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Simplify code in QExceptionSafetyPrimitives

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QExceptionSafetyPrimitives::Destructor doesn't need an additional
template argument, and the freeze() method was unused.

Some methods of the Constructor class could also be simplified.

Change-Id: Iacf35bc8634f402519a8bd875b5efea7841f9db5
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
This commit is contained in:
Lars Knoll 2020-11-09 14:34:44 +01:00
parent b6d6b3108b
commit fed055790a
2 changed files with 22 additions and 60 deletions
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39
src/corelib/tools/qarraydataops.h
View File

@ -85,11 +85,6 @@ struct QArrayExceptionSafetyPrimitives
T *const where;
size_t n = 0;
template<typename It>
using iterator_copy_value = decltype(*std::declval<It>());
template<typename It>
using iterator_move_value = decltype(std::move(*std::declval<It>()));
Constructor(T *w) noexcept : where(w) {}
qsizetype create(size_t size) noexcept(std::is_nothrow_default_constructible_v<T>)
{
@ -100,9 +95,7 @@ struct QArrayExceptionSafetyPrimitives
}
return qsizetype(std::exchange(n, 0));
}
template<typename ForwardIt>
qsizetype copy(ForwardIt first, ForwardIt last)
noexcept(std::is_nothrow_constructible_v<T, iterator_copy_value<ForwardIt>>)
qsizetype copy(const T *first, const T *last) noexcept(std::is_nothrow_copy_constructible_v<T>)
{
n = 0;
for (; first != last; ++first) {
@ -111,8 +104,7 @@ struct QArrayExceptionSafetyPrimitives
}
return qsizetype(std::exchange(n, 0));
}
qsizetype clone(size_t size, parameter_type t)
noexcept(std::is_nothrow_constructible_v<T, parameter_type>)
qsizetype clone(size_t size, parameter_type t) noexcept(std::is_nothrow_constructible_v<T, parameter_type>)
{
n = 0;
while (n != size) {
@ -121,9 +113,7 @@ struct QArrayExceptionSafetyPrimitives
}
return qsizetype(std::exchange(n, 0));
}
template<typename ForwardIt>
qsizetype move(ForwardIt first, ForwardIt last)
noexcept(std::is_nothrow_constructible_v<T, iterator_move_value<ForwardIt>>)
qsizetype move(T *first, T *last) noexcept(std::is_nothrow_move_constructible_v<T>)
{
n = 0;
for (; first != last; ++first) {
@ -139,30 +129,25 @@ struct QArrayExceptionSafetyPrimitives
}
};
// Watches passed iterator. Unless commit() is called, all the elements that
// Watches passed pointer. Unless commit() is called, all the elements that
// the watched iterator passes through are deleted at the end of object
// lifetime.
//
// Requirements: when not at starting position, the iterator is expected to
// point to a valid object (to initialized memory)
template<typename It = iterator>
struct Destructor
{
It *iter;
It end;
It intermediate;
T **iter;
T *end;
T *intermediate;
Destructor(It &it) noexcept(std::is_nothrow_copy_constructible_v<It>)
Destructor(T *&it) noexcept
: iter(std::addressof(it)), end(it)
{ }
void commit() noexcept
{
iter = std::addressof(end);
}
void freeze() noexcept(std::is_nothrow_copy_constructible_v<It>)
{
intermediate = *iter; iter = std::addressof(intermediate);
}
~Destructor() noexcept(std::is_nothrow_destructible_v<T>)
{
// Step is either 1 or -1 and depends on the interposition of *iter
@ -554,7 +539,7 @@ public:
Q_ASSERT(e <= where || b > this->end() || where == this->end()); // No overlap or append
Q_ASSERT((e - b) <= this->freeSpaceAtEnd());
typedef typename QArrayExceptionSafetyPrimitives<T>::template Destructor<T *> Destructor;
using Destructor = typename QArrayExceptionSafetyPrimitives<T>::Destructor;
// Array may be truncated at where in case of exceptions
@ -607,7 +592,7 @@ public:
Q_ASSERT(e <= where || b > this->end() || where == this->end()); // No overlap or append
Q_ASSERT((e - b) <= this->freeSpaceAtBegin());
typedef typename QArrayExceptionSafetyPrimitives<T>::template Destructor<T *> Destructor;
using Destructor = typename QArrayExceptionSafetyPrimitives<T>::Destructor;
T *begin = this->begin();
T *readIter = begin;
@ -655,7 +640,7 @@ public:
Q_ASSERT(where >= this->begin() && where <= this->end());
Q_ASSERT(size_t(this->freeSpaceAtEnd()) >= n);
typedef typename QArrayExceptionSafetyPrimitives<T>::template Destructor<T *> Destructor;
using Destructor = typename QArrayExceptionSafetyPrimitives<T>::Destructor;
// Array may be truncated at where in case of exceptions
T *end = this->end();
@ -705,7 +690,7 @@ public:
Q_ASSERT(where >= this->begin() && where <= this->end());
Q_ASSERT(size_t(this->freeSpaceAtBegin()) >= n);
typedef typename QArrayExceptionSafetyPrimitives<T>::template Destructor<T *> Destructor;
using Destructor = typename QArrayExceptionSafetyPrimitives<T>::Destructor;
T *begin = this->begin();
T *readIter = begin;

