| /************************************************************** |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| * |
| *************************************************************/ |
| |
| |
| |
| // MARKER(update_precomp.py): autogen include statement, do not remove |
| #include "precompiled_unotools.hxx" |
| #include "unotools/readwritemutexguard.hxx" |
| #include <tools/debug.hxx> |
| |
| |
| namespace utl { |
| |
| ReadWriteGuard::ReadWriteGuard( ReadWriteMutex& rMutexP, |
| sal_Int32 nRequestMode ) |
| : rMutex( rMutexP ) |
| { |
| // don't do anything until a pending write completed (or another |
| // ReadWriteGuard leaves the ctor phase) |
| ::osl::MutexGuard aGuard( rMutex.pWriteMutex ); |
| nMode = nRequestMode; |
| if ( nMode & ReadWriteGuardMode::nWrite ) |
| { |
| rMutex.pWriteMutex->acquire(); |
| // wait for any read to complete |
| // TODO: set up a waiting thread instead of a loop |
| sal_Bool bWait = sal_True; |
| do |
| { |
| rMutex.pMutex->acquire(); |
| bWait = (rMutex.nReadCount != 0); |
| if ( nMode & ReadWriteGuardMode::nCriticalChange ) |
| bWait |= (rMutex.nBlockCriticalCount != 0); |
| rMutex.pMutex->release(); |
| } while ( bWait ); |
| } |
| else if ( nMode & ReadWriteGuardMode::nBlockCritical ) |
| { |
| rMutex.pMutex->acquire(); |
| ++rMutex.nBlockCriticalCount; |
| rMutex.pMutex->release(); |
| } |
| else |
| { |
| rMutex.pMutex->acquire(); |
| ++rMutex.nReadCount; |
| rMutex.pMutex->release(); |
| } |
| } |
| |
| |
| ReadWriteGuard::~ReadWriteGuard() |
| { |
| if ( nMode & ReadWriteGuardMode::nWrite ) |
| rMutex.pWriteMutex->release(); |
| else if ( nMode & ReadWriteGuardMode::nBlockCritical ) |
| { |
| rMutex.pMutex->acquire(); |
| --rMutex.nBlockCriticalCount; |
| rMutex.pMutex->release(); |
| } |
| else |
| { |
| rMutex.pMutex->acquire(); |
| --rMutex.nReadCount; |
| rMutex.pMutex->release(); |
| } |
| } |
| |
| |
| void ReadWriteGuard::changeReadToWrite() |
| { |
| sal_Bool bOk = !(nMode & (ReadWriteGuardMode::nWrite | ReadWriteGuardMode::nBlockCritical)); |
| DBG_ASSERT( bOk, "ReadWriteGuard::changeReadToWrite: can't" ); |
| if ( bOk ) |
| { |
| // MUST release read before acquiring write mutex or dead lock would |
| // occur if there was a write in another thread waiting for this read |
| // to complete. |
| rMutex.pMutex->acquire(); |
| --rMutex.nReadCount; |
| rMutex.pMutex->release(); |
| |
| rMutex.pWriteMutex->acquire(); |
| nMode |= ReadWriteGuardMode::nWrite; |
| // wait for any other read to complete |
| // TODO: set up a waiting thread instead of a loop |
| sal_Bool bWait = sal_True; |
| do |
| { |
| rMutex.pMutex->acquire(); |
| bWait = (rMutex.nReadCount != 0); |
| rMutex.pMutex->release(); |
| } while ( bWait ); |
| } |
| } |
| |
| } // namespace utl |