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
168
169
170
171
172
|
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* 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 mozilla_storage_SQLiteMutex_h_
#define mozilla_storage_SQLiteMutex_h_
#include "mozilla/BlockingResourceBase.h"
#include "sqlite3.h"
namespace mozilla {
namespace storage {
/**
* Wrapper class for sqlite3_mutexes. To be used whenever we want to use a
* sqlite3_mutex.
*
* @warning Never EVER wrap the same sqlite3_mutex with a different SQLiteMutex.
* If you do this, you void the deadlock detector's warranty!
*/
class SQLiteMutex : private BlockingResourceBase
{
public:
/**
* Constructs a wrapper for a sqlite3_mutex that has deadlock detecting.
*
* @param aName
* A name which can be used to reference this mutex.
*/
explicit SQLiteMutex(const char *aName)
: BlockingResourceBase(aName, eMutex)
, mMutex(nullptr)
{
}
/**
* Sets the mutex that we are wrapping. We generally do not have access to
* our mutex at class construction, so we have to set it once we get access to
* it.
*
* @param aMutex
* The sqlite3_mutex that we are going to wrap.
*/
void initWithMutex(sqlite3_mutex *aMutex)
{
NS_ASSERTION(aMutex, "You must pass in a valid mutex!");
NS_ASSERTION(!mMutex, "A mutex has already been set for this!");
mMutex = aMutex;
}
#if !defined(DEBUG)
/**
* Acquires the mutex.
*/
void lock()
{
sqlite3_mutex_enter(mMutex);
}
/**
* Releases the mutex.
*/
void unlock()
{
sqlite3_mutex_leave(mMutex);
}
/**
* Asserts that the current thread owns the mutex.
*/
void assertCurrentThreadOwns()
{
}
/**
* Asserts that the current thread does not own the mutex.
*/
void assertNotCurrentThreadOwns()
{
}
#else
void lock()
{
NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
// While SQLite Mutexes may be recursive, in our own code we do not want to
// treat them as such.
CheckAcquire();
sqlite3_mutex_enter(mMutex);
Acquire(); // Call is protected by us holding the mutex.
}
void unlock()
{
NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
// While SQLite Mutexes may be recursive, in our own code we do not want to
// treat them as such.
Release(); // Call is protected by us holding the mutex.
sqlite3_mutex_leave(mMutex);
}
void assertCurrentThreadOwns()
{
NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
NS_ASSERTION(sqlite3_mutex_held(mMutex),
"Mutex is not held, but we expect it to be!");
}
void assertNotCurrentThreadOwns()
{
NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
NS_ASSERTION(sqlite3_mutex_notheld(mMutex),
"Mutex is held, but we expect it to not be!");
}
#endif // ifndef DEBUG
private:
sqlite3_mutex *mMutex;
};
/**
* Automatically acquires the mutex when it enters scope, and releases it when
* it leaves scope.
*/
class MOZ_STACK_CLASS SQLiteMutexAutoLock
{
public:
explicit SQLiteMutexAutoLock(SQLiteMutex &aMutex)
: mMutex(aMutex)
{
mMutex.lock();
}
~SQLiteMutexAutoLock()
{
mMutex.unlock();
}
private:
SQLiteMutex &mMutex;
};
/**
* Automatically releases the mutex when it enters scope, and acquires it when
* it leaves scope.
*/
class MOZ_STACK_CLASS SQLiteMutexAutoUnlock
{
public:
explicit SQLiteMutexAutoUnlock(SQLiteMutex &aMutex)
: mMutex(aMutex)
{
mMutex.unlock();
}
~SQLiteMutexAutoUnlock()
{
mMutex.lock();
}
private:
SQLiteMutex &mMutex;
};
} // namespace storage
} // namespace mozilla
#endif // mozilla_storage_SQLiteMutex_h_
|
