Merge branch 'master' of git@scm.dev.nokia.troll.no:qt/qt into qtscript-jsc-backend

Conflicts:
	src/script/qscriptextqobject.cpp

6 files changed, 277 insertions, 86 deletions

diff --git a/src/corelib/tools/qbytedata_p.h b/src/corelib/tools/qbytedata_p.h
index cc10ea2..f3724f6 100644
--- a/src/corelib/tools/qbytedata_p.h
+++ b/src/corelib/tools/qbytedata_p.h
@@ -42,8 +42,18 @@
 #ifndef QBYTEDATA_H
 #define QBYTEDATA_H
 
-#include <qbytearray.h>
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
 
+#include <qbytearray.h>
 
 QT_BEGIN_NAMESPACE
 
diff --git a/src/corelib/tools/qcontiguouscache.h b/src/corelib/tools/qcontiguouscache.h
index 0020d22..7221925 100644
--- a/src/corelib/tools/qcontiguouscache.h
+++ b/src/corelib/tools/qcontiguouscache.h
@@ -44,6 +44,7 @@
 
 #include <QtCore/qatomic.h>
 #include <limits.h>
+#include <new>
 
 QT_BEGIN_HEADER
 
@@ -76,6 +77,12 @@ struct QContiguousCacheTypedData
     int start;
     int offset;
     uint sharable : 1;
+    // uint unused : 31;
+
+    // total is 24 bytes (HP-UX aCC: 40 bytes)
+    // the next entry is already aligned to 8 bytes
+    // there will be an 8 byte gap here if T requires 16-byte alignment
+    //  (such as long double on 64-bit platforms, __int128, __float128)
 
     T array[1];
 };
diff --git a/src/corelib/tools/qshareddata.cpp b/src/corelib/tools/qshareddata.cpp
index 3cd37a7..6cd220c 100644
--- a/src/corelib/tools/qshareddata.cpp
+++ b/src/corelib/tools/qshareddata.cpp
@@ -51,7 +51,7 @@ QT_BEGIN_NAMESPACE
 
   QSharedData is designed to be used with QSharedDataPointer or
   QExplicitlySharedDataPointer to implement custom \l{implicitly
-  shared} or \l {explicitly shared} classes. QSharedData provides
+  shared} or explicitly shared classes. QSharedData provides
   \l{thread-safe} reference counting.
 
  See QSharedDataPointer and QExplicitlySharedDataPointer for details.
diff --git a/src/corelib/tools/qsharedpointer.cpp b/src/corelib/tools/qsharedpointer.cpp
index 59dfffe..f18dee8 100644
--- a/src/corelib/tools/qsharedpointer.cpp
+++ b/src/corelib/tools/qsharedpointer.cpp
@@ -128,7 +128,7 @@
 
     To access the pointer that QWeakPointer is tracking, you
     must first create a QSharedPointer object and verify if the pointer
-    is null or not.
+    is null or not. See QWeakPointer::toStrongRef() for more information.
 
     \sa QSharedPointer
 */
@@ -210,6 +210,8 @@
     If \tt T is a derived type of the template parameter of this
     class, QSharedPointer will perform an automatic cast. Otherwise,
     you will get a compiler error.
+
+    \sa QWeakPointer::toStrongRef()
 */
 
 /*!
@@ -362,6 +364,8 @@
 
     Returns a weak reference object that shares the pointer referenced
     by this object.
+
+    \sa QWeakPointer::QWeakPointer()
 */
 
