Merge branch 'master' of git@scm.dev.nokia.troll.no:qt/qt into kinetic-animations

Conflicts:
	src/corelib/kernel/kernel.pri
	src/corelib/kernel/qvariant_p.h
	src/corelib/tools/tools.pri
	src/gui/graphicsview/qgraphicsitem.cpp
	src/gui/graphicsview/qgraphicsitem.h
	src/gui/graphicsview/qgraphicswidget.h
	src/gui/gui.pro

12 files changed, 308 insertions, 312 deletions

diff --git a/src/corelib/kernel/kernel.pri b/src/corelib/kernel/kernel.pri
index b34e59d..ecef555 100644
--- a/src/corelib/kernel/kernel.pri
+++ b/src/corelib/kernel/kernel.pri
@@ -51,10 +51,11 @@ SOURCES += \
 	kernel/qtimer.cpp \
 	kernel/qtranslator.cpp \
 	kernel/qvariant.cpp \
-	kernel/qcoreglobaldata.cpp \
-	kernel/qsharedmemory.cpp \
-	kernel/qsystemsemaphore.cpp
-        
+        kernel/qcoreglobaldata.cpp \
+        kernel/qsharedmemory.cpp \
+        kernel/qsystemsemaphore.cpp \
+        kernel/qpointer.cpp
+
 win32 {
 	SOURCES += \
 		kernel/qeventdispatcher_win.cpp \
diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp
index a23b2dd..77ef096 100644
--- a/src/corelib/kernel/qcoreapplication.cpp
+++ b/src/corelib/kernel/qcoreapplication.cpp
@@ -377,12 +377,12 @@ QString qAppName()
     QLibrary) can be retrieved with libraryPaths() and manipulated by
     setLibraryPaths(), addLibraryPath(), and removeLibraryPath().
 
-	On Unix/Linux Qt is configured to use the system local settings by 
-	default. This can cause a conflict when using POSIX functions, for 
-	instance, when converting between data types such as floats and 
-	strings, since the notation may differ between locales. To get 
-	around this problem call the POSIX function setlocale(LC_NUMERIC,"C") 
-	right after initializing QApplication or QCoreApplication to reset 
+	On Unix/Linux Qt is configured to use the system local settings by
+	default. This can cause a conflict when using POSIX functions, for
+	instance, when converting between data types such as floats and
+	strings, since the notation may differ between locales. To get
+	around this problem call the POSIX function setlocale(LC_NUMERIC,"C")
+	right after initializing QApplication or QCoreApplication to reset
 	the locale that is used for number formatting to "C"-locale.
 
     \sa QApplication, QAbstractEventDispatcher, QEventLoop,
@@ -556,6 +556,20 @@ void QCoreApplication::setAttribute(Qt::ApplicationAttribute attribute, bool on)
         QCoreApplicationPrivate::attribs |= 1 << attribute;
     else
         QCoreApplicationPrivate::attribs &= ~(1 << attribute);
+#ifdef Q_OS_MAC
+    // Turn on the no native menubar here, since we used to
+    // do this implicitly. We DO NOT flip it off if someone sets
+    // it to false.
+    // Ideally, we'd have magic that would be something along the lines of
+    // "follow MacPluginApplication" unless explicitly set.
+    // Considering this attribute isn't only at the beginning
+    // it's unlikely it will ever be a problem, but I want
+    // to have the behavior documented here.
+    if (attribute == Qt::AA_MacPluginApplication && on
+          && !testAttribute(Qt::AA_DontUseNativeMenuBar)) {
+        setAttribute(Qt::AA_DontUseNativeMenuBar, true);
+    }
+#endif
 }
 
 /*!
@@ -1696,7 +1710,7 @@ QString QCoreApplication::applicationDirPath()
     }
 
     QCoreApplicationPrivate *d = self->d_func();
-    if (d->cachedApplicationDirPath == QString())
+    if (d->cachedApplicationDirPath.isNull())
         d->cachedApplicationDirPath = QFileInfo(applicationFilePath()).path();
     return d->cachedApplicationDirPath;
 }
@@ -1724,7 +1738,7 @@ QString QCoreApplication::applicationFilePath()
     }
 
     QCoreApplicationPrivate *d = self->d_func();
-    if (d->cachedApplicationFilePath != QString())
+    if (!d->cachedApplicationFilePath.isNull())
         return d->cachedApplicationFilePath;
 
 #if defined( Q_WS_WIN )
@@ -1908,8 +1922,7 @@ QStringList QCoreApplication::arguments()
                 l1arg == "-qdebug" ||
                 l1arg == "-reverse" ||
                 l1arg == "-stylesheet" ||
-                l1arg == "-widgetcount" ||
-                l1arg == "-direct3d")
+                l1arg == "-widgetcount")
                 ;
             else if (l1arg.startsWith("-style="))
                 ;
diff --git a/src/corelib/kernel/qfunctions_wince.cpp b/src/corelib/kernel/qfunctions_wince.cpp
index 1c929c7..e0f7687 100644
--- a/src/corelib/kernel/qfunctions_wince.cpp
+++ b/src/corelib/kernel/qfunctions_wince.cpp
@@ -285,11 +285,6 @@ int qt_wince_SetErrorMode(int newValue)
     return result;
 }
 
-HRESULT qt_wince_CoInitialize(void* reserved)
-{
-    return CoInitializeEx(reserved, 0);
-}
-
 bool qt_wince__chmod(const char *file, int mode)
 {
     return _wchmod( reinterpret_cast<const wchar_t *> (QString::fromLatin1(file).utf16()), mode);
diff --git a/src/corelib/kernel/qfunctions_wince.h b/src/corelib/kernel/qfunctions_wince.h
index 123bd23..5f08bb3 100644
--- a/src/corelib/kernel/qfunctions_wince.h
+++ b/src/corelib/kernel/qfunctions_wince.h
@@ -199,7 +199,9 @@ int qt_wince__fstat( int handle, struct stat *buffer);
 #define SEM_FAILCRITICALERRORS 0x0001
 #define SEM_NOOPENFILEERRORBOX 0x0002
 int qt_wince_SetErrorMode(int);
-HRESULT qt_wince_CoInitialize(void* reserved);
+#ifndef CoInitialize
+#define CoInitialize(x) CoInitializeEx(x, COINIT_MULTITHREADED)
+#endif
 
 bool qt_wince__chmod(const char *file, int mode);
 bool qt_wince__wchmod(const WCHAR *file, int mode);
@@ -376,7 +378,6 @@ typedef DWORD OLE_COLOR;
 #define _rename(a,b)            qt_wince__rename(a,b)
 #define _remove(a)              qt_wince__remove(a)
 #define SetErrorMode(a)         qt_wince_SetErrorMode(a)
-#define CoInitialize(a)         qt_wince_CoInitialize(a)
 #define _chmod(a,b)             qt_wince__chmod(a,b)
 #define _wchmod(a,b)            qt_wince__wchmod(a,b)
 #define CreateFileA(a,b,c,d,e,f,g) qt_wince_CreateFileA(a,b,c,d,e,f,g)
diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp
index 05015c0..cfd8493 100644
--- a/src/corelib/kernel/qobject.cpp
+++ b/src/corelib/kernel/qobject.cpp
@@ -58,6 +58,7 @@
 #include <qsemaphore.h>
 
