Mojo C++ bindings: add a new mode to generator to use native STL/WTF types

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

+// Copyright 2016 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_CLONE_EQUALS_UTIL_H_
+#define MOJO_PUBLIC_CPP_BINDINGS_LIB_CLONE_EQUALS_UTIL_H_
+
+#include <type_traits>
+#include <unordered_map>
+#include <vector>
+
+#include "base/optional.h"
+#include "mojo/public/cpp/bindings/lib/template_util.h"
+
+namespace mojo {
+namespace internal {
+
+template <typename T>
+struct HasCloneMethod {
+  template <typename U>
+  static char Test(decltype(&U::Clone));
+  template <typename U>
+  static int Test(...);
+  static const bool value = sizeof(Test<T>(0)) == sizeof(char);
+
+ private:
+  EnsureTypeIsComplete<T> check_t_;
+};
+
+template <typename T, bool has_clone_method = HasCloneMethod<T>::value>
+struct CloneTraits;
+
+template <typename T>
+T Clone(const T& input);
+
+template <typename T>
+struct CloneTraits<T, true> {
+  static T Clone(const T& input) { return input.Clone(); }
+};
+
+template <typename T>
+struct CloneTraits<T, false> {
+  static T Clone(const T& input) { return input; }
+};
+
+template <typename T>
+struct CloneTraits<base::Optional<T>, false> {
+  static base::Optional<T> Clone(const base::Optional<T>& input) {
+    if (!input)
+      return base::nullopt;
+
+    return base::Optional<T>(internal::Clone(*input));
+  }
+};
+
+template <typename T>
+struct CloneTraits<std::vector<T>, false> {
+  static std::vector<T> Clone(const std::vector<T>& input) {
+    std::vector<T> result;
+    result.reserve(input.size());
+    for (const auto& element : input)
+      result.push_back(internal::Clone(element));
+
+    return result;
+  }
+};
+
+template <typename K, typename V>
+struct CloneTraits<std::unordered_map<K, V>, false> {
+  static std::unordered_map<K, V> Clone(const std::unordered_map<K, V>& input) {
+    std::unordered_map<K, V> result;
+    for (const auto& element : input) {
+      result.insert(std::make_pair(internal::Clone(element.first),
+                                   internal::Clone(element.second)));
+    }
+    return result;
+  }
+};
+
+template <typename T>
+T Clone(const T& input) {
+  return CloneTraits<T>::Clone(input);
+};
+
+template <typename T>
+struct HasEqualsMethod {
+  template <typename U>
+  static char Test(decltype(&U::Equals));
+  template <typename U>
+  static int Test(...);
+  static const bool value = sizeof(Test<T>(0)) == sizeof(char);
+
+ private:
+  EnsureTypeIsComplete<T> check_t_;
+};
+
+template <typename T, bool has_equals_method = HasEqualsMethod<T>::value>
+struct EqualsTraits;
+
+template <typename T>
+bool Equals(const T& a, const T& b);
+
+template <typename T>
+struct EqualsTraits<T, true> {
+  static bool Equals(const T& a, const T& b) { return a.Equals(b); }
+};
+
+template <typename T>
+struct EqualsTraits<T, false> {
+  static bool Equals(const T& a, const T& b) { return a == b; }
+};
+
+template <typename T>
+struct EqualsTraits<base::Optional<T>, false> {
+  static bool Equals(const base::Optional<T>& a, const base::Optional<T>& b) {
+    if (!a && !b)
+      return true;
+    if (!a || !b)
+      return false;
+
+    return internal::Equals(*a, *b);
+  }
+};
+
+template <typename T>
+struct EqualsTraits<std::vector<T>, false> {
+  static bool Equals(const std::vector<T>& a, const std::vector<T>& b) {
+    if (a.size() != b.size())
+      return false;
+    for (size_t i = 0; i < a.size(); ++i) {
+      if (!internal::Equals(a[i], b[i]))
+        return false;
+    }
+    return true;
+  }
+};
+
+template <typename K, typename V>
+struct EqualsTraits<std::unordered_map<K, V>, false> {
+  static bool Equals(const std::unordered_map<K, V>& a,
+                     const std::unordered_map<K, V>& b) {
+    if (a.size() != b.size())
+      return false;
+    for (const auto& element : a) {
+      auto iter = b.find(element.first);
+      if (iter == b.end() || !internal::Equals(element.second, iter->second))
+        return false;
+    }
+    return true;
+  }
+};
+
+template <typename T>
+bool Equals(const T& a, const T& b) {
+  return EqualsTraits<T>::Equals(a, b);
+}
+
+}  // namespace internal
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_CLONE_EQUALS_UTIL_H_