summaryrefslogtreecommitdiff
path: root/ext/thread/thread.c
blob: de094acd919b8a1c219996378638e63b54ce7e3b (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
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
#include <ruby.h>

enum {
    CONDVAR_WAITERS,
    END_CONDVAR
};

enum {
    QUEUE_QUE,
    QUEUE_WAITERS,
    SZQUEUE_WAITERS,
    SZQUEUE_MAX,
    END_QUEUE
};

#define GET_CONDVAR_WAITERS(cv) get_array((cv), CONDVAR_WAITERS)

#define GET_QUEUE_QUE(q)        get_array((q), QUEUE_QUE)
#define GET_QUEUE_WAITERS(q)    get_array((q), QUEUE_WAITERS)
#define GET_SZQUEUE_WAITERS(q)  get_array((q), SZQUEUE_WAITERS)
#define GET_SZQUEUE_MAX(q)      RSTRUCT_GET((q), SZQUEUE_MAX)
#define GET_SZQUEUE_ULONGMAX(q) NUM2ULONG(GET_SZQUEUE_MAX(q))

static VALUE
get_array(VALUE obj, int idx)
{
    VALUE ary = RSTRUCT_GET(obj, idx);
    if (!RB_TYPE_P(ary, T_ARRAY)) {
	rb_raise(rb_eTypeError, "%+"PRIsVALUE" not initialized", obj);
    }
    return ary;
}

static VALUE
ary_buf_new(void)
{
    return rb_ary_tmp_new(1);
}

static void
wakeup_first_thread(VALUE list)
{
    VALUE thread;

    while (!NIL_P(thread = rb_ary_shift(list))) {
	if (RTEST(rb_thread_wakeup_alive(thread))) break;
    }
}

static void
wakeup_all_threads(VALUE list)
{
    VALUE thread;
    long i;

    for (i=0; i<RARRAY_LEN(list); i++) {
	thread = RARRAY_AREF(list, i);
	rb_thread_wakeup_alive(thread);
    }
    rb_ary_clear(list);
}

/*
 *  Document-class: ConditionVariable
 *
 *  ConditionVariable objects augment class Mutex. Using condition variables,
 *  it is possible to suspend while in the middle of a critical section until a
 *  resource becomes available.
 *
 *  Example:
 *
 *    require 'thread'
 *
 *    mutex = Mutex.new
 *    resource = ConditionVariable.new
 *
 *    a = Thread.new {
 *	 mutex.synchronize {
 *	   # Thread 'a' now needs the resource
 *	   resource.wait(mutex)
 *	   # 'a' can now have the resource
 *	 }
 *    }
 *
 *    b = Thread.new {
 *	 mutex.synchronize {
 *	   # Thread 'b' has finished using the resource
 *	   resource.signal
 *	 }
 *    }
 */

/*
 * Document-method: ConditionVariable::new
 *
 * Creates a new condition variable instance.
 */

static VALUE
rb_condvar_initialize(VALUE self)
{
    RSTRUCT_SET(self, CONDVAR_WAITERS, ary_buf_new());
    return self;
}

struct sleep_call {
    VALUE mutex;
    VALUE timeout;
};

static ID id_sleep;

static VALUE
do_sleep(VALUE args)
{
    struct sleep_call *p = (struct sleep_call *)args;
    return rb_funcall2(p->mutex, id_sleep, 1, &p->timeout);
}

static VALUE
delete_current_thread(VALUE ary)
{
    return rb_ary_delete(ary, rb_thread_current());
}

