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+// Copyright 2014 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef LIBCHROMEOS_BRILLO_BIND_LAMBDA_H_
+#define LIBCHROMEOS_BRILLO_BIND_LAMBDA_H_
+
+#include <base/bind.h>
+
+////////////////////////////////////////////////////////////////////////////////
+// This file is an extension to base/bind_internal.h and adds a RunnableAdapter
+// class specialization that wraps a functor (including lambda objects), so
+// they can be used in base::Callback/base::Bind constructs.
+// By including this file you will gain the ability to write expressions like:
+// base::Callback<int(int)> callback = base::Bind([](int value) {
+// return value * value;
+// });
+////////////////////////////////////////////////////////////////////////////////
+namespace base {
+namespace internal {
+
+// LambdaAdapter is a helper class that specializes on different function call
+// signatures and provides the RunType and Run() method required by
+// RunnableAdapter<> class.
+template <typename Lambda, typename Sig>
+class LambdaAdapter;
+
+// R(...)
+template <typename Lambda, typename R, typename... Args>
+class LambdaAdapter<Lambda, R(Lambda::*)(Args... args)> {
+ public:
+ typedef R(RunType)(Args...);
+ LambdaAdapter(Lambda lambda) : lambda_(lambda) {}
+ R Run(Args... args) { return lambda_(CallbackForward(args)...); }
+
+ private:
+ Lambda lambda_;
+};
+
+// R(...) const
+template <typename Lambda, typename R, typename... Args>
+class LambdaAdapter<Lambda, R(Lambda::*)(Args... args) const> {
+ public:
+ typedef R(RunType)(Args...);
+ LambdaAdapter(Lambda lambda) : lambda_(lambda) {}
+ R Run(Args... args) { return lambda_(CallbackForward(args)...); }
+
+ private:
+ Lambda lambda_;
+};
+
+template <typename Lambda>
+class RunnableAdapter
+ : public LambdaAdapter<Lambda, decltype(&Lambda::operator())> {
+ public:
+ explicit RunnableAdapter(Lambda lambda)
+ : LambdaAdapter<Lambda, decltype(&Lambda::operator())>(lambda) {}
+};
+
+} // namespace internal
+} // namespace base
+
+#endif // LIBCHROMEOS_BRILLO_BIND_LAMBDA_H_