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Branched from the monolithic repo, Qt master branch, at commit
896db169ea224deb96c59ce8af800d019de63f12

1 files changed, 329 insertions, 0 deletions

diff --git a/src/corelib/thread/qthreadstorage.cpp b/src/corelib/thread/qthreadstorage.cpp
new file mode 100644
index 0000000000..2b353333ee
--- /dev/null
+++ b/src/corelib/thread/qthreadstorage.cpp
@@ -0,0 +1,329 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qthreadstorage.h"
+
+#ifndef QT_NO_THREAD
+#include "qthread.h"
+#include "qthread_p.h"
+#include "qmutex.h"
+
+#include <string.h>
+
+QT_BEGIN_NAMESPACE
+
+// #define THREADSTORAGE_DEBUG
+#ifdef THREADSTORAGE_DEBUG
+#  define DEBUG_MSG qtsDebug
+
+#  include <stdio.h>
+#  include <stdarg.h>
+void qtsDebug(const char *fmt, ...)
+{
+    va_list va;
+    va_start(va, fmt);
+
+    fprintf(stderr, "QThreadStorage: ");
+    vfprintf(stderr, fmt, va);
+    fprintf(stderr, "\n");
+
+    va_end(va);
+}
+#else
+#  define DEBUG_MSG if(false)qDebug
+#endif
+
+Q_GLOBAL_STATIC(QMutex, mutex)
+typedef QVector<void (*)(void *)> DestructorMap;
+Q_GLOBAL_STATIC(DestructorMap, destructors)
+
+QThreadStorageData::QThreadStorageData(void (*func)(void *))
+{
+    QMutexLocker locker(mutex());
+    DestructorMap *destr = destructors();
+    if (!destr) {
+        /*
+         the destructors vector has already been destroyed, yet a new
+         QThreadStorage is being allocated. this can only happen during global
+         destruction, at which point we assume that there is only one thread.
+         in order to keep QThreadStorage working, we need somewhere to store
+         the data, best place we have in this situation is at the tail of the
+         current thread's tls vector. the destructor is ignored, since we have
+         no where to store it, and no way to actually call it.
+         */
+        QThreadData *data = QThreadData::current();
+        id = data->tls.count();
+        DEBUG_MSG("QThreadStorageData: Allocated id %d, destructor %p cannot be stored", id, func);
+        return;
+    }
+    for (id = 0; id < destr->count(); id++) {
+        if (destr->at(id) == 0)
+            break;
+    }
+    if (id == destr->count()) {
+        destr->append(func);
+    } else {
+        (*destr)[id] = func;
+    }
+    DEBUG_MSG("QThreadStorageData: Allocated id %d, destructor %p", id, func);
+}
+
+QThreadStorageData::~QThreadStorageData()
+{
+    DEBUG_MSG("QThreadStorageData: Released id %d", id);
+    QMutexLocker locker(mutex());
+    if (destructors())
+        (*destructors())[id] = 0;
+}
+
+void **QThreadStorageData::get() const
+{
+    QThreadData *data = QThreadData::current();
+    if (!data) {
+        qWarning("QThreadStorage::get: QThreadStorage can only be used with threads started with QThread");
+        return 0;
+    }
+    QVector<void *> &tls = data->tls;
+    if (tls.size() <= id)
+        tls.resize(id + 1);
+    void **v = &tls[id];
+
+    DEBUG_MSG("QThreadStorageData: Returning storage %d, data %p, for thread %p",
+          id,
+          *v,
+          data->thread);
+
+    return *v ? v : 0;
+}
+
+void **QThreadStorageData::set(void *p)
+{
+    QThreadData *data = QThreadData::current();
+    if (!data) {
+        qWarning("QThreadStorage::set: QThreadStorage can only be used with threads started with QThread");
+        return 0;
+    }
+    QVector<void *> &tls = data->tls;
+    if (tls.size() <= id)
+        tls.resize(id + 1);
+
+    void *&value = tls[id];
+    // delete any previous data
+    if (value != 0) {
+        DEBUG_MSG("QThreadStorageData: Deleting previous storage %d, data %p, for thread %p",
+                id,
+                value,
+                data->thread);
+
+        QMutexLocker locker(mutex());
+        DestructorMap *destr = destructors();
+        void (*destructor)(void *) = destr ? destr->value(id) : 0;
+        locker.unlock();
+
+        void *q = value;
+        value = 0;
+
+        if (destructor)
+            destructor(q);
+    }
+
+    // store new data
+    value = p;
+    DEBUG_MSG("QThreadStorageData: Set storage %d for thread %p to %p", id, data->thread, p);
+    return &value;
+}
+
+void QThreadStorageData::finish(void **p)
+{
+    QVector<void *> *tls = reinterpret_cast<QVector<void *> *>(p);
+    if (!tls || tls->isEmpty() || !mutex())
+        return; // nothing to do
+
+    DEBUG_MSG("QThreadStorageData: Destroying storage for thread %p", QThread::currentThread());
+    while (!tls->isEmpty()) {
+        void *&value = tls->last();
+        void *q = value;
+        value = 0;
+        int i = tls->size() - 1;
+        tls->resize(i);
+
+        if (!q) {
+            // data already deleted
+            continue;
+        }
+
+        QMutexLocker locker(mutex());
+        void (*destructor)(void *) = destructors()->value(i);
+        locker.unlock();
+
+        if (!destructor) {
+            if (QThread::currentThread())
+                qWarning("QThreadStorage: Thread %p exited after QThreadStorage %d destroyed",
+                         QThread::currentThread(), i);
+            continue;
+        }
+        destructor(q); //crash here might mean the thread exited after qthreadstorage was destroyed
+
+        if (tls->size() > i) {
+            //re reset the tls in case it has been recreated by its own destructor.
