src/video/x11/SDL_x11dyn.c
author Ryan C. Gordon <icculus@icculus.org>
Sat, 05 Nov 2005 19:53:37 +0000
changeset 1168 045f186426e1
child 1171 f84c6f1397cd
permissions -rw-r--r--
Dynamically load X11 libraries like we currently do for alsa, esd, etc.
This allows you to run an SDL program on a system without Xlib, since it'll
just report the x11 target unavailable at runtime.
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2004 Sam Lantinga
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Library General Public
     7     License as published by the Free Software Foundation; either
     8     version 2 of the License, or (at your option) any later version.
     9 
    10     This library is distributed in the hope that it will be useful,
    11     but WITHOUT ANY WARRANTY; without even the implied warranty of
    12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13     Library General Public License for more details.
    14 
    15     You should have received a copy of the GNU Library General Public
    16     License along with this library; if not, write to the Free
    17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21 */
    22 
    23 /*#define DEBUG_DYNAMIC_X11 1*/
    24 
    25 #include "SDL_x11dyn.h"
    26 
    27 #ifdef DEBUG_DYNAMIC_X11
    28 #include <stdio.h>
    29 #endif
    30 
    31 #ifdef X11_DYNAMIC
    32 #include <dlfcn.h>
    33 #include "SDL_name.h"
    34 #include "SDL_loadso.h"
    35 static const char *x11_library = X11_DYNAMIC;
    36 static void *x11_handle = NULL;
    37 static const char *x11ext_library = X11EXT_DYNAMIC;
    38 static void *x11ext_handle = NULL;
    39 
    40 static void *X11_GetSym(const char *fnname, int *rc)
    41 {
    42 	void *fn = NULL;
    43 	if (*rc) {  /* haven't already failed on a previous lookup? */
    44 		fn = SDL_LoadFunction(x11_handle, fnname);
    45 		#if DEBUG_DYNAMIC_X11
    46 		if (fn != NULL)
    47 			printf("X11: Found '%s' in libX11 (%p)\n", fnname, fn);
    48 		#endif
    49 
    50 		if (fn == NULL) {  /* not found? Check libX11ext ... */
    51 			fn = SDL_LoadFunction(x11ext_handle, fnname);
    52 			#if DEBUG_DYNAMIC_X11
    53 			if (fn != NULL)
    54 				printf("X11: Found '%s' in libXext (%p)\n", fnname, fn);
    55 			else
    56 				printf("X11: Symbol '%s' NOT FOUND!\n", fnname);
    57 			#endif
    58 		}
    59 		*rc = (fn != NULL);
    60 	}
    61 
    62 	return fn;
    63 }
    64 #endif  /* defined X11_DYNAMIC */
    65 
    66 /* Define all the function pointers... */
    67 #define SDL_X11_SYM(ret,fn,params) ret (*p##fn) params = NULL;
    68 #include "SDL_x11sym.h"
    69 #undef SDL_X11_SYM
    70 
    71 static int x11_load_refcount = 0;
    72 
    73 void SDL_X11_UnloadSymbols(void)
    74 {
    75 	/* Don't actually unload if more than one module is using the libs... */
    76 	if (x11_load_refcount > 0) {
    77 		if (--x11_load_refcount == 0) {
    78 			/* set all the function pointers to NULL. */
    79 			#define SDL_X11_SYM(ret,fn,params) p##fn = NULL;
    80 			#include "SDL_x11sym.h"
    81 			#undef SDL_X11_SYM
    82 
    83 			#ifdef X11_DYNAMIC
    84 			if (x11_handle != NULL) {
    85 				SDL_UnloadObject(x11_handle);
    86 				x11_handle = NULL;
    87 			}
    88 			if (x11ext_handle != NULL) {
    89 				SDL_UnloadObject(x11ext_handle);
    90 				x11ext_handle = NULL;
    91 			}
    92 			#endif
    93 		}
    94 	}
    95 }
    96 
    97 /* returns non-zero if all needed symbols were loaded. */
    98 int SDL_X11_LoadSymbols(void)
    99 {
   100 	int rc = 1;
   101 
   102     /* deal with multiple modules (dga, x11, etc) needing these symbols... */
   103 	if (x11_load_refcount++ == 0) {
   104 		#ifdef X11_DYNAMIC
   105 			x11_handle = SDL_LoadObject(x11_library);
   106 			x11ext_handle = SDL_LoadObject(x11ext_library);
   107 			if ((x11_handle != NULL) && (x11ext_handle != NULL)) {
   108 				#define SDL_X11_SYM(r,fn,arg) p##fn = X11_GetSym(#fn, &rc);
   109 				#include "SDL_x11sym.h"
   110 				#undef SDL_X11_SYM
   111 			}
   112 
   113 			if (!rc)
   114 				SDL_X11_UnloadSymbols();  /* in case one of these loaded... */
   115 
   116 		#else
   117 			#define SDL_X11_SYM(r,fn,arg) p##fn = fn;
   118 			#include "SDL_x11sym.h"
   119 			#undef SDL_X11_SYM
   120 		#endif
   121 	}
   122 
   123 	return rc;
   124 }
   125 
   126 /* end of SDL_x11dyn.c ... */
   127