LockFileBase.h

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//===-- LockFileBase.h ------------------------------------------*- C++ -*-===//
//
// Part of the LLVM 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
//
//===----------------------------------------------------------------------===//
 
#ifndef LLDB_HOST_LOCKFILEBASE_H
#define LLDB_HOST_LOCKFILEBASE_H
 
#include "lldb/Utility/Status.h"
 
#include <functional>
 
namespace lldb_private {
 
class LockFileBase {
public:
  virtual ~LockFileBase() = default;
 
  bool IsLocked() const;
 
  Status WriteLock(const uint64_t start, const uint64_t len);
  Status TryWriteLock(const uint64_t start, const uint64_t len);
 
  Status ReadLock(const uint64_t start, const uint64_t len);
  Status TryReadLock(const uint64_t start, const uint64_t len);
 
  Status Unlock();
 
protected:
  using Locker = std::function<Status(const uint64_t, const uint64_t)>;
 
  LockFileBase(int fd);
 
  virtual bool IsValidFile() const;
 
  virtual Status DoWriteLock(const uint64_t start, const uint64_t len) = 0;
  virtual Status DoTryWriteLock(const uint64_t start, const uint64_t len) = 0;
 
  virtual Status DoReadLock(const uint64_t start, const uint64_t len) = 0;
  virtual Status DoTryReadLock(const uint64_t start, const uint64_t len) = 0;
 
  virtual Status DoUnlock() = 0;
 
  Status DoLock(const Locker &locker, const uint64_t start, const uint64_t len);
 
  int m_fd; // not owned.
  bool m_locked;
  uint64_t m_start;
  uint64_t m_len;
};
}
 
#endif