/*

 * Copyright 2018 Google Inc.

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#ifndef MemoryCache_DEFINED

#define MemoryCache_DEFINED

#include "include/core/SkData.h"

#include "include/gpu/GrContextOptions.h"

#include "src/core/SkChecksum.h"

#include <unordered_map>

namespace sk_gpu_test {

/**

 * This class can be used to maintain an in memory record of all programs cached by GrContext.

 * It can be shared by multiple GrContexts so long as those GrContexts are created with the same

 * options and will have the same GrCaps (e.g. same backend, same GL context creation parameters,

 * ...).

 */

class MemoryCache : public GrContextOptions::PersistentCache {

public:

    MemoryCache() = default;

    MemoryCache(const MemoryCache&) = delete;

    MemoryCache& operator=(const MemoryCache&) = delete;

    void reset() {

        this->resetCacheStats();

        fMap.clear();

    }

    sk_sp<SkData> load(const SkData& key) override;

    void store(const SkData& key, const SkData& data, const SkString& description) override;

    int numCacheMisses() const { return fCacheMissCnt; }

    int numCacheStores() const { return fCacheStoreCnt; }

    void resetCacheStats() {

        fCacheMissCnt = 0;

        fCacheStoreCnt = 0;

    }

    void writeShadersToDisk(const char* path, GrBackendApi backend);

    template <typename Fn>

    void foreach(Fn&& fn) {

        for (auto it = fMap.begin(); it != fMap.end(); ++it) {

            fn(it->first.fKey, it->second.fData, it->second.fDescription, it->second.fHitCount);

        }

    }

private:

    struct Key {

        Key() = default;

        Key(const SkData& key) : fKey(SkData::MakeWithCopy(key.data(), key.size())) {}

        Key(const Key& that) = default;

        Key& operator=(const Key&) = default;

        bool operator==(const Key& that) const {

            return that.fKey->size() == fKey->size() &&

                   !memcmp(fKey->data(), that.fKey->data(), that.fKey->size());

        }

        sk_sp<const SkData> fKey;

    };

    struct Value {

        Value() = default;

        Value(const SkData& data, const SkString& description)

            : fData(SkData::MakeWithCopy(data.data(), data.size()))

            , fDescription(description)

            , fHitCount(1) {}

        Value(const Value& that) = default;

        Value& operator=(const Value&) = default;

        sk_sp<SkData> fData;

        SkString      fDescription;

        int           fHitCount;

    };

    struct Hash {

        using argument_type = Key;

        using result_type = uint32_t;

        uint32_t operator()(const Key& key) const {

            return key.fKey ? SkChecksum::Hash32(key.fKey->data(), key.fKey->size()) : 0;

        }

    };

    int fCacheMissCnt = 0;

    int fCacheStoreCnt = 0;

    std::unordered_map<Key, Value, Hash> fMap;

};

}  // namespace sk_gpu_test

#endif