summaryrefslogtreecommitdiff
path: root/Build/source/libs/cairo/cairo-1.12.8/src/cairo-xcb-shm.c
blob: 7c2a67535c10f0f1d4f18df9f1aa645ab86ee8e6 (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
/* Cairo - a vector graphics library with display and print output
 *
 * Copyright © 2007 Chris Wilson
 * Copyright © 2009 Intel Corporation
 *
 * This library is free software; you can redistribute it and/or
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
 * You should have received a copy of the MPL along with this library
 * in the file COPYING-MPL-1.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 *
 * The Original Code is the cairo graphics library.
 *
 * The Initial Developer of the Original Code is Red Hat, Inc.
 *
 * Contributors(s):
 *	Chris Wilson <chris@chris-wilson.co.uk>
 */

#include "cairoint.h"

#if CAIRO_HAS_XCB_SHM_FUNCTIONS

#include "cairo-xcb-private.h"
#include "cairo-list-inline.h"
#include "cairo-mempool-private.h"

#include <xcb/shm.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <errno.h>

#define CAIRO_MAX_SHM_MEMORY (16*1024*1024)

/* a simple buddy allocator for memory pools
 * XXX fragmentation? use Doug Lea's malloc?
 */

typedef struct _cairo_xcb_shm_mem_block cairo_xcb_shm_mem_block_t;

typedef enum {
    PENDING_WAIT,
    PENDING_POLL
} shm_wait_type_t;

struct _cairo_xcb_shm_mem_pool {
    int shmid;
    uint32_t shmseg;

    cairo_mempool_t mem;

    cairo_list_t link;
};

static void
_cairo_xcb_shm_mem_pool_destroy (cairo_xcb_shm_mem_pool_t *pool)
{
    cairo_list_del (&pool->link);

    shmdt (pool->mem.base);
    _cairo_mempool_fini (&pool->mem);

    free (pool);
}

static void
_cairo_xcb_shm_info_finalize (cairo_xcb_shm_info_t *shm_info)
{
    cairo_xcb_connection_t *connection = shm_info->connection;

    assert (CAIRO_MUTEX_IS_LOCKED (connection->shm_mutex));

    _cairo_mempool_free (&shm_info->pool->mem, shm_info->mem);
    _cairo_freepool_free (&connection->shm_info_freelist, shm_info);

    /* scan for old, unused pools - hold at least one in reserve */
    if (! cairo_list_is_singular (&connection->shm_pools))
    {
	cairo_xcb_shm_mem_pool_t *pool, *next;
	cairo_list_t head;

	cairo_list_init (&head);
	cairo_list_move (connection->shm_pools.next, &head);

	cairo_list_foreach_entry_safe (pool, next, cairo_xcb_shm_mem_pool_t,
				       &connection->shm_pools, link)
	{
	    if (pool->mem.free_bytes == pool->mem.max_bytes) {
		_cairo_xcb_connection_shm_detach (connection, pool->shmseg);
		_cairo_xcb_shm_mem_pool_destroy (pool);
	    }
	}

	cairo_list_move (head.next, &connection->shm_pools);
    }
}

static void
_cairo_xcb_shm_process_pending (cairo_xcb_connection_t *connection, shm_wait_type_t wait)
{
    cairo_xcb_shm_info_t *info, *next;
    xcb_get_input_focus_reply_t *reply;

    assert (CAIRO_MUTEX_IS_LOCKED (connection->shm_mutex));
    cairo_list_foreach_entry_safe (info, next, cairo_xcb_shm_info_t,
				   &connection->shm_pending, pending)
    {
	switch (wait) {
	case PENDING_WAIT:
	     reply = xcb_wait_for_reply (connection->xcb_connection,
					 info->sync.sequence, NULL);
	     break;
	case PENDING_POLL:
	    if (! xcb_poll_for_reply (connection->xcb_connection,
				      info->sync.sequence,
				      (void **) &reply, NULL))
		/* We cannot be sure the server finished with this image yet, so
		 * try again later. All other shm info are guaranteed to have a
		 * larger sequence number and thus don't have to be checked. */
		return;
	    break;
	default:
	    /* silence Clang static analyzer warning */
	    ASSERT_NOT_REACHED;
	    reply = NULL;
	}

	free (reply);
	cairo_list_del (&info->pending);
	_cairo_xcb_shm_info_finalize (info);
    }
}

cairo_int_status_t
_cairo_xcb_connection_allocate_shm_info (cairo_xcb_connection_t *connection,
					 size_t size,
					 cairo_bool_t might_reuse,
					 cairo_xcb_shm_info_t **shm_info_out)
{
    cairo_xcb_shm_info_t *shm_info;
    cairo_xcb_shm_mem_pool_t *pool, *next;
    size_t bytes, maxbits = 16, minbits = 8;
    size_t shm_allocated = 0;
    void *mem = NULL;
    cairo_status_t status;
    void *base;

    assert (connection->flags & CAIRO_XCB_HAS_SHM);

    CAIRO_MUTEX_LOCK (connection->shm_mutex);
    _cairo_xcb_shm_process_pending (connection, PENDING_POLL);

    if (might_reuse) {
	cairo_list_foreach_entry (shm_info, cairo_xcb_shm_info_t,
		&connection->shm_pending, pending) {
	    if (shm_info->size >= size) {
		cairo_list_del (&shm_info->pending);
		CAIRO_MUTEX_UNLOCK (connection->shm_mutex);

		xcb_discard_reply (connection->xcb_connection, shm_info->sync.sequence);
		shm_info->sync.sequence = XCB_NONE;

