summaryrefslogtreecommitdiffstats
path: root/xpcom/build/IOInterposerPrivate.h
blob: 549321062654d4592aa5381e25fe66fd3f4d8142 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef xpcom_build_IOInterposerPrivate_h
#define xpcom_build_IOInterposerPrivate_h

/* This header file contains declarations for helper classes that are
   to be used exclusively by IOInterposer and its observers. This header
   file is not to be used by anything else and MUST NOT be exported! */

#include <prcvar.h>
#include <prlock.h>

namespace mozilla {
namespace IOInterposer {

/**
 * The following classes are simple wrappers for PRLock and PRCondVar.
 * IOInterposer and friends use these instead of Mozilla::Mutex et al because
 * of the fact that IOInterposer is permitted to run until the process
 * terminates; we can't use anything that plugs into leak checkers or deadlock
 * detectors because IOInterposer will outlive those and generate false
 * positives.
 */

class Monitor
{
public:
  Monitor()
    : mLock(PR_NewLock())
    , mCondVar(PR_NewCondVar(mLock))
  {
  }

  ~Monitor()
  {
    PR_DestroyCondVar(mCondVar);
    mCondVar = nullptr;
    PR_DestroyLock(mLock);
    mLock = nullptr;
  }

  void Lock()
  {
    PR_Lock(mLock);
  }

  void Unlock()
  {
    PR_Unlock(mLock);
  }

  bool Wait(PRIntervalTime aTimeout = PR_INTERVAL_NO_TIMEOUT)
  {
    return PR_WaitCondVar(mCondVar, aTimeout) == PR_SUCCESS;
  }

  bool Notify()
  {
    return PR_NotifyCondVar(mCondVar) == PR_SUCCESS;
  }

private:
  PRLock*    mLock;
  PRCondVar* mCondVar;
};

class MonitorAutoLock
{
public:
  explicit MonitorAutoLock(Monitor& aMonitor)
    : mMonitor(aMonitor)
  {
    mMonitor.Lock();
  }

  ~MonitorAutoLock()
  {
    mMonitor.Unlock();
  }

  bool Wait(PRIntervalTime aTimeout = PR_INTERVAL_NO_TIMEOUT)
  {
    return mMonitor.Wait(aTimeout);
  }

  bool Notify()
  {
    return mMonitor.Notify();
  }

private:
  Monitor&  mMonitor;
};

class MonitorAutoUnlock
{
public:
  explicit MonitorAutoUnlock(Monitor& aMonitor)
    : mMonitor(aMonitor)
  {
    mMonitor.Unlock();
  }

  ~MonitorAutoUnlock()
  {
    mMonitor.Lock();
  }

private:
  Monitor&  mMonitor;
};

class Mutex
{
public:
  Mutex()
    : mPRLock(PR_NewLock())
  {
  }

  ~Mutex()
  {
    PR_DestroyLock(mPRLock);
    mPRLock = nullptr;
  }

  void Lock()
  {
    PR_Lock(mPRLock);
  }

  void Unlock()
  {
    PR_Unlock(mPRLock);
  }

private:
  PRLock*   mPRLock;
};

class AutoLock
{
public:
  explicit AutoLock(Mutex& aLock)
    : mLock(aLock)
  {
    mLock.Lock();
  }

  ~AutoLock()
  {
    mLock.Unlock();
  }

private:
  Mutex&     mLock;
};

} // namespace IOInterposer
} // namespace mozilla

#endif // xpcom_build_IOInterposerPrivate_h