 #include <private/qorderedmutexlocker_p.h>
+#include <private/qmutexpool_p.h>
 
 #include <new>
 
@@ -70,7 +71,7 @@ static int DIRECT_CONNECTION_ONLY = 0;
 
 static int *queuedConnectionTypes(const QList<QByteArray> &typeNames)
 {
-    int *types = static_cast<int *>(qMalloc((typeNames.count() + 1) * sizeof(int)));
+    int *types = new int [typeNames.count() + 1];
     for (int i = 0; i < typeNames.count(); ++i) {
         const QByteArray typeName = typeNames.at(i);
         if (typeName.endsWith('*'))
@@ -82,7 +83,7 @@ static int *queuedConnectionTypes(const QList<QByteArray> &typeNames)
             qWarning("QObject::connect: Cannot queue arguments of type '%s'\n"
                      "(Make sure '%s' is registered using qRegisterMetaType().)",
                      typeName.constData(), typeName.constData());
-            qFree(types);
+            delete [] types;
             return 0;
         }
     }
@@ -91,12 +92,35 @@ static int *queuedConnectionTypes(const QList<QByteArray> &typeNames)
     return types;
 }
 
+QBasicAtomicPointer<QMutexPool> signalSlotMutexes = Q_BASIC_ATOMIC_INITIALIZER(0);
+QBasicAtomicInt objectCount = Q_BASIC_ATOMIC_INITIALIZER(0);
+
+/** \internal
+ * mutex to be locked when accessing the connectionlists or the senders list
+ */
+static QMutex *signalSlotLock(const QObject *o)
+{
+    if (!signalSlotMutexes) {
+        QMutexPool *mp = new QMutexPool;
+        if (!signalSlotMutexes.testAndSetOrdered(0, mp)) {
+            delete mp;
+        }
+    }
+    return signalSlotMutexes->get(o);
+}
+
 extern "C" Q_CORE_EXPORT void qt_addObject(QObject *)
 {
+    objectCount.ref();
 }
 
 extern "C" Q_CORE_EXPORT void qt_removeObject(QObject *)
 {
+    if(!objectCount.deref()) {
+        QMutexPool *old = signalSlotMutexes;
+        signalSlotMutexes.testAndSetAcquire(old, 0);
+        delete old;
+    }
 }
 
 QObjectPrivate::QObjectPrivate(int version)
@@ -216,19 +240,20 @@ public:
     }
 };
 
+// Used by QAccessibleWidget
 bool QObjectPrivate::isSender(const QObject *receiver, const char *signal) const
 {
     Q_Q(const QObject);
     int signal_index = q->metaObject()->indexOfSignal(signal);
     if (signal_index < 0)
         return false;
-    QMutexLocker locker(&threadData->mutex);
+    QMutexLocker locker(signalSlotLock(q));
     if (connectionLists) {
         if (signal_index < connectionLists->count()) {
             const ConnectionList &connectionList = connectionLists->at(signal_index);
             for (int i = 0; i < connectionList.count(); ++i) {
-                const QObjectPrivate::Connection &c = connectionList.at(i);
-                if (c.receiver && c.receiver == receiver)
+                const QObjectPrivate::Connection *c = connectionList.at(i);
+                if (c->receiver == receiver)
                     return true;
             }
         }
@@ -236,6 +261,7 @@ bool QObjectPrivate::isSender(const QObject *receiver, const char *signal) const
     return false;
 }
 
+// Used by QAccessibleWidget
 QObjectList QObjectPrivate::receiverList(const char *signal) const
 {
     Q_Q(const QObject);
@@ -243,26 +269,27 @@ QObjectList QObjectPrivate::receiverList(const char *signal) const
     int signal_index = q->metaObject()->indexOfSignal(signal);
     if (signal_index < 0)
         return returnValue;
-    QMutexLocker locker(&threadData->mutex);
+    QMutexLocker locker(signalSlotLock(q));
     if (connectionLists) {
         if (signal_index < connectionLists->count()) {
             const ConnectionList &connectionList = connectionLists->at(signal_index);
             for (int i = 0; i < connectionList.count(); ++i) {
-                const QObjectPrivate::Connection &c = connectionList.at(i);
-                if (c.receiver)
-                    returnValue << c.receiver;
+                const QObjectPrivate::Connection *c = connectionList.at(i);
+                if (c->receiver)
+                    returnValue << c->receiver;
             }
         }
     }
     return returnValue;
 }
 
+// Used by QAccessibleWidget
 QObjectList QObjectPrivate::senderList() const
 {
     QObjectList returnValue;
-    QMutexLocker locker(&threadData->mutex);
+    QMutexLocker locker(signalSlotLock(q_func()));
     for (int i = 0; i < senders.count(); ++i)
-        returnValue << senders.at(i).sender;
+        returnValue << senders.at(i)->sender;
     return returnValue;
 }
 
@@ -274,33 +301,11 @@ void QObjectPrivate::addConnection(int signal, Connection *c)
         connectionLists->resize(signal + 1);
 
     ConnectionList &connectionList = (*connectionLists)[signal];
-    connectionList.append(*c);
+    connectionList.append(c);
 
     cleanConnectionLists();
 }
 
-void QObjectPrivate::removeReceiver(int signal, QObject *receiver)
-{
-    if (!connectionLists)
-        return;
-
-    if (signal >= connectionLists->count())
-        return;
-
-    ConnectionList &connectionList = (*connectionLists)[signal];
-    for (int i = 0; i < connectionList.count(); ++i) {
-        Connection &c = connectionList[i];
-        if (c.receiver == receiver) {
-            c.receiver = 0;
-            if (c.argumentTypes && c.argumentTypes != &DIRECT_CONNECTION_ONLY) {
-                qFree(c.argumentTypes);
-                c.argumentTypes = 0;
-            }
-            connectionLists->dirty = true;
-        }
-    }
-}
-
 void QObjectPrivate::cleanConnectionLists()
 {
     if (connectionLists->dirty && !connectionLists->inUse) {
@@ -308,55 +313,17 @@ void QObjectPrivate::cleanConnectionLists()
         for (int signal = -1; signal < connectionLists->count(); ++signal) {
             QObjectPrivate::ConnectionList &connectionList = (*connectionLists)[signal];
             for (int i = 0; i < connectionList.count(); ++i) {
-                const QObjectPrivate::Connection &c = connectionList.at(i);
-                if (!c.receiver)
+                QObjectPrivate::Connection *c = connectionList.at(i);
+                if (!c->receiver) {
+                    delete c;
                     connectionList.removeAt(i--);
+                }
             }
         }
         connectionLists->dirty = false;
     }
 }
 
-void QObjectPrivate::refSender(QObject *sender, int signal)
-{
-    for (int i = 0; i < senders.count(); ++i) {
-        Sender &s = senders[i];
-        if (s.sender == sender && s.signal == signal) {
-            ++s.ref;
-            return;
-        }
-    }
-
-    Sender s = { sender, signal, 1 };
-    senders.append(s);
-}
-
-void QObjectPrivate::derefSender(QObject *sender, int signal)
-{
-    for (int i = 0; i < senders.count(); ++i) {
-        Sender &s = senders[i];
-        if (s.sender == sender && s.signal == signal) {
-            if (--s.ref == 0) {
-                senders.removeAt(i);
-                break;
-            }
-        }
-    }
-    // Q_ASSERT_X(false, "QObjectPrivate::derefSender", "sender not found");
-}
-
-void QObjectPrivate::removeSender(QObject *sender, int signal)
-{
-    for (int i = 0; i < senders.count(); ++i) {
-        Sender &s = senders[i];
-        if (s.sender == sender && s.signal == signal) {
-            senders.removeAt(i);
-            return;
-        }
-    }
-    // Q_ASSERT_X(false, "QObjectPrivate::removeSender", "sender not found");
-}
-
 QObjectPrivate::Sender *QObjectPrivate::setCurrentSender(QObject *receiver,
                                                          Sender *sender)
 {
@@ -769,7 +736,7 @@ QObject::~QObject()
     emit destroyed(this);
 
     {
-        QMutexLocker locker(&d->threadData->mutex);
+        QMutexLocker locker(signalSlotLock(this));
 
