Make has_property_on_prototype fallible

2 files changed, 33 insertions, 15 deletions

diff --git a/components/script/dom/bindings/codegen/CodegenRust.py b/components/script/dom/bindings/codegen/CodegenRust.py
index 8e04fc76a10..4eb02f796e0 100644
--- a/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/components/script/dom/bindings/codegen/CodegenRust.py
@@ -4724,10 +4724,17 @@ class CGDOMJSProxyHandler_getOwnPropertyDescriptor(CGAbstractExternMethod):
             # Once we start supporting OverrideBuiltins we need to make
             # ResolveOwnProperty or EnumerateOwnProperties filter out named
             # properties that shadow prototype properties.
-            namedGet = ("\n" +
-                        "if RUST_JSID_IS_STRING(id) && !has_property_on_prototype(cx, proxy, id) {\n" +
-                        CGIndenter(CGProxyNamedGetter(self.descriptor, templateValues)).define() + "\n" +
-                        "}\n")
+            namedGet = """
+if RUST_JSID_IS_STRING(id) {
+    let mut has_on_proto = false;
+    if !has_property_on_prototype(cx, proxy, id, &mut has_on_proto) {
+        return false;
+    }
+    if !has_on_proto {
+        %s
+    }
+}
+""" % CGIndenter(CGProxyNamedGetter(self.descriptor, templateValues), 8).define()
         else:
             namedGet = ""
 
@@ -4952,12 +4959,20 @@ class CGDOMJSProxyHandler_hasOwn(CGAbstractExternMethod):
 
         namedGetter = self.descriptor.operations['NamedGetter']
         if namedGetter:
-            named = ("if RUST_JSID_IS_STRING(id) && !has_property_on_prototype(cx, proxy, id) {\n" +
-                     CGIndenter(CGProxyNamedGetter(self.descriptor)).define() + "\n" +
-                     "    *bp = found;\n"
-                     "    return true;\n"
-                     "}\n" +
-                     "\n")
+            named = """\
+if RUST_JSID_IS_STRING(id) {
+    let mut has_on_proto = false;
+    if !has_property_on_prototype(cx, proxy, id, &mut has_on_proto) {
+        return false;
+    }
+    if !has_on_proto {
+        %s
+        *bp = found;
+        return true;
+    }
+}
+
+""" % CGIndenter(CGProxyNamedGetter(self.descriptor), 8).define()
         else:
             named = ""
 
diff --git a/components/script/dom/bindings/utils.rs b/components/script/dom/bindings/utils.rs
index 53b69fc0b40..666dba519a4 100644
--- a/components/script/dom/bindings/utils.rs
+++ b/components/script/dom/bindings/utils.rs
@@ -284,12 +284,15 @@ pub fn set_dictionary_property(cx: *mut JSContext,
 /// Returns whether `proxy` has a property `id` on its prototype.
 pub unsafe fn has_property_on_prototype(cx: *mut JSContext,
                                         proxy: HandleObject,
-                                        id: HandleId)
+                                        id: HandleId,
+                                        found: &mut bool)
                                         -> bool {
-    let mut found = false;
-    !get_property_on_prototype(
-        cx, proxy, id, &mut found,
-        MutableHandleValue::from_marked_location(ptr::null_mut())) || found
+    rooted!(in(cx) let mut proto = ptr::null_mut());
+    if !JS_GetPrototype(cx, proxy, proto.handle_mut()) {
+        return false;
+    }
+    assert!(!proto.is_null());
+    JS_HasPropertyById(cx, proto.handle(), id, found)
 }
 
 /// Drop the resources held by reserved slots of a global object