src/dawn/common/ConcurrentCache.h

// Copyright 2021 The Dawn & Tint Authors
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#ifndef SRC_DAWN_COMMON_CONCURRENTCACHE_H_
#define SRC_DAWN_COMMON_CONCURRENTCACHE_H_

#include <mutex>
#include <unordered_set>
#include <utility>

#include "dawn/common/NonMovable.h"

namespace dawn {

template <typename T>
class ConcurrentCache : public NonMovable {
  public:
    ConcurrentCache() = default;

    T* Find(T* object) {
        std::lock_guard<std::mutex> lock(mMutex);
        auto iter = mCache.find(object);
        if (iter == mCache.end()) {
            return nullptr;
        }
        return *iter;
    }

    std::pair<T*, bool> Insert(T* object) {
        std::lock_guard<std::mutex> lock(mMutex);
        auto [value, inserted] = mCache.insert(object);
        return {*value, inserted};
    }

    size_t Erase(T* object) {
        std::lock_guard<std::mutex> lock(mMutex);
        return mCache.erase(object);
    }

  private:
    std::mutex mMutex;
    std::unordered_set<T*, typename T::HashFunc, typename T::EqualityFunc> mCache;
};

}  // namespace dawn

#endif  // SRC_DAWN_COMMON_CONCURRENTCACHE_H_