         // set ref to zero to indicate that this object has been deleted
         if (d->currentSender != 0)
@@ -782,23 +749,21 @@ QObject::~QObject()
             for (int signal = -1; signal < d->connectionLists->count(); ++signal) {
                 QObjectPrivate::ConnectionList &connectionList = (*d->connectionLists)[signal];
                 for (int i = 0; i < connectionList.count(); ++i) {
-                    QObjectPrivate::Connection *c = &connectionList[i];
-                    if (!c->receiver)
+                    QObjectPrivate::Connection *c = connectionList[i];
+                    if (!c->receiver) {
+                        delete c;
                         continue;
+                    }
 
-                    QMutex *m = &c->receiver->d_func()->threadData->mutex;
+                    QMutex *m = signalSlotLock(c->receiver);
                     bool needToUnlock = QOrderedMutexLocker::relock(locker.mutex(), m);
-                    c = &connectionList[i];
+                    c = connectionList[i];
                     if (c->receiver)
-                        c->receiver->d_func()->removeSender(this, signal);
+                        c->receiver->d_func()->senders.removeOne(c);
                     if (needToUnlock)
                         m->unlock();
 
-                    if (c->argumentTypes && c->argumentTypes != &DIRECT_CONNECTION_ONLY) {
-                        qFree(c->argumentTypes);
-                        c->argumentTypes = 0;
-                    }
-                    c->receiver = 0;
+                    delete c;
                 }
             }
 
@@ -811,18 +776,26 @@ QObject::~QObject()
         }
 
         // disconnect all senders
-        for (int i = 0; i < d->senders.count(); ++i) {
-            QObjectPrivate::Sender *s = &d->senders[i];
-            if (!s->sender)
-                continue;
+        for (int i = 0; i < d->senders.count(); ) {
+            QObjectPrivate::Connection *s = d->senders[i];
 
-            QMutex *m = &s->sender->d_func()->threadData->mutex;
+            QMutex *m = signalSlotLock(s->sender);
             bool needToUnlock = QOrderedMutexLocker::relock(locker.mutex(), m);
-            s = &d->senders[i];
-            if (s->sender)
-                s->sender->d_func()->removeReceiver(s->signal, this);
+            if (m < locker.mutex()) {
+                if (i >= d->senders.count() || s != d->senders[i]) {
+                    if (needToUnlock)
+                        m->unlock();
+                    continue;
+                }
+            }
+            s->receiver = 0;
+            QObjectConnectionListVector *senderLists = s->sender->d_func()->connectionLists;
+            if (senderLists)
+                senderLists->dirty = true;
+
             if (needToUnlock)
                 m->unlock();
+            ++i;
         }
 
         d->senders.clear();
@@ -866,6 +839,12 @@ QObject::~QObject()
     d_ptr = 0;
 }
 
+QObjectPrivate::Connection::~Connection()
+{
+    if (argumentTypes != &DIRECT_CONNECTION_ONLY)
+        delete [] argumentTypes;
+}
+
 
 /*!
     \fn QMetaObject *QObject::metaObject() const
@@ -2297,14 +2276,14 @@ QObject *QObject::sender() const
 {
     Q_D(const QObject);
 
-    QMutexLocker(&d->threadData->mutex);
+    QMutexLocker(signalSlotLock(this));
     if (!d->currentSender)
         return 0;
 
     // Return 0 if d->currentSender isn't in d->senders
     bool found = false;
     for (int i = 0; !found && i < d->senders.count(); ++i)
-        found = (d->senders.at(i).sender == d->currentSender->sender);
+        found = (d->senders.at(i)->sender == d->currentSender->sender);
     if (!found)
         return 0;
     return d->currentSender->sender;
@@ -2353,14 +2332,14 @@ int QObject::receivers(const char *signal) const
         }
 
         Q_D(const QObject);
-        QMutexLocker locker(&d->threadData->mutex);
+        QMutexLocker locker(signalSlotLock(this));
         if (d->connectionLists) {
             if (signal_index < d->connectionLists->count()) {
                 const QObjectPrivate::ConnectionList &connectionList =
                     d->connectionLists->at(signal_index);
                 for (int i = 0; i < connectionList.count(); ++i) {
-                    const QObjectPrivate::Connection &c = connectionList.at(i);
-                    receivers += c.receiver ? 1 : 0;
+                    const QObjectPrivate::Connection *c = connectionList.at(i);
+                    receivers += c->receiver ? 1 : 0;
                 }
             }
         }
@@ -2793,20 +2772,18 @@ bool QMetaObject::connect(const QObject *sender, int signal_index,
     QObject *s = const_cast<QObject *>(sender);
     QObject *r = const_cast<QObject *>(receiver);
 
-    QOrderedMutexLocker locker(&s->d_func()->threadData->mutex,
-                               &r->d_func()->threadData->mutex);
+    QObjectPrivate::Connection *c = new QObjectPrivate::Connection;
+    c->sender = s;
+    c->receiver = r;
+    c->method = method_index;
+    c->connectionType = type;
+    c->argumentTypes = types;
 
-#if defined(Q_CC_HPACC) && defined(QT_ARCH_PARISC)
-    QObjectPrivate::Connection c;
-    c.receiver = r;
-    c.method = method_index;
-    c.connectionType = type;
-    c.argumentTypes = types;
-#else
-    QObjectPrivate::Connection c = { r, method_index, type, Q_BASIC_ATOMIC_INITIALIZER(types) };
-#endif
-    s->d_func()->addConnection(signal_index, &c);
-    r->d_func()->refSender(s, signal_index);
+    QOrderedMutexLocker locker(signalSlotLock(sender),
+                               signalSlotLock(receiver));
+
+    s->d_func()->addConnection(signal_index, c);
+    r->d_func()->senders.append(c);
 
     if (signal_index < 0)
         sender->d_func()->connectedSignals = ~0u;
@@ -2828,8 +2805,8 @@ bool QMetaObject::disconnect(const QObject *sender, int signal_index,
     QObject *s = const_cast<QObject *>(sender);
     QObject *r = const_cast<QObject *>(receiver);
 
-    QMutex *senderMutex = &s->d_func()->threadData->mutex;
-    QMutex *receiverMutex = r ? &r->d_func()->threadData->mutex : 0;
+    QMutex *senderMutex = signalSlotLock(sender);
+    QMutex *receiverMutex = receiver ? signalSlotLock(receiver) : 0;
     QOrderedMutexLocker locker(senderMutex, receiverMutex);
 
     QObjectConnectionListVector *connectionLists = s->d_func()->connectionLists;
@@ -2845,27 +2822,23 @@ bool QMetaObject::disconnect(const QObject *sender, int signal_index,
         for (signal_index = -1; signal_index < connectionLists->count(); ++signal_index) {
             QObjectPrivate::ConnectionList &connectionList = (*connectionLists)[signal_index];
             for (int i = 0; i < connectionList.count(); ++i) {
-                QObjectPrivate::Connection *c = &connectionList[i];
+                QObjectPrivate::Connection *c = connectionList[i];
                 if (c->receiver
                     && (r == 0 || (c->receiver == r
                                    && (method_index < 0 || c->method == method_index)))) {
-                    QMutex *m = &c->receiver->d_func()->threadData->mutex;
+                    QMutex *m = signalSlotLock(c->receiver);
+                    bool needToUnlock = false;
                     if (!receiverMutex && senderMutex != m) {
                         // need to relock this receiver and sender in the correct order
-                        bool needToUnlock = QOrderedMutexLocker::relock(senderMutex, m);
-                        c = &connectionList[i];
-                        if (c->receiver)
-                            c->receiver->d_func()->derefSender(s, signal_index);
-                        if (needToUnlock)
-                            m->unlock();
-                    } else {
-                        // no need to unlock
-                        c->receiver->d_func()->derefSender(s, signal_index);
-                    }
-                    if (c->argumentTypes && c->argumentTypes != &DIRECT_CONNECTION_ONLY) {
-                        qFree(c->argumentTypes);
-                        c->argumentTypes = 0;
+                        needToUnlock = QOrderedMutexLocker::relock(senderMutex, m);
+                        c = connectionList[i];
                     }
+                    if (c->receiver)
+                        c->receiver->d_func()->senders.removeOne(c);
+
+                    if (needToUnlock)
+                        m->unlock();
+
                     c->receiver = 0;
 
