Mojo: Cancel WaitingCallbacks when their HandleWrappers are closed.

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 "base/logging.h"
+
 namespace gin {
 
 gin::WrapperInfo HandleWrapper::kWrapperInfo = { gin::kEmbedderNativeGin };
 
 HandleWrapper::HandleWrapper(MojoHandle handle)
     : handle_(mojo::Handle(handle)) {
 }
 
 HandleWrapper::~HandleWrapper() {
+  NotifyCloseObservers();
+}
+
+void HandleWrapper::Close() {
+  NotifyCloseObservers();
+  handle_.reset();
+}
+
+void HandleWrapper::AddCloseObserver(CloseObserver* observer) {
+  bool inserted = observers_.insert(observer).second;
+  DCHECK(inserted);
+}
+
+void HandleWrapper::RemoveCloseObserver(CloseObserver* observer) {
+  size_t removed = observers_.erase(observer);
+  DCHECK_EQ(removed, 1u);
+}
+
+void HandleWrapper::NotifyCloseObservers() {
+  for (std::set<CloseObserver*>::iterator it = observers_.begin();
+       it != observers_.end();) {
+    (*it++)->OnHandleClosed();

[abarth-chromium, 2014/09/03 05:21:55]

What if observers_ is modified during this iteration?

[Sam McNally, 2014/09/03 05:37:27]

Done.

+  }
+  observers_.clear();
 }
 
 v8::Handle<v8::Value> Converter<mojo::Handle>::ToV8(v8::Isolate* isolate,
                                                     const mojo::Handle& val) {
   if (!val.is_valid())
     return v8::Null(isolate);
   return HandleWrapper::Create(isolate, val.value()).ToV8();
 }
 
 bool Converter<mojo::Handle>::FromV8(v8::Isolate* isolate,
                                      v8::Handle<v8::Value> val,
                                      mojo::Handle* out) {
   if (val->IsNull()) {
     *out = mojo::Handle();
     return true;
   }
 
   gin::Handle<HandleWrapper> handle;
   if (!Converter<gin::Handle<HandleWrapper> >::FromV8(isolate, val, &handle))
     return false;
 
   *out = handle->get();
   return true;
 }
 
 }  // namespace gin