text: //===-- LockFileBase.cpp --------------------------------------------------===//
  //
  // 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
  //
  //===----------------------------------------------------------------------===//
  
  #include "lldb/Host/LockFileBase.h"
  
  using namespace lldb;
  using namespace lldb_private;
  
  namespace {
  
  Status AlreadyLocked() { return Status("Already locked"); }
  
  Status NotLocked() { return Status("Not locked"); }
  }
  
  LockFileBase::LockFileBase(int fd)
      : m_fd(fd), m_locked(false), m_start(0), m_len(0) {}
  
  bool LockFileBase::IsLocked() const { return m_locked; }
  
  Status LockFileBase::WriteLock(const uint64_t start, const uint64_t len) {
    return DoLock([&](const uint64_t start,
                      const uint64_t len) { return DoWriteLock(start, len); },
                  start, len);
  }
  
  Status LockFileBase::TryWriteLock(const uint64_t start, const uint64_t len) {
    return DoLock([&](const uint64_t start,
                      const uint64_t len) { return DoTryWriteLock(start, len); },
                  start, len);
  }
  
  Status LockFileBase::ReadLock(const uint64_t start, const uint64_t len) {
    return DoLock([&](const uint64_t start,
                      const uint64_t len) { return DoReadLock(start, len); },
                  start, len);
  }
  
  Status LockFileBase::TryReadLock(const uint64_t start, const uint64_t len) {
    return DoLock([&](const uint64_t start,
                      const uint64_t len) { return DoTryReadLock(start, len); },
                  start, len);
  }
  
  Status LockFileBase::Unlock() {
    if (!IsLocked())
      return NotLocked();
  
    const auto error = DoUnlock();
    if (error.Success()) {
      m_locked = false;
      m_start = 0;
      m_len = 0;
    }
    return error;
  }
  
  bool LockFileBase::IsValidFile() const { return m_fd != -1; }
  
  Status LockFileBase::DoLock(const Locker &locker, const uint64_t start,
                              const uint64_t len) {
    if (!IsValidFile())
      return Status("File is invalid");
  
    if (IsLocked())
      return AlreadyLocked();
  
    const auto error = locker(start, len);
    if (error.Success()) {
      m_locked = true;
      m_start = start;
      m_len = len;
    }
  
    return error;
  }
  