/*
 * Document-method: ConditionVariable#wait
 * call-seq: wait(mutex, timeout=nil)
 *
 * Releases the lock held in +mutex+ and waits; reacquires the lock on wakeup.
 *
 * If +timeout+ is given, this method returns after +timeout+ seconds passed,
 * even if no other thread doesn't signal.
 */

static VALUE
rb_condvar_wait(int argc, VALUE *argv, VALUE self)
{
    VALUE waiters = GET_CONDVAR_WAITERS(self);
    VALUE mutex, timeout;
    struct sleep_call args;

    rb_scan_args(argc, argv, "11", &mutex, &timeout);

    args.mutex   = mutex;
    args.timeout = timeout;
    rb_ary_push(waiters, rb_thread_current());
    rb_ensure(do_sleep, (VALUE)&args, delete_current_thread, waiters);

    return self;
}

/*
 * Document-method: ConditionVariable#signal
 *
 * Wakes up the first thread in line waiting for this lock.
 */

static VALUE
rb_condvar_signal(VALUE self)
{
    wakeup_first_thread(GET_CONDVAR_WAITERS(self));
    return self;
}

/*
 * Document-method: ConditionVariable#broadcast
 *
 * Wakes up all threads waiting for this lock.
 */

static VALUE
rb_condvar_broadcast(VALUE self)
{
    wakeup_all_threads(GET_CONDVAR_WAITERS(self));
    return self;
}

/*
 *  Document-class: Queue
 *
 *  This class provides a way to synchronize communication between threads.
 *
 *  Example:
 *
 *	require 'thread'
 *    	queue = Queue.new
 *
 *	producer = Thread.new do
 *	  5.times do |i|
 *	     sleep rand(i) # simulate expense
 *	     queue << i
 *	     puts "#{i} produced"
 *	  end
 *	end
 *
 *	consumer = Thread.new do
 *	  5.times do |i|
 *	     value = queue.pop
 *	     sleep rand(i/2) # simulate expense
 *	     puts "consumed #{value}"
 *	  end
 *	end
 *
 */

/*
 * Document-method: Queue::new
 *
 * Creates a new queue instance.
 */

static VALUE
rb_queue_initialize(VALUE self)
{
    RSTRUCT_SET(self, QUEUE_QUE, ary_buf_new());
    RSTRUCT_SET(self, QUEUE_WAITERS, ary_buf_new());
    return self;
}

static VALUE
queue_do_push(VALUE self, VALUE obj)
{
    rb_ary_push(GET_QUEUE_QUE(self), obj);
    wakeup_first_thread(GET_QUEUE_WAITERS(self));
    return self;
}

/*
 * Document-method: Queue#push
 * call-seq:
 *   push(object)
 *   enq(object)
 *   <<(object)
 *
 * Pushes the given +object+ to the queue.
 */

static VALUE
rb_queue_push(VALUE self, VALUE obj)
{
    return queue_do_push(self, obj);
}

static unsigned long
queue_length(VALUE self)
{
    VALUE que = GET_QUEUE_QUE(self);
    return RARRAY_LEN(que);
}

static unsigned long
queue_num_waiting(VALUE self)
{
    VALUE waiters = GET_QUEUE_WAITERS(self);
    return RARRAY_LEN(waiters);
}

struct waiting_delete {
    VALUE waiting;
    VALUE th;
};

static VALUE
queue_delete_from_waiting(struct waiting_delete *p)
{
    rb_ary_delete(p->waiting, p->th);
    return Qnil;
}

static VALUE
queue_sleep(VALUE arg)
{
    rb_thread_sleep_deadly();
    return Qnil;
}

static VALUE
queue_do_pop(VALUE self, int should_block)
{
    struct waiting_delete args;
    args.waiting = GET_QUEUE_WAITERS(self);
    args.th	 = rb_thread_current();

    while (queue_length(self) == 0) {
	if (!should_block) {
	    rb_raise(rb_eThreadError, "queue empty");
	}
	rb_ary_push(args.waiting, args.th);
	rb_ensure(queue_sleep, (VALUE)0, queue_delete_from_waiting, (VALUE)&args);
    }

    return rb_ary_shift(GET_QUEUE_QUE(self));
}

static int
queue_pop_should_block(int argc, const VALUE *argv)
{
    int should_block = 1;
    rb_check_arity(argc, 0, 1);
    if (argc > 0) {
	should_block = !RTEST(argv[0]);
    }
    return should_block;
}

