Introduce QArrayData::detachCapacity

This follows QArrayData::detachFlags's lead. Given the (known) size for
a detached container, the function helps determine capacity, ensuring
the capacityReserved flag is respected.

This further helps aggregating behaviour on detach in QArrayData itself.

SimpleVector was previously using qMax(capacity(), newSize), but there's
no reason to pin the previous capacity value if reserve() wasn't
requested. It now uses detachCapacity().

Change-Id: Ide2d99ea7ecd2cd98ae4c1aa397b4475d09c8485
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
João Abecasis 2012-03-05 17:43:34 +01:00 committed by Qt by Nokia
parent 646dc6c5da
commit 8c413f3eff
4 changed files with 21 additions and 8 deletions

View File

@ -91,6 +91,13 @@ struct Q_CORE_EXPORT QArrayData
Q_DECLARE_FLAGS(AllocationOptions, AllocationOption)
size_t detachCapacity(size_t newSize) const
{
if (capacityReserved && newSize < alloc)
return alloc;
return newSize;
}
AllocationOptions detachFlags() const
{
AllocationOptions result;

View File

@ -171,7 +171,7 @@ public:
private:
Data *clone(QArrayData::AllocationOptions options) const Q_REQUIRED_RESULT
{
QArrayDataPointer copy(Data::allocate(d->alloc ? d->alloc : d->size,
QArrayDataPointer copy(Data::allocate(d->detachCapacity(d->size),
options));
if (d->size)
copy->copyAppend(d->begin(), d->end());

View File

@ -184,7 +184,7 @@ public:
if (d->ref.isShared()
|| capacity() - size() < size_t(last - first)) {
SimpleVector detached(Data::allocate(
qMax(capacity(), size() + (last - first)),
d->detachCapacity(size() + (last - first)),
d->detachFlags() | Data::Grow));
detached.d->copyAppend(first, last);
@ -205,7 +205,7 @@ public:
if (d->ref.isShared()
|| capacity() - size() < size_t(last - first)) {
SimpleVector detached(Data::allocate(
qMax(capacity(), size() + (last - first)),
d->detachCapacity(size() + (last - first)),
d->detachFlags() | Data::Grow));
if (d->size) {
@ -245,7 +245,7 @@ public:
if (d->ref.isShared()
|| capacity() - size() < size_t(last - first)) {
SimpleVector detached(Data::allocate(
qMax(capacity(), size() + (last - first)),
d->detachCapacity(size() + (last - first)),
d->detachFlags() | Data::Grow));
if (position)

View File

@ -1175,8 +1175,10 @@ void tst_QArrayData::setSharable_data()
QArrayDataPointer<int> emptyReserved(QTypedArrayData<int>::allocate(5,
QArrayData::CapacityReserved));
QArrayDataPointer<int> nonEmpty(QTypedArrayData<int>::allocate(10,
QArrayDataPointer<int> nonEmpty(QTypedArrayData<int>::allocate(5,
QArrayData::Default));
QArrayDataPointer<int> nonEmptyExtraCapacity(
QTypedArrayData<int>::allocate(10, QArrayData::Default));
QArrayDataPointer<int> nonEmptyReserved(QTypedArrayData<int>::allocate(15,
QArrayData::CapacityReserved));
QArrayDataPointer<int> staticArray(
@ -1185,13 +1187,15 @@ void tst_QArrayData::setSharable_data()
QTypedArrayData<int>::fromRawData(staticArrayData.data, 10));
nonEmpty->copyAppend(5, 1);
nonEmptyExtraCapacity->copyAppend(5, 1);
nonEmptyReserved->copyAppend(7, 2);
QTest::newRow("shared-null") << null << size_t(0) << size_t(0) << false << 0;
QTest::newRow("shared-empty") << empty << size_t(0) << size_t(0) << false << 0;
// unsharable-empty implicitly tested in shared-empty
QTest::newRow("empty-reserved") << emptyReserved << size_t(0) << size_t(5) << true << 0;
QTest::newRow("non-empty") << nonEmpty << size_t(5) << size_t(10) << false << 1;
QTest::newRow("non-empty") << nonEmpty << size_t(5) << size_t(5) << false << 1;
QTest::newRow("non-empty-extra-capacity") << nonEmptyExtraCapacity << size_t(5) << size_t(10) << false << 1;
QTest::newRow("non-empty-reserved") << nonEmptyReserved << size_t(7) << size_t(15) << true << 2;
QTest::newRow("static-array") << staticArray << size_t(10) << size_t(0) << false << 3;
QTest::newRow("raw-data") << rawData << size_t(10) << size_t(0) << false << 3;
@ -1229,8 +1233,10 @@ void tst_QArrayData::setSharable()
// Unshare, must detach
array.setSharable(false);
// Immutability (alloc == 0) is lost on detach
if (capacity == 0 && size != 0)
// Immutability (alloc == 0) is lost on detach, as is additional capacity
// if capacityReserved flag is not set.
if ((capacity == 0 && size != 0)
|| (!isCapacityReserved && capacity > size))
capacity = size;
QVERIFY(!array->ref.isShared());