[rac] Temporarily copy libaddressinput to Chrome.

third_party/libaddressinput/chromium/cpp/include/libaddressinput/callback.h

+// Copyright (C) 2013 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// An object to store a pointer to a method in an object with the following
+// signature:
+//
+//    void Observer::ObserveEvent(bool success,
+//                                const Key& key,
+//                                const Data& data);
+
+#ifndef I18N_ADDRESSINPUT_CALLBACK_H_
+#define I18N_ADDRESSINPUT_CALLBACK_H_
+
+#include <cassert>
+#include <cstddef>
+
+namespace i18n {
+namespace addressinput {
+
+// Stores a pointer to a method in an object. Sample usage:
+//    class MyClass {
+//     public:
+//      typedef Callback<MyType, MyDataType> MyCallback;
+//
+//      void GetDataAsynchronously() {
+//        scoped_ptr<MyCallback> callback(BuildCallback(
+//            this, &MyClass::OnDataReady));
+//        bool success = ...
+//        MyKeyType key = ...
+//        MyDataType data = ...
+//        (*callback)(success, key, data);
+//      }
+//
+//      void OnDataReady(bool success,
+//                       const MyKeyType& key,
+//                       const MyDataType& data) {
+//        ...
+//      }
+//    };
+template <typename Key, typename Data>
+class Callback {
+ public:
+  virtual ~Callback() {}
+
+  virtual void operator()(bool success,
+                          const Key& key,
+                          const Data& data) const = 0;
+};
+
+namespace {
+
+template <typename Observer, typename Key, typename Data>
+class CallbackImpl : public Callback<Key, Data> {
+ public:
+  typedef void (Observer::*ObserveEvent)(bool, const Key&, const Data&);
+
+  CallbackImpl(Observer* observer, ObserveEvent observe_event)
+      : observer_(observer),
+        observe_event_(observe_event) {
+    assert(observer_ != NULL);
+    assert(observe_event_ != NULL);
+  }
+
+  virtual ~CallbackImpl() {}
+
+  virtual void operator()(bool success,
+                          const Key& key,
+                          const Data& data) const {
+    (observer_->*observe_event_)(success, key, data);
+  }
+
+ private:
+  Observer* observer_;
+  ObserveEvent observe_event_;
+};
+
+}  // namespace
+
+// Returns a callback to |observer->observe_event| method. The caller owns the
+// result.
+template <typename Observer, typename Key, typename Data>
+Callback<Key, Data>* BuildCallback(
+    Observer* observer,
+    void (Observer::*observe_event)(bool, const Key&, const Data&)) {
+  return new CallbackImpl<Observer, Key, Data>(observer, observe_event);
+}
+
+}  // namespace addressinput
+}  // namespace i18n
+
+#endif  // I18N_ADDRESSINPUT_CALLBACK_H_