RFC: Add epoxy_set_resolver_failure_handler()

include/epoxy/gl.h

@@ -92,6 +92,20 @@ EPOXY_PUBLIC bool epoxy_has_gl_extension(const char *extension);
 EPOXY_PUBLIC bool epoxy_is_desktop_gl(void);
 EPOXY_PUBLIC int epoxy_gl_version(void);
 
+/*
+ * the type of the stub function that the failure handler must return;
+ * this function will be called on subsequent calls to the same bogus
+ * function name
+ */
+typedef void (*epoxy_resolver_stub_t)(void);
+
+/* the type of the failure handler itself */
+typedef epoxy_resolver_stub_t
+(*epoxy_resolver_failure_handler_t)(const char *name);
+
+EPOXY_PUBLIC epoxy_resolver_failure_handler_t
+epoxy_set_resolver_failure_handler(epoxy_resolver_failure_handler_t handler);
+
 EPOXY_END_DECLS
 
 #endif /* EPOXY_GL_H */

src/dispatch_common.c

@@ -845,3 +845,21 @@ WRAPPER(epoxy_glEnd)(void)
 
 PFNGLBEGINPROC epoxy_glBegin = epoxy_glBegin_wrapped;
 PFNGLENDPROC epoxy_glEnd = epoxy_glEnd_wrapped;
+
+epoxy_resolver_failure_handler_t epoxy_resolver_failure_handler;
+
+epoxy_resolver_failure_handler_t
+epoxy_set_resolver_failure_handler(epoxy_resolver_failure_handler_t handler)
+{
+#ifdef _WIN32
+    return InterlockedExchangePointer(&epoxy_resolver_failure_handler,
+				      handler);
+#else
+    epoxy_resolver_failure_handler_t old;
+    pthread_mutex_lock(&api.mutex);
+    old = epoxy_resolver_failure_handler;
+    epoxy_resolver_failure_handler = handler;
+    pthread_mutex_unlock(&api.mutex);
+    return old;
+#endif
+}

src/dispatch_common.h

@@ -172,6 +172,8 @@ bool epoxy_extension_in_string(const char *extension_list, const char *ext);
 extern void UNWRAPPED_PROTO(glBegin_unwrapped)(GLenum primtype);
 extern void UNWRAPPED_PROTO(glEnd_unwrapped)(void);
 
+extern epoxy_resolver_failure_handler_t epoxy_resolver_failure_handler;
+
 #if USING_DISPATCH_TABLE
 void gl_init_dispatch_table(void);
 void gl_switch_to_dispatch_table(void);

src/gen_dispatch.py

@@ -709,6 +709,10 @@ def write_provider_resolver(self):
         self.outln('    }')
         self.outln('')
 
+        self.outln('    if (epoxy_resolver_failure_handler)')
+        self.outln('        return epoxy_resolver_failure_handler(name);')
+        self.outln('')
+
         # If the function isn't provided by any known extension, print
         # something useful for the poor application developer before
         # aborting.  (In non-epoxy GL usage, the app developer would