/* 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)

{

    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);

}