		*shm_info_out = shm_info;
		return CAIRO_STATUS_SUCCESS;
	    }
	}
    }

    cairo_list_foreach_entry_safe (pool, next, cairo_xcb_shm_mem_pool_t,
				   &connection->shm_pools, link)
    {
	if (pool->mem.free_bytes > size) {
	    mem = _cairo_mempool_alloc (&pool->mem, size);
	    if (mem != NULL) {
		/* keep the active pools towards the front */
		cairo_list_move (&pool->link, &connection->shm_pools);
		goto allocate_shm_info;
	    }
	}
	/* scan for old, unused pools */
	if (pool->mem.free_bytes == pool->mem.max_bytes) {
	    _cairo_xcb_connection_shm_detach (connection,
					      pool->shmseg);
	    _cairo_xcb_shm_mem_pool_destroy (pool);
	} else {
	    shm_allocated += pool->mem.max_bytes;
	}
    }

    if (unlikely (shm_allocated >= CAIRO_MAX_SHM_MEMORY)) {
	CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
	return _cairo_error (CAIRO_STATUS_NO_MEMORY);
    }

    pool = malloc (sizeof (cairo_xcb_shm_mem_pool_t));
    if (unlikely (pool == NULL)) {
	CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
	return _cairo_error (CAIRO_STATUS_NO_MEMORY);
    }

    bytes = 1 << maxbits;
    while (bytes <= size)
	bytes <<= 1, maxbits++;
    bytes <<= 3;

    do {
	pool->shmid = shmget (IPC_PRIVATE, bytes, IPC_CREAT | 0600);
	if (pool->shmid != -1)
	    break;

	/* If the allocation failed because we asked for too much memory, we try
	 * again with a smaller request, as long as our allocation still fits. */
	bytes >>= 1;
	if (errno != EINVAL || bytes < size)
	    break;
    } while (TRUE);
    if (pool->shmid == -1) {
	int err = errno;
	if (! (err == EINVAL || err == ENOMEM))
	    connection->flags &= ~CAIRO_XCB_HAS_SHM;
	free (pool);
	CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
	return CAIRO_INT_STATUS_UNSUPPORTED;
    }

    base = shmat (pool->shmid, NULL, 0);
    if (unlikely (base == (char *) -1)) {
	shmctl (pool->shmid, IPC_RMID, NULL);
	free (pool);
	CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
	return _cairo_error (CAIRO_STATUS_NO_MEMORY);
    }

    status = _cairo_mempool_init (&pool->mem, base, bytes,
				  minbits, maxbits - minbits + 1);
    if (unlikely (status)) {
	shmdt (base);
	free (pool);
	CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
	return status;
    }

    pool->shmseg = _cairo_xcb_connection_shm_attach (connection, pool->shmid, FALSE);
    shmctl (pool->shmid, IPC_RMID, NULL);

    cairo_list_add (&pool->link, &connection->shm_pools);
    mem = _cairo_mempool_alloc (&pool->mem, size);

  allocate_shm_info:
    shm_info = _cairo_freepool_alloc (&connection->shm_info_freelist);
    if (unlikely (shm_info == NULL)) {
	_cairo_mempool_free (&pool->mem, mem);
	CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
	return _cairo_error (CAIRO_STATUS_NO_MEMORY);
    }

    shm_info->connection = connection;
    shm_info->pool = pool;
    shm_info->shm = pool->shmseg;
    shm_info->size = size;
    shm_info->offset = (char *) mem - (char *) pool->mem.base;
    shm_info->mem = mem;
    shm_info->sync.sequence = XCB_NONE;

    /* scan for old, unused pools */
    cairo_list_foreach_entry_safe (pool, next, cairo_xcb_shm_mem_pool_t,
				   &connection->shm_pools, link)
    {
	if (pool->mem.free_bytes == pool->mem.max_bytes) {
	    _cairo_xcb_connection_shm_detach (connection,
					      pool->shmseg);
	    _cairo_xcb_shm_mem_pool_destroy (pool);
	}
    }
    CAIRO_MUTEX_UNLOCK (connection->shm_mutex);

    *shm_info_out = shm_info;
    return CAIRO_STATUS_SUCCESS;
}

void
_cairo_xcb_shm_info_destroy (cairo_xcb_shm_info_t *shm_info)
{
    cairo_xcb_connection_t *connection = shm_info->connection;

    /* We can only return shm_info->mem to the allocator when we can be sure
     * that the X server no longer reads from it. Since the X server processes
     * requests in order, we send a GetInputFocus here.
     * _cairo_xcb_shm_process_pending () will later check if the reply for that
     * request was received and then actually mark this memory area as free. */

    CAIRO_MUTEX_LOCK (connection->shm_mutex);
    assert (shm_info->sync.sequence == XCB_NONE);
    shm_info->sync = xcb_get_input_focus (connection->xcb_connection);

    cairo_list_init (&shm_info->pending);
    cairo_list_add_tail (&shm_info->pending, &connection->shm_pending);
    CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
}

void
_cairo_xcb_connection_shm_mem_pools_flush (cairo_xcb_connection_t *connection)
{
    CAIRO_MUTEX_LOCK (connection->shm_mutex);
    _cairo_xcb_shm_process_pending (connection, PENDING_WAIT);
    CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
}

void
_cairo_xcb_connection_shm_mem_pools_fini (cairo_xcb_connection_t *connection)
{
    assert (cairo_list_is_empty (&connection->shm_pending));
    while (! cairo_list_is_empty (&connection->shm_pools)) {
	_cairo_xcb_shm_mem_pool_destroy (cairo_list_first_entry (&connection->shm_pools,
								 cairo_xcb_shm_mem_pool_t,
								 link));
    }
}

#endif /* CAIRO_HAS_XCB_SHM_FUNCTIONS */