3 files changed, 44 insertions, 13 deletions

diff --git a/src/corelib/tools/qarraydata.cpp b/src/corelib/tools/qarraydata.cpp
index 150f23cc12..efed984aef 100644
--- a/src/corelib/tools/qarraydata.cpp
+++ b/src/corelib/tools/qarraydata.cpp
@@ -49,7 +49,7 @@ static const QArrayData qt_array_empty = { Q_REFCOUNT_INITIALIZE_STATIC, 0, 0, 0
 static const QArrayData qt_array_unsharable_empty = { { Q_BASIC_ATOMIC_INITIALIZER(0) }, 0, 0, 0, 0 };
 
 QArrayData *QArrayData::allocate(size_t objectSize, size_t alignment,
-        size_t capacity, bool reserve, bool sharable)
+        size_t capacity, AllocateOptions options)
 {
     // Alignment is a power of two
     Q_ASSERT(alignment >= Q_ALIGNOF(QArrayData)
@@ -57,7 +57,7 @@ QArrayData *QArrayData::allocate(size_t objectSize, size_t alignment,
 
     // Don't allocate empty headers
     if (!capacity)
-        return sharable
+        return !(options & Unsharable)
             ? const_cast<QArrayData *>(&qt_array_empty)
             : const_cast<QArrayData *>(&qt_array_unsharable_empty);
 
@@ -73,10 +73,10 @@ QArrayData *QArrayData::allocate(size_t objectSize, size_t alignment,
         quintptr data = (quintptr(header) + sizeof(QArrayData) + alignment - 1)
                 & ~(alignment - 1);
 
-        header->ref.atomic.store(sharable ? 1 : 0);
+        header->ref.atomic.store(bool(!(options & Unsharable)));
         header->size = 0;
         header->alloc = capacity;
-        header->capacityReserved = reserve;
+        header->capacityReserved = bool(options & CapacityReserved);
         header->offset = data - quintptr(header);
     }
 
diff --git a/src/corelib/tools/qarraydata.h b/src/corelib/tools/qarraydata.h
index 2486bebafa..8eb543ee51 100644
--- a/src/corelib/tools/qarraydata.h
+++ b/src/corelib/tools/qarraydata.h
@@ -73,14 +73,43 @@ struct Q_CORE_EXPORT QArrayData
         return reinterpret_cast<const char *>(this) + offset;
     }
 
+    enum AllocateOption {
+        CapacityReserved = 0x1,
+        Unsharable = 0x2,
+
+        Default = 0
+    };
+
+    Q_DECLARE_FLAGS(AllocateOptions, AllocateOption)
+
+    AllocateOptions detachFlags() const
+    {
+        AllocateOptions result;
+        if (!ref.isSharable())
+            result |= Unsharable;
+        if (capacityReserved)
+            result |= CapacityReserved;
+        return result;
+    }
+
+    AllocateOptions cloneFlags() const
+    {
+        AllocateOptions result;
+        if (capacityReserved)
+            result |= CapacityReserved;
+        return result;
+    }
+
     static QArrayData *allocate(size_t objectSize, size_t alignment,
-            size_t capacity, bool reserve, bool sharable) Q_REQUIRED_RESULT;
+            size_t capacity, AllocateOptions options = Default) Q_REQUIRED_RESULT;
     static void deallocate(QArrayData *data, size_t objectSize,
             size_t alignment);
 
     static const QArrayData shared_null;
 };
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(QArrayData::AllocateOptions)
+
 template <class T>
 struct QTypedArrayData
     : QArrayData
@@ -98,11 +127,11 @@ struct QTypedArrayData
 
     class AlignmentDummy { QArrayData header; T data; };
 
-    static QTypedArrayData *allocate(size_t capacity, bool reserve = false,
-            bool sharable = true) Q_REQUIRED_RESULT
+    static QTypedArrayData *allocate(size_t capacity,
+            AllocateOptions options = Default) Q_REQUIRED_RESULT
     {
         return static_cast<QTypedArrayData *>(QArrayData::allocate(sizeof(T),
-                    Q_ALIGNOF(AlignmentDummy), capacity, reserve, sharable));
+                    Q_ALIGNOF(AlignmentDummy), capacity, options));
     }
 
     static void deallocate(QArrayData *data)
diff --git a/src/corelib/tools/qarraydatapointer.h b/src/corelib/tools/qarraydatapointer.h
index c03e2ef849..1dc02daa63 100644
--- a/src/corelib/tools/qarraydatapointer.h
+++ b/src/corelib/tools/qarraydatapointer.h
@@ -66,7 +66,7 @@ public:
     QArrayDataPointer(const QArrayDataPointer &other)
         : d(other.d->ref.ref()
             ? other.d
-            : other.clone())
+            : other.clone(other.d->cloneFlags()))
     {
     }
 
@@ -115,7 +115,9 @@ public:
     void setSharable(bool sharable)
     {
         if (d->alloc == 0 && d->size == 0) {
-            d = Data::allocate(0, false, sharable);
+            d = Data::allocate(0, sharable
+                    ? QArrayData::Default
+                    : QArrayData::Unsharable);
             return;
         }
 
@@ -137,7 +139,7 @@ public:
     bool detach()
     {
         if (d->ref.isShared()) {
-            Data *copy = clone();
+            Data *copy = clone(d->detachFlags());
             QArrayDataPointer old(d);
             d = copy;
             return true;
@@ -147,10 +149,10 @@ public:
     }
 
 private:
-    Data *clone() const Q_REQUIRED_RESULT
+    Data *clone(QArrayData::AllocateOptions options) const Q_REQUIRED_RESULT
     {
         QArrayDataPointer copy(Data::allocate(d->alloc ? d->alloc : d->size,
-                    d->capacityReserved));
+                    options));
         if (d->size)
             copy->copyAppend(d->begin(), d->end());