Mojo JS Bindings: Mojo handles need a toString() method

mojo/bindings/js/handle.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/bindings/js/handle.h"
 
+#include <sstream>
 #include "mojo/bindings/js/handle_close_observer.h"
 
 namespace mojo {
 namespace js {
 
 gin::WrapperInfo HandleWrapper::kWrapperInfo = { gin::kEmbedderNativeGin };
 
 HandleWrapper::HandleWrapper(MojoHandle handle)
     : handle_(mojo::Handle(handle)) {
 }
 
 HandleWrapper::~HandleWrapper() {
   NotifyCloseObservers();
 }
 
+std::string HandleWrapper::ToString() {
+  std::ostringstream oss;
+  oss << "[mojo::Handle ";
+  if (handle_.is_valid())
+    oss << handle_.get().value();
+  else
+    oss << "null";
+  oss << " " << std::hex << this;

[abarth-chromium, 2014/10/24 17:13:27]

I don't think you want to leak the address of |this|.  That can be a security
risk because it leaks where things are arranged in memory...

[hansmuller, 2014/10/24 18:14:02]

OK, I've removed that.

+  oss << "]";
+  return oss.str();
+}
+
+gin::ObjectTemplateBuilder HandleWrapper::GetObjectTemplateBuilder(
+    v8::Isolate* isolate) {
+  return Wrappable<HandleWrapper>::GetObjectTemplateBuilder(isolate)
+      .SetMethod("toString", &HandleWrapper::ToString);
+}
+
 void HandleWrapper::Close() {
   NotifyCloseObservers();
   handle_.reset();
 }
 
 void HandleWrapper::AddCloseObserver(HandleCloseObserver* observer) {
   close_observers_.AddObserver(observer);
 }
 
 void HandleWrapper::RemoveCloseObserver(HandleCloseObserver* observer) {
@@ skipping 30 matching lines @@
   gin::Handle<mojo::js::HandleWrapper> handle;
   if (!Converter<gin::Handle<mojo::js::HandleWrapper> >::FromV8(
       isolate, val, &handle))
     return false;
 
   *out = handle->get();
   return true;
 }
 
 }  // namespace gin