                     success = true;
@@ -2876,27 +2849,22 @@ bool QMetaObject::disconnect(const QObject *sender, int signal_index,
     } else if (signal_index < connectionLists->count()) {
         QObjectPrivate::ConnectionList &connectionList = (*connectionLists)[signal_index];
         for (int i = 0; i < connectionList.count(); ++i) {
-            QObjectPrivate::Connection *c = &connectionList[i];
+            QObjectPrivate::Connection *c = connectionList[i];
             if (c->receiver
                 && (r == 0 || (c->receiver == r
                                && (method_index < 0 || c->method == method_index)))) {
-                QMutex *m = &c->receiver->d_func()->threadData->mutex;
+                QMutex *m = signalSlotLock(c->receiver);
+                bool needToUnlock = false;
                 if (!receiverMutex && senderMutex != m) {
                     // need to relock this receiver and sender in the correct order
-                    bool needToUnlock = QOrderedMutexLocker::relock(senderMutex, m);
-                    c = &connectionList[i];
-                    if (c->receiver)
-                        c->receiver->d_func()->derefSender(s, signal_index);
-                    if (needToUnlock)
-                        m->unlock();
-                } else {
-                    // no need to unlock
-                    c->receiver->d_func()->derefSender(s, signal_index);
-                }
-                if (c->argumentTypes && c->argumentTypes != &DIRECT_CONNECTION_ONLY) {
-                    qFree(c->argumentTypes);
-                    c->argumentTypes = 0;
+                    needToUnlock = QOrderedMutexLocker::relock(senderMutex, m);
+                    c = connectionList[i];
                 }
+                if (c->receiver)
+                    c->receiver->d_func()->senders.removeOne(c);
+
+                if (needToUnlock)
+                    m->unlock();
                 c->receiver = 0;
 
                 success = true;
@@ -2979,32 +2947,31 @@ void QMetaObject::connectSlotsByName(QObject *o)
     }
 }
 
-static void queued_activate(QObject *sender, int signal, const QObjectPrivate::Connection &c,
+static void queued_activate(QObject *sender, int signal, QObjectPrivate::Connection *c,
                             void **argv, QSemaphore *semaphore = 0)
 {
-    if (!c.argumentTypes || c.argumentTypes != &DIRECT_CONNECTION_ONLY) {
+    if (!c->argumentTypes && c->argumentTypes != &DIRECT_CONNECTION_ONLY) {
         QMetaMethod m = sender->metaObject()->method(signal);
-        QObjectPrivate::Connection &x = const_cast<QObjectPrivate::Connection &>(c);
         int *tmp = queuedConnectionTypes(m.parameterTypes());
         if (!tmp) // cannot queue arguments
             tmp = &DIRECT_CONNECTION_ONLY;
-        if (!x.argumentTypes.testAndSetOrdered(0, tmp)) {
+        if (!c->argumentTypes.testAndSetOrdered(0, tmp)) {
             if (tmp != &DIRECT_CONNECTION_ONLY)
-                qFree(tmp);
+                delete [] tmp;
         }
     }
-    if (c.argumentTypes == &DIRECT_CONNECTION_ONLY) // cannot activate
+    if (c->argumentTypes == &DIRECT_CONNECTION_ONLY) // cannot activate
         return;
     int nargs = 1; // include return type
-    while (c.argumentTypes[nargs-1])
+    while (c->argumentTypes[nargs-1])
         ++nargs;
     int *types = (int *) qMalloc(nargs*sizeof(int));
     void **args = (void **) qMalloc(nargs*sizeof(void *));
     types[0] = 0; // return type
     args[0] = 0; // return value
     for (int n = 1; n < nargs; ++n)
-        args[n] = QMetaType::construct((types[n] = c.argumentTypes[n-1]), argv[n]);
-    QCoreApplication::postEvent(c.receiver, new QMetaCallEvent(c.method,
+        args[n] = QMetaType::construct((types[n] = c->argumentTypes[n-1]), argv[n]);
+    QCoreApplication::postEvent(c->receiver, new QMetaCallEvent(c->method,
                                                                sender,
                                                                signal,
                                                                nargs,
@@ -3013,13 +2980,13 @@ static void queued_activate(QObject *sender, int signal, const QObjectPrivate::C
                                                                semaphore));
 }
 
-static void blocking_activate(QObject *sender, int signal, const QObjectPrivate::Connection &c, void **argv)
+static void blocking_activate(QObject *sender, int signal, QObjectPrivate::Connection *c, void **argv)
 {
-    if (QThread::currentThread() == c.receiver->thread()) {
+    if (QThread::currentThread() == c->receiver->thread()) {
         qWarning("Qt: Dead lock detected while activating a BlockingQueuedConnection: "
                  "Sender is %s(%p), receiver is %s(%p)",
                  sender->metaObject()->className(), sender,
-                 c.receiver->metaObject()->className(), c.receiver);
+                 c->receiver->metaObject()->className(), c->receiver);
     }
 
 #ifdef QT_NO_THREAD
@@ -3027,7 +2994,7 @@ static void blocking_activate(QObject *sender, int signal, const QObjectPrivate:
 #else
     QSemaphore semaphore;
     queued_activate(sender, signal, c, argv, &semaphore);
-    QMutex *mutex = &QThreadData::get2(sender->thread())->mutex;
+    QMutex *mutex = signalSlotLock(sender);
     mutex->unlock();
     semaphore.acquire();
     mutex->lock();
@@ -3047,7 +3014,7 @@ void QMetaObject::activate(QObject *sender, int from_signal_index, int to_signal
                                                          argv ? argv : empty_argv);
     }
 
-    QMutexLocker locker(&sender->d_func()->threadData->mutex);
+    QMutexLocker locker(signalSlotLock(sender));
     QThreadData *currentThreadData = QThreadData::current();
 
     QObjectConnectionListVector *connectionLists = sender->d_func()->connectionLists;
@@ -3069,7 +3036,7 @@ void QMetaObject::activate(QObject *sender, int from_signal_index, int to_signal
         }
         int count = connectionLists->at(signal).count();
         for (int i = 0; i < count; ++i) {
-            const QObjectPrivate::Connection *c = &connectionLists->at(signal)[i];
+            QObjectPrivate::Connection *c = connectionLists->at(signal)[i];
             if (!c->receiver)
                 continue;
 
@@ -3081,10 +3048,10 @@ void QMetaObject::activate(QObject *sender, int from_signal_index, int to_signal
                  && (currentThreadData != sender->d_func()->threadData
                      || receiver->d_func()->threadData != sender->d_func()->threadData))
                 || (c->connectionType == Qt::QueuedConnection)) {
-                queued_activate(sender, signal, *c, argv);
+                queued_activate(sender, signal, c, argv);
                 continue;
             } else if (c->connectionType == Qt::BlockingQueuedConnection) {
-                blocking_activate(sender, signal, *c, argv);
+                blocking_activate(sender, signal, c, argv);
                 continue;
             }
 
@@ -3399,7 +3366,7 @@ void QObject::dumpObjectInfo()
            objectName().isEmpty() ? "unnamed" : objectName().toLocal8Bit().data());
 