+            (*tls)[i] = 0;
+        }
+    }
+    tls->clear();
+}
+
+/*!
+    \class QThreadStorage
+    \brief The QThreadStorage class provides per-thread data storage.
+
+    \threadsafe
+
+    \ingroup thread
+
+    QThreadStorage is a template class that provides per-thread data
+    storage.
+
+    The setLocalData() function stores a single thread-specific value
+    for the calling thread. The data can be accessed later using
+    localData().
+
+    The hasLocalData() function allows the programmer to determine if
+    data has previously been set using the setLocalData() function.
+    This is also useful for lazy initializiation.
+
+    If T is a pointer type, QThreadStorage takes ownership of the data
+    (which must be created on the heap with \c new) and deletes it when
+    the thread exits, either normally or via termination.
+
+    For example, the following code uses QThreadStorage to store a
+    single cache for each thread that calls the cacheObject() and
+    removeFromCache() functions. The cache is automatically
+    deleted when the calling thread exits.
+
+    \snippet doc/src/snippets/threads/threads.cpp 7
+    \snippet doc/src/snippets/threads/threads.cpp 8
+    \snippet doc/src/snippets/threads/threads.cpp 9
+
+    \section1 Caveats
+
+    \list
+
+    \o The QThreadStorage destructor does not delete per-thread data.
+    QThreadStorage only deletes per-thread data when the thread exits
+    or when setLocalData() is called multiple times.
+
+    \o QThreadStorage can be used to store data for the \c main()
+    thread. QThreadStorage deletes all data set for the \c main()
+    thread when QApplication is destroyed, regardless of whether or
+    not the \c main() thread has actually finished.
+
+    \endlist
+
+    \sa QThread
+*/
+
+/*!
+    \fn QThreadStorage::QThreadStorage()
+
+    Constructs a new per-thread data storage object.
+*/
+
+/*!
+    \fn QThreadStorage::~QThreadStorage()
+
+    Destroys the per-thread data storage object.
+
+    Note: The per-thread data stored is not deleted. Any data left
+    in QThreadStorage is leaked. Make sure that all threads using
+    QThreadStorage have exited before deleting the QThreadStorage.
+
+    \sa hasLocalData()
+*/
+
+/*!
+    \fn bool QThreadStorage::hasLocalData() const
+
+    If T is a pointer type, returns true if the calling thread has
+    non-zero data available.
+
+    If T is a value type, returns whether the data has already been
+    constructed by calling setLocalData or localData.
+
+    \sa localData()
+*/
+
+/*!
+    \fn T &QThreadStorage::localData()
+
+    Returns a reference to the data that was set by the calling
+    thread.
+
+    If no data has been set, this will create a default constructed
+    instance of type T.
+
+    \sa hasLocalData()
+*/
+
+/*!
+    \fn const T QThreadStorage::localData() const
+    \overload
+
+    Returns a copy of the data that was set by the calling thread.
+
+    \sa hasLocalData()
+*/
+
+/*!
+    \fn void QThreadStorage::setLocalData(T data)
+
+    Sets the local data for the calling thread to \a data. It can be
+    accessed later using the localData() functions.
+
+    If T is a pointer type, QThreadStorage takes ownership of the data
+    and deletes it automatically either when the thread exits (either
+    normally or via termination) or when setLocalData() is called again.
+
+    \sa localData(), hasLocalData()
+*/
+
+#endif // QT_NO_THREAD
+
+QT_END_NAMESPACE