src/glx/glx_query.c

/*
 * (C) Copyright IBM Corporation 2004
 * All Rights Reserved.
 *
 * 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
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, 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 (including the next
 * paragraph) 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 NON-INFRINGEMENT.  IN NO EVENT SHALL
 * IBM AND/OR THEIR SUPPLIERS 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.
 */

/**
 * \file glx_query.c
 * Generic utility functions to query internal data from the server.
 *
 * \author Ian Romanick <idr@us.ibm.com>
 */

#include "glxclient.h"

#if defined(USE_XCB)
# include <X11/Xlib-xcb.h>
# include <xcb/xcb.h>
# include <xcb/glx.h>
#endif

#ifdef USE_XCB

/**
 * Exchange a protocol request for glXQueryServerString.
 */
char *
__glXQueryServerString(Display * dpy, int opcode, CARD32 screen, CARD32 name)
{
   xcb_connection_t *c = XGetXCBConnection(dpy);
   xcb_glx_query_server_string_reply_t *reply =
      xcb_glx_query_server_string_reply(c,
                                        xcb_glx_query_server_string(c,
                                                                    screen,
                                                                    name),
                                        NULL);

   /* The spec doesn't mention this, but the Xorg server replies with
    * a string already terminated with '\0'. */
   uint32_t len = xcb_glx_query_server_string_string_length(reply);
   char *buf = Xmalloc(len);
   memcpy(buf, xcb_glx_query_server_string_string(reply), len);
   free(reply);

   return buf;
}

/**
 * Exchange a protocol request for glGetString.
 */
char *
__glXGetString(Display * dpy, int opcode, CARD32 contextTag, CARD32 name)
{
   xcb_connection_t *c = XGetXCBConnection(dpy);
   xcb_glx_get_string_reply_t *reply = xcb_glx_get_string_reply(c,
                                                                xcb_glx_get_string
                                                                (c,
                                                                 contextTag,
                                                                 name),
                                                                NULL);

   /* The spec doesn't mention this, but the Xorg server replies with
    * a string already terminated with '\0'. */
   uint32_t len = xcb_glx_get_string_string_length(reply);
   char *buf = Xmalloc(len);
   memcpy(buf, xcb_glx_get_string_string(reply), len);
   free(reply);

   return buf;
}

#else

/**
 * GLX protocol structure for the ficticious "GXLGenericGetString" request.
 *
 * This is a non-existant protocol packet.  It just so happens that all of
 * the real protocol packets used to request a string from the server have
 * an identical binary layout.  The only difference between them is the
 * meaning of the \c for_whom field and the value of the \c glxCode.
 */
typedef struct GLXGenericGetString
{
   CARD8 reqType;
   CARD8 glxCode;
   CARD16 length B16;
   CARD32 for_whom B32;
   CARD32 name B32;
} xGLXGenericGetStringReq;

/* These defines are only needed to make the GetReq macro happy.
 */
#define sz_xGLXGenericGetStringReq 12
#define X_GLXGenericGetString 0

/**
 * Query the Server GLX string.
 * This routine will allocate the necessay space for the string.
 */
static char *
__glXGetStringFromServer(Display * dpy, int opcode, CARD32 glxCode,
                         CARD32 for_whom, CARD32 name)
{
   xGLXGenericGetStringReq *req;
   xGLXSingleReply reply;
   int length;
   int numbytes;
   char *buf;


   LockDisplay(dpy);


   /* All of the GLX protocol requests for getting a string from the server
    * look the same.  The exact meaning of the for_whom field is usually
    * either the screen number (for glXQueryServerString) or the context tag
    * (for GLXSingle).
    */

   GetReq(GLXGenericGetString, req);
   req->reqType = opcode;
   req->glxCode = glxCode;
   req->for_whom = for_whom;
   req->name = name;

   _XReply(dpy, (xReply *) & reply, 0, False);

   length = reply.length * 4;
   numbytes = reply.size;

   buf = (char *) Xmalloc(numbytes);
   if (buf != NULL) {
      _XRead(dpy, buf, numbytes);
      length -= numbytes;
   }

   _XEatData(dpy, length);

   UnlockDisplay(dpy);
   SyncHandle();

   return buf;
}

char *
__glXQueryServerString(Display * dpy, int opcode, CARD32 screen, CARD32 name)
{
   return __glXGetStringFromServer(dpy, opcode,
                                   X_GLXQueryServerString, screen, name);
}

char *
__glXGetString(Display * dpy, int opcode, CARD32 contextTag, CARD32 name)
{
   return __glXGetStringFromServer(dpy, opcode, X_GLsop_GetString,
                                   contextTag, name);
}

#endif /* USE_XCB */