 /*!
@@ -478,10 +482,78 @@
 */
 
 /*!
+    \fn T *QWeakPointer::data() const
+    \since 4.6
+
+    Returns the value of the pointer being tracked by this QWeakPointer,
+    \b without ensuring that it cannot get deleted. To have that guarantee,
+    use toStrongRef(), which returns a QSharedPointer object. If this
+    function can determine that the pointer has already been deleted, it
+    returns 0.
+
+    It is ok to obtain the value of the pointer and using that value itself,
+    like for example in debugging statements:
+
+    \code
+        qDebug("Tracking %p", weakref.data());
+    \endcode
+
+    However, dereferencing the pointer is only allowed if you can guarantee
+    by external means that the pointer does not get deleted. For example,
+    if you can be certain that no other thread can delete it, nor the
+    functions that you may call.
+
+    If that is the case, then the following code is valid:
+
+    \code
+        // this pointer cannot be used in another thread
+        // so other threads cannot delete it
+        QWeakPointer<int> weakref = obtainReference();
+
+        Object *obj = weakref.data();
+        if (obj) {
+            // if the pointer wasn't deleted yet, we know it can't get
+            // deleted by our own code here nor the functions we call
+            otherFunction(obj);
+        }
+    \endcode
+
+    Use this function with care.
+
+    \sa isNull(), toStrongRef()
+*/
+
+/*!
     \fn QSharedPointer<T> QWeakPointer::toStrongRef() const
 
     Promotes this weak reference to a strong one and returns a
-    QSharedPointer object holding that reference.
+    QSharedPointer object holding that reference. When promoting to
+    QSharedPointer, this function verifies if the object has been deleted
+    already or not. If it hasn't, this function increases the reference
+    count to the shared object, thus ensuring that it will not get
+    deleted.
+
+    Since this function can fail to obtain a valid strong reference to the
+    shared object, you should always verify if the conversion succeeded,
+    by calling QSharedPointer::isNull() on the returned object.
+
+    For example, the following code promotes a QWeakPointer that was held
+    to a strong reference and, if it succeeded, it prints the value of the
+    integer that was held:
+
+    \code
+        QWeakPointer<int> weakref;
+
+        // ...
+
+        QSharedPointer<int> strong = weakref.toStrongRef();
+        if (strong)
+            qDebug() << "The value is:" << *strong;
+        else
+            qDebug() << "The value has already been deleted";
+    \endcode
+
+    \sa QSharedPointer::QSharedPointer()
 */
 
 /*!
@@ -792,6 +864,56 @@
 #include <qset.h>
 #include <qmutex.h>
 
+#if !defined(QT_NO_QOBJECT)
+#include "../kernel/qobject_p.h"
+
+/*!
+    \internal
+    This function is called for a just-created QObject \a obj, to enable
+    the use of QSharedPointer and QWeakPointer.
+
+    When QSharedPointer is active in a QObject, the object must not be deleted
+    directly: the lifetime is managed by the QSharedPointer object. In that case,
+    the deleteLater() and parent-child relationship in QObject only decrease
+    the strong reference count, instead of deleting the object.
+*/
+void QtSharedPointer::ExternalRefCountData::setQObjectShared(const QObject *obj, bool)
+{
+    Q_ASSERT(obj);
+    QObjectPrivate *d = QObjectPrivate::get(const_cast<QObject *>(obj));
+
+    if (d->sharedRefcount)
+        qFatal("QSharedPointer: pointer %p already has reference counting", obj);
+    d->sharedRefcount = this;
+
+    // QObject decreases the refcount too, so increase it up
+    weakref.ref();
+}
+
+QtSharedPointer::ExternalRefCountData *QtSharedPointer::ExternalRefCountData::getAndRef(const QObject *obj)
+{
+    Q_ASSERT(obj);
+    QObjectPrivate *d = QObjectPrivate::get(const_cast<QObject *>(obj));
+    ExternalRefCountData *that = d->sharedRefcount;
+    if (that) {
+        that->weakref.ref();
+        return that;
+    }
+
+    // we can create the refcount data because it doesn't exist
+    ExternalRefCountData *x = new ExternalRefCountData(Qt::Uninitialized);
+    x->strongref = -1;
+    x->weakref = 2;  // the QWeakPointer that called us plus the QObject itself
+    if (!d->sharedRefcount.testAndSetRelease(0, x)) {
+        delete x;
+        d->sharedRefcount->weakref.ref();
+    }
+    return d->sharedRefcount;
+}
+#endif
+
+
+
 #if !defined(QT_NO_MEMBER_TEMPLATES)
 
