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"),
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  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
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  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     CARD8 reqType;
  45     CARD8 glxCode;
  46     CARD16 length B16;
  47     CARD32 for_whom B32;
  48     CARD32 name B32;
  49 } xGLXGenericGetStringReq;
  50
  51 /* These defines are only needed to make the GetReq macro happy.
  52  */
  53 #define sz_xGLXGenericGetStringReq 12
  54 #define X_GLXGenericGetString 0
  55
  56 /**
  57  * Query the Server GLX string and cache it in the display private.
  58  * This routine will allocate the necessay space for the string.
  59  */
  60 char *
  61 __glXGetStringFromServer( Display * dpy, int opcode, CARD32 glxCode,
  62                           CARD32 for_whom, CARD32 name )
  63 {
  64     xGLXGenericGetStringReq *req;
  65     xGLXSingleReply reply;
  66     int length;
  67     int numbytes;
  68     char * buf;
  69
  70
  71     LockDisplay( dpy );
  72
  73
  74     /* All of the GLX protocol requests for getting a string from the server
  75      * look the same.  The exact meaning of the for_whom field is usually
  76      * either the screen number (for glXQueryServerString) or the context tag
  77      * (for GLXSingle).
  78      */
  79
  80     GetReq( GLXGenericGetString, req );
  81     req->reqType = opcode;
  82     req->glxCode = glxCode;
  83     req->for_whom = for_whom;
  84     req->name = name;
  85
  86     _XReply( dpy, (xReply *) & reply, 0, False );
  87
  88     length = reply.length * 4;
  89     numbytes = reply.size;
  90
  91     buf = (char *) Xmalloc( numbytes );
  92     if ( buf != NULL ) {
  93         _XRead( dpy, buf, numbytes );
  94         length -= numbytes;
  95     }
  96
  97     _XEatData( dpy, length );
  98
  99     UnlockDisplay( dpy );
 100     SyncHandle();
 101
 102     return buf;
 103 }