Mojo cpp bindings: add support for validating incoming messages.

mojo/public/cpp/bindings/lib/filter_chain.cc

Index: mojo/public/cpp/bindings/lib/filter_chain.cc
diff --git a/mojo/public/cpp/bindings/lib/filter_chain.cc b/mojo/public/cpp/bindings/lib/filter_chain.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7101eff13ff7aeb99be84acb6e1f246cf1e9d9f9
--- /dev/null
+++ b/mojo/public/cpp/bindings/lib/filter_chain.cc
@@ -0,0 +1,58 @@
+// 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/public/cpp/bindings/lib/filter_chain.h"
+
+#include <algorithm>
+
+namespace mojo {
+namespace internal {
+
+FilterChain::FilterChain(MessageReceiver* sink) : sink_(sink) {
+}
+
+FilterChain::FilterChain(RValue other) : sink_(other.object->sink_) {
+  other.object->sink_ = NULL;
+  filters_.swap(other.object->filters_);
+}
+
+FilterChain& FilterChain::operator=(RValue other) {
+  std::swap(sink_, other.object->sink_);
+  filters_.swap(other.object->filters_);
+  return *this;
+}
+
+FilterChain::~FilterChain() {
+  for (std::vector<MessageFilter*>::iterator iter = filters_.begin();
+       iter != filters_.end();
+       ++iter) {
+    delete *iter;
+  }
+}
+
+FilterChain& FilterChain::Append(MessageFilter* filter) {
+  if (!filters_.empty())
+    filters_.back()->set_sink(filter);
+  filters_.push_back(filter);
+
+  return *this;
+}
+
+FilterChain& FilterChain::Append(PassThroughFilter* filter) {
+  delete filter;
+  return *this;
+}
+
+MessageReceiver* FilterChain::GetHead() {
+  assert(sink_);
+
+  if (filters_.empty())
+    return sink_;
+
+  filters_.back()->set_sink(sink_);
+  return filters_.front();
+}
+
+}  // namespace internal
+}  // namespace mojo