File: tevent_queue.c

package info (click to toggle)
tevent 0.9.37-1
  • links: PTS, VCS
  • area: main
  • in suites: buster, sid
  • size: 3,332 kB
  • sloc: python: 21,531; ansic: 21,401; xml: 812; sh: 209; makefile: 145
file content (370 lines) | stat: -rw-r--r-- 7,505 bytes parent folder | download | duplicates (3)
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
/*
   Unix SMB/CIFS implementation.
   Infrastructure for async requests
   Copyright (C) Volker Lendecke 2008
   Copyright (C) Stefan Metzmacher 2009

     ** NOTE! The following LGPL license applies to the tevent
     ** library. This does NOT imply that all of Samba is released
     ** under the LGPL

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 3 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/

#include "replace.h"
#include "tevent.h"
#include "tevent_internal.h"
#include "tevent_util.h"

struct tevent_queue_entry {
	struct tevent_queue_entry *prev, *next;
	struct tevent_queue *queue;

	bool triggered;

	struct tevent_req *req;
	struct tevent_context *ev;

	tevent_queue_trigger_fn_t trigger;
	void *private_data;
};

struct tevent_queue {
	const char *name;
	const char *location;

	bool running;
	struct tevent_immediate *immediate;

	size_t length;
	struct tevent_queue_entry *list;
};

static void tevent_queue_immediate_trigger(struct tevent_context *ev,
					   struct tevent_immediate *im,
					   void *private_data);

static int tevent_queue_entry_destructor(struct tevent_queue_entry *e)
{
	struct tevent_queue *q = e->queue;

	if (!q) {
		return 0;
	}

	DLIST_REMOVE(q->list, e);
	q->length--;

	if (!q->running) {
		return 0;
	}

	if (!q->list) {
		return 0;
	}

	if (q->list->triggered) {
		return 0;
	}

	tevent_schedule_immediate(q->immediate,
				  q->list->ev,
				  tevent_queue_immediate_trigger,
				  q);

	return 0;
}

static int tevent_queue_destructor(struct tevent_queue *q)
{
	q->running = false;

	while (q->list) {
		struct tevent_queue_entry *e = q->list;
		talloc_free(e);
	}

	return 0;
}

struct tevent_queue *_tevent_queue_create(TALLOC_CTX *mem_ctx,
					  const char *name,
					  const char *location)
{
	struct tevent_queue *queue;

	queue = talloc_zero(mem_ctx, struct tevent_queue);
	if (!queue) {
		return NULL;
	}

	queue->name = talloc_strdup(queue, name);
	if (!queue->name) {
		talloc_free(queue);
		return NULL;
	}
	queue->immediate = tevent_create_immediate(queue);
	if (!queue->immediate) {
		talloc_free(queue);
		return NULL;
	}

	queue->location = location;

	/* queue is running by default */
	queue->running = true;

	talloc_set_destructor(queue, tevent_queue_destructor);
	return queue;
}

static void tevent_queue_immediate_trigger(struct tevent_context *ev,
					   struct tevent_immediate *im,
					   void *private_data)
{
	struct tevent_queue *q =
		talloc_get_type_abort(private_data,
		struct tevent_queue);

	if (!q->running) {
		return;
	}

	if (!q->list) {
		return;
	}

	q->list->triggered = true;
	q->list->trigger(q->list->req, q->list->private_data);
}

static struct tevent_queue_entry *tevent_queue_add_internal(
					struct tevent_queue *queue,
					struct tevent_context *ev,
					struct tevent_req *req,
					tevent_queue_trigger_fn_t trigger,
					void *private_data,
					bool allow_direct)
{
	struct tevent_queue_entry *e;

	e = talloc_zero(req, struct tevent_queue_entry);
	if (e == NULL) {
		return NULL;
	}

	e->queue = queue;
	e->req = req;
	e->ev = ev;
	e->trigger = trigger;
	e->private_data = private_data;

