glx/apple: locate dispatch table functions to wrap by name

Avoid reaching into the dispatch table internals (and thus having to deal
with the complexities of remap etc.) by identifying functions to wrap by
name.

See:
https://lists.freedesktop.org/archives/mesa-dev/2015-June/086721.html et seq.
https://bugs.freedesktop.org/show_bug.cgi?id=90311

Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

src/glx/apple/apple_glapi.c

@@ -41,7 +41,6 @@
 #include "main/glheader.h"
 #include "glapi.h"
 #include "glapitable.h"
-#include "main/dispatch.h"
 
 #include "apple_glx.h"
 #include "apple_xgl_api.h"
@@ -61,12 +60,11 @@ static void _apple_glapi_create_table(void) {
     assert(__applegl_api);
     memcpy(__applegl_api, __ogl_framework_api, sizeof(struct _glapi_table));
 
-    SET_ReadPixels(__applegl_api, __applegl_glReadPixels);
-    SET_CopyPixels(__applegl_api, __applegl_glCopyPixels);
-    SET_CopyColorTable(__applegl_api, __applegl_glCopyColorTable);
-    SET_DrawBuffer(__applegl_api, __applegl_glDrawBuffer);
-    SET_DrawBuffers(__applegl_api, __applegl_glDrawBuffers);
-    SET_Viewport(__applegl_api, __applegl_glViewport);
+    _glapi_table_patch(__applegl_api, "ReadPixels", __applegl_glReadPixels);
+    _glapi_table_patch(__applegl_api, "CopyPixels", __applegl_glCopyPixels);
+    _glapi_table_patch(__applegl_api, "CopyColorTable", __applegl_glCopyColorTable);
+    _glapi_table_patch(__applegl_api, "DrawBuffers", __applegl_glDrawBuffer);
+    _glapi_table_patch(__applegl_api, "Viewport", __applegl_glViewport);
 }
 
 void apple_glapi_set_dispatch(void) {

src/mapi/glapi/gen/gl_gentable.py

@@ -56,6 +56,7 @@ header = """/* GLXEXT is the define used in the xserver when the GLX extension i
 #endif
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 
 #include "main/glheader.h"
 
@@ -144,6 +145,19 @@ _glapi_create_table_from_handle(void *handle, const char *symbol_prefix) {
 
     return disp;
 }
+
+void
+ _glapi_table_patch(struct _glapi_table *table, const char *name, void *wrapper)
+{
+   for (int func_index = 0; func_index < GLAPI_TABLE_COUNT; ++func_index) {
+      if (!strcmp(_glapi_table_func_names[func_index], name)) {
+            ((void **)table)[func_index] = wrapper;
+            return;
+         }
+   }
+   fprintf(stderr, "could not patch %s in dispatch table\\n", name);
+}
+
 """
 
 

src/mapi/glapi/glapi.h

@@ -161,6 +161,9 @@ _glapi_get_proc_name(unsigned int offset);
 #if defined(GLX_USE_APPLEGL) || defined(GLX_USE_WINDOWSGL)
 _GLAPI_EXPORT struct _glapi_table *
 _glapi_create_table_from_handle(void *handle, const char *symbol_prefix);
+
+_GLAPI_EXPORT void
+_glapi_table_patch(struct _glapi_table *, const char *name, void *wrapper);
 #endif