 //#  define QT_SHARED_POINTER_BACKTRACE_SUPPORT
@@ -897,6 +1019,7 @@ QT_BEGIN_NAMESPACE
 namespace QtSharedPointer {
     Q_CORE_EXPORT void internalSafetyCheckAdd(const volatile void *);
     Q_CORE_EXPORT void internalSafetyCheckRemove(const volatile void *);
+    Q_AUTOTEST_EXPORT void internalSafetyCheckCleanCheck();
 }
 
 /*!
@@ -961,6 +1084,7 @@ void QtSharedPointer::internalSafetyCheckAdd2(const void *d_ptr, const volatile
 
     kp->dPointers.insert(d_ptr, data);
     kp->dataPointers.insert(ptr, d_ptr);
+    Q_ASSERT(kp->dPointers.size() == kp->dataPointers.size());
 }
 
 /*!
@@ -985,10 +1109,29 @@ void QtSharedPointer::internalSafetyCheckRemove2(const void *d_ptr)
     Q_ASSERT(it2 != kp->dataPointers.end());
 
     //qDebug("Removing d=%p value=%p", d_ptr, it->pointer);
-    
+
     // remove entries
     kp->dataPointers.erase(it2);
     kp->dPointers.erase(it);
+    Q_ASSERT(kp->dPointers.size() == kp->dataPointers.size());
+}
+
+/*!
+    \internal
+    Called by the QSharedPointer autotest
+*/
+void QtSharedPointer::internalSafetyCheckCleanCheck()
+{
+#  ifdef QT_BUILD_INTERNAL
+    KnownPointers *const kp = knownPointers();
+    Q_ASSERT_X(kp, "internalSafetyCheckSelfCheck()", "Called after global statics deletion!");
+
+    if (kp->dPointers.size() != kp->dataPointers.size())
+        qFatal("Internal consistency error: the number of pointers is not equal!");
+
+    if (!kp->dPointers.isEmpty())
+        qFatal("Pointer cleaning failed: %d entries remaining", kp->dPointers.size());
+#  endif
 }
 
 QT_END_NAMESPACE
diff --git a/src/corelib/tools/qsharedpointer.h b/src/corelib/tools/qsharedpointer.h
index abd83ad..2f86ce7 100644
--- a/src/corelib/tools/qsharedpointer.h
+++ b/src/corelib/tools/qsharedpointer.h
@@ -115,6 +115,7 @@ public:
     QWeakPointer<T> operator=(const QWeakPointer<T> &other);
     QWeakPointer<T> operator=(const QSharedPointer<T> &other);
 
+    T *data() const;
     void clear();
 
     QSharedPointer<T> toStrongRef() const;
diff --git a/src/corelib/tools/qsharedpointer_impl.h b/src/corelib/tools/qsharedpointer_impl.h
index b8f4139..8a34362 100644
--- a/src/corelib/tools/qsharedpointer_impl.h
+++ b/src/corelib/tools/qsharedpointer_impl.h
@@ -94,26 +94,27 @@ namespace QtSharedPointer {
     template <class T> class InternalRefCount;
     template <class T> class ExternalRefCount;
 
-    template <class X, class T> QSharedPointer<X> strongRefFromWeakHelper(const QWeakPointer<T> &, X*);
     template <class X, class Y> QSharedPointer<X> copyAndSetPointer(X * ptr, const QSharedPointer<Y> &src);
 
     // used in debug mode to verify the reuse of pointers
     Q_CORE_EXPORT void internalSafetyCheckAdd2(const void *, const volatile void *);
     Q_CORE_EXPORT void internalSafetyCheckRemove2(const void *);
-    
+
     template <class T, typename Klass, typename RetVal>
     inline void executeDeleter(T *t, RetVal (Klass:: *memberDeleter)())
     { (t->*memberDeleter)(); }
     template <class T, typename Deleter>
     inline void executeDeleter(T *t, Deleter d)
     { d(t); }
+    template <class T> inline void normalDeleter(T *t) { delete t; }
+
+    // this uses partial template specialization
+    // the only compilers that didn't support this were MSVC 6.0 and 2002
+    template <class T> struct RemovePointer;
+    template <class T> struct RemovePointer<T *> { typedef T Type; };
+    template <class T> struct RemovePointer<QSharedPointer<T> > { typedef T Type; };
+    template <class T> struct RemovePointer<QWeakPointer<T> > { typedef T Type; };
 
