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tqt3/src/tools/qthreadstorage_unix.cpp

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/****************************************************************************
**
** ...
**
** Copyright (C) 2005-2008 Trolltech ASA. All rights reserved.
**
** This file is part of the tools module of the TQt GUI Toolkit.
**
** This file may be used under the terms of the GNU General
** Public License versions 2.0 or 3.0 as published by the Free
** Software Foundation and appearing in the files LICENSE.GPL2
** and LICENSE.GPL3 included in the packaging of this file.
** Alternatively you may (at your option) use any later version
** of the GNU General Public License if such license has been
** publicly approved by Trolltech ASA (or its successors, if any)
** and the KDE Free TQt Foundation.
**
** Please review the following information to ensure GNU General
** Public Licensing requirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/.
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** review the following information:
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** or contact the sales department at sales@trolltech.com.
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** This file may be used under the terms of the Q Public License as
** defined by Trolltech ASA and appearing in the file LICENSE.TQPL
** included in the packaging of this file. Licensees holding valid TQt
** Commercial licenses may use this file in accordance with the TQt
** Commercial License Agreement provided with the Software.
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** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE. Trolltech reserves all rights not granted
** herein.
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**********************************************************************/
#ifdef QT_THREAD_SUPPORT
#include "qplatformdefs.h"
#include "ntqthreadstorage.h"
#include <private/qthreadinstance_p.h>
#include <string.h>
// #define TQTHREADSTORAGE_DEBUG
// keep this in sync with the implementation in qthreadstorage.cpp
static const int MAX_THREAD_STORAGE = 257; // 256 maximum + 1 used in TQRegExp
static pthread_mutex_t thread_storage_mutex = PTHREAD_MUTEX_INITIALIZER;
static bool thread_storage_init = FALSE;
static struct {
bool used;
void (*func)( void * );
} thread_storage_usage[MAX_THREAD_STORAGE];
TQThreadStorageData::TQThreadStorageData( void (*func)( void * ) )
: id( 0 )
{
pthread_mutex_lock( &thread_storage_mutex );
// make sure things are initialized
if ( ! thread_storage_init )
memset( thread_storage_usage, 0, sizeof( thread_storage_usage ) );
thread_storage_init = TRUE;
for ( ; id < MAX_THREAD_STORAGE; ++id ) {
if ( !thread_storage_usage[id].used )
break;
}
Q_ASSERT( id >= 0 && id < MAX_THREAD_STORAGE );
thread_storage_usage[id].used = TRUE;
thread_storage_usage[id].func = func;
#ifdef TQTHREADSTORAGE_DEBUG
qDebug( "TQThreadStorageData: allocated id %d", id );
#endif // TQTHREADSTORAGE_DEBUG
pthread_mutex_unlock( &thread_storage_mutex );
}
TQThreadStorageData::~TQThreadStorageData()
{
pthread_mutex_lock( &thread_storage_mutex );
thread_storage_usage[id].used = FALSE;
thread_storage_usage[id].func = 0;
#ifdef TQTHREADSTORAGE_DEBUG
qDebug( "TQThreadStorageData: released id %d", id );
#endif // TQTHREADSTORAGE_DEBUG
pthread_mutex_unlock( &thread_storage_mutex );
}
void **TQThreadStorageData::get() const
{
TQThreadInstance *d = TQThreadInstance::current();
if (!d) {
qWarning("TQThreadStorage can only be used with threads started with TQThread");
return 0;
}
TQMutexLocker locker( d->mutex() );
return d->thread_storage && d->thread_storage[id] ? &d->thread_storage[id] : 0;
}
void **TQThreadStorageData::set( void *p )
{
TQThreadInstance *d = TQThreadInstance::current();
if (!d) {
qWarning("TQThreadStorage can only be used with threads started with TQThread");
return 0;
}
TQMutexLocker locker( d->mutex() );
if ( !d->thread_storage ) {
#ifdef TQTHREADSTORAGE_DEBUG
qDebug( "TQThreadStorageData: allocating storage for thread %lx",
(unsigned long) pthread_self() );
#endif // TQTHREADSTORAGE_DEBUG
d->thread_storage = new void*[MAX_THREAD_STORAGE];
memset( d->thread_storage, 0, sizeof( void* ) * MAX_THREAD_STORAGE );
}
// delete any previous data
if ( d->thread_storage[id] )
thread_storage_usage[id].func( d->thread_storage[id] );
// store new data
d->thread_storage[id] = p;
return &d->thread_storage[id];
}
void TQThreadStorageData::finish( void **thread_storage )
{
if ( ! thread_storage ) return; // nothing to do
#ifdef TQTHREADSTORAGE_DEBUG
qDebug( "TQThreadStorageData: destroying storage for thread %lx",
(unsigned long) pthread_self() );
#endif // TQTHREADSTORAGE_DEBUG
for ( int i = 0; i < MAX_THREAD_STORAGE; ++i ) {
if ( ! thread_storage[i] ) continue;
if ( ! thread_storage_usage[i].used ) {
#ifdef QT_CHECK_STATE
qWarning( "TQThreadStorage: thread %lx exited after TQThreadStorage destroyed",
(unsigned long) pthread_self() );
#endif // QT_CHECK_STATE
continue;
}
thread_storage_usage[i].func( thread_storage[i] );
}
delete [] thread_storage;
}
/*!
