Move webrtc/{base => rtc_base}

webrtc/base/function_view.h

 /*
  *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_BASE_FUNCTION_VIEW_H_
 #define WEBRTC_BASE_FUNCTION_VIEW_H_
 
-#include <type_traits>
-#include <utility>
 
-#include "webrtc/base/checks.h"
-
-// Just like std::function, FunctionView will wrap any callable and hide its
-// actual type, exposing only its signature. But unlike std::function,
-// FunctionView doesn't own its callable---it just points to it. Thus, it's a
-// good choice mainly as a function argument when the callable argument will
-// not be called again once the function has returned.
-//
-// Its constructors are implicit, so that callers won't have to convert lambdas
-// and other callables to FunctionView<Blah(Blah, Blah)> explicitly. This is
-// safe because FunctionView is only a reference to the real callable.
-//
-// Example use:
-//
-//   void SomeFunction(rtc::FunctionView<int(int)> index_transform);
-//   ...
-//   SomeFunction([](int i) { return 2 * i + 1; });
-//
-// Note: FunctionView is tiny (essentially just two pointers) and trivially
-// copyable, so it's probably cheaper to pass it by value than by const
-// reference.
-
-namespace rtc {
-
-template <typename T>
-class FunctionView;  // Undefined.
-
-template <typename RetT, typename... ArgT>
-class FunctionView<RetT(ArgT...)> final {
- public:
-  // Constructor for lambdas and other callables; it accepts every type of
-  // argument except those noted in its enable_if call.
-  template <
-      typename F,
-      typename std::enable_if<
-          // Not for function pointers; we have another constructor for that
-          // below.
-          !std::is_function<typename std::remove_pointer<
-              typename std::remove_reference<F>::type>::type>::value &&
-
-          // Not for nullptr; we have another constructor for that below.
-          !std::is_same<std::nullptr_t,
-                        typename std::remove_cv<F>::type>::value &&
-
-          // Not for FunctionView objects; we have another constructor for that
-          // (the implicitly declared copy constructor).
-          !std::is_same<FunctionView,
-                        typename std::remove_cv<typename std::remove_reference<
-                            F>::type>::type>::value>::type* = nullptr>
-  FunctionView(F&& f)
-      : call_(CallVoidPtr<typename std::remove_reference<F>::type>) {
-    f_.void_ptr = &f;
-  }
-
-  // Constructor that accepts function pointers. If the argument is null, the
-  // result is an empty FunctionView.
-  template <
-      typename F,
-      typename std::enable_if<std::is_function<typename std::remove_pointer<
-          typename std::remove_reference<F>::type>::type>::value>::type* =
-          nullptr>
-  FunctionView(F&& f)
-      : call_(f ? CallFunPtr<typename std::remove_pointer<F>::type> : nullptr) {
-    f_.fun_ptr = reinterpret_cast<void (*)()>(f);
-  }
-
-  // Constructor that accepts nullptr. It creates an empty FunctionView.
-  template <typename F,
-            typename std::enable_if<std::is_same<
-                std::nullptr_t,
-                typename std::remove_cv<F>::type>::value>::type* = nullptr>
-  FunctionView(F&& f) : call_(nullptr) {}
-
-  // Default constructor. Creates an empty FunctionView.
-  FunctionView() : call_(nullptr) {}
-
-  RetT operator()(ArgT... args) const {
-    RTC_DCHECK(call_);
-    return call_(f_, std::forward<ArgT>(args)...);
-  }
-
-  // Returns true if we have a function, false if we don't (i.e., we're null).
-  explicit operator bool() const { return !!call_; }
-
- private:
-  union VoidUnion {
-    void* void_ptr;
-    void (*fun_ptr)();
-  };
-
-  template <typename F>
-  static RetT CallVoidPtr(VoidUnion vu, ArgT... args) {
-    return (*static_cast<F*>(vu.void_ptr))(std::forward<ArgT>(args)...);
-  }
-  template <typename F>
-  static RetT CallFunPtr(VoidUnion vu, ArgT... args) {
-    return (reinterpret_cast<typename std::add_pointer<F>::type>(vu.fun_ptr))(
-        std::forward<ArgT>(args)...);
-  }
-
-  // A pointer to the callable thing, with type information erased. It's a
-  // union because we have to use separate types depending on if the callable
-  // thing is a function pointer or something else.
-  VoidUnion f_;
-
-  // Pointer to a dispatch function that knows the type of the callable thing
-  // that's stored in f_, and how to call it. A FunctionView object is empty
-  // (null) iff call_ is null.
-  RetT (*call_)(VoidUnion, ArgT...);
-};
-
-}  // namespace rtc
+// This header is deprecated and is just left here temporarily during
+// refactoring. See https://bugs.webrtc.org/7634 for more details.
+#include "webrtc/rtc_base/function_view.h"
 
 #endif  // WEBRTC_BASE_FUNCTION_VIEW_H_