/*
 * Document-method: Queue#pop
 * call-seq:
 *   pop(non_block=false)
 *   deq(non_block=false)
 *   shift(non_block=false)
 *
 * Retrieves data from the queue.
 *
 * If the queue is empty, the calling thread is suspended until data is pushed
 * onto the queue. If +non_block+ is true, the thread isn't suspended, and an
 * exception is raised.
 */

static VALUE
rb_queue_pop(int argc, VALUE *argv, VALUE self)
{
    int should_block = queue_pop_should_block(argc, argv);
    return queue_do_pop(self, should_block);
}

/*
 * Document-method: Queue#empty?
 * call-seq: empty?
 *
 * Returns +true+ if the queue is empty.
 */

static VALUE
rb_queue_empty_p(VALUE self)
{
    return queue_length(self) == 0 ? Qtrue : Qfalse;
}

/*
 * Document-method: Queue#clear
 *
 * Removes all objects from the queue.
 */

static VALUE
rb_queue_clear(VALUE self)
{
    rb_ary_clear(GET_QUEUE_QUE(self));
    return self;
}

/*
 * Document-method: Queue#length
 * call-seq:
 *   length
 *   size
 *
 * Returns the length of the queue.
 */

static VALUE
rb_queue_length(VALUE self)
{
    unsigned long len = queue_length(self);
    return ULONG2NUM(len);
}

/*
 * Document-method: Queue#num_waiting
 *
 * Returns the number of threads waiting on the queue.
 */

static VALUE
rb_queue_num_waiting(VALUE self)
{
    unsigned long len = queue_num_waiting(self);
    return ULONG2NUM(len);
}

/*
 *  Document-class: SizedQueue
 *
 * This class represents queues of specified size capacity.  The push operation
 * may be blocked if the capacity is full.
 *
 * See Queue for an example of how a SizedQueue works.
 */

/*
 * Document-method: SizedQueue::new
 * call-seq: new(max)
 *
 * Creates a fixed-length queue with a maximum size of +max+.
 */

static VALUE
rb_szqueue_initialize(VALUE self, VALUE vmax)
{
    long max;

    max = NUM2LONG(vmax);
    if (max <= 0) {
	rb_raise(rb_eArgError, "queue size must be positive");
    }

    RSTRUCT_SET(self, QUEUE_QUE, ary_buf_new());
    RSTRUCT_SET(self, QUEUE_WAITERS, ary_buf_new());
    RSTRUCT_SET(self, SZQUEUE_WAITERS, ary_buf_new());
    RSTRUCT_SET(self, SZQUEUE_MAX, vmax);

    return self;
}

/*
 * Document-method: SizedQueue#max
 *
 * Returns the maximum size of the queue.
 */

static VALUE
rb_szqueue_max_get(VALUE self)
{
    return GET_SZQUEUE_MAX(self);
}

/*
 * Document-method: SizedQueue#max=
 * call-seq: max=(number)
 *
 * Sets the maximum size of the queue to the given +number+.
 */

static VALUE
rb_szqueue_max_set(VALUE self, VALUE vmax)
{
    long max = NUM2LONG(vmax), diff = 0;
    VALUE t;

    if (max <= 0) {
	rb_raise(rb_eArgError, "queue size must be positive");
    }
    if ((unsigned long)max > GET_SZQUEUE_ULONGMAX(self)) {
	diff = max - GET_SZQUEUE_ULONGMAX(self);
    }
    RSTRUCT_SET(self, SZQUEUE_MAX, vmax);
    while (diff-- > 0 && !NIL_P(t = rb_ary_shift(GET_SZQUEUE_WAITERS(self)))) {
	rb_thread_wakeup_alive(t);
    }
    return vmax;
}

static int
szqueue_push_should_block(int argc, const VALUE *argv)
{
    int should_block = 1;
    rb_check_arity(argc, 1, 2);
    if (argc > 1) {
	should_block = !RTEST(argv[1]);
    }
    return should_block;
}