\class TQThreadStorage
\brief The TQThreadStorage class provides per-thread data storage.
\threadsafe
\ingroup thread
\ingroup environment
TQThreadStorage is a template class that provides per-thread data
storage.
\e{Note that due to compiler limitations, TQThreadStorage can only
store pointers.}
The setLocalData() function stores a single thread-specific value
for the calling thread. The data can be accessed later using the
localData() functions. TQThreadStorage takes ownership of the
data (which must be created on the heap with \e new) and deletes
it when the thread exits (either normally or via termination).
The hasLocalData() function allows the programmer to determine if
data has previously been set using the setLocalData() function.
This is useful for lazy initializiation.
For example, the following code uses TQThreadStorage to store a
single cache for each thread that calls the \e cacheObject() and
\e removeFromCache() functions. The cache is automatically
deleted when the calling thread exits (either normally or via
termination).
\code
TQThreadStorage<TQCache<SomeClass> *> caches;
void cacheObject( const TQString &key, SomeClass *object )
{
if ( ! caches.hasLocalData() )
caches.setLocalData( new TQCache<SomeClass> );
caches.localData()->insert( key, object );
}
void removeFromCache( const TQString &key )
{
if ( ! caches.hasLocalData() )
return; // nothing to do
caches.localData()->remove( key );
}
\endcode
\section1 Caveats
\list
\i As noted above, TQThreadStorage can only store pointers due to
compiler limitations. Support for value-based objects will be
added when the majority of compilers are able to support partial
template specialization.
\i The \link ~TQThreadStorage() destructor\endlink does \e not
delete per-thread data. TQThreadStorage only deletes per-thread
data when the thread exits or when setLocalData() is called
multiple times.
\i TQThreadStorage can only be used with threads started with
TQThread. It \e cannot be used with threads started with
platform-specific APIs.
\i As a corollary to the above, platform-specific APIs cannot be
used to exit or terminate a TQThread using TQThreadStorage. Doing so
will cause all per-thread data to be leaked. See TQThread::exit()
and TQThread::terminate().
\i TQThreadStorage \e can be used to store data for the \e main()
thread \e after TQApplication has been constructed. TQThreadStorage
deletes all data set for the \e main() thread when TQApplication is
destroyed, regardless of whether or not the \e main() thread has
actually finished.
\i The implementation of TQThreadStorage limits the total number of
TQThreadStorage objects to 256. An unlimited number of threads
can store per-thread data in each TQThreadStorage object.
\endlist
*/
/*!
\fn TQThreadStorage::TQThreadStorage()
Constructs a new per-thread data storage object.
*/
/*!
\fn TQThreadStorage::~TQThreadStorage()
Destroys the per-thread data storage object.
Note: The per-thread data stored is \e not deleted. Any data left
in TQThreadStorage is leaked. Make sure that all threads using
TQThreadStorage have exited before deleting the TQThreadStorage.
\sa hasLocalData()
*/
/*!
\fn bool TQThreadStorage::hasLocalData() const
Returns TRUE if the calling thread has non-zero data available;
otherwise returns FALSE.
\sa localData()
*/
/*!
\fn T& TQThreadStorage::localData()
Returns a reference to the data that was set by the calling
thread.
Note: TQThreadStorage can only store pointers. This function
returns a \e reference to the pointer that was set by the calling
thread. The value of this reference is 0 if no data was set by
the calling thread,
\sa hasLocalData()
*/
/*
### addition to the above documentation when we start supporting
### partial template specialization, and TQThreadStorage can store
### values *and* pointers
When using TQThreadStorage to store values (not pointers), this
function stores an object of type \e T (created with its default
constructor) and returns a reference to that object.
*/
/*!
\fn const T TQThreadStorage::localData() const
\overload
Returns a copy of the data that was set by the calling thread.
Note: TQThreadStorage can only store pointers. This function
returns a pointer to the data that was set by the calling thread.
If no data was set by the calling thread, this function returns 0.
\sa hasLocalData()
*/
/*
### addition to the above documentation when we start supporting
### partial template specialization, and TQThreadStorage can store
### values *and* pointers
When using TQThreadStorage to store values (not pointers), this
function returns an object of type \e T (created with its default
constructor). Unlike the above function, this object is \e not
stored automatically. You will need to call setLocalData() to store
the object.
*/
/*!
\fn void TQThreadStorage::setLocalData( T data )
Sets the local data for the calling thread to \a data. It can be
accessed later using the localData() functions.
If \a data is 0, this function deletes the previous data (if
any) and returns immediately.
If \a data is non-zero, TQThreadStorage takes ownership of the \a
data and deletes it automatically either when the thread exits
(either normally or via termination) or when setLocalData() is
called again.
Note: TQThreadStorage can only store pointers. The \a data
argument must be either a pointer to an object created on the heap
(i.e. using \e new) or 0. You should not delete \a data
yourself; TQThreadStorage takes ownership and will delete the \a
data itself.
\sa localData() hasLocalData()
*/
#endif // QT_THREAD_SUPPORT