/*

 * Copyright (C) 2019 The Android Open Source Project

 *

 * 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.

 */

#pragma once

#include <pthread.h>

#include <stdint.h>

#include <memory>

#include <mutex>

#include <optional>

#include <unordered_map>

#include <unwindstack/Memory.h>

namespace unwindstack {

class MemoryCacheBase : public Memory {

 public:

  MemoryCacheBase(Memory* memory) : impl_(memory) {}

  virtual ~MemoryCacheBase() = default;

  MemoryCacheBase* AsMemoryCacheBase() override { return this; }

  const std::shared_ptr<Memory>& UnderlyingMemory() { return impl_; }

  size_t Read(uint64_t addr, void* dst, size_t size) override {

    // Only look at the cache for small reads.

    if (size > 64) {

      return impl_->Read(addr, dst, size);

    }

    return CachedRead(addr, dst, size);

  }

  long ReadTag(uint64_t addr) override { return impl_->ReadTag(addr); }

 protected:

  constexpr static size_t kCacheBits = 12;

  constexpr static size_t kCacheMask = (1 << kCacheBits) - 1;

  constexpr static size_t kCacheSize = 1 << kCacheBits;

  using CacheDataType = std::unordered_map<uint64_t, uint8_t[kCacheSize]>;

  virtual size_t CachedRead(uint64_t addr, void* dst, size_t size) = 0;

  size_t InternalCachedRead(uint64_t addr, void* dst, size_t size, CacheDataType* cache);

  std::shared_ptr<Memory> impl_;

};

class MemoryCache : public MemoryCacheBase {

 public:

  MemoryCache(Memory* memory) : MemoryCacheBase(memory) {}

  virtual ~MemoryCache() = default;

  size_t CachedRead(uint64_t addr, void* dst, size_t size) override;

  void Clear() override;

 protected:

  CacheDataType cache_;

  std::mutex cache_lock_;

};

class MemoryThreadCache : public MemoryCacheBase {

 public:

  MemoryThreadCache(Memory* memory);

  virtual ~MemoryThreadCache();

  size_t CachedRead(uint64_t addr, void* dst, size_t size) override;

  void Clear() override;

 protected:

  std::optional<pthread_key_t> thread_cache_;

};

}  // namespace unwindstack