MPIStorageCache.h

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//===-- MPIStorageCache.h -- MPI storage cache base class header --===//
//
// Part of the Proteus Project, under the Apache License v2.0 with LLVM
// Exceptions. See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Base class for MPI-based storage caches. Provides shared infrastructure for
// store forwarding, disk persistence, and communication thread lifecycle.
// Subclasses implement lookup() and optionally override handleMessage() to
// handle additional message types.
//
//===----------------------------------------------------------------------===//
 
#ifndef PROTEUS_MPISTORAGECACHE_H
#define PROTEUS_MPISTORAGECACHE_H
 
#include "proteus/impl/Caching/MPIHelpers.h"
#include "proteus/impl/Caching/ObjectCache.h"
#include "proteus/impl/CompiledLibrary.h"
#include "proteus/impl/Hashing.h"
 
#include <atomic>
#include <cstdint>
#include <memory>
#include <string>
 
namespace proteus {
 
class MPIStorageCache : public ObjectCache {
public:
  MPIStorageCache(const std::string &Label);
  ~MPIStorageCache() override;
 
  void store(const HashT &HashValue, const CacheEntry &Entry) override;
  void finalize() override;
  void printStats() override;
  uint64_t getHits() const override { return Hits; }
  uint64_t getAccesses() const override { return Accesses; }
 
protected:
  void startCommThread();
  std::unique_ptr<CompiledLibrary> lookupFromDisk(const HashT &HashValue);
  virtual void handleMessage(MPI_Status &Status, MPITag Tag);
 
  void forwardToWriter(const HashT &HashValue, const CacheEntry &Entry);
  void saveToDisk(const HashT &HashValue, const char *Data, size_t Size,
                  bool IsDynLib);
 
  uint64_t Hits = 0;
  uint64_t Accesses = 0;
  const std::string StorageDirectory;
  const std::string Label;
  MPICommHandle CommHandle;
  CommThreadHandle CommThread;
 
private:
  void communicationThreadMain();
  void handleStoreMessage(MPI_Status &Status);
 
  std::atomic<bool> ShutdownRequested{false};
  bool Finalized = false;
};
 
} // namespace proteus
 
#endif