_Value *tv);
// Wait for the queue to become non-empty.
virtual int signal_enqueue_waiters (void);
// Inform any threads waiting to enqueue that they can procede.
virtual int signal_dequeue_waiters (void);
// Inform any threads waiting to dequeue that they can procede.
MSG_Q_ID msgq (void);
// Access the underlying msgQ.
private:
int max_messages_;
// Maximum number of messages that can be queued.
int max_message_length_;
// Maximum message size, in bytes.
int options_;
// Native message queue options.
// = Disallow these operations.
ACE_UNIMPLEMENTED_FUNC (void operator= (const ACE_Message_Queue_Vx &))
ACE_UNIMPLEMENTED_FUNC (ACE_Message_Queue_Vx (const ACE_Message_Queue_Vx &))
ACE_UNIMPLEMENTED_FUNC (virtual int peek_dequeue_head
(ACE_Message_Block *&first_item,
ACE_Time_Value *tv = 0))
};
#endif /* VXWORKS */
// This must go here to avoid problems with circular includes.
#include "ace/Strategies.h"
#if defined (__ACE_INLINE__)
#include "ace/Message_Queue.i"
#endif /* __ACE_INLINE__ */
#endif /* ACE_MESSAGE_QUEUE_H */
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