src/glx/x11/glx_query.c

   1 /* -*- mode: c; tab-width: 3; indent-tabs-mode: nil; c-basic-offset: 3; coding: utf-8-unix -*- */
   2 /*
   3  * (C) Copyright IBM Corporation 2004
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * on the rights to use, copy, modify, merge, publish, distribute, sub
  10  * license, and/or sell copies of the Software, and to permit persons to whom
  11  * the Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the next
  14  * paragraph) shall be included in all copies or substantial portions of the
  15  * Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
  20  * IBM AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  23  * DEALINGS IN THE SOFTWARE.
  24  */
  25
  26 /**
  27  * \file glx_query.c
  28  * Generic utility functions to query internal data from the server.
  29  *
  30  * \author Ian Romanick <idr@us.ibm.com>
  31  */
  32
  33 #include "glxclient.h"
  34
  35 /**
  36  * GLX protocol structure for the ficticious "GXLGenericGetString" request.
  37  *
  38  * This is a non-existant protocol packet.  It just so happens that all of
  39  * the real protocol packets used to request a string from the server have
  40  * an identical binary layout.  The only difference between them is the
  41  * meaning of the \c for_whom field and the value of the \c glxCode.
  42  */
  43 typedef struct GLXGenericGetString
  44 {
  45    CARD8 reqType;
  46    CARD8 glxCode;
  47    CARD16 length B16;
  48    CARD32 for_whom B32;
  49    CARD32 name B32;
  50 } xGLXGenericGetStringReq;
  51
  52 /* These defines are only needed to make the GetReq macro happy.
  53  */
  54 #define sz_xGLXGenericGetStringReq 12
  55 #define X_GLXGenericGetString 0
  56
  57 /**
  58  * Query the Server GLX string.
  59  * This routine will allocate the necessay space for the string.
  60  */
  61 char *
  62 __glXGetStringFromServer(Display * dpy, int opcode, CARD32 glxCode,
  63                          CARD32 for_whom, CARD32 name)
  64 {
  65    xGLXGenericGetStringReq *req;
  66    xGLXSingleReply reply;
  67    int length;
  68    int numbytes;
  69    char *buf;
  70
  71
  72    LockDisplay(dpy);
  73
  74
  75    /* All of the GLX protocol requests for getting a string from the server
  76     * look the same.  The exact meaning of the for_whom field is usually
  77     * either the screen number (for glXQueryServerString) or the context tag
  78     * (for GLXSingle).
  79     */
  80
  81    GetReq(GLXGenericGetString, req);
  82    req->reqType = opcode;
  83    req->glxCode = glxCode;
  84    req->for_whom = for_whom;
  85    req->name = name;
  86
  87    _XReply(dpy, (xReply *) & reply, 0, False);
  88
  89    length = reply.length * 4;
  90    numbytes = reply.size;
  91
  92    buf = (char *) Xmalloc(numbytes);
  93    if (buf != NULL) {
  94       _XRead(dpy, buf, numbytes);
  95       length -= numbytes;
  96    }
  97
  98    _XEatData(dpy, length);
  99
 100    UnlockDisplay(dpy);
 101    SyncHandle();
 102
 103    return buf;
 104 }