[gin] Allow interceptors to signal whether a they intercepted something

TEST=InterceptorTest.BypassInterceptor*
R=abarth@chromium.org,raymes@chromium.org
BUG=none

Review URL: https://codereview.chromium.org/467243002

Cr-Commit-Position: refs/heads/master@{#289325}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@289325 0039d316-1c4b-4281-b951-d872f2087c98

gin/interceptor.cc

@@ -26,9 +26,11 @@ v8::Local<v8::Value> NamedPropertyInterceptor::GetNamedProperty(
   return v8::Local<v8::Value>();
 }
 
-void NamedPropertyInterceptor::SetNamedProperty(v8::Isolate* isolate,
+bool NamedPropertyInterceptor::SetNamedProperty(v8::Isolate* isolate,
                                                 const std::string& property,
-                                                v8::Local<v8::Value> value) {}
+                                                v8::Local<v8::Value> value) {
+  return false;
+}
 
 std::vector<std::string> NamedPropertyInterceptor::EnumerateNamedProperties(
     v8::Isolate* isolate) {
@@ -51,10 +53,12 @@ v8::Local<v8::Value> IndexedPropertyInterceptor::GetIndexedProperty(
   return v8::Local<v8::Value>();
 }
 
-void IndexedPropertyInterceptor::SetIndexedProperty(
+bool IndexedPropertyInterceptor::SetIndexedProperty(
     v8::Isolate* isolate,
     uint32_t index,
-    v8::Local<v8::Value> value) {}
+    v8::Local<v8::Value> value) {
+  return false;
+}
 
 std::vector<uint32_t> IndexedPropertyInterceptor::EnumerateIndexedProperties(
     v8::Isolate* isolate) {

gin/interceptor.h

@@ -25,7 +25,8 @@ class GIN_EXPORT NamedPropertyInterceptor {
 
   virtual v8::Local<v8::Value> GetNamedProperty(v8::Isolate* isolate,
                                                 const std::string& property);
-  virtual void SetNamedProperty(v8::Isolate* isolate,
+  // Return true if the set was interecepted.
+  virtual bool SetNamedProperty(v8::Isolate* isolate,
                                 const std::string& property,
                                 v8::Local<v8::Value> value);
   virtual std::vector<std::string> EnumerateNamedProperties(
@@ -45,7 +46,8 @@ class GIN_EXPORT IndexedPropertyInterceptor {
 
   virtual v8::Local<v8::Value> GetIndexedProperty(v8::Isolate* isolate,
                                                   uint32_t index);
-  virtual void SetIndexedProperty(v8::Isolate* isolate,
+  // Return true if the set was interecepted.
+  virtual bool SetIndexedProperty(v8::Isolate* isolate,
                                   uint32_t index,
                                   v8::Local<v8::Value> value);
   virtual std::vector<uint32_t> EnumerateIndexedProperties(

gin/interceptor_unittest.cc

@@ -42,12 +42,14 @@ class MyInterceptor : public Wrappable<MyInterceptor>,
       return v8::Local<v8::Value>();
     }
   }
-  virtual void SetNamedProperty(v8::Isolate* isolate,
+  virtual bool SetNamedProperty(v8::Isolate* isolate,
                                 const std::string& property,
                                 v8::Local<v8::Value> value) OVERRIDE {
-    if (property != "value")
-      return;
-    ConvertFromV8(isolate, value, &value_);
+    if (property == "value") {
+      ConvertFromV8(isolate, value, &value_);
+      return true;
+    }
+    return false;
   }
   virtual std::vector<std::string> EnumerateNamedProperties(
       v8::Isolate* isolate) OVERRIDE {
@@ -64,12 +66,15 @@ class MyInterceptor : public Wrappable<MyInterceptor>,
       return ConvertToV8(isolate, value_);
     return v8::Local<v8::Value>();
   }
-  virtual void SetIndexedProperty(v8::Isolate* isolate,
+  virtual bool SetIndexedProperty(v8::Isolate* isolate,
                                   uint32_t index,
                                   v8::Local<v8::Value> value) OVERRIDE {
-    if (index != 0)
-      return;
-    ConvertFromV8(isolate, value, &value_);
+    if (index == 0) {
+      ConvertFromV8(isolate, value, &value_);
+      return true;
+    }
+    // Don't allow bypassing the interceptor.
+    return true;
   }
   virtual std::vector<uint32_t> EnumerateIndexedProperties(v8::Isolate* isolate)
       OVERRIDE {
@@ -172,4 +177,20 @@ TEST_F(InterceptorTest, IndexedInterceptor) {
       "   else obj[0] = 191; })");
 }
 
+TEST_F(InterceptorTest, BypassInterceptorAllowed) {
+  RunInterceptorTest(
+      "(function (obj) {"
+      "   obj.value = 191 /* make test happy */;"
+      "   obj.foo = 23;"
+      "   if (obj.foo !== 23) throw 'FAIL'; })");
+}
+
+TEST_F(InterceptorTest, BypassInterceptorForbidden) {
+  RunInterceptorTest(
+      "(function (obj) {"
+      "   obj.value = 191 /* make test happy */;"
+      "   obj[1] = 23;"
+      "   if (obj[1] === 23) throw 'FAIL'; })");
+}
+
 }  // namespace gin

gin/object_template_builder.cc

@@ -69,7 +69,8 @@ void NamedPropertySetter(v8::Local<v8::String> property,
     return;
   std::string name;
   ConvertFromV8(isolate, property, &name);
-  interceptor->SetNamedProperty(isolate, name, value);
+  if (interceptor->SetNamedProperty(isolate, name, value))
+    info.GetReturnValue().Set(value);
 }
 
 void NamedPropertyQuery(v8::Local<v8::String> property,
@@ -114,7 +115,8 @@ void IndexedPropertySetter(uint32_t index,
       IndexedInterceptorFromV8(isolate, info.Holder());
   if (!interceptor)
     return;
-  interceptor->SetIndexedProperty(isolate, index, value);
+  if (interceptor->SetIndexedProperty(isolate, index, value))
+    info.GetReturnValue().Set(value);
 }
 
 void IndexedPropertyEnumerator(