IABSD.fr/xenocara/dist/libxcb/src/xcb_ext.c

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• Author : matthieu
  Date : 2012-11-22 20:31:32
  Hash : 6d8faa15
  Message : Update to libxcb 1.9.0. tested by ajacoutot@ and naddy@ on a full ports build

• dist/libxcb/src/xcb_ext.c

• /* 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);
  }