1 files changed, 39 insertions, 9 deletions

diff --git a/src/corelib/tools/qarraydatapointer.h b/src/corelib/tools/qarraydatapointer.h
index eb20330f0f..6657d40cf9 100644
--- a/src/corelib/tools/qarraydatapointer.h
+++ b/src/corelib/tools/qarraydatapointer.h
@@ -27,27 +27,39 @@ public:
 
     typedef typename std::conditional<pass_parameter_by_value, T, const T &>::type parameter_type;
 
+    Q_NODISCARD_CTOR
     constexpr QArrayDataPointer() noexcept
         : d(nullptr), ptr(nullptr), size(0)
     {
     }
 
+    Q_NODISCARD_CTOR
     QArrayDataPointer(const QArrayDataPointer &other) noexcept
         : d(other.d), ptr(other.ptr), size(other.size)
     {
         ref();
     }
 
+    Q_NODISCARD_CTOR
     constexpr QArrayDataPointer(Data *header, T *adata, qsizetype n = 0) noexcept
         : d(header), ptr(adata), size(n)
     {
     }
 
-    explicit QArrayDataPointer(QPair<QTypedArrayData<T> *, T *> adata, qsizetype n = 0) noexcept
+    Q_NODISCARD_CTOR
+    explicit QArrayDataPointer(std::pair<QTypedArrayData<T> *, T *> adata, qsizetype n = 0) noexcept
         : d(adata.first), ptr(adata.second), size(n)
     {
     }
 
+    Q_NODISCARD_CTOR explicit
+    QArrayDataPointer(qsizetype alloc, qsizetype n = 0,
+                      QArrayData::AllocationOption option = QArrayData::KeepSize)
+        : QArrayDataPointer(Data::allocate(alloc, option), n)
+    {
+    }
+
+    Q_NODISCARD_CTOR
     static QArrayDataPointer fromRawData(const T *rawData, qsizetype length) noexcept
     {
         Q_ASSERT(rawData || !length);
@@ -61,12 +73,12 @@ public:
         return *this;
     }
 
+    Q_NODISCARD_CTOR
     QArrayDataPointer(QArrayDataPointer &&other) noexcept
-        : d(other.d), ptr(other.ptr), size(other.size)
+        : d(std::exchange(other.d, nullptr)),
+          ptr(std::exchange(other.ptr, nullptr)),
+          size(std::exchange(other.size, 0))
     {
-        other.d = nullptr;
-        other.ptr = nullptr;
-        other.size = 0;
     }
 
     QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QArrayDataPointer)
@@ -320,13 +332,11 @@ public:
         if constexpr (IsFwdIt) {
             const qsizetype n = std::distance(first, last);
             if (needsDetach() || n > constAllocatedCapacity()) {
-                QArrayDataPointer allocated(Data::allocate(detachCapacity(n)));
-                Q_CHECK_PTR(allocated.data());
+                QArrayDataPointer allocated(detachCapacity(n));
                 swap(allocated);
             }
         } else if (needsDetach()) {
-            QArrayDataPointer allocated(Data::allocate(allocatedCapacity()));
-            Q_CHECK_PTR(allocated.data());
+            QArrayDataPointer allocated(allocatedCapacity());
             swap(allocated);
             // We don't want to copy data that we know we'll overwrite
         }
@@ -402,6 +412,26 @@ public:
         size = dst - begin();
     }
 
+    QArrayDataPointer sliced(qsizetype pos, qsizetype n) const &
+    {
+        QArrayDataPointer result(n);
+        std::uninitialized_copy_n(begin() + pos, n, result.begin());
+        result.size = n;
+        return result;
+    }
+
+    QArrayDataPointer sliced(qsizetype pos, qsizetype n) &&
+    {
+        if (needsDetach())
+            return sliced(pos, n);
+        T *newBeginning = begin() + pos;
+        std::destroy(begin(), newBeginning);
+        std::destroy(newBeginning + n, end());
+        setBegin(newBeginning);
+        size = n;
+        return std::move(*this);
+    }
+
     // forwards from QArrayData
     qsizetype allocatedCapacity() noexcept { return d ? d->allocatedCapacity() : 0; }
     qsizetype constAllocatedCapacity() const noexcept { return d ? d->constAllocatedCapacity() : 0; }