summaryrefslogtreecommitdiff
path: root/ace/Message_Queue.h
blob: 01328a6655bb7c78c8318bee291e720755b09acb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
/* -*- 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().
  };

  ACE_Message_Queue_Base (void);

  virtual int close (void) = 0;
  // Close down the message queue and release all resources.

  virtual ~ACE_Message_Queue_Base (void);
  // Close down the message queue and release all resources.

  // = Enqueue and dequeue methods.

  // For the following enqueue and dequeue methods if <timeout> == 0,
  // the caller will block until action is possible, else will wait
  // until the absolute time specified in *<timeout> elapses).  These
  // calls will return, however, when queue is closed, deactivated,
  // when a signal occurs, or if the time specified in timeout
  // elapses, (in which case errno = EWOULDBLOCK).

  virtual int enqueue_tail (ACE_Message_Block *new_item,
                            ACE_Time_Value *timeout = 0) = 0;
  virtual int enqueue (ACE_Message_Block *new_item,
                       ACE_Time_Value *timeout = 0) = 0;
  // Enqueue a <ACE_Message_Block *> into the tail of the queue.
  // Return -1 on failure, number of items in queue otherwise.

  virtual int dequeue_head (ACE_Message_Block *&first_item,
                            ACE_Time_Value *timeout = 0) = 0;
  virtual int dequeue (ACE_Message_Block *&first_item,
                       ACE_Time_Value *timeout = 0) = 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.

  // = Check if queue is full/empty.
  virtual int is_full (void) = 0;
  // True if queue is full, else false.
  virtual int is_empty (void) = 0;
  // True if queue is empty, else false.

  // = Queue statistic methods.
  virtual size_t message_bytes (void) = 0;
  // Number of total bytes on the queue.
  virtual size_t message_count (void) = 0;
  // Number of total messages on the queue.

  // = Activation control methods.

  virtual int deactivate (void) = 0;
  // 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 activate (void) = 0;
  // 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 deactivated (void) = 0;
  // Returns true if <deactivated_> is enabled.

  // = Notification hook.

  virtual void dump (void) const = 0;
  // Dump the state of an object.

  ACE_ALLOC_HOOK_DECLARE;
  // Declare the dynamic allocation hooks.

private:
  // = Disallow these operations.
  ACE_UNIMPLEMENTED_FUNC (void operator= (const ACE_Message_Queue_Base &))
  ACE_UNIMPLEMENTED_FUNC (ACE_Message_Queue_Base (const ACE_Message_Queue_Base &))
};

// 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 interrupt 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 */

#if defined (ACE_WIN32) && (ACE_HAS_WINNT4 != 0)
class ACE_Export ACE_Message_Queue_NT : public ACE_Message_Queue_Base
{
  // = TITLE
  //     Message Queue implementation using IO completion port on NT.
  //
  // = DESCRIPTION
  //     Implementation of a strip-downed ACE_Message_Queue using NT's
  //     IO completion port mechanism.
  //
  //     NOTE: *Many* ACE_Message_Queue features are not supported with
  //     this implementation, including:
  //     * open method have different signatures.
  //     * dequeue_head () *requires* that the ACE_Message_Block
  //       pointer argument point to an ACE_Message_Block that was
  //       allocated by the caller.
  //     * peek_dequeue_head ().
  //     * ACE_Message_Queue_Iterators.
  //     * No flow control.
public:
  // = Initialization and termination methods.
  ACE_Message_Queue_NT (size_t max_threads = ACE_Message_Queue_Base::DEFAULT_HWM);

  virtual int open (size_t max_threads = ACE_Message_Queue_Base::DEFAULT_HWM);
  // Initialize the Message Queue by creating a new NT I/O completion
  // port.  The first arguemnt specifies the number of threads
  // released by the MQ that are allowed to run concurrently.  Return
  // 0 when succeeds, -1 otherwise.

  virtual int close (void);
  // Close down the underlying I/O completion port.  You need to
  // re-open the MQ after this function is executed.

  virtual ~ACE_Message_Queue_NT (void);
  // Close down the message queue and release all resources.

  // = Enqueue and dequeue methods.

  virtual int enqueue_tail (ACE_Message_Block *new_item,
                            ACE_Time_Value *timeout = 0);
  virtual int enqueue (ACE_Message_Block *new_item,
                       ACE_Time_Value *timeout = 0);
  // Enqueue an <ACE_Message_Block *> at the end 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);
  virtual int dequeue (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.

  // = Check if queue is full/empty.
  virtual int is_full (void);
  // Always return false.
  virtual int is_empty (void);
  // True if queue is empty, else false.  Notice the return value is
  // only transient.

  // = Queue statistic methods (transient.)
  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.

  virtual size_t max_threads (void);
  // Get the max concurrent thread number.

  // = Activation control methods.

  virtual int deactivate (void);
  // Deactivate the queue and wakeup all threads waiting on the queue
  // so they can continue.  Messages already in the queue get removed.
  // If there are more messages in the queue than there are threads
  // waiting on the queue, the left over messages will not be removed.
  // Any other enqueue/dequeue 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 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.

  virtual int deactivated (void);
  // Returns true if <deactivated_> is enabled.

  // = Notification hook.

  virtual void dump (void) const;
  // Dump the state of an object.

  virtual ACE_HANDLE completion_port (void);
  // Get the handle to the underlying completion port.

  ACE_ALLOC_HOOK_DECLARE;
  // Declare the dynamic allocation hooks.

private:
  // = Internal states.

  size_t max_cthrs_;
  // Maximum threads that can be released (and run) concurrently.

  size_t cur_thrs_;
  // Current number of threads waiting to dequeue messages.

  size_t cur_bytes_;
  // Current number of bytes in queue.

  size_t cur_count_;
  // Current number of messages in the queue.

  ACE_Thread_Mutex lock_;
  // Synchronizer.  This should really be an ACE_Recursive_Thread_Mutex
  // but since this class is only supported on NT, it's okay to use
  // ACE_Thread_Mutex here.

  int deactivated_;
  // Indicates that the queue is inactive.

  ACE_HANDLE completion_port_;
  // Underlying NT IoCompletionPort.

  // = Disallow these operations.
  ACE_UNIMPLEMENTED_FUNC (void operator= (const ACE_Message_Queue_NT &))
  ACE_UNIMPLEMENTED_FUNC (ACE_Message_Queue_NT (const ACE_Message_Queue_NT &))
};
#endif /* ACE_WIN32 && ACE_HAS_WINNT4 != 0 */

// 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 */