1 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2 : * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
3 : * ***** BEGIN LICENSE BLOCK *****
4 : * Version: MPL 1.1/GPL 2.0/LGPL 2.1
5 : *
6 : * The contents of this file are subject to the Mozilla Public License Version
7 : * 1.1 (the "License"); you may not use this file except in compliance with
8 : * the License. You may obtain a copy of the License at
9 : * http://www.mozilla.org/MPL/
10 : *
11 : * Software distributed under the License is distributed on an "AS IS" basis,
12 : * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13 : * for the specific language governing rights and limitations under the
14 : * License.
15 : *
16 : * The Original Code is mozilla.org code.
17 : *
18 : * The Initial Developer of the Original Code is
19 : * Mozilla Corporation.
20 : * Portions created by the Initial Developer are Copyright (C) 2009
21 : * the Initial Developer. All Rights Reserved.
22 : *
23 : * Contributor(s):
24 : * Shawn Wilsher <me@shawnwilsher.com> (Original Author)
25 : *
26 : * Alternatively, the contents of this file may be used under the terms of
27 : * either the GNU General Public License Version 2 or later (the "GPL"), or
28 : * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
29 : * in which case the provisions of the GPL or the LGPL are applicable instead
30 : * of those above. If you wish to allow use of your version of this file only
31 : * under the terms of either the GPL or the LGPL, and not to allow others to
32 : * use your version of this file under the terms of the MPL, indicate your
33 : * decision by deleting the provisions above and replace them with the notice
34 : * and other provisions required by the GPL or the LGPL. If you do not delete
35 : * the provisions above, a recipient may use your version of this file under
36 : * the terms of any one of the MPL, the GPL or the LGPL.
37 : *
38 : * ***** END LICENSE BLOCK ***** */
39 :
40 : #ifndef mozilla_storage_SQLiteMutex_h_
41 : #define mozilla_storage_SQLiteMutex_h_
42 :
43 : #include "mozilla/BlockingResourceBase.h"
44 : #include "sqlite3.h"
45 :
46 : namespace mozilla {
47 : namespace storage {
48 :
49 : /**
50 : * Wrapper class for sqlite3_mutexes. To be used whenever we want to use a
51 : * sqlite3_mutex.
52 : *
53 : * @warning Never EVER wrap the same sqlite3_mutex with a different SQLiteMutex.
54 : * If you do this, you void the deadlock detector's warranty!
55 : */
56 : class SQLiteMutex : private BlockingResourceBase
57 3282 : {
58 : public:
59 : /**
60 : * Constructs a wrapper for a sqlite3_mutex that has deadlock detecting.
61 : *
62 : * @param aName
63 : * A name which can be used to reference this mutex.
64 : */
65 3289 : SQLiteMutex(const char *aName)
66 : : BlockingResourceBase(aName, eMutex)
67 3289 : , mMutex(NULL)
68 : {
69 3289 : }
70 :
71 : /**
72 : * Sets the mutex that we are wrapping. We generally do not have access to
73 : * our mutex at class construction, so we have to set it once we get access to
74 : * it.
75 : *
76 : * @param aMutex
77 : * The sqlite3_mutex that we are going to wrap.
78 : */
79 3285 : void initWithMutex(sqlite3_mutex *aMutex)
80 : {
81 3285 : NS_ASSERTION(aMutex, "You must pass in a valid mutex!");
82 3285 : NS_ASSERTION(!mMutex, "A mutex has already been set for this!");
83 3285 : mMutex = aMutex;
84 3285 : }
85 :
86 : #if !defined(DEBUG) || defined(MOZ_NATIVE_SQLITE)
87 : /**
88 : * Acquires the mutex.
89 : */
90 : void lock()
91 : {
92 : sqlite3_mutex_enter(mMutex);
93 : }
94 :
95 : /**
96 : * Releases the mutex.
97 : */
98 : void unlock()
99 : {
100 : sqlite3_mutex_leave(mMutex);
101 : }
102 :
103 : /**
104 : * Asserts that the current thread owns the mutex.
105 : */
106 : void assertCurrentThreadOwns()
107 : {
108 : }
109 :
110 : /**
111 : * Asserts that the current thread does not own the mutex.
112 : */
113 : void assertNotCurrentThreadOwns()
114 : {
115 : }
116 :
117 : #else
118 1065795 : void lock()
119 : {
120 1065795 : NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
121 :
122 : // While SQLite Mutexes may be recursive, in our own code we do not want to
123 : // treat them as such.
124 1065795 : CallStack callContext = CallStack();
125 :
126 1065781 : CheckAcquire(callContext);
127 1065864 : sqlite3_mutex_enter(mMutex);
128 1065836 : Acquire(callContext); // Call is protected by us holding the mutex.
129 1065787 : }
130 :
131 1065873 : void unlock()
132 : {
133 1065873 : NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
134 :
135 : // While SQLite Mutexes may be recursive, in our own code we do not want to
136 : // treat them as such.
137 1065873 : Release(); // Call is protected by us holding the mutex.
138 1065873 : sqlite3_mutex_leave(mMutex);
139 1065873 : }
140 :
141 1107 : void assertCurrentThreadOwns()
142 : {
143 1107 : NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
144 1107 : NS_ASSERTION(sqlite3_mutex_held(mMutex),
145 : "Mutex is not held, but we expect it to be!");
146 1107 : }
147 :
148 32 : void assertNotCurrentThreadOwns()
149 : {
150 32 : NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
151 32 : NS_ASSERTION(sqlite3_mutex_notheld(mMutex),
152 : "Mutex is held, but we expect it to not be!");
153 32 : }
154 : #endif // ifndef DEBUG
155 :
156 : private:
157 : sqlite3_mutex *mMutex;
158 : };
159 :
160 : /**
161 : * Automatically acquires the mutex when it enters scope, and releases it when
162 : * it leaves scope.
163 : */
164 : class NS_STACK_CLASS SQLiteMutexAutoLock
165 : {
166 : public:
167 165851 : SQLiteMutexAutoLock(SQLiteMutex &aMutex)
168 165851 : : mMutex(aMutex)
169 : {
170 165851 : mMutex.lock();
171 165851 : }
172 :
173 165851 : ~SQLiteMutexAutoLock()
174 : {
175 165851 : mMutex.unlock();
176 165851 : }
177 :
178 : private:
179 : SQLiteMutex &mMutex;
180 : };
181 :
182 : /**
183 : * Automatically releases the mutex when it enters scope, and acquires it when
184 : * it leaves scope.
185 : */
186 : class NS_STACK_CLASS SQLiteMutexAutoUnlock
187 : {
188 : public:
189 22 : SQLiteMutexAutoUnlock(SQLiteMutex &aMutex)
190 22 : : mMutex(aMutex)
191 : {
192 22 : mMutex.unlock();
193 22 : }
194 :
195 22 : ~SQLiteMutexAutoUnlock()
196 : {
197 22 : mMutex.lock();
198 22 : }
199 :
200 : private:
201 : SQLiteMutex &mMutex;
202 : };
203 :
204 : } // namespace storage
205 : } // namespace mozilla
206 :
207 : #endif // mozilla_storage_SQLiteMutex_h_
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