Make the fuchsia mojo/public repo the source of truth.

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 <functional>
-#include <type_traits>
-
-#include "mojo/public/cpp/bindings/lib/callback_internal.h"
-#include "mojo/public/cpp/bindings/lib/shared_ptr.h"
-#include "mojo/public/cpp/bindings/lib/template_util.h"
-
-namespace mojo {
-
-template <typename Sig>
-class Callback;
-
-// 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.
-        typename internal::Callback_ParamTraits<Args>::ForwardType...)
-        const = 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_(runnable) {}
-
-  // Adapts any type that is copy-constructable and has a compatible Run method
-  // or is convertible to std::function<void(Args...)> (such as a lambda of the
-  // correct type).
-  template <typename Sink>
-  Callback(const Sink& sink) {
-    using sink_type = typename std::conditional<
-        std::is_convertible<Sink, std::function<void(Args...)>>::value,
-        FunctorAdapter<Sink>, RunnableAdapter<Sink>>::type;
-    sink_ = internal::SharedPtr<Runnable>(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 FunctionPtrAdapter(function_ptr)) {}
-
-  // Executes the callback function, invoking Pass() on move-only types.
-  void Run(typename internal::Callback_ParamTraits<Args>::ForwardType... args)
-      const {
-    if (sink_.get())
-      sink_->Run(internal::Forward(args)...);
-  }
-
-  bool is_null() const { return !sink_.get(); }
-
-  // Resets the callback to the "null" state.
-  void reset() { sink_.reset(); }
-
- 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)
-        const override {
-      sink.Run(internal::Forward(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)
-        const override {
-      sink.operator()(internal::Forward(args)...);
-    }
-    Sink sink;
-  };
-
-  // Adapts a function pointer.
-  struct FunctionPtrAdapter : public Runnable {
-    explicit FunctionPtrAdapter(void (*function_ptr)(
-        typename internal::Callback_ParamTraits<Args>::ForwardType...))
-        : function_ptr(function_ptr) {}
-    virtual void Run(
-        typename internal::Callback_ParamTraits<Args>::ForwardType... args)
-        const override {
-      (*function_ptr)(internal::Forward(args)...);
-    }
-    void (*function_ptr)(
-        typename internal::Callback_ParamTraits<Args>::ForwardType...);
-  };
-
-  internal::SharedPtr<Runnable> sink_;
-};
-
-// A specialization of Callback which takes no parameters.
-typedef Callback<void()> Closure;
-
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_CPP_BINDINGS_CALLBACK_H_