1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/storage/src/SQLiteMutex.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,174 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef mozilla_storage_SQLiteMutex_h_
1.11 +#define mozilla_storage_SQLiteMutex_h_
1.12 +
1.13 +#include "mozilla/BlockingResourceBase.h"
1.14 +#include "sqlite3.h"
1.15 +
1.16 +namespace mozilla {
1.17 +namespace storage {
1.18 +
1.19 +/**
1.20 + * Wrapper class for sqlite3_mutexes. To be used whenever we want to use a
1.21 + * sqlite3_mutex.
1.22 + *
1.23 + * @warning Never EVER wrap the same sqlite3_mutex with a different SQLiteMutex.
1.24 + * If you do this, you void the deadlock detector's warranty!
1.25 + */
1.26 +class SQLiteMutex : private BlockingResourceBase
1.27 +{
1.28 +public:
1.29 + /**
1.30 + * Constructs a wrapper for a sqlite3_mutex that has deadlock detecting.
1.31 + *
1.32 + * @param aName
1.33 + * A name which can be used to reference this mutex.
1.34 + */
1.35 + SQLiteMutex(const char *aName)
1.36 + : BlockingResourceBase(aName, eMutex)
1.37 + , mMutex(nullptr)
1.38 + {
1.39 + }
1.40 +
1.41 + /**
1.42 + * Sets the mutex that we are wrapping. We generally do not have access to
1.43 + * our mutex at class construction, so we have to set it once we get access to
1.44 + * it.
1.45 + *
1.46 + * @param aMutex
1.47 + * The sqlite3_mutex that we are going to wrap.
1.48 + */
1.49 + void initWithMutex(sqlite3_mutex *aMutex)
1.50 + {
1.51 + NS_ASSERTION(aMutex, "You must pass in a valid mutex!");
1.52 + NS_ASSERTION(!mMutex, "A mutex has already been set for this!");
1.53 + mMutex = aMutex;
1.54 + }
1.55 +
1.56 +#if !defined(DEBUG) || defined(MOZ_NATIVE_SQLITE)
1.57 + /**
1.58 + * Acquires the mutex.
1.59 + */
1.60 + void lock()
1.61 + {
1.62 + sqlite3_mutex_enter(mMutex);
1.63 + }
1.64 +
1.65 + /**
1.66 + * Releases the mutex.
1.67 + */
1.68 + void unlock()
1.69 + {
1.70 + sqlite3_mutex_leave(mMutex);
1.71 + }
1.72 +
1.73 + /**
1.74 + * Asserts that the current thread owns the mutex.
1.75 + */
1.76 + void assertCurrentThreadOwns()
1.77 + {
1.78 + }
1.79 +
1.80 + /**
1.81 + * Asserts that the current thread does not own the mutex.
1.82 + */
1.83 + void assertNotCurrentThreadOwns()
1.84 + {
1.85 + }
1.86 +
1.87 +#else
1.88 + void lock()
1.89 + {
1.90 + NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
1.91 +
1.92 + // While SQLite Mutexes may be recursive, in our own code we do not want to
1.93 + // treat them as such.
1.94 + CallStack callContext = CallStack();
1.95 +
1.96 + CheckAcquire(callContext);
1.97 + sqlite3_mutex_enter(mMutex);
1.98 + Acquire(callContext); // Call is protected by us holding the mutex.
1.99 + }
1.100 +
1.101 + void unlock()
1.102 + {
1.103 + NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
1.104 +
1.105 + // While SQLite Mutexes may be recursive, in our own code we do not want to
1.106 + // treat them as such.
1.107 + Release(); // Call is protected by us holding the mutex.
1.108 + sqlite3_mutex_leave(mMutex);
1.109 + }
1.110 +
1.111 + void assertCurrentThreadOwns()
1.112 + {
1.113 + NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
1.114 + NS_ASSERTION(sqlite3_mutex_held(mMutex),
1.115 + "Mutex is not held, but we expect it to be!");
1.116 + }
1.117 +
1.118 + void assertNotCurrentThreadOwns()
1.119 + {
1.120 + NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
1.121 + NS_ASSERTION(sqlite3_mutex_notheld(mMutex),
1.122 + "Mutex is held, but we expect it to not be!");
1.123 + }
1.124 +#endif // ifndef DEBUG
1.125 +
1.126 +private:
1.127 + sqlite3_mutex *mMutex;
1.128 +};
1.129 +
1.130 +/**
1.131 + * Automatically acquires the mutex when it enters scope, and releases it when
1.132 + * it leaves scope.
1.133 + */
1.134 +class MOZ_STACK_CLASS SQLiteMutexAutoLock
1.135 +{
1.136 +public:
1.137 + SQLiteMutexAutoLock(SQLiteMutex &aMutex)
1.138 + : mMutex(aMutex)
1.139 + {
1.140 + mMutex.lock();
1.141 + }
1.142 +
1.143 + ~SQLiteMutexAutoLock()
1.144 + {
1.145 + mMutex.unlock();
1.146 + }
1.147 +
1.148 +private:
1.149 + SQLiteMutex &mMutex;
1.150 +};
1.151 +
1.152 +/**
1.153 + * Automatically releases the mutex when it enters scope, and acquires it when
1.154 + * it leaves scope.
1.155 + */
1.156 +class MOZ_STACK_CLASS SQLiteMutexAutoUnlock
1.157 +{
1.158 +public:
1.159 + SQLiteMutexAutoUnlock(SQLiteMutex &aMutex)
1.160 + : mMutex(aMutex)
1.161 + {
1.162 + mMutex.unlock();
1.163 + }
1.164 +
1.165 + ~SQLiteMutexAutoUnlock()
1.166 + {
1.167 + mMutex.lock();
1.168 + }
1.169 +
1.170 +private:
1.171 + SQLiteMutex &mMutex;
1.172 +};
1.173 +
1.174 +} // namespace storage
1.175 +} // namespace mozilla
1.176 +
1.177 +#endif // mozilla_storage_SQLiteMutex_h_