     Q_D(QObject);
-    QMutexLocker locker(&d->threadData->mutex);
+    QMutexLocker locker(signalSlotLock(this));
 
     // first, look for connections where this object is the sender
     qDebug("  SIGNALS OUT");
@@ -3412,16 +3379,16 @@ void QObject::dumpObjectInfo()
             // receivers
             const QObjectPrivate::ConnectionList &connectionList = d->connectionLists->at(signal_index);
             for (int i = 0; i < connectionList.count(); ++i) {
-                const QObjectPrivate::Connection &c = connectionList.at(i);
-                if (!c.receiver) {
+                const QObjectPrivate::Connection *c = connectionList.at(i);
+                if (!c->receiver) {
                     qDebug("          <Disconnected receiver>");
                     continue;
                 }
-                const QMetaObject *receiverMetaObject = c.receiver->metaObject();
-                const QMetaMethod method = receiverMetaObject->method(c.method);
+                const QMetaObject *receiverMetaObject = c->receiver->metaObject();
+                const QMetaMethod method = receiverMetaObject->method(c->method);
                 qDebug("          --> %s::%s %s",
                        receiverMetaObject->className(),
-                       c.receiver->objectName().isEmpty() ? "unnamed" : qPrintable(c.receiver->objectName()),
+                       c->receiver->objectName().isEmpty() ? "unnamed" : qPrintable(c->receiver->objectName()),
                        method.signature());
             }
         }
@@ -3434,13 +3401,12 @@ void QObject::dumpObjectInfo()
 
     if (!d->senders.isEmpty()) {
         for (int i = 0; i < d->senders.count(); ++i) {
-            const QObjectPrivate::Sender &s = d->senders.at(i);
-            const QMetaObject *senderMetaObject = s.sender->metaObject();
-            const QMetaMethod signal = senderMetaObject->method(s.signal);
-            qDebug("          <-- %s::%s %s",
-                   senderMetaObject->className(),
-                   s.sender->objectName().isEmpty() ? "unnamed" : qPrintable(s.sender->objectName()),
-                   signal.signature());
+            const QObjectPrivate::Connection *s = d->senders.at(i);
+            const QMetaMethod slot = metaObject()->method(s->method);
+            qDebug("          <-- %s::%s  %s",
+                   s->sender->metaObject()->className(),
+                   s->sender->objectName().isEmpty() ? "unnamed" : qPrintable(s->sender->objectName()),
+                   slot.signature());
         }
     } else {
 	qDebug("        <None>");
diff --git a/src/corelib/kernel/qobject_p.h b/src/corelib/kernel/qobject_p.h
index b324334..96d79af 100644
--- a/src/corelib/kernel/qobject_p.h
+++ b/src/corelib/kernel/qobject_p.h
@@ -114,7 +114,6 @@ public:
         int signal;
         int ref;
     };
-
     // object currently activating the object
     Sender *currentSender;
 
@@ -148,22 +147,20 @@ public:
     // Note: you must hold the signalSlotLock() before accessing the lists below or calling the functions
     struct Connection
     {
+        QObject *sender;
         QObject *receiver;
         int method;
         uint connectionType : 3; // 0 == auto, 1 == direct, 2 == queued, 4 == blocking
         QBasicAtomicPointer<int> argumentTypes;
+        ~Connection();
     };
-    typedef QList<Connection> ConnectionList;
+    typedef QList<Connection *> ConnectionList;
 
     QObjectConnectionListVector *connectionLists;
     void addConnection(int signal, Connection *c);
-    void removeReceiver(int signal, QObject *receiver);
     void cleanConnectionLists();
 
-    QList<Sender> senders;
-    void refSender(QObject *sender, int signal);
-    void derefSender(QObject *sender, int signal);
-    void removeSender(QObject *sender, int signal);
+    ConnectionList senders;
 
     static Sender *setCurrentSender(QObject *receiver,
                                     Sender *sender);
@@ -208,7 +205,7 @@ private:
     QSemaphore *semaphore_;
 };
 
-class Q_CORE_EXPORT QBoolBlocker
+class QBoolBlocker
 {
 public:
     inline QBoolBlocker(bool &b, bool value=true):block(b), reset(b){block = value;}
diff --git a/src/corelib/kernel/qsharedmemory.cpp b/src/corelib/kernel/qsharedmemory.cpp
index 9853079..87e154f 100644
--- a/src/corelib/kernel/qsharedmemory.cpp
+++ b/src/corelib/kernel/qsharedmemory.cpp
@@ -129,6 +129,10 @@ QSharedMemoryPrivate::makePlatformSafeKey(const QString &key,
   detached from the segment, and no references to the segment
   remain. Do not mix using QtSharedMemory and QSharedMemory. Port
   everything to QSharedMemory.
+
+  \warning QSharedMemory changes the key in a Qt-specific way.
+  It is therefore currently not possible to use the shared memory of
+  non-Qt applications with QSharedMemory.
  */
 
 /*!
diff --git a/src/corelib/kernel/qsharedmemory_unix.cpp b/src/corelib/kernel/qsharedmemory_unix.cpp
index 487c653..cd248dc 100644
--- a/src/corelib/kernel/qsharedmemory_unix.cpp
+++ b/src/corelib/kernel/qsharedmemory_unix.cpp
@@ -47,12 +47,9 @@
 #include <qdir.h>
 #include <qdebug.h>
 
-#include <errno.h>
-
-QT_BEGIN_NAMESPACE
-
 #ifndef QT_NO_SHAREDMEMORY
 
+#include <errno.h>
 #include <sys/types.h>
 #include <sys/ipc.h>
 #include <sys/shm.h>
@@ -61,6 +58,8 @@ QT_BEGIN_NAMESPACE
 #include <fcntl.h>
 #include <unistd.h>
 
+QT_BEGIN_NAMESPACE
+
 QSharedMemoryPrivate::QSharedMemoryPrivate()
     : QObjectPrivate(), memory(0), size(0), error(QSharedMemory::NoError),
 #ifndef QT_NO_SYSTEMSEMAPHORE
diff --git a/src/corelib/kernel/qtimer.cpp b/src/corelib/kernel/qtimer.cpp
index 01e81ab..4b3feb0 100644
--- a/src/corelib/kernel/qtimer.cpp
+++ b/src/corelib/kernel/qtimer.cpp
@@ -77,7 +77,7 @@ QT_BEGIN_NAMESPACE
 
     In multithreaded applications, you can use QTimer in any thread
     that has an event loop. To start an event loop from a non-GUI
-    thread, use QThread::exec(). Qt uses the the timer's
+    thread, use QThread::exec(). Qt uses the timer's
     \l{QObject::thread()}{thread affinity} to determine which thread
     will emit the \l{QTimer::}{timeout()} signal. Because of this, you
     must start and stop the timer in its thread; it is not possible to
diff --git a/src/corelib/kernel/qvariant.cpp b/src/corelib/kernel/qvariant.cpp
index b4427c0..2ff9818 100644
--- a/src/corelib/kernel/qvariant.cpp
+++ b/src/corelib/kernel/qvariant.cpp
@@ -71,27 +71,6 @@ QT_BEGIN_NAMESPACE
 #  define FLT_DIG 6
 #endif
 
