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// $Id$
// ============================================================================
//
// = LIBRARY
// tests
//
// = FILENAME
// Priority_Buffer_Test.cpp
//
// = DESCRIPTION
// This is a simple test to illustrate the priority mechanism of
// <ACE_Message_Queue>s. The producer uses an <ACE_Message_Queue>
// to enqueue a bunch of messages with different priorities which
// are then dequeued by the consumer.
//
// = AUTHOR
// Prashant Jain <pjain@cs.wustl.edu> and
// Douglas C. Schmidt <schmidt@cs.wustl.edu>
//
// ============================================================================
#include "test_config.h"
#include "ace/Message_Queue.h"
#include "ace/Thread_Manager.h"
ACE_RCSID(tests, Priority_Buffer_Test, "$Id$")
#if defined (ACE_HAS_THREADS)
static const char ACE_ALPHABET[] = "abcdefghijklmnopqrstuvwxyz";
// Global message count.
static int message_count = 0;
// Make the queue be capable of being *very* large.
static const long max_queue = LONG_MAX;
// The consumer dequeues a message from the ACE_Message_Queue, writes
// the message to the stderr stream, and deletes the message. The
// producer sends a 0-sized message to inform the consumer to stop
// reading and exit.
static void *
consumer (void *args)
{
ACE_Message_Queue<ACE_MT_SYNCH> *msg_queue =
reinterpret_cast<ACE_Message_Queue<ACE_MT_SYNCH> *> (args);
u_long cur_priority = 27;
ACE_UNUSED_ARG (cur_priority);
// To suppress ghs warning about unused local variable
// "cur_priority".
int local_count = 0;
// Keep looping, reading a message out of the queue, until we get a
// message with a length == 0, which signals us to quit.
for (char c = 'z'; ; c--)
{
ACE_Message_Block *mb = 0;
int result = msg_queue->dequeue_head (mb);
if (result == -1)
break;
local_count++;
size_t length = mb->length ();
if (length > 0)
{
// This isn't a "shutdown" message, so process it
// "normally."
ACE_ASSERT (c == *mb->rd_ptr ());
ACE_ASSERT (mb->msg_priority () < cur_priority);
cur_priority = mb->msg_priority ();
}
// Free up the buffer memory and the Message_Block. Note that
// the destructor of Message Block will delete the the actual
// buffer.
mb->release ();
if (length == 0)
// This was a "shutdown" message, so break out of the loop.
break;
}
ACE_ASSERT (local_count == message_count);
return 0;
}
// The producer reads data from the stdin stream, creates a message,
// and then queues the message in the message list, where it is
// removed by the consumer thread. A 0-sized message is enqueued when
// there is no more data to read. The consumer uses this as a flag to
// know when to exit.
static void *
producer (void *args)
{
ACE_Message_Queue<ACE_MT_SYNCH> *msg_queue =
reinterpret_cast<ACE_Message_Queue<ACE_MT_SYNCH> *> (args);
ACE_Message_Block *mb = 0;
for (const char *c = ACE_ALPHABET; *c != '\0'; c++)
{
++message_count;
// Allocate a new message
ACE_NEW_RETURN (mb,
ACE_Message_Block (1),
0);
*mb->wr_ptr () = *c;
// Set the priority.
mb->msg_priority (message_count);
mb->wr_ptr (1);
// Enqueue in priority order.
if (msg_queue->enqueue_prio (mb) == -1)
ACE_ERROR_RETURN ((LM_ERROR,
ACE_TEXT ("(%t) %p\n"),
ACE_TEXT ("put_next")),
0);
}
// Now send a 0-sized shutdown message to the other thread
ACE_NEW_RETURN (mb,
ACE_Message_Block ((size_t) 0),
0);
if (msg_queue->enqueue_tail (mb) == -1)
ACE_ERROR ((LM_ERROR,
ACE_TEXT ("(%t) %p\n"),
ACE_TEXT ("put_next")));
++message_count;
// Now read all the items out in priority order (i.e., ordered by
// the size of the lines!).
consumer (msg_queue);
return 0;
}
#endif /* ACE_HAS_THREADS */
// Spawn off one thread that copies stdin to stdout in order of the
// size of each line.
int
run_main (int, ACE_TCHAR *[])
{
ACE_START_TEST (ACE_TEXT ("Priority_Buffer_Test"));
#if defined (ACE_HAS_THREADS)
// Message queue.
ACE_Message_Queue<ACE_MT_SYNCH> msg_queue (max_queue);
if (ACE_Thread_Manager::instance ()->spawn
(ACE_THR_FUNC (producer),
(void *) &msg_queue,
THR_NEW_LWP | THR_DETACHED) == -1)
ACE_ERROR_RETURN ((LM_ERROR,
ACE_TEXT ("%p\n"),
ACE_TEXT ("spawn")),
1);
// Wait for producer and consumer threads to exit.
ACE_Thread_Manager::instance ()->wait ();
#else
ACE_ERROR ((LM_INFO,
ACE_TEXT ("threads not supported on this platform\n")));
#endif /* ACE_HAS_THREADS */
ACE_END_TEST;
return 0;
}
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