xcb_xid.c revision 602e473d 
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#include <assert.h>
29#include <stdlib.h>
30#include "xcb.h"
31#include "xcbext.h"
32#include "xcbint.h"
33#include "xc_misc.h"
34
35/* Public interface */
36
37uint32_t xcb_generate_id(xcb_connection_t *c)
38{
39    uint32_t ret;
40    if(c->has_error)
41        return -1;
42    pthread_mutex_lock(&c->xid.lock);
43    if(c->xid.last >= c->xid.max - c->xid.inc + 1)
44    {
45        xcb_xc_misc_get_xid_range_reply_t *range;
46        assert(c->xid.last == c->xid.max);
47        if (c->xid.last == 0) {
48            /* finish setting up initial range */
49            c->xid.max = c->setup->resource_id_mask;
50        } else {
51            /* check for extension */
52            const xcb_query_extension_reply_t *xc_misc_reply =
53              xcb_get_extension_data(c, &xcb_xc_misc_id);
54            if (!xc_misc_reply) {
55                pthread_mutex_unlock(&c->xid.lock);
56                return -1;
57            }
58            /* get new range */
59            range = xcb_xc_misc_get_xid_range_reply(c,
60                      xcb_xc_misc_get_xid_range(c), 0);
61            /* XXX The latter disjunct is what the server returns
62               when it is out of XIDs.  Sweet. */
63            if(!range || (range->start_id == 0 && range->count == 1))
64            {
65                pthread_mutex_unlock(&c->xid.lock);
66                return -1;
67            }
68            assert(range->count > 0 && range->start_id > 0);
69            c->xid.last = range->start_id;
70            c->xid.max = range->start_id + (range->count - 1) * c->xid.inc;
71            free(range);
72        }
73    } else {
74        c->xid.last += c->xid.inc;
75    }
76    ret = c->xid.last | c->xid.base;
77    pthread_mutex_unlock(&c->xid.lock);
78    return ret;
79}
80
81/* Private interface */
82
83int _xcb_xid_init(xcb_connection_t *c)
84{
85    if(pthread_mutex_init(&c->xid.lock, 0))
86        return 0;
87    c->xid.last = 0;
88    c->xid.max = 0;
89    c->xid.base = c->setup->resource_id_base;
90    c->xid.inc = c->setup->resource_id_mask & -(c->setup->resource_id_mask);
91    return 1;
92}
93
94void _xcb_xid_destroy(xcb_connection_t *c)
95{
96    pthread_mutex_destroy(&c->xid.lock);
97}
98