-
-static const void *constDataHelper(const QVariant::Private &d)
-{
-    switch (d.type) {
-    case QVariant::Int:
-        return &d.data.i;
-    case QVariant::UInt:
-        return &d.data.u;
-    case QVariant::Bool:
-        return &d.data.b;
-    case QVariant::LongLong:
-        return &d.data.ll;
-    case QVariant::ULongLong:
-        return &d.data.ull;
-    case QVariant::Double:
-        return &d.data.d;
-    default:
-        return d.is_shared ? d.data.shared->ptr : reinterpret_cast<const void *>(&d.data.ptr);
-    }
-}
-
 static void construct(QVariant::Private *x, const void *copy)
 {
     x->is_shared = false;
@@ -179,6 +158,9 @@ static void construct(QVariant::Private *x, const void *copy)
     case QVariant::Double:
         x->data.d = copy ? *static_cast<const double*>(copy) : 0.0;
         break;
+    case QMetaType::Float:
+        x->data.f = copy ? *static_cast<const float*>(copy) : 0.0f;
+        break;
     case QVariant::LongLong:
         x->data.ll = copy ? *static_cast<const qlonglong *>(copy) : Q_INT64_C(0);
         break;
@@ -274,6 +256,7 @@ static void clear(QVariant::Private *d)
     case QVariant::LongLong:
     case QVariant::ULongLong:
     case QVariant::Double:
+    case QMetaType::Float:
         break;
     case QVariant::Invalid:
     case QVariant::UserType:
@@ -342,6 +325,7 @@ static bool isNull(const QVariant::Private *d)
     case QVariant::ULongLong:
     case QVariant::Bool:
     case QVariant::Double:
+    case QMetaType::Float:
         break;
     }
     return d->is_null;
@@ -433,6 +417,8 @@ static bool compare(const QVariant::Private *a, const QVariant::Private *b)
         return a->data.b == b->data.b;
     case QVariant::Double:
         return a->data.d == b->data.d;
+    case QMetaType::Float:
+        return a->data.f == b->data.f;
     case QVariant::Date:
         return *v_cast<QDate>(a) == *v_cast<QDate>(b);
     case QVariant::Time:
@@ -491,7 +477,7 @@ static qlonglong qMetaTypeNumber(const QVariant::Private *d)
     case QMetaType::Long:
         return qlonglong(*static_cast<long *>(d->data.shared->ptr));
     case QMetaType::Float:
-        return qRound64(*static_cast<float *>(d->data.shared->ptr));
+        return qRound64(d->data.f);
     case QVariant::Double:
         return qRound64(d->data.d);
     }
@@ -628,7 +614,7 @@ static bool convert(const QVariant::Private *d, QVariant::Type t, void *result,
             *str = QString::number(qMetaTypeUNumber(d));
             break;
         case QMetaType::Float:
-            *str = QString::number(*static_cast<float *>(d->data.shared->ptr), 'g', FLT_DIG);
+            *str = QString::number(d->data.f, 'g', FLT_DIG);
             break;
         case QVariant::Double:
             *str = QString::number(d->data.d, 'g', DBL_DIG);
@@ -799,7 +785,7 @@ static bool convert(const QVariant::Private *d, QVariant::Type t, void *result,
             *ba = QByteArray::number(d->data.d, 'g', DBL_DIG);
             break;
         case QMetaType::Float:
-            *ba = QByteArray::number(*static_cast<float *>(d->data.shared->ptr), 'g', FLT_DIG);
+            *ba = QByteArray::number(d->data.f, 'g', FLT_DIG);
             break;
         case QMetaType::Char:
         case QMetaType::UChar:
@@ -901,7 +887,7 @@ static bool convert(const QVariant::Private *d, QVariant::Type t, void *result,
             *f = double(d->data.b);
             break;
         case QMetaType::Float:
-            *f = *static_cast<float *>(d->data.shared->ptr);
+            *f = double(d->data.f);
             break;
         case QVariant::LongLong:
         case QVariant::Int:
@@ -1035,7 +1021,7 @@ static bool convert(const QVariant::Private *d, QVariant::Type t, void *result,
 #if !defined(QT_NO_DEBUG_STREAM) && !defined(Q_BROKEN_DEBUG_STREAM)
 static void streamDebug(QDebug dbg, const QVariant &v)
 {
-    switch (v.type()) {
+    switch (v.userType()) {
     case QVariant::Int:
         dbg.nospace() << v.toInt();
         break;
@@ -1048,6 +1034,9 @@ static void streamDebug(QDebug dbg, const QVariant &v)
     case QVariant::ULongLong:
         dbg.nospace() << v.toULongLong();
         break;
+    case QMetaType::Float:
+        dbg.nospace() << qVariantValue<float>(v);
+        break;
     case QVariant::Double:
         dbg.nospace() << v.toDouble();
         break;
@@ -1187,8 +1176,9 @@ const QVariant::Handler *QVariant::handler = &qt_kernel_variant_handler;
     and versatile, but may prove less memory and speed efficient than
     storing specific types in standard data structures.
 
-    QVariant also supports the notion of null values, where you have
-    a defined type with no value set.
+    QVariant also supports the notion of null values, where you can 
+    have a defined type with no value set. However, note that QVariant 
+    types can only be cast when they have had a value set.
 
     \snippet doc/src/snippets/code/src_corelib_kernel_qvariant.cpp 1
 
@@ -1355,7 +1345,7 @@ void QVariant::create(int type, const void *copy)
 
 QVariant::~QVariant()
 {
-    if (d.type > Char && (!d.is_shared || !d.data.shared->ref.deref()))
+    if (d.type > Char && d.type != QMetaType::Float && (!d.is_shared || !d.data.shared->ref.deref()))
         handler->clear(&d);
 }
 
@@ -1371,7 +1361,7 @@ QVariant::QVariant(const QVariant &p)
 {
     if (d.is_shared) {
         d.data.shared->ref.ref();
-    } else if (p.d.type > Char) {
+    } else if (p.d.type > Char && p.d.type != QMetaType::Float) {
         handler->construct(&d, p.constData());
         d.is_null = p.d.is_null;
     }
@@ -1565,6 +1555,12 @@ QVariant::QVariant(const char *val)
 */
 
 /*!
+  \fn QVariant::QVariant(float val)
+
+    Constructs a new variant with a floating point value, \a val.
+*/
+
+/*!
     \fn QVariant::QVariant(const QList<QVariant> &val)
 
     Constructs a new variant with a list value, \a val.
@@ -1619,44 +1615,44 @@ QVariant::QVariant(double val)
 { d.is_null = false; d.type = Double; d.data.d = val; }
 
 QVariant::QVariant(const QByteArray &val)
-{ create(ByteArray, &val); }
+{ d.is_null = false; d.type = ByteArray; v_construct<QByteArray>(&d, val); }
 QVariant::QVariant(const QBitArray &val)
-{ create(BitArray, &val); }
+{ d.is_null = false; d.type = BitArray; v_construct<QBitArray>(&d, val);  }
 QVariant::QVariant(const QString &val)
-{ create(String, &val); }
+{ d.is_null = false; d.type = String; v_construct<QString>(&d, val);  }
 QVariant::QVariant(const QChar &val)
-{ create (Char, &val); }
+{ d.is_null = false; d.type = Char; v_construct<QChar>(&d, val);  }
 QVariant::QVariant(const QLatin1String &val)
-{ QString str(val); create(String, &str); }
+{ QString str(val); d.is_null = false; d.type = String; v_construct<QString>(&d, str); }
 QVariant::QVariant(const QStringList &val)
-{ create(StringList, &val); }
+{ d.is_null = false; d.type = StringList; v_construct<QStringList>(&d, val); }
 
