mirror of
https://github.com/classilla/tenfourfox.git
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174 lines
3.9 KiB
C++
174 lines
3.9 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_storage_SQLiteMutex_h_
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#define mozilla_storage_SQLiteMutex_h_
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#include "mozilla/BlockingResourceBase.h"
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#include "sqlite3.h"
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namespace mozilla {
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namespace storage {
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/**
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* Wrapper class for sqlite3_mutexes. To be used whenever we want to use a
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* sqlite3_mutex.
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*
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* @warning Never EVER wrap the same sqlite3_mutex with a different SQLiteMutex.
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* If you do this, you void the deadlock detector's warranty!
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*/
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class SQLiteMutex : private BlockingResourceBase
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{
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public:
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/**
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* Constructs a wrapper for a sqlite3_mutex that has deadlock detecting.
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*
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* @param aName
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* A name which can be used to reference this mutex.
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*/
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explicit SQLiteMutex(const char *aName)
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: BlockingResourceBase(aName, eMutex)
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, mMutex(nullptr)
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{
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}
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/**
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* Sets the mutex that we are wrapping. We generally do not have access to
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* our mutex at class construction, so we have to set it once we get access to
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* it.
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*
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* @param aMutex
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* The sqlite3_mutex that we are going to wrap.
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*/
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void initWithMutex(sqlite3_mutex *aMutex)
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{
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NS_ASSERTION(aMutex, "You must pass in a valid mutex!");
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NS_ASSERTION(!mMutex, "A mutex has already been set for this!");
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mMutex = aMutex;
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}
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#if !defined(DEBUG) || defined(MOZ_NATIVE_SQLITE)
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/**
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* Acquires the mutex.
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*/
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void lock()
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{
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sqlite3_mutex_enter(mMutex);
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}
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/**
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* Releases the mutex.
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*/
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void unlock()
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{
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sqlite3_mutex_leave(mMutex);
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}
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/**
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* Asserts that the current thread owns the mutex.
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*/
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void assertCurrentThreadOwns()
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{
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}
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/**
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* Asserts that the current thread does not own the mutex.
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*/
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void assertNotCurrentThreadOwns()
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{
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}
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#else
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void lock()
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{
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NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
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// While SQLite Mutexes may be recursive, in our own code we do not want to
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// treat them as such.
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CheckAcquire();
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sqlite3_mutex_enter(mMutex);
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Acquire(); // Call is protected by us holding the mutex.
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}
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void unlock()
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{
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NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
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// While SQLite Mutexes may be recursive, in our own code we do not want to
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// treat them as such.
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Release(); // Call is protected by us holding the mutex.
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sqlite3_mutex_leave(mMutex);
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}
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void assertCurrentThreadOwns()
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{
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NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
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NS_ASSERTION(sqlite3_mutex_held(mMutex),
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"Mutex is not held, but we expect it to be!");
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}
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void assertNotCurrentThreadOwns()
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{
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NS_ASSERTION(mMutex, "No mutex associated with this wrapper!");
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NS_ASSERTION(sqlite3_mutex_notheld(mMutex),
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"Mutex is held, but we expect it to not be!");
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}
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#endif // ifndef DEBUG
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private:
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sqlite3_mutex *mMutex;
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};
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/**
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* Automatically acquires the mutex when it enters scope, and releases it when
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* it leaves scope.
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*/
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class MOZ_STACK_CLASS SQLiteMutexAutoLock
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{
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public:
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explicit SQLiteMutexAutoLock(SQLiteMutex &aMutex)
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: mMutex(aMutex)
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{
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mMutex.lock();
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}
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~SQLiteMutexAutoLock()
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{
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mMutex.unlock();
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}
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private:
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SQLiteMutex &mMutex;
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};
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/**
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* Automatically releases the mutex when it enters scope, and acquires it when
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* it leaves scope.
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*/
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class MOZ_STACK_CLASS SQLiteMutexAutoUnlock
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{
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public:
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explicit SQLiteMutexAutoUnlock(SQLiteMutex &aMutex)
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: mMutex(aMutex)
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{
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mMutex.unlock();
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}
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~SQLiteMutexAutoUnlock()
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{
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mMutex.lock();
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}
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private:
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SQLiteMutex &mMutex;
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};
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} // namespace storage
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} // namespace mozilla
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#endif // mozilla_storage_SQLiteMutex_h_
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