clang-r468909b/include/lldb/Host/LockFileBase.h

//===-- 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