 QVariant::QVariant(const QDate &val)
-{ create(Date, &val); }
+{ d.is_null = false; d.type = Date; v_construct<QDate>(&d, val); }
 QVariant::QVariant(const QTime &val)
-{ create(Time, &val); }
+{ d.is_null = false; d.type = Time; v_construct<QTime>(&d, val); }
 QVariant::QVariant(const QDateTime &val)
-{ create(DateTime, &val); }
+{ d.is_null = false; d.type = DateTime; v_construct<QDateTime>(&d, val); }
 QVariant::QVariant(const QList<QVariant> &list)
-{ create(List, &list); }
+{ d.is_null = false; d.type = List; v_construct<QVariantList>(&d, list); }
 QVariant::QVariant(const QMap<QString, QVariant> &map)
-{ create(Map, &map); }
+{ d.is_null = false; d.type = Map; v_construct<QVariantMap>(&d, map); }
 QVariant::QVariant(const QHash<QString, QVariant> &hash)
-{ create(Hash, &hash); }
+{ d.is_null = false; d.type = Hash; v_construct<QVariantHash>(&d, hash); }
 #ifndef QT_NO_GEOM_VARIANT
-QVariant::QVariant(const QPoint &pt) { create(Point, &pt); }
-QVariant::QVariant(const QPointF &pt) { create (PointF, &pt); }
-QVariant::QVariant(const QRectF &r) { create (RectF, &r); }
-QVariant::QVariant(const QLineF &l) { create (LineF, &l); }
-QVariant::QVariant(const QLine &l) { create (Line, &l); }
-QVariant::QVariant(const QRect &r) { create(Rect, &r); }
-QVariant::QVariant(const QSize &s) { create(Size, &s); }
-QVariant::QVariant(const QSizeF &s) { create(SizeF, &s); }
+QVariant::QVariant(const QPoint &pt) { d.is_null = false; d.type = Point; v_construct<QPoint>(&d, pt); }
+QVariant::QVariant(const QPointF &pt) { d.is_null = false; d.type = PointF; v_construct<QPointF>(&d, pt); }
+QVariant::QVariant(const QRectF &r) { d.is_null = false; d.type = RectF; v_construct<QRectF>(&d, r); }
+QVariant::QVariant(const QLineF &l) { d.is_null = false; d.type = LineF; v_construct<QLineF>(&d, l); }
+QVariant::QVariant(const QLine &l) { d.is_null = false; d.type = Line; v_construct<QLine>(&d, l); }
+QVariant::QVariant(const QRect &r) { d.is_null = false; d.type = Rect; v_construct<QRect>(&d, r); }
+QVariant::QVariant(const QSize &s) { d.is_null = false; d.type = Size; v_construct<QSize>(&d, s); }
+QVariant::QVariant(const QSizeF &s) { d.is_null = false; d.type = SizeF; v_construct<QSizeF>(&d, s); }
 #endif
-QVariant::QVariant(const QUrl &u) { create(Url, &u); }
-QVariant::QVariant(const QLocale &l) { create(Locale, &l); }
+QVariant::QVariant(const QUrl &u) { d.is_null = false; d.type = Url; v_construct<QUrl>(&d, u); }
+QVariant::QVariant(const QLocale &l) { d.is_null = false; d.type = Locale; v_construct<QLocale>(&d, l); }
 #ifndef QT_NO_REGEXP
-QVariant::QVariant(const QRegExp &regExp) { create(RegExp, &regExp); }
+QVariant::QVariant(const QRegExp &regExp) { d.is_null = false; d.type = RegExp; v_construct<QRegExp>(&d, regExp); }
 #endif
 QVariant::QVariant(Qt::GlobalColor color) { create(62, &color); }
 
@@ -1721,7 +1717,7 @@ QVariant& QVariant::operator=(const QVariant &variant)
     if (variant.d.is_shared) {
         variant.d.data.shared->ref.ref();
         d = variant.d;
-    } else if (variant.d.type > Char) {
+    } else if (variant.d.type > Char && variant.d.type != QMetaType::Float) {
         d.type = variant.d.type;
         handler->construct(&d, variant.constData());
         d.is_null = variant.d.is_null;
@@ -1907,7 +1903,7 @@ void QVariant::load(QDataStream &s)
     }
 
     // const cast is safe since we operate on a newly constructed variant
-    if (!QMetaType::load(s, d.type, const_cast<void *>(constDataHelper(d)))) {
+    if (!QMetaType::load(s, d.type, const_cast<void *>(constData()))) {
         s.setStatus(QDataStream::ReadCorruptData);
         qWarning("QVariant::load: unable to load type %d.", d.type);
     }
@@ -1947,7 +1943,7 @@ void QVariant::save(QDataStream &s) const
         return;
     }
 
-    if (!QMetaType::save(s, d.type, constDataHelper(d))) {
+    if (!QMetaType::save(s, d.type, constData())) {
         Q_ASSERT_X(false, "QVariant::save", "Invalid type to save");
         qWarning("QVariant::save: unable to save type %d.", d.type);
     }
@@ -2565,57 +2561,63 @@ static const quint32 qCanConvertMatrix[QVariant::LastCoreType + 1] =
 */
 bool QVariant::canConvert(Type t) const
 {
-    if (d.type == uint(t))
+    //we can treat floats as double
+    //the reason for not doing it the "proper" way is that QMetaType::Float's value is 135,
+    //which can't be handled by qCanConvertMatrix
+    //In addition QVariant::Type doesn't have a Float value, so we're using QMetaType::Float
+    const uint currentType = ((d.type == QMetaType::Float) ? QVariant::Double : d.type);
+    if (uint(t) == uint(QMetaType::Float)) t = QVariant::Double;
+
+    if (currentType == uint(t))
         return true;
 
-    if (d.type > QVariant::LastCoreType || t > QVariant::LastCoreType) {
+    if (currentType > QVariant::LastCoreType || t > QVariant::LastCoreType) {
         switch (uint(t)) {
         case QVariant::Int:
-            return d.type == QVariant::KeySequence
-                   || d.type == QMetaType::ULong
-                   || d.type == QMetaType::Long
-                   || d.type == QMetaType::UShort
-                   || d.type == QMetaType::UChar
-                   || d.type == QMetaType::Char
-                   || d.type == QMetaType::Short;
+            return currentType == QVariant::KeySequence
+                   || currentType == QMetaType::ULong
+                   || currentType == QMetaType::Long
+                   || currentType == QMetaType::UShort
+                   || currentType == QMetaType::UChar
+                   || currentType == QMetaType::Char
+                   || currentType == QMetaType::Short;
         case QVariant::Image:
-            return d.type == QVariant::Pixmap || d.type == QVariant::Bitmap;
+            return currentType == QVariant::Pixmap || currentType == QVariant::Bitmap;
         case QVariant::Pixmap:
-            return d.type == QVariant::Image || d.type == QVariant::Bitmap
-                              || d.type == QVariant::Brush;
+            return currentType == QVariant::Image || currentType == QVariant::Bitmap
+                              || currentType == QVariant::Brush;
         case QVariant::Bitmap:
-            return d.type == QVariant::Pixmap || d.type == QVariant::Image;
+            return currentType == QVariant::Pixmap || currentType == QVariant::Image;
         case QVariant::ByteArray:
-            return d.type == QVariant::Color;
+            return currentType == QVariant::Color;
         case QVariant::String:
-            return d.type == QVariant::KeySequence || d.type == QVariant::Font
-                              || d.type == QVariant::Color;
+            return currentType == QVariant::KeySequence || currentType == QVariant::Font
+                              || currentType == QVariant::Color;
         case QVariant::KeySequence:
-            return d.type == QVariant::String || d.type == QVariant::Int;
+            return currentType == QVariant::String || currentType == QVariant::Int;
         case QVariant::Font:
-            return d.type == QVariant::String;
+            return currentType == QVariant::String;
         case QVariant::Color:
-            return d.type == QVariant::String || d.type == QVariant::ByteArray
-                              || d.type == QVariant::Brush;
+            return currentType == QVariant::String || currentType == QVariant::ByteArray
+                              || currentType == QVariant::Brush;
         case QVariant::Brush:
-            return d.type == QVariant::Color || d.type == QVariant::Pixmap;
+            return currentType == QVariant::Color || currentType == QVariant::Pixmap;
         case QMetaType::Long:
         case QMetaType::Char:
         case QMetaType::UChar:
         case QMetaType::ULong:
         case QMetaType::Short:
         case QMetaType::UShort:
-        case QMetaType::Float:
-            return qCanConvertMatrix[QVariant::Int] & (1 << d.type) || d.type == QVariant::Int;
+            return qCanConvertMatrix[QVariant::Int] & (1 << currentType) || currentType == QVariant::Int;
         default:
             return false;
         }
     }
 