-    //
-    // Depending on its template parameter, QSharedPointer derives from either
-    // QtSharedPointer::InternalRefCount or from QtSharedPointer::ExternalRefCount.
-    // Both of these classes derive from QtSharedPointer::Basic, which provides common
-    // operations,
-    //
     template <class T>
     class Basic
     {
@@ -129,21 +130,10 @@ namespace QtSharedPointer {
         inline T *operator->() const { return data(); }
 
     protected:
-        inline Basic() : value(0) { }
+        inline Basic(T *ptr = 0) : value(ptr) { }
+        inline Basic(Qt::Initialization) { }
         // ~Basic();
 
-        inline void verifyReconstruction(const T *ptr)
-        {
-            Q_ASSERT_X(!ptr || value != ptr, "QSharedPointer",
-                       "QSharedPointer violation: you cannot create two QSharedPointer objects "
-                       "from the same pointer");
-
-            // make use of the "ptr" variable in the no-op statement below
-            // since this function is in a public header, we don't
-            // want warnings on "unused variables" to show up everywhere
-            ptr = 0;
-        }
-
         inline void internalConstruct(T *ptr)
         {
             value = ptr;
@@ -160,14 +150,26 @@ namespace QtSharedPointer {
 
     struct ExternalRefCountData
     {
-        QAtomicInt weakref;
-        QAtomicInt strongref;
+        QBasicAtomicInt weakref;
+        QBasicAtomicInt strongref;
 
-        inline ExternalRefCountData() : weakref(1), strongref(1) { }
-        virtual inline ~ExternalRefCountData() { Q_ASSERT(!weakref); Q_ASSERT(!strongref); }
+        inline ExternalRefCountData()
+        {
+            QBasicAtomicInt proto = Q_BASIC_ATOMIC_INITIALIZER(1);
+            weakref = strongref = proto;
+        }
+        inline ExternalRefCountData(Qt::Initialization) { }
+        virtual inline ~ExternalRefCountData() { Q_ASSERT(!weakref); Q_ASSERT(strongref <= 0); }
 
         virtual inline bool destroy() { return false; }
+
+#ifndef QT_NO_QOBJECT
+        Q_CORE_EXPORT static ExternalRefCountData *getAndRef(const QObject *);
+        Q_CORE_EXPORT void setQObjectShared(const QObject *, bool enable);
+#endif
+        inline void setQObjectShared(...) { }
     };
+    // sizeof(ExternalRefCount) = 12 (32-bit) / 16 (64-bit)
 
     template <class T, typename Deleter>
     struct CustomDeleter
@@ -177,6 +179,9 @@ namespace QtSharedPointer {
 
         inline CustomDeleter(T *p, Deleter d) : deleter(d), ptr(p) {}
     };
+    // sizeof(CustomDeleter) = sizeof(Deleter) + sizeof(void*)
+    // for Deleter = function pointer:  8 (32-bit) / 16 (64-bit)
+    // for Deleter = PMF: 12 (32-bit) / 24 (64-bit)  (GCC)
 
     struct ExternalRefCountWithDestroyFn: public ExternalRefCountData
     {
@@ -190,6 +195,7 @@ namespace QtSharedPointer {
         inline bool destroy() { destroyer(this); return true; }
         inline void operator delete(void *ptr) { ::operator delete(ptr); }
     };
+    // sizeof(ExternalRefCountWithDestroyFn) = 16 (32-bit) / 24 (64-bit)
 
     template <class T, typename Deleter>
     struct ExternalRefCountWithCustomDeleter: public ExternalRefCountWithDestroyFn
@@ -203,11 +209,23 @@ namespace QtSharedPointer {
         {
             Self *realself = static_cast<Self *>(self);
             executeDeleter(realself->extra.ptr, realself->extra.deleter);
+
+            // delete the deleter too
+            realself->extra.~Next();
+        }
+        static void safetyCheckDeleter(ExternalRefCountData *self)
+        {
+            internalSafetyCheckRemove2(self);
+            deleter(self);
         }
 
         static inline Self *create(T *ptr, Deleter userDeleter)
         {
+# ifdef QT_SHAREDPOINTER_TRACK_POINTERS
+            DestroyerFn destroy = &safetyCheckDeleter;
+# else
             DestroyerFn destroy = &deleter;
+# endif
             Self *d = static_cast<Self *>(::operator new(sizeof(Self)));
 