	/*
	 * if there is no trigger, it is just a blocker
	 */
	if (trigger == NULL) {
		e->triggered = true;
	}

	if (queue->length > 0) {
		/*
		 * if there are already entries in the
		 * queue do not optimize.
		 */
		allow_direct = false;
	}

	if (req->async.fn != NULL) {
		/*
		 * If the caller wants to optimize for the
		 * empty queue case, call the trigger only
		 * if there is no callback defined for the
		 * request yet.
		 */
		allow_direct = false;
	}

	DLIST_ADD_END(queue->list, e);
	queue->length++;
	talloc_set_destructor(e, tevent_queue_entry_destructor);

	if (!queue->running) {
		return e;
	}

	if (queue->list->triggered) {
		return e;
	}

	/*
	 * If allowed we directly call the trigger
	 * avoiding possible delays caused by
	 * an immediate event.
	 */
	if (allow_direct) {
		queue->list->triggered = true;
		queue->list->trigger(queue->list->req,
				     queue->list->private_data);
		return e;
	}

	tevent_schedule_immediate(queue->immediate,
				  queue->list->ev,
				  tevent_queue_immediate_trigger,
				  queue);

	return e;
}

bool tevent_queue_add(struct tevent_queue *queue,
		      struct tevent_context *ev,
		      struct tevent_req *req,
		      tevent_queue_trigger_fn_t trigger,
		      void *private_data)
{
	struct tevent_queue_entry *e;

	e = tevent_queue_add_internal(queue, ev, req,
				      trigger, private_data, false);
	if (e == NULL) {
		return false;
	}

	return true;
}

struct tevent_queue_entry *tevent_queue_add_entry(
					struct tevent_queue *queue,
					struct tevent_context *ev,
					struct tevent_req *req,
					tevent_queue_trigger_fn_t trigger,
					void *private_data)
{
	return tevent_queue_add_internal(queue, ev, req,
					 trigger, private_data, false);
}

struct tevent_queue_entry *tevent_queue_add_optimize_empty(
					struct tevent_queue *queue,
					struct tevent_context *ev,
					struct tevent_req *req,
					tevent_queue_trigger_fn_t trigger,
					void *private_data)
{
	return tevent_queue_add_internal(queue, ev, req,
					 trigger, private_data, true);
}

void tevent_queue_entry_untrigger(struct tevent_queue_entry *entry)
{
	if (entry->queue->running) {
		abort();
	}

	if (entry->queue->list != entry) {
		abort();
	}

	entry->triggered = false;
}

void tevent_queue_start(struct tevent_queue *queue)
{
	if (queue->running) {
		/* already started */
		return;
	}

	queue->running = true;

	if (!queue->list) {
		return;
	}

	if (queue->list->triggered) {
		return;
	}

	tevent_schedule_immediate(queue->immediate,
				  queue->list->ev,
				  tevent_queue_immediate_trigger,
				  queue);
}

void tevent_queue_stop(struct tevent_queue *queue)
{
	queue->running = false;
}

size_t tevent_queue_length(struct tevent_queue *queue)
{
	return queue->length;
}

bool tevent_queue_running(struct tevent_queue *queue)
{
	return queue->running;
}

struct tevent_queue_wait_state {
	uint8_t dummy;
};

static void tevent_queue_wait_trigger(struct tevent_req *req,
				      void *private_data);

struct tevent_req *tevent_queue_wait_send(TALLOC_CTX *mem_ctx,
					  struct tevent_context *ev,
					  struct tevent_queue *queue)
{
	struct tevent_req *req;
	struct tevent_queue_wait_state *state;
	bool ok;

	req = tevent_req_create(mem_ctx, &state,
				struct tevent_queue_wait_state);
	if (req == NULL) {
		return NULL;
	}

	ok = tevent_queue_add(queue, ev, req,
			      tevent_queue_wait_trigger,
			      NULL);
	if (!ok) {
		tevent_req_oom(req);
		return tevent_req_post(req, ev);
	}

	return req;
}

static void tevent_queue_wait_trigger(struct tevent_req *req,
					 void *private_data)
{
	tevent_req_done(req);
}

bool tevent_queue_wait_recv(struct tevent_req *req)
{
	enum tevent_req_state state;
	uint64_t err;

	if (tevent_req_is_error(req, &state, &err)) {
		tevent_req_received(req);
		return false;
	}

	tevent_req_received(req);
	return true;
}