/*
 * Document-method: SizedQueue#push
 * call-seq:
 *   push(object, non_block=false)
 *   enq(object, non_block=false)
 *   <<(object)
 *
 * Pushes +object+ to the queue.
 *
 * If there is no space left in the queue, waits until space becomes
 * available, unless +non_block+ is true.  If +non_block+ is true, the
 * thread isn't suspended, and an exception is raised.
 */

static VALUE
rb_szqueue_push(int argc, VALUE *argv, VALUE self)
{
    struct waiting_delete args;
    int should_block = szqueue_push_should_block(argc, argv);
    args.waiting = GET_SZQUEUE_WAITERS(self);
    args.th      = rb_thread_current();

    while (queue_length(self) >= GET_SZQUEUE_ULONGMAX(self)) {
	if (!should_block) {
	    rb_raise(rb_eThreadError, "queue full");
	}
	rb_ary_push(args.waiting, args.th);
	rb_ensure((VALUE (*)())rb_thread_sleep_deadly, (VALUE)0, queue_delete_from_waiting, (VALUE)&args);
    }
    return queue_do_push(self, argv[0]);
}

static VALUE
szqueue_do_pop(VALUE self, int should_block)
{
    VALUE retval = queue_do_pop(self, should_block);

    if (queue_length(self) < GET_SZQUEUE_ULONGMAX(self)) {
	wakeup_first_thread(GET_SZQUEUE_WAITERS(self));
    }

    return retval;
}

/*
 * Document-method: SizedQueue#pop
 * call-seq:
 *   pop(non_block=false)
 *   deq(non_block=false)
 *   shift(non_block=false)
 *
 * Retrieves data from the queue.
 *
 * If the queue is empty, the calling thread is suspended until data is pushed
 * onto the queue. If +non_block+ is true, the thread isn't suspended, and an
 * exception is raised.
 */

static VALUE
rb_szqueue_pop(int argc, VALUE *argv, VALUE self)
{
    int should_block = queue_pop_should_block(argc, argv);
    return szqueue_do_pop(self, should_block);
}

/*
 * Document-method: Queue#clear
 *
 * Removes all objects from the queue.
 */

static VALUE
rb_szqueue_clear(VALUE self)
{
    rb_ary_clear(GET_QUEUE_QUE(self));
    wakeup_all_threads(GET_SZQUEUE_WAITERS(self));
    return self;
}

/*
 * Document-method: SizedQueue#num_waiting
 *
 * Returns the number of threads waiting on the queue.
 */

static VALUE
rb_szqueue_num_waiting(VALUE self)
{
    long len = queue_num_waiting(self);
    VALUE waiters = GET_SZQUEUE_WAITERS(self);
    len += RARRAY_LEN(waiters);
    return ULONG2NUM(len);
}

#ifndef UNDER_THREAD
#define UNDER_THREAD 1
#endif

/* :nodoc: */
static VALUE
undumpable(VALUE obj)
{
    rb_raise(rb_eTypeError, "can't dump %"PRIsVALUE, rb_obj_class(obj));
    UNREACHABLE;
}

void
Init_thread(void)
{
#if UNDER_THREAD
#define ALIAS_GLOBAL_CONST(name) do {	              \
	ID id = rb_intern_const(#name);	              \
	if (!rb_const_defined_at(rb_cObject, id)) {   \
	    rb_const_set(rb_cObject, id, rb_c##name); \
	}                                             \
    } while (0)
#define OUTER rb_cThread
#else
#define ALIAS_GLOBAL_CONST(name) do { /* nothing */ } while (0)
#define OUTER 0
#endif

