1/* Copyright (C) 2001-2004 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/* A cache for QueryExtension results. */
27
28#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#include <stdlib.h>
33#include <string.h>
34
35#include "xcb.h"
36#include "xcbext.h"
37#include "xcbint.h"
38
39typedef struct lazyreply {
40    enum lazy_reply_tag tag;
41    union {
42        xcb_query_extension_cookie_t cookie;
43        xcb_query_extension_reply_t *reply;
44    } value;
45} lazyreply;
46
47static lazyreply *get_index(xcb_connection_t *c, int idx)
48{
49    if(idx > c->ext.extensions_size)
50    {
51        int new_size = idx << 1;
52        lazyreply *new_extensions = realloc(c->ext.extensions, sizeof(lazyreply) * new_size);
53        if(!new_extensions)
54            return 0;
55        memset(new_extensions + c->ext.extensions_size, 0, sizeof(lazyreply) * (new_size - c->ext.extensions_size));
56        c->ext.extensions = new_extensions;
57        c->ext.extensions_size = new_size;
58    }
59    return c->ext.extensions + idx - 1;
60}
61
62static lazyreply *get_lazyreply(xcb_connection_t *c, xcb_extension_t *ext)
63{
64    static pthread_mutex_t global_lock = PTHREAD_MUTEX_INITIALIZER;
65    static int next_global_id;
66
67    lazyreply *data;
68
69    pthread_mutex_lock(&global_lock);
70    if(!ext->global_id)
71        ext->global_id = ++next_global_id;
72    pthread_mutex_unlock(&global_lock);
73
74    data = get_index(c, ext->global_id);
75    if(data && data->tag == LAZY_NONE)
76    {
77        /* cache miss: query the server */
78        data->tag = LAZY_COOKIE;
79        data->value.cookie = xcb_query_extension(c, strlen(ext->name), ext->name);
80    }
81    return data;
82}
83
84/* Public interface */
85
86/* Do not free the returned xcb_query_extension_reply_t - on return, it's aliased
87 * from the cache. */
88const xcb_query_extension_reply_t *xcb_get_extension_data(xcb_connection_t *c, xcb_extension_t *ext)
89{
90    lazyreply *data;
91    if(c->has_error)
92        return 0;
93
94    pthread_mutex_lock(&c->ext.lock);
95    data = get_lazyreply(c, ext);
96    if(data && data->tag == LAZY_COOKIE)
97    {
98        data->tag = LAZY_FORCED;
99        data->value.reply = xcb_query_extension_reply(c, data->value.cookie, 0);
100    }
101    pthread_mutex_unlock(&c->ext.lock);
102
103    return data ? data->value.reply : 0;
104}
105
106void xcb_prefetch_extension_data(xcb_connection_t *c, xcb_extension_t *ext)
107{
108    if(c->has_error)
109        return;
110    pthread_mutex_lock(&c->ext.lock);
111    get_lazyreply(c, ext);
112    pthread_mutex_unlock(&c->ext.lock);
113}
114
115/* Private interface */
116
117int _xcb_ext_init(xcb_connection_t *c)
118{
119    if(pthread_mutex_init(&c->ext.lock, 0))
120        return 0;
121    return 1;
122}
123
124void _xcb_ext_destroy(xcb_connection_t *c)
125{
126    pthread_mutex_destroy(&c->ext.lock);
127    while(c->ext.extensions_size-- > 0)
128        if(c->ext.extensions[c->ext.extensions_size].tag == LAZY_FORCED)
129            free(c->ext.extensions[c->ext.extensions_size].value.reply);
130    free(c->ext.extensions);
131}
132