mojo::Callback -> base::Callback

mojo/public/cpp/bindings/callback.h

 // 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.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_CALLBACK_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_CALLBACK_H_
 
-#include <memory>
-#include <type_traits>
-#include <utility>
-
-#include "base/memory/ref_counted.h"
-#include "mojo/public/cpp/bindings/lib/callback_internal.h"
-#include "mojo/public/cpp/bindings/lib/template_util.h"
+#include "base/callback.h"
 
 namespace mojo {
 
 template <typename Sig>
-class Callback;
+using Callback = base::Callback<Sig>;

[yzshen1, 2016/06/18 00:01:18]

Woohoo!

 
-// Represents a callback with any number of parameters and no return value. The
-// callback is executed by calling its Run() method. The callback may be "null",
-// meaning it does nothing.
-template <typename... Args>
-class Callback<void(Args...)> {
- public:
-  // An interface that may be implemented to define the Run() method.
-  struct Runnable {
-    virtual ~Runnable() {}
-    virtual void Run(
-        // ForwardType ensures String is passed as a const reference. Can't use
-        // universal refs (Args&&) here since this method itself isn't templated
-        // because it is a virtual interface. So we have to take the arguments
-        // all by value (except String which we take as a const reference due to
-        // ForwardType).
-        typename internal::Callback_ParamTraits<Args>::ForwardType...) = 0;
-  };
-
-  // Constructs a "null" callback that does nothing.
-  Callback() {}
-
-  // Constructs a callback that will run |runnable|. The callback takes
-  // ownership of |runnable|.
-  explicit Callback(Runnable* runnable) : sink_(new RunnableHolder(runnable)) {}
-
-  // As above, but can take an object that isn't derived from Runnable, so long
-  // as it has a compatible operator() or Run() method. operator() will be
-  // preferred if the type has both.
-  //
-  // The std::enable_if is used to disable this constructor if the argument is
-  // derived from Runnable. This is needed because the compiler will pick this
-  // constructor instead of the Runnable* one above when the argument is of the
-  // type of the derived class instead of down casted to a Runnable. i.e:
-  // class Foo : public Callback::Runnable {
-  //   ...
-  // };
-  // Callback cb(new Foo);
-  //
-  // The call site can fix this by using a static_cast to down cast to a
-  // Runnable*, but that shouldn't be necessary.
-  template <
-      typename Sink,
-      typename std::enable_if<!std::is_base_of<
-          Runnable,
-          typename std::remove_pointer<Sink>::type>::value>::type* = nullptr>
-  Callback(const Sink& sink) {
-    using sink_type = typename internal::Conditional<
-        internal::HasCompatibleCallOperator<Sink, Args...>::value,
-        FunctorAdapter<Sink>, RunnableAdapter<Sink>>::type;
-    sink_ = new RunnableHolder(new sink_type(sink));
-  }
-
-  // As above, but can take a compatible function pointer.
-  Callback(void (*function_ptr)(
-      typename internal::Callback_ParamTraits<Args>::ForwardType...))
-      : sink_(new RunnableHolder(new FunctionPtrAdapter(function_ptr))) {}
-
-  // Executes the callback function.
-  void Run(typename internal::Callback_ParamTraits<Args>::ForwardType... args)
-      const {
-    if (sink_)
-      sink_->runnable->Run(std::forward<
-                 typename internal::Callback_ParamTraits<Args>::ForwardType>(
-          args)...);
-  }
-
-  bool is_null() const { return !sink_.get(); }
-
-  // Resets the callback to the "null" state.
-  void reset() { sink_ = nullptr; }
-
- private:
-  // Adapts a class that has a Run() method but is not derived from Runnable to
-  // be callable by Callback.
-  template <typename Sink>
-  struct RunnableAdapter : public Runnable {
-    explicit RunnableAdapter(const Sink& sink) : sink(sink) {}
-    virtual void Run(
-        typename internal::Callback_ParamTraits<Args>::ForwardType... args)
-        override {
-      sink.Run(std::forward<
-               typename internal::Callback_ParamTraits<Args>::ForwardType>(
-          args)...);
-    }
-    Sink sink;
-  };
-
-  // Adapts a class that has a compatible operator() to be callable by Callback.
-  template <typename Sink>
-  struct FunctorAdapter : public Runnable {
-    explicit FunctorAdapter(const Sink& sink) : sink(sink) {}
-    virtual void Run(
-        typename internal::Callback_ParamTraits<Args>::ForwardType... args)
-        override {
-      sink.operator()(
-          std::forward<
-              typename internal::Callback_ParamTraits<Args>::ForwardType>(
-              args)...);
-    }
-    Sink sink;
-  };
-
-  // Adapts a function pointer.
-  struct FunctionPtrAdapter : public Runnable {
-   private:
-    using FunctionPtr =
-        void (*)(typename internal::Callback_ParamTraits<Args>::ForwardType...);
-
-   public:
-    explicit FunctionPtrAdapter(FunctionPtr function_ptr)
-        : function_ptr(function_ptr) {}
-    virtual void Run(
-        typename internal::Callback_ParamTraits<Args>::ForwardType... args)
-        override {
-      (*function_ptr)(
-          std::forward<
-              typename internal::Callback_ParamTraits<Args>::ForwardType>(
-              args)...);
-    }
-    FunctionPtr function_ptr;
-  };
-
-  struct RunnableHolder : public base::RefCountedThreadSafe<RunnableHolder> {
-    explicit RunnableHolder(Runnable* runnable) : runnable(runnable) {}
-
-    std::unique_ptr<Runnable> runnable;
-
-   private:
-    friend class base::RefCountedThreadSafe<RunnableHolder>;
-    ~RunnableHolder() {}
-  };
-
-  scoped_refptr<RunnableHolder> sink_;
-};
-
-// A specialization of Callback which takes no parameters.
-typedef Callback<void()> Closure;
+using Closure = base::Closure;
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_CALLBACK_H_