[gjs] GIRepositoryFunction: make it inherit from Function

[Giovanni Campagna <gcampagna src gnome org>]

commit cb55783db06a35040ac7a94718cc0ed46f1f7fe3
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Tue Apr 5 20:50:13 2011 +0200

    GIRepositoryFunction: make it inherit from Function
    
    Set the prototype of GIRepositoryFunction to Function.prototype, so
    methods bind(), call() and apply() are available, and instanceof
    reports correct results.
    Also ensures that method invocations are applied on GObjects of the
    correct type, and adds an explicit toString() method to GIRepositoryFunction,
    since Function.prototype.toString() throws when called on objects
    of the wrong class.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=646852

 gi/function.c |   62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 60 insertions(+), 2 deletions(-)
---
diff --git a/gi/function.c b/gi/function.c
index 379cd9d..aa17644 100644
--- a/gi/function.c
+++ b/gi/function.c
@@ -477,7 +477,20 @@ gjs_invoke_c_function(JSContext      *context,
         } else if (type == GI_INFO_TYPE_UNION) {
             in_arg_cvalues[0].v_pointer = gjs_c_union_from_union(context, obj);
         } else { /* by fallback is always object */
+            GType gtype;
+
             in_arg_cvalues[0].v_pointer = gjs_g_object_from_object(context, obj);
+
+            gtype = g_registered_type_info_get_g_type ((GIRegisteredTypeInfo *)container);
+            if (!g_type_is_a (G_TYPE_FROM_INSTANCE (in_arg_cvalues[0].v_pointer),
+                              gtype)) {
+                gjs_throw(context,
+                          "Expected type '%s' but got '%s'",
+                          g_type_name(gtype),
+                          g_type_name(G_TYPE_FROM_INSTANCE(in_arg_cvalues[0].v_pointer)));
+                failed = TRUE;
+                goto release;
+            }
         }
         in_arg_pointers[0] = &in_arg_cvalues[0];
         ++in_args_pos;
@@ -954,6 +967,45 @@ function_finalize(JSContext *context,
     g_slice_free(Function, priv);
 }
 
+static JSBool
+function_to_string (JSContext *context,
+                    guint      argc,
+                    jsval     *vp)
+{
+    Function *priv;
+    gchar *string;
+    gboolean free;
+    JSObject *self;
+    jsval retval;
+    JSBool ret = JS_FALSE;
+
+    self = JS_THIS_OBJECT(context, vp);
+    if (!self) {
+        gjs_throw(context, "this cannot be null");
+        return JS_FALSE;
+    }
+
+    priv = priv_from_js (context, self);
+
+    if (priv == NULL) {
+        string = "function () {\n}";
+        free = FALSE;
+    } else {
+        string = g_strdup_printf("function %s(){\n\t[native code]\n}",
+                                 g_base_info_get_name ((GIBaseInfo *) priv->info));
+        free = TRUE;
+    }
+
+    if (gjs_string_from_utf8(context, string, -1, &retval)) {
+        JS_SET_RVAL(context, vp, retval);
+        ret = JS_TRUE;
+    }
+
+    if (free)
+        g_free(string);
+    return ret;
+}
+
 /* The bizarre thing about this vtable is that it applies to both
  * instances of the object, and to the prototype that instances of the
  * class have.
@@ -986,8 +1038,11 @@ static JSPropertySpec gjs_function_proto_props[] = {
     { NULL }
 };
 
+/* The original Function.prototype.toString complains when
+   given a GIRepository function as an argument */
 static JSFunctionSpec gjs_function_proto_funcs[] = {
-    { NULL }
+    JS_FN("toString", function_to_string, 0, 0),
+    JS_FS_END
 };
 
 static gboolean
@@ -1107,8 +1162,11 @@ function_new(JSContext      *context,
     if (!gjs_object_has_property(context, global, gjs_function_class.name)) {
         JSObject *prototype;
         JSObject *parent_proto;
+        jsval native_function;
 
-        parent_proto = NULL;
+        JS_GetProperty(context, global, "Function", &native_function);
+        /* We take advantage from that fact that Function.__proto__ is Function.prototype */
+        parent_proto = JS_GetPrototype(context, JSVAL_TO_OBJECT(native_function));
 
         prototype = JS_InitClass(context, global,
                                  /* parent prototype JSObject* for