             // initialize the two sub-objects
@@ -234,10 +252,19 @@ namespace QtSharedPointer {
                     static_cast<ExternalRefCountWithContiguousData *>(self);
             that->data.~T();
         }
+        static void safetyCheckDeleter(ExternalRefCountData *self)
+        {
+            internalSafetyCheckRemove2(self);
+            deleter(self);
+        }
 
         static inline ExternalRefCountData *create(T **ptr)
         {
+# ifdef QT_SHAREDPOINTER_TRACK_POINTERS
+            DestroyerFn destroy = &safetyCheckDeleter;
+# else
             DestroyerFn destroy = &deleter;
+# endif
             ExternalRefCountWithContiguousData *d =
                 static_cast<ExternalRefCountWithContiguousData *>(::operator new(sizeof(ExternalRefCountWithContiguousData)));
 
@@ -258,9 +285,9 @@ namespace QtSharedPointer {
     template <class T>
     class ExternalRefCount: public Basic<T>
     {
-        typedef ExternalRefCountData Data;
-        typedef void (*DeleterFunction)(T *);
     protected:
+        typedef ExternalRefCountData Data;
+
         inline void ref() const { d->weakref.ref(); d->strongref.ref(); }
         inline bool deref()
         {
@@ -272,42 +299,51 @@ namespace QtSharedPointer {
 
         inline void internalConstruct(T *ptr)
         {
-            Basic<T>::internalConstruct(ptr);
-            Q_ASSERT(!d);
+#ifdef QT_SHAREDPOINTER_TRACK_POINTERS
+            internalConstruct<void (*)(T *)>(ptr, normalDeleter);
+#else
             if (ptr)
                 d = new Data;
-#ifdef QT_SHAREDPOINTER_TRACK_POINTERS
-            if (ptr) internalSafetyCheckAdd2(d, ptr);
+            else
+                d = 0;
+            internalFinishConstruction(ptr);
 #endif
         }
 
         template <typename Deleter>
         inline void internalConstruct(T *ptr, Deleter deleter)
         {
-            Basic<T>::internalConstruct(ptr);
-            Q_ASSERT(!d);
             if (ptr)
                 d = ExternalRefCountWithCustomDeleter<T, Deleter>::create(ptr, deleter);
-#ifdef QT_SHAREDPOINTER_TRACK_POINTERS
-            if (ptr) internalSafetyCheckAdd2(d, ptr);
-#endif
+            else
+                d = 0;
+            internalFinishConstruction(ptr);
         }
 
         inline void internalCreate()
         {
             T *ptr;
             d = ExternalRefCountWithContiguousData<T>::create(&ptr);
+            Basic<T>::internalConstruct(ptr);
+        }
 
+        inline void internalFinishConstruction(T *ptr)
+        {
             Basic<T>::internalConstruct(ptr);
+            if (ptr) d->setQObjectShared(ptr, true);
 #ifdef QT_SHAREDPOINTER_TRACK_POINTERS
             if (ptr) internalSafetyCheckAdd2(d, ptr);
 #endif
         }
 
         inline ExternalRefCount() : d(0) { }
-        inline ~ExternalRefCount() { if (d && !deref()) delete d; }
+        inline ExternalRefCount(Qt::Initialization i) : Basic<T>(i) { }
         inline ExternalRefCount(const ExternalRefCount<T> &other) : Basic<T>(other), d(other.d)
         { if (d) ref(); }
+        template <class X>
+        inline ExternalRefCount(const ExternalRefCount<X> &other) : Basic<T>(other.value), d(other.d)
+        { if (d) ref(); }
+        inline ~ExternalRefCount() { if (d && !deref()) delete d; }
 
         template <class X>
         inline void internalCopy(const ExternalRefCount<X> &other)
@@ -317,32 +353,35 @@ namespace QtSharedPointer {
 
         inline void internalDestroy()
         {
-#ifdef QT_SHAREDPOINTER_TRACK_POINTERS
-            internalSafetyCheckRemove2(d);
-#endif
             if (!d->destroy())
                 delete this->value;
         }
 
