| // 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_WTF_HASH_UTIL_H_ |
| #define MOJO_PUBLIC_CPP_BINDINGS_LIB_WTF_HASH_UTIL_H_ |
| |
| #include <type_traits> |
| |
| #include "mojo/public/cpp/bindings/lib/hash_util.h" |
| #include "mojo/public/cpp/bindings/struct_ptr.h" |
| #include "third_party/WebKit/Source/wtf/HashFunctions.h" |
| #include "third_party/WebKit/Source/wtf/text/StringHash.h" |
| #include "third_party/WebKit/Source/wtf/text/WTFString.h" |
| |
| namespace mojo { |
| namespace internal { |
| |
| template <typename T> |
| size_t WTFHashCombine(size_t seed, const T& value) { |
| // Based on proposal in: |
| // http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1756.pdf |
| // |
| // TODO(tibell): We'd like to use WTF::DefaultHash instead of std::hash, but |
| // there is no general template specialization of DefaultHash for enums |
| // and there can't be an instance for bool. |
| return seed ^ (std::hash<T>()(value) + (seed << 6) + (seed >> 2)); |
| } |
| |
| template <typename T, bool has_hash_method = HasHashMethod<T>::value> |
| struct WTFHashTraits; |
| |
| template <typename T> |
| size_t WTFHash(size_t seed, const T& value); |
| |
| template <typename T> |
| struct WTFHashTraits<T, true> { |
| static size_t Hash(size_t seed, const T& value) { return value.Hash(seed); } |
| }; |
| |
| template <typename T> |
| struct WTFHashTraits<T, false> { |
| static size_t Hash(size_t seed, const T& value) { |
| return WTFHashCombine(seed, value); |
| } |
| }; |
| |
| template <> |
| struct WTFHashTraits<WTF::String, false> { |
| static size_t Hash(size_t seed, const WTF::String& value) { |
| return HashCombine(seed, WTF::StringHash::hash(value)); |
| } |
| }; |
| |
| template <typename T> |
| size_t WTFHash(size_t seed, const T& value) { |
| return WTFHashTraits<T>::Hash(seed, value); |
| } |
| |
| template <typename T> |
| struct StructPtrHashFn { |
| static unsigned hash(const StructPtr<T>& value) { |
| return value.Hash(kHashSeed); |
| } |
| static bool equal(const StructPtr<T>& left, const StructPtr<T>& right) { |
| return left.Equals(right); |
| } |
| static const bool safeToCompareToEmptyOrDeleted = false; |
| }; |
| |
| template <typename T> |
| struct InlinedStructPtrHashFn { |
| static unsigned hash(const InlinedStructPtr<T>& value) { |
| return value.Hash(kHashSeed); |
| } |
| static bool equal(const InlinedStructPtr<T>& left, |
| const InlinedStructPtr<T>& right) { |
| return left.Equals(right); |
| } |
| static const bool safeToCompareToEmptyOrDeleted = false; |
| }; |
| |
| } // namespace internal |
| } // namespace mojo |
| |
| namespace WTF { |
| |
| template <typename T> |
| struct DefaultHash<mojo::StructPtr<T>> { |
| using Hash = mojo::internal::StructPtrHashFn<T>; |
| }; |
| |
| template <typename T> |
| struct HashTraits<mojo::StructPtr<T>> |
| : public GenericHashTraits<mojo::StructPtr<T>> { |
| static const bool hasIsEmptyValueFunction = true; |
| static bool isEmptyValue(const mojo::StructPtr<T>& value) { |
| return value.is_null(); |
| } |
| static void constructDeletedValue(mojo::StructPtr<T>& slot, bool) { |
| mojo::internal::StructPtrWTFHelper<T>::ConstructDeletedValue(slot); |
| } |
| static bool isDeletedValue(const mojo::StructPtr<T>& value) { |
| return mojo::internal::StructPtrWTFHelper<T>::IsHashTableDeletedValue( |
| value); |
| } |
| }; |
| |
| template <typename T> |
| struct DefaultHash<mojo::InlinedStructPtr<T>> { |
| using Hash = mojo::internal::InlinedStructPtrHashFn<T>; |
| }; |
| |
| template <typename T> |
| struct HashTraits<mojo::InlinedStructPtr<T>> |
| : public GenericHashTraits<mojo::InlinedStructPtr<T>> { |
| static const bool hasIsEmptyValueFunction = true; |
| static bool isEmptyValue(const mojo::InlinedStructPtr<T>& value) { |
| return value.is_null(); |
| } |
| static void constructDeletedValue(mojo::InlinedStructPtr<T>& slot, bool) { |
| mojo::internal::InlinedStructPtrWTFHelper<T>::ConstructDeletedValue(slot); |
| } |
| static bool isDeletedValue(const mojo::InlinedStructPtr<T>& value) { |
| return mojo::internal::InlinedStructPtrWTFHelper< |
| T>::IsHashTableDeletedValue(value); |
| } |
| }; |
| |
| } // namespace WTF |
| |
| #endif // MOJO_PUBLIC_CPP_BINDINGS_LIB_WTF_HASH_UTIL_H_ |