-    if(t == String && d.type == StringList)
+    if(t == String && currentType == StringList)
         return v_cast<QStringList>(&d)->count() == 1;
     else
-        return qCanConvertMatrix[t] & (1 << d.type);
+        return qCanConvertMatrix[t] & (1 << currentType);
 }
 
 /*!
@@ -2726,7 +2728,7 @@ bool QVariant::cmp(const QVariant &v) const
 
 const void *QVariant::constData() const
 {
-    return constDataHelper(d);
+    return d.is_shared ? d.data.shared->ptr : reinterpret_cast<const void *>(&d.data.ptr);
 }
 
 /*!
@@ -2739,7 +2741,7 @@ const void *QVariant::constData() const
 void* QVariant::data()
 {
     detach();
-    return const_cast<void *>(constDataHelper(d));
+    return const_cast<void *>(constData());
 }
 
 
diff --git a/src/corelib/kernel/qvariant.h b/src/corelib/kernel/qvariant.h
index d7b7e3c..d73fcbc 100644
--- a/src/corelib/kernel/qvariant.h
+++ b/src/corelib/kernel/qvariant.h
@@ -181,6 +181,7 @@ class Q_CORE_EXPORT QVariant
     QVariant(qulonglong ull);
     QVariant(bool b);
     QVariant(double d);
+    QVariant(float f) { d.is_null = false; d.type = QMetaType::Float; d.data.f = f; }
 #ifndef QT_NO_CAST_FROM_ASCII
     QT_ASCII_CAST_WARN_CONSTRUCTOR QVariant(const char *str);
 #endif
@@ -349,6 +350,7 @@ class Q_CORE_EXPORT QVariant
             uint u;
             bool b;
             double d;
+            float f;
             qlonglong ll;
             qulonglong ull;
             void *ptr;
@@ -443,7 +445,18 @@ inline QVariant qVariantFromValue(const QVariant &t) { return t; }
 template <typename T>
 inline void qVariantSetValue(QVariant &v, const T &t)
 {
-    v = QVariant(qMetaTypeId<T>(reinterpret_cast<T *>(0)), &t);
+    //if possible we reuse the current QVariant private
+    const int type = qMetaTypeId<T>(reinterpret_cast<T *>(0));
+    QVariant::Private &d = v.data_ptr();
+    if (type <= int(QVariant::Char) || (type == d.type && v.isDetached())) {
+        d.type = type;
+        T *old = reinterpret_cast<T*>(d.is_shared ? d.data.shared->ptr : &d.data.ptr);
+        if (QTypeInfo<T>::isComplex)
+            old->~T();
+        new (old) T(t); //call the copy constructor
+    } else {
+        v = QVariant(type, &t);
+    }
 }
 
 inline QVariant::QVariant() {}
diff --git a/src/corelib/kernel/qvariant_p.h b/src/corelib/kernel/qvariant_p.h
index 0764fe3..033b760 100644
--- a/src/corelib/kernel/qvariant_p.h
+++ b/src/corelib/kernel/qvariant_p.h
@@ -60,8 +60,6 @@
 
 QT_BEGIN_NAMESPACE
 
-extern Q_CORE_EXPORT const QVariant::Handler *qExtendedVariantHandler;
-
 #ifdef Q_CC_SUN // Sun CC picks the wrong overload, so introduce awful hack
 
 template <typename T>
@@ -70,7 +68,7 @@ inline T *v_cast(const QVariant::Private *nd, T * = 0)
     QVariant::Private *d = const_cast<QVariant::Private *>(nd);
     return ((sizeof(T) > sizeof(QVariant::Private::Data))
             ? static_cast<T *>(d->data.shared->ptr)
-            : reinterpret_cast<T*>(&d->data.c));
+            : static_cast<T *>(static_cast<void *>(&d->data.c)));
 }
 
 #else // every other compiler in this world
@@ -80,7 +78,7 @@ inline const T *v_cast(const QVariant::Private *d, T * = 0)
 {
     return ((sizeof(T) > sizeof(QVariant::Private::Data))
             ? static_cast<const T *>(d->data.shared->ptr)
-            : reinterpret_cast<const T *>(&d->data.c));
+            : static_cast<const T *>(static_cast<const void *>(&d->data.c)));
 }
 
 template <typename T>
@@ -88,15 +86,17 @@ inline T *v_cast(QVariant::Private *d, T * = 0)
 {
     return ((sizeof(T) > sizeof(QVariant::Private::Data))
             ? static_cast<T *>(d->data.shared->ptr)
-            : reinterpret_cast<T *>(&d->data.c));
+            : static_cast<T *>(static_cast<void *>(&d->data.c)));
 }
 
 #endif
 
-//a simple template that avoids to allocate 2 buffers when creating a QVariant
+
+//a simple template that avoids to allocate 2 memory chunks when creating a QVariant
 template <class T> class QVariantPrivateSharedEx : public QVariant::PrivateShared
 {
 public:
+    QVariantPrivateSharedEx() : QVariant::PrivateShared(&m_t) { }
     QVariantPrivateSharedEx(const T&t) : QVariant::PrivateShared(&m_t), m_t(t) { }
 
 private:
@@ -105,14 +105,12 @@ private:
 
 // constructs a new variant if copy is 0, otherwise copy-constructs
 template <class T>
-inline void v_construct(QVariant::Private *x, const T& t)
+inline void v_construct(QVariant::Private *x, const T &t)
 {
-    x->type = qMetaTypeId<T>(reinterpret_cast<T *>(0));
     if (sizeof(T) > sizeof(QVariant::Private::Data)) {
         x->data.shared = new QVariantPrivateSharedEx<T>(t);
         x->is_shared = true;
     } else {
-        x->is_shared = false;
         new (&x->data.ptr) T(t);
     }
 }
@@ -120,24 +118,31 @@ inline void v_construct(QVariant::Private *x, const T& t)
 template <class T>
 inline void v_construct(QVariant::Private *x, const void *copy, T * = 0)
 {
-    if (copy) {
-      v_construct<T>(x, *reinterpret_cast<const T*>(copy));
+    if (sizeof(T) > sizeof(QVariant::Private::Data)) {
+        x->data.shared = copy ? new QVariantPrivateSharedEx<T>(*static_cast<const T *>(copy))
+                              : new QVariantPrivateSharedEx<T>;
+        x->is_shared = true;
     } else {
-      T t;
-      v_construct<T>(x, t);
+        if (copy)
+            new (&x->data.ptr) T(*static_cast<const T *>(copy));
+        else
+            new (&x->data.ptr) T;
     }
 }
 
-
 // deletes the internal structures
 template <class T>
 inline void v_clear(QVariant::Private *d, T* = 0)
 {
-    //now we need to call the destructor in any case
-    //because QVariant::PrivateShared doesn't have a virtual destructor
-    v_cast<T>(d)->~T();
-    if (sizeof(T) > sizeof(QVariant::Private::Data))
-        delete d->data.shared;
+    
+    if (sizeof(T) > sizeof(QVariant::Private::Data)) {
+        //now we need to cast
+        //because QVariant::PrivateShared doesn't have a virtual destructor
+        delete static_cast<QVariantPrivateSharedEx<T>*>(d->data.shared);
+    } else {
+        v_cast<T>(d)->~T();
+    }
+
 }
 
 QT_END_NAMESPACE