1//===-- LockFileBase.cpp ----------------------------------------*- C++ -*-===//
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
14namespace {
15
16Status AlreadyLocked() { return Status("Already locked"); }
17
18Status NotLocked() { return Status("Not locked"); }
19}
20
21LockFileBase::LockFileBase(int fd)
22    : m_fd(fd), m_locked(false), m_start(0), m_len(0) {}
23
24bool LockFileBase::IsLocked() const { return m_locked; }
25
26Status LockFileBase::WriteLock(const uint64_t start, const uint64_t len) {
27  return DoLock([&](const uint64_t start,
28                    const uint64_t len) { return DoWriteLock(start, len); },
29                start, len);
30}
31
32Status LockFileBase::TryWriteLock(const uint64_t start, const uint64_t len) {
33  return DoLock([&](const uint64_t start,
34                    const uint64_t len) { return DoTryWriteLock(start, len); },
35                start, len);
36}
37
38Status LockFileBase::ReadLock(const uint64_t start, const uint64_t len) {
39  return DoLock([&](const uint64_t start,
40                    const uint64_t len) { return DoReadLock(start, len); },
41                start, len);
42}
43
44Status LockFileBase::TryReadLock(const uint64_t start, const uint64_t len) {
45  return DoLock([&](const uint64_t start,
46                    const uint64_t len) { return DoTryReadLock(start, len); },
47                start, len);
48}
49
50Status LockFileBase::Unlock() {
51  if (!IsLocked())
52    return NotLocked();
53
54  const auto error = DoUnlock();
55  if (error.Success()) {
56    m_locked = false;
57    m_start = 0;
58    m_len = 0;
59  }
60  return error;
61}
62
63bool LockFileBase::IsValidFile() const { return m_fd != -1; }
64
65Status LockFileBase::DoLock(const Locker &locker, const uint64_t start,
66                            const uint64_t len) {
67  if (!IsValidFile())
68    return Status("File is invalid");
69
70  if (IsLocked())
71    return AlreadyLocked();
72
73  const auto error = locker(start, len);
74  if (error.Success()) {
75    m_locked = true;
76    m_start = start;
77    m_len = len;
78  }
79
80  return error;
81}
82