43
tests/auto/corelib/tools/qarraydata/tst_qarraydata.cpp
View File

@ -2384,7 +2384,7 @@ void tst_QArrayData::exceptionSafetyPrimitives_constructor()
{
auto data = createDataPointer<ThrowingType>(20, 10);
const auto originalSize = data.size;
const std::array<ThrowingType, 0> emptyRange{};
std::array<ThrowingType, 0> emptyRange{};
doConstruction(data, data.end(), [] (Constructor &ctor) { return ctor.create(0); });
QCOMPARE(data.size, originalSize);
@ -2450,7 +2450,7 @@ void tst_QArrayData::exceptionSafetyPrimitives_constructor()
{
auto data = createDataPointer<ThrowingType>(20, 10);
auto reference = createDataPointer<ThrowingType>(20, 10);
const std::array<ThrowingType, 3> source = {
std::array<ThrowingType, 3> source = {
ThrowingType(42), ThrowingType(43), ThrowingType(44)
};
reference->copyAppend(source.begin(), source.end());
@ -2542,7 +2542,7 @@ void tst_QArrayData::exceptionSafetyPrimitives_constructor()
{
auto data = createDataPointer<ThrowingType>(20, 10);
auto reference = createDataPointer<ThrowingType>(20, 10);
const std::array<ThrowingType, 4> source = {
std::array<ThrowingType, 4> source = {
ThrowingType(42), ThrowingType(43), ThrowingType(44), ThrowingType(170)
};
@ -2570,7 +2570,7 @@ void tst_QArrayData::exceptionSafetyPrimitives_constructor()
void tst_QArrayData::exceptionSafetyPrimitives_destructor()
{
using Prims = QtPrivate::QArrayExceptionSafetyPrimitives<ThrowingType>;
using Destructor = typename Prims::Destructor<>;
using Destructor = typename Prims::Destructor;
struct WatcherScope
{
@ -2590,7 +2590,7 @@ void tst_QArrayData::exceptionSafetyPrimitives_destructor()
WatcherScope scope; Q_UNUSED(scope);
{
auto where = data.end() - 1;
ThrowingType *where = data.end() - 1;
Destructor destroyer(where);
for (int i = 0; i < 2; ++i) {
new (where + 1) ThrowingType(42);
@ -2613,7 +2613,7 @@ void tst_QArrayData::exceptionSafetyPrimitives_destructor()
WatcherScope scope; Q_UNUSED(scope);
try {
auto where = data.end() - 1;
ThrowingType *where = data.end() - 1;
Destructor destroyer(where);
for (int i = 0; i < 2; ++i) {
new (where + 1) ThrowingType(42 + i);
@ -2644,7 +2644,7 @@ void tst_QArrayData::exceptionSafetyPrimitives_destructor()
data.size -= 2;
WatcherScope scope; Q_UNUSED(scope);
{
auto where = data.begin() + 2; // Note: not updated data ptr, so begin + 2
ThrowingType *where = data.begin() + 2; // Note: not updated data ptr, so begin + 2
Destructor destroyer(where);
for (int i = 0; i < 2; ++i) {
new (where - 1) ThrowingType(42);
@ -2670,7 +2670,7 @@ void tst_QArrayData::exceptionSafetyPrimitives_destructor()
data.size -= 2;
WatcherScope scope; Q_UNUSED(scope);
try {
auto where = data.begin() + 2; // Note: not updated data ptr, so begin + 2
ThrowingType *where = data.begin() + 2; // Note: not updated data ptr, so begin + 2
Destructor destroyer(where);
for (int i = 0; i < 2; ++i) {
new (where - 1) ThrowingType(42 + i);
@ -2697,7 +2697,7 @@ void tst_QArrayData::exceptionSafetyPrimitives_destructor()
WatcherScope scope; Q_UNUSED(scope);
try {
auto where = data.end() - 1;
ThrowingType *where = data.end() - 1;
Destructor destroyer(where);
ThrowingType::throwOnce = 1;
new (where + 1) ThrowingType(42);
@ -2725,7 +2725,7 @@ void tst_QArrayData::exceptionSafetyPrimitives_destructor()
data.size -= 2;
WatcherScope scope; Q_UNUSED(scope);
try {
auto where = data.begin() - 1; // Note: intentionally out of range
ThrowingType *where = data.begin() - 1; // Note: intentionally out of range
Destructor destroyer(where);
for (int i = 0; i < 2; ++i) {
new (where + 1) ThrowingType(42);
@ -2742,29 +2742,6 @@ void tst_QArrayData::exceptionSafetyPrimitives_destructor()
QVERIFY(throwingTypeWatcher().destroyedIds[0] == 42);
}
}
// extra: special case of freezing the position
{
auto data = createDataPointer<ThrowingType>(20, 10);
auto reference = createDataPointer<ThrowingType>(20, 10);
reference->erase(reference.end() - 1, reference.end());
data.data()[data.size - 1] = ThrowingType(42);
WatcherScope scope; Q_UNUSED(scope);
{
auto where = data.end();
Destructor destroyer(where);
for (int i = 0; i < 3; ++i) {
--where;
destroyer.freeze();
}
}
--data.size; // destroyed 1 element above
for (qsizetype i = 0; i < data.size; ++i)
QCOMPARE(data.data()[i], reference.data()[i]);
QVERIFY(throwingTypeWatcher().destroyedIds.size() == 1);
QCOMPARE(throwingTypeWatcher().destroyedIds[0], 42);
}
}
void tst_QArrayData::exceptionSafetyPrimitives_mover()