-    private:
 #if defined(Q_NO_TEMPLATE_FRIENDS)
     public:
 #else
         template <class X> friend class ExternalRefCount;
         template <class X> friend class QWeakPointer;
         template <class X, class Y> friend QSharedPointer<X> copyAndSetPointer(X * ptr, const QSharedPointer<Y> &src);
-        template <class X, class Y> friend QSharedPointer<X> QtSharedPointer::strongRefFromWeakHelper(const QWeakPointer<Y> &src, X *);
 #endif
 
         inline void internalSet(Data *o, T *actual)
         {
-            if (d == o) return;
-            if (o && !o->strongref)
-                o = 0;
             if (o) {
-                verifyReconstruction(actual);
-                o->weakref.ref();
-                o->strongref.ref();
+                // increase the strongref, but never up from zero
+                // or less (-1 is used by QWeakPointer on untracked QObject)
+                register int tmp = o->strongref;
+                while (tmp > 0) {
+                    // try to increment from "tmp" to "tmp + 1"
+                    if (o->strongref.testAndSetRelaxed(tmp, tmp + 1))
+                        break;   // succeeded
+                    tmp = o->strongref;  // failed, try again
+                }
+
+                if (tmp > 0)
+                    o->weakref.ref();
+                else
+                    o = 0;
             }
             if (d && !deref())
                 delete d;
@@ -350,9 +389,6 @@ namespace QtSharedPointer {
             this->value = d && d->strongref ? actual : 0;
         }
 
-#if defined(QT_BUILD_INTERNAL)
-    public:
-#endif
         Data *d;
 
     private:
@@ -368,7 +404,8 @@ public:
     inline QSharedPointer() { }
     // inline ~QSharedPointer() { }
 
-    inline explicit QSharedPointer(T *ptr) { internalConstruct(ptr); }
+    inline explicit QSharedPointer(T *ptr) : BaseClass(Qt::Uninitialized)
+    { internalConstruct(ptr); }
 
     template <typename Deleter>
     inline QSharedPointer(T *ptr, Deleter d) { internalConstruct(ptr, d); }
@@ -380,13 +417,9 @@ public:
         return *this;
     }
 
-    inline QSharedPointer(const QWeakPointer<T> &other)
-    { *this = QtSharedPointer::strongRefFromWeakHelper(other, static_cast<T*>(0)); }
-    inline QSharedPointer<T> &operator=(const QWeakPointer<T> &other)
-    { *this = QtSharedPointer::strongRefFromWeakHelper(other, static_cast<T*>(0)); return *this; }
-
     template <class X>
-    inline QSharedPointer(const QSharedPointer<X> &other) { *this = other; }
+    inline QSharedPointer(const QSharedPointer<X> &other) : BaseClass(other)
+    { }
 
     template <class X>
     inline QSharedPointer<T> &operator=(const QSharedPointer<X> &other)
@@ -397,12 +430,12 @@ public:
     }
 
     template <class X>
-    inline QSharedPointer(const QWeakPointer<X> &other)
-    { *this = QtSharedPointer::strongRefFromWeakHelper(other, static_cast<T *>(0)); }
+    inline QSharedPointer(const QWeakPointer<X> &other) : BaseClass(Qt::Uninitialized)
+    { this->d = 0; *this = other; }
 
     template <class X>
     inline QSharedPointer<T> &operator=(const QWeakPointer<X> &other)
-    { *this = strongRefFromWeakHelper(other, static_cast<T *>(0)); return *this; }
+    { internalSet(other.d, other.value); return *this; }
 
     template <class X>
     QSharedPointer<X> staticCast() const
@@ -434,14 +467,18 @@ public:
 
