Mojo cpp bindings: add support for validating incoming messages.

mojo/public/cpp/bindings/lib/validator_chain.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/public/cpp/bindings/lib/validator_chain.h"
+
+#include <algorithm>
+
+namespace mojo {
+namespace internal {
+
+ValidatorChain::ValidatorChain(MessageReceiver* sink) : sink_(sink) {
+}
+
+ValidatorChain::ValidatorChain(RValue other) : sink_(other.object->sink_) {
+  other.object->sink_ = NULL;
+  validators_.swap(other.object->validators_);
+}
+
+ValidatorChain& ValidatorChain::operator=(RValue other) {
+  std::swap(sink_, other.object->sink_);
+  validators_.swap(other.object->validators_);
+  return *this;
+}
+
+ValidatorChain::~ValidatorChain() {
+  for (std::vector<MessageValidator*>::iterator iter = validators_.begin();
+       iter != validators_.end();
+       ++iter) {
+    delete *iter;
+  }
+}
+
+ValidatorChain& ValidatorChain::Append(MessageValidator* validator) {
+  if (!validators_.empty())
+    validators_.back()->set_next(validator);
+  validators_.push_back(validator);
+
+  return *this;
+}
+
+ValidatorChain& ValidatorChain::Append(NoValidator* validator) {
+  delete validator;
+  return *this;
+}
+
+MessageReceiver* ValidatorChain::GetHead() {
+  assert(sink_);
+
+  if (validators_.empty())
+    return sink_;
+
+  validators_.back()->set_next(sink_);
+  return validators_.front();
+}
+
+}  // namespace internal
+}  // namespace mojo