Report more details on argument conversion failure

Will hopefully help users and developers to debug conversion problems more easily. For now prints .toString() of the JS object and the GITypeTag of the expected data. In the future the exception could output the GType information.
piotras · Aug 28, 2012 · c9722a5 · c9722a5
1 parent 764c00b
commit c9722a5
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Showing 3 changed files with 39 additions and 5 deletions.
diff --git a/src/function.cc b/src/function.cc
@@ -141,21 +141,31 @@ v8::Handle<v8::Value> Func::CallAndGetPtr(GObject *obj, GIFunctionInfo *info, co
          * o.__call__("func_name", args) VS o.func_name(args) */
         const int real_arg_idx = ignore_function_name ? i : i + offset_;
         GIArgInfo *arg = g_callable_info_get_arg(info, i);
+        GITypeInfo *arg_type_info = g_arg_info_get_type(arg);
         GIDirection dir = g_arg_info_get_direction(arg);
+
         if(dir == GI_DIRECTION_IN || dir == GI_DIRECTION_INOUT) {
             if(!Args::ToGType(args[real_arg_idx], &in_args[in_c], arg, NULL, FALSE)) {
-                return BAD_ARGS("IN arguments conversion failed");
+                gchar *instance_desc = Util::utf8StringFromValue(args[real_arg_idx]);
+                gchar *exc_msg = g_strdup_printf("Failed to convert argument %d \"%s\" to GI Type tag \"%s\"",
+                                                 in_c, instance_desc, g_type_tag_to_string(g_type_info_get_tag(arg_type_info)));
+                g_free(instance_desc);
+                return BAD_ARGS(exc_msg);
             }
-            //printf("IN ARG (%d) '%s' \n", in_c, in_args[in_c].v_string);
             in_c++;
         }
         if(dir == GI_DIRECTION_OUT || dir == GI_DIRECTION_INOUT) { 
             if(!Args::ToGType(args[real_arg_idx], &out_args[out_c], arg, NULL, TRUE)) {
-                return BAD_ARGS("OUT arguments conversion failed");
+                gchar *instance_desc = Util::utf8StringFromValue(args[real_arg_idx]);
+                gchar *exc_msg = g_strdup_printf("Failed to convert output %d \"%s\" to GI Type tag \"%s\"",
+                                                 out_c, instance_desc, g_type_tag_to_string(g_type_info_get_tag(arg_type_info)));
+                g_free(instance_desc);
+                return BAD_ARGS(exc_msg);
             }
             out_c++;
         }
         g_base_info_unref(arg);
+        g_base_info_unref(arg_type_info);
     }
 
     GError *error = NULL;

diff --git a/src/util.cc b/src/util.cc
@@ -2,7 +2,6 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
-#include <glib.h>
 
 static char *_format_message(const char *fmt, va_list args)
 {
@@ -28,3 +27,17 @@ extern "C" void debug_printf(const char *fmt, ...)
 	printf("%s", msg);
 	g_free(msg);
 }
+
+namespace gir {
+namespace Util {
+
+gchar *utf8StringFromValue(v8::Handle<v8::Value> value)
+{
+    v8::Local<v8::String> string = value->ToString();
+    gchar *buffer = g_new(gchar, string->Utf8Length());
+    string->WriteUtf8(buffer);
+    return buffer;
+}
+
+}
+}
diff --git a/src/util.h b/src/util.h
@@ -1,13 +1,16 @@
 #ifndef GIR_UTIL_H
 #define GIR_UTIL_H
 
+#include <glib.h>
+#include <v8.h>
+
 #define GIR_DEFINE_CONSTANT(target, name, constant)                      \
   (target)->Set(v8::String::NewSymbol(name),                              \
             v8::Integer::New(constant),                               \
             static_cast<v8::PropertyAttribute>(v8::ReadOnly|v8::DontDelete))
 
 #define BAD_ARGS(_msg) \
-    ThrowException(Exception::Error(String::New(_msg)));
+    ThrowException(Exception::TypeError(String::New(_msg)));
 
 #define NO_UNDERLYING_OBJECT() \
     ThrowException(Exception::Error(String::New("no underlying object found")));
@@ -17,4 +20,12 @@
 
 extern "C" void debug_printf(const char *fmt, ...);
 
+namespace gir {
+
+namespace Util {
+    gchar *utf8StringFromValue(v8::Handle<v8::Value> value);
+}
+
+}
+
 #endif