    VALUE rb_cConditionVariable = rb_struct_define_without_accessor_under(
	OUTER,
	"ConditionVariable", rb_cObject, rb_struct_alloc_noinit,
	"waiters", NULL);
    VALUE rb_cQueue = rb_struct_define_without_accessor_under(
	OUTER,
	"Queue", rb_cObject, rb_struct_alloc_noinit,
	"que", "waiters", NULL);
    VALUE rb_cSizedQueue = rb_struct_define_without_accessor_under(
	OUTER,
	"SizedQueue", rb_cQueue, rb_struct_alloc_noinit,
	"que", "waiters", "queue_waiters", "size", NULL);

#if 0
    rb_cConditionVariable = rb_define_class("ConditionVariable", rb_cObject); /* teach rdoc ConditionVariable */
    rb_cQueue = rb_define_class("Queue", rb_cObject); /* teach rdoc Queue */
    rb_cSizedQueue = rb_define_class("SizedQueue", rb_cObject); /* teach rdoc SizedQueue */
#endif

    id_sleep = rb_intern("sleep");

    rb_define_method(rb_cConditionVariable, "initialize", rb_condvar_initialize, 0);
    rb_undef_method(rb_cConditionVariable, "initialize_copy");
    rb_define_method(rb_cConditionVariable, "marshal_dump", undumpable, 0);
    rb_define_method(rb_cConditionVariable, "wait", rb_condvar_wait, -1);
    rb_define_method(rb_cConditionVariable, "signal", rb_condvar_signal, 0);
    rb_define_method(rb_cConditionVariable, "broadcast", rb_condvar_broadcast, 0);

    rb_define_method(rb_cQueue, "initialize", rb_queue_initialize, 0);
    rb_undef_method(rb_cQueue, "initialize_copy");
    rb_define_method(rb_cQueue, "marshal_dump", undumpable, 0);
    rb_define_method(rb_cQueue, "push", rb_queue_push, 1);
    rb_define_method(rb_cQueue, "pop", rb_queue_pop, -1);
    rb_define_method(rb_cQueue, "empty?", rb_queue_empty_p, 0);
    rb_define_method(rb_cQueue, "clear", rb_queue_clear, 0);
    rb_define_method(rb_cQueue, "length", rb_queue_length, 0);
    rb_define_method(rb_cQueue, "num_waiting", rb_queue_num_waiting, 0);

    /* Alias for #push. */
    rb_define_alias(rb_cQueue, "enq", "push");
    /* Alias for #push. */
    rb_define_alias(rb_cQueue, "<<", "push");
    /* Alias for #pop. */
    rb_define_alias(rb_cQueue, "deq", "pop");
    /* Alias for #pop. */
    rb_define_alias(rb_cQueue, "shift", "pop");
    /* Alias for #length. */
    rb_define_alias(rb_cQueue, "size", "length");

    rb_define_method(rb_cSizedQueue, "initialize", rb_szqueue_initialize, 1);
    rb_define_method(rb_cSizedQueue, "max", rb_szqueue_max_get, 0);
    rb_define_method(rb_cSizedQueue, "max=", rb_szqueue_max_set, 1);
    rb_define_method(rb_cSizedQueue, "push", rb_szqueue_push, -1);
    rb_define_method(rb_cSizedQueue, "pop", rb_szqueue_pop, -1);
    rb_define_method(rb_cSizedQueue, "clear", rb_szqueue_clear, 0);
    rb_define_method(rb_cSizedQueue, "num_waiting", rb_szqueue_num_waiting, 0);

    /* Alias for #push. */
    rb_define_alias(rb_cSizedQueue, "enq", "push");
    /* Alias for #push. */
    rb_define_alias(rb_cSizedQueue, "<<", "push");
    /* Alias for #pop. */
    rb_define_alias(rb_cSizedQueue, "deq", "pop");
    /* Alias for #pop. */
    rb_define_alias(rb_cSizedQueue, "shift", "pop");

    rb_provide("thread.rb");
    ALIAS_GLOBAL_CONST(ConditionVariable);
    ALIAS_GLOBAL_CONST(Queue);
    ALIAS_GLOBAL_CONST(SizedQueue);
}