1 // Copyright 2020 The Dawn Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef DAWNNATIVE_OBJECT_CONTENT_HASHER_H_ 16 #define DAWNNATIVE_OBJECT_CONTENT_HASHER_H_ 17 18 #include "common/HashUtils.h" 19 20 #include <string> 21 #include <vector> 22 23 namespace dawn_native { 24 25 // ObjectContentHasher records a hash that can be used as a key to lookup a cached object in a 26 // cache. 27 class ObjectContentHasher { 28 public: 29 // Record calls the appropriate record function based on the type. 30 template <typename T, typename... Args> Record(const T & value,const Args &...args)31 void Record(const T& value, const Args&... args) { 32 RecordImpl<T, Args...>::Call(this, value, args...); 33 } 34 35 size_t GetContentHash() const; 36 37 private: 38 template <typename T, typename... Args> 39 struct RecordImpl { CallRecordImpl40 static constexpr void Call(ObjectContentHasher* recorder, 41 const T& value, 42 const Args&... args) { 43 HashCombine(&recorder->mContentHash, value, args...); 44 } 45 }; 46 47 template <typename T> 48 struct RecordImpl<T*> { 49 static constexpr void Call(ObjectContentHasher* recorder, T* obj) { 50 // Calling Record(objPtr) is not allowed. This check exists to only prevent such 51 // mistakes. 52 static_assert(obj == nullptr, ""); 53 } 54 }; 55 56 template <typename T> 57 struct RecordImpl<std::vector<T>> { 58 static constexpr void Call(ObjectContentHasher* recorder, const std::vector<T>& vec) { 59 recorder->RecordIterable<std::vector<T>>(vec); 60 } 61 }; 62 63 template <typename IteratorT> 64 constexpr void RecordIterable(const IteratorT& iterable) { 65 for (auto it = iterable.begin(); it != iterable.end(); ++it) { 66 Record(*it); 67 } 68 } 69 70 size_t mContentHash = 0; 71 }; 72 73 template <> 74 struct ObjectContentHasher::RecordImpl<std::string> { 75 static constexpr void Call(ObjectContentHasher* recorder, const std::string& str) { 76 recorder->RecordIterable<std::string>(str); 77 } 78 }; 79 80 } // namespace dawn_native 81 82 #endif // DAWNNATIVE_OBJECT_CONTENT_HASHER_H_ 83