xcb_xid.c revision 8ffb90f1 
1/* Copyright (C) 2001-2008 Bart Massey and Jamey Sharp.
2 *
3 * Permission is hereby granted, free of charge, to any person obtaining a
4 * copy of this software and associated documentation files (the "Software"),
5 * to deal in the Software without restriction, including without limitation
6 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
7 * and/or sell copies of the Software, and to permit persons to whom the
8 * Software is furnished to do so, subject to the following conditions:
9 *
10 * The above copyright notice and this permission notice shall be included in
11 * all copies or substantial portions of the Software.
12 *
13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16 * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
17 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
18 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
19 *
20 * Except as contained in this notice, the names of the authors or their
21 * institutions shall not be used in advertising or otherwise to promote the
22 * sale, use or other dealings in this Software without prior written
23 * authorization from the authors.
24 */
25
26/* XID allocators. */
27
28#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#include <assert.h>
33#include <stdlib.h>
34#include "xcb.h"
35#include "xcbext.h"
36#include "xcbint.h"
37#include "xc_misc.h"
38
39/* Public interface */
40
41uint32_t xcb_generate_id(xcb_connection_t *c)
42{
43    uint32_t ret;
44    if(c->has_error)
45        return -1;
46    pthread_mutex_lock(&c->xid.lock);
47    if(c->xid.last >= c->xid.max - c->xid.inc + 1)
48    {
49        xcb_xc_misc_get_xid_range_reply_t *range;
50        assert(c->xid.last == c->xid.max);
51        if (c->xid.last == 0) {
52            /* finish setting up initial range */
53            c->xid.max = c->setup->resource_id_mask;
54        } else {
55            /* check for extension */
56            const xcb_query_extension_reply_t *xc_misc_reply =
57              xcb_get_extension_data(c, &xcb_xc_misc_id);
58            if (!xc_misc_reply || !xc_misc_reply->present) {
59                pthread_mutex_unlock(&c->xid.lock);
60                return -1;
61            }
62            /* get new range */
63            range = xcb_xc_misc_get_xid_range_reply(c,
64                      xcb_xc_misc_get_xid_range(c), 0);
65            /* XXX The latter disjunct is what the server returns
66               when it is out of XIDs.  Sweet. */
67            if(!range || (range->start_id == 0 && range->count == 1))
68            {
69                pthread_mutex_unlock(&c->xid.lock);
70                return -1;
71            }
72            assert(range->count > 0 && range->start_id > 0);
73            c->xid.last = range->start_id;
74            c->xid.max = range->start_id + (range->count - 1) * c->xid.inc;
75            free(range);
76        }
77    } else {
78        c->xid.last += c->xid.inc;
79    }
80    ret = c->xid.last | c->xid.base;
81    pthread_mutex_unlock(&c->xid.lock);
82    return ret;
83}
84
85/* Private interface */
86
87int _xcb_xid_init(xcb_connection_t *c)
88{
89    if(pthread_mutex_init(&c->xid.lock, 0))
90        return 0;
91    c->xid.last = 0;
92    c->xid.max = 0;
93    c->xid.base = c->setup->resource_id_base;
94    c->xid.inc = c->setup->resource_id_mask & -(c->setup->resource_id_mask);
95    return 1;
96}
97
98void _xcb_xid_destroy(xcb_connection_t *c)
99{
100    pthread_mutex_destroy(&c->xid.lock);
101}
102