Mojo C++ bindings: more consistent Clone() and Equals().

mojo/public/cpp/bindings/lib/value_traits.h

-// Copyright 2015 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_LIB_VALUE_TRAITS_H_
-#define MOJO_PUBLIC_CPP_BINDINGS_LIB_VALUE_TRAITS_H_
-
-#include "mojo/public/cpp/bindings/lib/template_util.h"
-
-namespace mojo {
-
-template <typename T>
-class Array;
-
-template <typename T>
-class AssociatedInterfacePtrInfo;
-
-template <typename T>
-class AssociatedInterfaceRequest;
-
-template <typename T>
-class InlinedStructPtr;
-
-template <typename T>
-class InterfacePtr;
-
-template <typename T>
-class InterfaceRequest;
-
-template <typename K, typename V>
-class Map;
-
-template <typename T>
-class ScopedHandleBase;
-
-template <typename T>
-class StructPtr;
-
-template <typename T>
-class WTFArray;
-
-namespace internal {
-
-template <typename T, typename Enable = void>
-struct ValueTraits {
-  static bool Equals(const T& a, const T& b) { return a == b; }
-};
-
-template <typename T>
-struct ValueTraits<
-    T,
-    typename EnableIf<IsSpecializationOf<Array, T>::value ||
-                      IsSpecializationOf<WTFArray, T>::value ||
-                      IsSpecializationOf<Map, T>::value ||
-                      IsSpecializationOf<StructPtr, T>::value ||
-                      IsSpecializationOf<InlinedStructPtr, T>::value>::type> {
-  static bool Equals(const T& a, const T& b) { return a.Equals(b); }
-};
-
-template <typename T>
-struct ValueTraits<ScopedHandleBase<T>> {
-  static bool Equals(const ScopedHandleBase<T>& a,
-                     const ScopedHandleBase<T>& b) {
-    return a.get().value() == b.get().value();
-  }
-};
-
-template <typename T>
-struct ValueTraits<
-    T,
-    typename EnableIf<
-        IsSpecializationOf<InterfaceRequest, T>::value ||
-        IsSpecializationOf<AssociatedInterfaceRequest, T>::value>::type> {
-  static bool Equals(const T& a, const T& b) {
-    if (&a == &b)
-      return true;
-
-    // Now that |a| and |b| refer to different objects, they are equivalent if
-    // and only if they are both invalid.
-    return !a.is_pending() && !b.is_pending();
-  }
-};
-
-template <typename T>
-struct ValueTraits<InterfacePtr<T>> {
-  static bool Equals(const InterfacePtr<T>& a, const InterfacePtr<T>& b) {
-    if (&a == &b)
-      return true;
-
-    // Now that |a| and |b| refer to different objects, they are equivalent if
-    // and only if they are both null.
-    return !a && !b;
-  }
-};
-
-template <typename T>
-struct ValueTraits<AssociatedInterfacePtrInfo<T>> {
-  static bool Equals(const AssociatedInterfacePtrInfo<T>& a,
-                     const AssociatedInterfacePtrInfo<T>& b) {
-    if (&a == &b)
-      return true;
-
-    // Now that |a| and |b| refer to different objects, they are equivalent if
-    // and only if they are both invalid.
-    return !a.is_valid() && !b.is_valid();
-  }
-};
-
-}  // namespace internal
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_VALUE_TRAITS_H_