1//===-- LockFileBase.cpp --------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "lldb/Host/LockFileBase.h"
10
11using namespace lldb;
12using namespace lldb_private;
13
14static Status AlreadyLocked() { return Status("Already locked"); }
15
16static Status NotLocked() { return Status("Not locked"); }
17
18LockFileBase::LockFileBase(int fd)
19    : m_fd(fd), m_locked(false), m_start(0), m_len(0) {}
20
21bool LockFileBase::IsLocked() const { return m_locked; }
22
23Status LockFileBase::WriteLock(const uint64_t start, const uint64_t len) {
24  return DoLock([&](const uint64_t start,
25                    const uint64_t len) { return DoWriteLock(start, len); },
26                start, len);
27}
28
29Status LockFileBase::TryWriteLock(const uint64_t start, const uint64_t len) {
30  return DoLock([&](const uint64_t start,
31                    const uint64_t len) { return DoTryWriteLock(start, len); },
32                start, len);
33}
34
35Status LockFileBase::ReadLock(const uint64_t start, const uint64_t len) {
36  return DoLock([&](const uint64_t start,
37                    const uint64_t len) { return DoReadLock(start, len); },
38                start, len);
39}
40
41Status LockFileBase::TryReadLock(const uint64_t start, const uint64_t len) {
42  return DoLock([&](const uint64_t start,
43                    const uint64_t len) { return DoTryReadLock(start, len); },
44                start, len);
45}
46
47Status LockFileBase::Unlock() {
48  if (!IsLocked())
49    return NotLocked();
50
51  const auto error = DoUnlock();
52  if (error.Success()) {
53    m_locked = false;
54    m_start = 0;
55    m_len = 0;
56  }
57  return error;
58}
59
60bool LockFileBase::IsValidFile() const { return m_fd != -1; }
61
62Status LockFileBase::DoLock(const Locker &locker, const uint64_t start,
63                            const uint64_t len) {
64  if (!IsValidFile())
65    return Status("File is invalid");
66
67  if (IsLocked())
68    return AlreadyLocked();
69
70  const auto error = locker(start, len);
71  if (error.Success()) {
72    m_locked = true;
73    m_start = start;
74    m_len = len;
75  }
76
77  return error;
78}
79