     QWeakPointer<T> toWeakRef() const;
 
+protected:
+    inline QSharedPointer(Qt::Initialization i) : BaseClass(i) {}
+
 public:
     static inline QSharedPointer<T> create()
     {
-        QSharedPointer<T> result;
+        QSharedPointer<T> result(Qt::Uninitialized);
         result.internalCreate();
 
         // now initialize the data
         new (result.data()) T();
+        result.internalFinishConstruction(result.data());
         return result;
     }
 };
@@ -456,9 +493,19 @@ public:
     inline bool isNull() const { return d == 0 || d->strongref == 0 || value == 0; }
     inline operator RestrictedBool() const { return isNull() ? 0 : &QWeakPointer::value; }
     inline bool operator !() const { return isNull(); }
+    inline T *data() const { return d == 0 || d->strongref == 0 ? 0 : value; }
 
     inline QWeakPointer() : d(0), value(0) { }
     inline ~QWeakPointer() { if (d && !d->weakref.deref()) delete d; }
+
+    // special constructor that is enabled only if X derives from QObject
+    template <class X>
+    inline QWeakPointer(X *ptr) : d(ptr ? d->getAndRef(ptr) : 0), value(ptr)
+    { }
+    template <class X>
+    inline QWeakPointer &operator=(X *ptr)
+    { return *this = QWeakPointer(ptr); }
+
     inline QWeakPointer(const QWeakPointer<T> &o) : d(o.d), value(o.value)
     { if (d) d->weakref.ref(); }
     inline QWeakPointer<T> &operator=(const QWeakPointer<T> &o)
@@ -510,7 +557,7 @@ public:
 
     template <class X>
     inline bool operator==(const QSharedPointer<X> &o) const
-    { return d == o.d && value == static_cast<const T *>(o.data()); }
+    { return d == o.d; }
 
     template <class X>
     inline bool operator!=(const QSharedPointer<X> &o) const
@@ -525,7 +572,7 @@ private:
 #if defined(Q_NO_TEMPLATE_FRIENDS)
 public:
 #else
-    template <class X, class Y> friend QSharedPointer<X> QtSharedPointer::strongRefFromWeakHelper(const QWeakPointer<Y> &src, X *);
+    template <class X> friend class QSharedPointer;
 #endif
 
     inline void internalSet(Data *o, T *actual)
@@ -602,14 +649,6 @@ namespace QtSharedPointer {
         result.internalSet(src.d, ptr);
         return result;
     }
-    template <class X, class T>
-    Q_INLINE_TEMPLATE QSharedPointer<X> strongRefFromWeakHelper
-        (const QT_PREPEND_NAMESPACE(QWeakPointer<T>) &src, X *)
-    {
-        QSharedPointer<X> result;
-        result.internalSet(src.d, src.value);
-        return result;
-    }
 }
 
 // cast operators
@@ -669,14 +708,6 @@ Q_INLINE_TEMPLATE QSharedPointer<X> qSharedPointerObjectCast(const QWeakPointer<
     return qSharedPointerObjectCast<X>(src.toStrongRef());
 }
 
-# ifndef QT_NO_PARTIAL_TEMPLATE_SPECIALIZATION
-namespace QtSharedPointer {
-    template <class T> struct RemovePointer;
-    template <class T> struct RemovePointer<T *> { typedef T Type; };
-    template <class T> struct RemovePointer<QSharedPointer<T> > { typedef T Type; };
-    template <class T> struct RemovePointer<QWeakPointer<T> > { typedef T Type; };
-}
-
 template <class X, class T>
 inline QSharedPointer<typename QtSharedPointer::RemovePointer<X>::Type>
 qobject_cast(const QSharedPointer<T> &src)
@@ -689,7 +720,6 @@ qobject_cast(const QWeakPointer<T> &src)
 {
     return qSharedPointerObjectCast<typename QtSharedPointer::RemovePointer<X>::Type, T>(src);
 }
-# endif
 
 #endif