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// Copyright 2020 The Dawn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef DAWNNATIVE_OBJECT_CONTENT_HASHER_H_
#define DAWNNATIVE_OBJECT_CONTENT_HASHER_H_
#include "common/HashUtils.h"
#include <string>
#include <vector>
namespace dawn_native {
// ObjectContentHasher records a hash that can be used as a key to lookup a cached object in a
// cache.
class ObjectContentHasher {
public:
// Record calls the appropriate record function based on the type.
template <typename T, typename... Args>
void Record(const T& value, const Args&... args) {
RecordImpl<T, Args...>::Call(this, value, args...);
}
size_t GetContentHash() const;
private:
template <typename T, typename... Args>
struct RecordImpl {
static constexpr void Call(ObjectContentHasher* recorder,
const T& value,
const Args&... args) {
HashCombine(&recorder->mContentHash, value, args...);
}
};
template <typename T>
struct RecordImpl<T*> {
static constexpr void Call(ObjectContentHasher* recorder, T* obj) {
// Calling Record(objPtr) is not allowed. This check exists to only prevent such
// mistakes.
static_assert(obj == nullptr, "");
}
};
template <typename T>
struct RecordImpl<std::vector<T>> {
static constexpr void Call(ObjectContentHasher* recorder, const std::vector<T>& vec) {
recorder->RecordIterable<std::vector<T>>(vec);
}
};
template <typename IteratorT>
constexpr void RecordIterable(const IteratorT& iterable) {
for (auto it = iterable.begin(); it != iterable.end(); ++it) {
Record(*it);
}
}
size_t mContentHash = 0;
};
template <>
struct ObjectContentHasher::RecordImpl<std::string> {
static constexpr void Call(ObjectContentHasher* recorder, const std::string& str) {
recorder->RecordIterable<std::string>(str);
}
};
} // namespace dawn_native
#endif // DAWNNATIVE_OBJECT_CONTENT_HASHER_H_