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Fix moveAppend() implementation

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When appending multiple items, we are fine with providing
weak exception safety only. This implies that we can simplify
the moveAppend() code and avoid having to potentiall
call destructors in there.

Change-Id: I31cef0e8589e28f3d3521c54db3f7910628e686f
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Lars Knoll 2020-11-10 11:30:04 +01:00
parent 07c7cbf1a0
commit f1db4d6e38
2 changed files with 7 additions and 68 deletions
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22
src/corelib/tools/qarraydataops.h
View File

@ -113,15 +113,6 @@ struct QArrayExceptionSafetyPrimitives
}
return qsizetype(std::exchange(n, 0));
}
qsizetype move(T *first, T *last) noexcept(std::is_nothrow_move_constructible_v<T>)
{
n = 0;
for (; first != last; ++first) {
new (where + n) T(std::move(*first));
++n;
}
return qsizetype(std::exchange(n, 0));
}
~Constructor() noexcept(std::is_nothrow_destructible_v<T>)
{
while (n)
@ -544,13 +535,12 @@ public:
if (b == e)
return;
typedef typename QArrayExceptionSafetyPrimitives<T>::Constructor CopyConstructor;
// Provides strong exception safety guarantee,
// provided T::~T() nothrow
CopyConstructor copier(this->end());
this->size += copier.move(b, e);
T *data = this->begin();
while (b < e) {
new (data + this->size) T(std::move(*b));
++b;
++this->size;
}
}
void truncate(size_t newSize)

53
tests/auto/corelib/tools/qarraydata/tst_qarraydata.cpp
View File

@ -2375,7 +2375,7 @@ void tst_QArrayData::exceptionSafetyPrimitives_constructor()
{
auto data = createDataPointer<ThrowingType>(20, 10);
const auto originalSize = data.size;
std::array<ThrowingType, 0> emptyRange{};
const std::array<ThrowingType, 0> emptyRange{};
doConstruction(data, data.end(), [] (Constructor &ctor) { return ctor.create(0); });
QCOMPARE(data.size, originalSize);
@ -2389,11 +2389,6 @@ void tst_QArrayData::exceptionSafetyPrimitives_constructor()
return ctor.clone(0, ThrowingType(42));
});
QCOMPARE(data.size, originalSize);
doConstruction(data, data.end(), [emptyRange] (Constructor &ctor) mutable {
return ctor.move(emptyRange.begin(), emptyRange.end());
});
QCOMPARE(data.size, originalSize);
}
// successful create
@ -2437,24 +2432,6 @@ void tst_QArrayData::exceptionSafetyPrimitives_constructor()
QCOMPARE(data.data()[i], reference.data()[i]);
}
// successful move
{
auto data = createDataPointer<ThrowingType>(20, 10);
auto reference = createDataPointer<ThrowingType>(20, 10);
std::array<ThrowingType, 3> source = {
ThrowingType(42), ThrowingType(43), ThrowingType(44)
};
reference->copyAppend(source.begin(), source.end());
doConstruction(data, data.end(), [source] (Constructor &ctor) mutable {
return ctor.move(source.begin(), source.end());
});
QCOMPARE(data.size, reference.size);
for (qsizetype i = 0; i < data.size; ++i)
QCOMPARE(data.data()[i], reference.data()[i]);
}
// failed create
{
auto data = createDataPointer<ThrowingType>(20, 10);
@ -2528,34 +2505,6 @@ void tst_QArrayData::exceptionSafetyPrimitives_constructor()
}
}
}
// failed move
{
auto data = createDataPointer<ThrowingType>(20, 10);
auto reference = createDataPointer<ThrowingType>(20, 10);
std::array<ThrowingType, 4> source = {
ThrowingType(42), ThrowingType(43), ThrowingType(44), ThrowingType(170)
};
for (uint throwOnNthConstruction : {1, 3}) {
WatcherScope scope; Q_UNUSED(scope);
try {
ThrowingType::throwOnce = throwOnNthConstruction;
doConstruction(data, data.end(), [source] (Constructor &ctor) mutable {
return ctor.move(source.begin(), source.end());
});
} catch (const std::runtime_error &e) {
QCOMPARE(std::string(e.what()), ThrowingType::throwString);
QCOMPARE(data.size, reference.size);
for (qsizetype i = 0; i < data.size; ++i)
QCOMPARE(data.data()[i], reference.data()[i]);
const auto destroyedSize = throwingTypeWatcher().destroyedIds.size();
QCOMPARE(destroyedSize, (throwOnNthConstruction - 1));
for (size_t i = 0; i < destroyedSize; ++i)
QCOMPARE(throwingTypeWatcher().destroyedIds[i], source[destroyedSize - i - 1]);
}
}
}
}
void tst_QArrayData::exceptionSafetyPrimitives_destructor()