aboutsummaryrefslogtreecommitdiff
path: root/libxcb/src/xcb_ext.c
blob: 990c67a9640a7bd653482299ec34d6722e9603b1 (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
/* Copyright (C) 2001-2004 Bart Massey and Jamey Sharp.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * 
 * Except as contained in this notice, the names of the authors or their
 * institutions shall not be used in advertising or otherwise to promote the
 * sale, use or other dealings in this Software without prior written
 * authorization from the authors.
 */

/* A cache for QueryExtension results. */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdlib.h>
#include <string.h>

#include "xcb.h"
#include "xcbext.h"
#include "xcbint.h"

typedef struct lazyreply {
    enum lazy_reply_tag tag;
    union {
        xcb_query_extension_cookie_t cookie;
        xcb_query_extension_reply_t *reply;
    } value;
} lazyreply;

static lazyreply *get_index(xcb_connection_t *c, int idx)
{
    if(idx > c->ext.extensions_size)
    {
        int new_size = idx << 1;
        lazyreply *new_extensions = realloc(c->ext.extensions, sizeof(lazyreply) * new_size);
        if(!new_extensions)
            return 0;
        memset(new_extensions + c->ext.extensions_size, 0, sizeof(lazyreply) * (new_size - c->ext.extensions_size));
        c->ext.extensions = new_extensions;
        c->ext.extensions_size = new_size;
    }
    return c->ext.extensions + idx - 1;
}

static lazyreply *get_lazyreply(xcb_connection_t *c, xcb_extension_t *ext)
{
    static pthread_mutex_t global_lock = PTHREAD_MUTEX_INITIALIZER;
    static int next_global_id;

    lazyreply *data;

    pthread_mutex_lock(&global_lock);
    if(!ext->global_id)
        ext->global_id = ++next_global_id;
    pthread_mutex_unlock(&global_lock);

    data = get_index(c, ext->global_id);
    if(data && data->tag == LAZY_NONE)
    {
        /* cache miss: query the server */
        data->tag = LAZY_COOKIE;
        data->value.cookie = xcb_query_extension(c, strlen(ext->name), ext->name);
    }
    return data;
}

/* Public interface */

/* Do not free the returned xcb_query_extension_reply_t - on return, it's aliased
 * from the cache. */
const xcb_query_extension_reply_t *xcb_get_extension_data(xcb_connection_t *c, xcb_extension_t *ext)
{
    lazyreply *data;
    if(c->has_error)
        return 0;

    pthread_mutex_lock(&c->ext.lock);
    data = get_lazyreply(c, ext);
    if(data && data->tag == LAZY_COOKIE)
    {
        data->tag = LAZY_FORCED;
        data->value.reply = xcb_query_extension_reply(c, data->value.cookie, 0);
    }
    pthread_mutex_unlock(&c->ext.lock);

    return data ? data->value.reply : 0;
}

void xcb_prefetch_extension_data(xcb_connection_t *c, xcb_extension_t *ext)
{
    if(c->has_error)
        return;
    pthread_mutex_lock(&c->ext.lock);
    get_lazyreply(c, ext);
    pthread_mutex_unlock(&c->ext.lock);
}

/* Private interface */

int _xcb_ext_init(xcb_connection_t *c)
{
    if(pthread_mutex_init(&c->ext.lock, 0))
        return 0;
    return 1;
}

void _xcb_ext_destroy(xcb_connection_t *c)
{
    if (!c->ext.lock)
      return; /* mutex is not initialised */
    pthread_mutex_destroy(&c->ext.lock);
    while(c->ext.extensions_size-- > 0)
        if(c->ext.extensions[c->ext.extensions_size].tag == LAZY_FORCED)
            free(c->ext.extensions[c->ext.extensions_size].value.reply);
    free(c->ext.extensions);
}