qt6-bb10/src/corelib/kernel/qpropertyprivate.h

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/****************************************************************************
**
** Copyright (C) 2020 The Qt Company Ltd.
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**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
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** Alternatively, this file may be used under the terms of the GNU Lesser
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#ifndef QPROPERTYPRIVATE_H
#define QPROPERTYPRIVATE_H
//
// W A R N I N G
// -------------
//
// This file is not part of the Qt API. It exists for the convenience
// of qapplication_*.cpp, qwidget*.cpp and qfiledialog.cpp. This header
// file may change from version to version without notice, or even be removed.
//
// We mean it.
//
#include <QtCore/qglobal.h>
#include <QtCore/qtaggedpointer.h>
#include <QtCore/qmetatype.h>
#include <functional>
QT_BEGIN_NAMESPACE
namespace QtPrivate {
// QPropertyBindingPrivatePtr operates on a RefCountingMixin solely so that we can inline
// the constructor and copy constructor
struct RefCounted {
int ref = 0;
void addRef() {++ref;}
bool deref() {--ref; return ref;}
};
}
class QPropertyBindingPrivate;
class QPropertyBindingPrivatePtr
{
public:
using T = QtPrivate::RefCounted;
T &operator*() const { return *d; }
T *operator->() noexcept { return d; }
T *operator->() const noexcept { return d; }
explicit operator T *() { return d; }
explicit operator const T *() const noexcept { return d; }
T *data() const noexcept { return d; }
T *get() const noexcept { return d; }
const T *constData() const noexcept { return d; }
T *take() noexcept { T *x = d; d = nullptr; return x; }
QPropertyBindingPrivatePtr() noexcept : d(nullptr) { }
~QPropertyBindingPrivatePtr()
{
if (d && (--d->ref == 0))
destroyAndFreeMemory();
}
Q_CORE_EXPORT void destroyAndFreeMemory();
explicit QPropertyBindingPrivatePtr(T *data) noexcept : d(data) { if (d) d->addRef(); }
QPropertyBindingPrivatePtr(const QPropertyBindingPrivatePtr &o) noexcept
: d(o.d) { if (d) d->addRef(); }
void reset(T *ptr = nullptr) noexcept;
QPropertyBindingPrivatePtr &operator=(const QPropertyBindingPrivatePtr &o) noexcept
{
reset(o.d);
return *this;
}
QPropertyBindingPrivatePtr &operator=(T *o) noexcept
{
reset(o);
return *this;
}
QPropertyBindingPrivatePtr(QPropertyBindingPrivatePtr &&o) noexcept : d(qExchange(o.d, nullptr)) {}
QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QPropertyBindingPrivatePtr)
operator bool () const noexcept { return d != nullptr; }
bool operator!() const noexcept { return d == nullptr; }
void swap(QPropertyBindingPrivatePtr &other) noexcept
{ qSwap(d, other.d); }
friend bool operator==(const QPropertyBindingPrivatePtr &p1, const QPropertyBindingPrivatePtr &p2) noexcept
{ return p1.d == p2.d; }
friend bool operator!=(const QPropertyBindingPrivatePtr &p1, const QPropertyBindingPrivatePtr &p2) noexcept
{ return p1.d != p2.d; }
friend bool operator==(const QPropertyBindingPrivatePtr &p1, const T *ptr) noexcept
{ return p1.d == ptr; }
friend bool operator!=(const QPropertyBindingPrivatePtr &p1, const T *ptr) noexcept
{ return p1.d != ptr; }
friend bool operator==(const T *ptr, const QPropertyBindingPrivatePtr &p2) noexcept
{ return ptr == p2.d; }
friend bool operator!=(const T *ptr, const QPropertyBindingPrivatePtr &p2) noexcept
{ return ptr != p2.d; }
friend bool operator==(const QPropertyBindingPrivatePtr &p1, std::nullptr_t) noexcept
{ return !p1; }
friend bool operator!=(const QPropertyBindingPrivatePtr &p1, std::nullptr_t) noexcept
{ return p1; }
friend bool operator==(std::nullptr_t, const QPropertyBindingPrivatePtr &p2) noexcept
{ return !p2; }
friend bool operator!=(std::nullptr_t, const QPropertyBindingPrivatePtr &p2) noexcept
{ return p2; }
private:
QtPrivate::RefCounted *d;
};
class QUntypedPropertyBinding;
class QPropertyBindingPrivate;
struct QPropertyBindingDataPointer;
class QUntypedPropertyData
{
public:
// sentinel to check whether a class inherits QUntypedPropertyData
struct InheritsQUntypedPropertyData {};
};
template <typename T>
class QPropertyData;
namespace QtPrivate {
struct BindingFunctionVTable
{
using CallFn = bool(*)(QMetaType, QUntypedPropertyData *, void *);
using DtorFn = void(*)(void *);
using MoveCtrFn = void(*)(void *, void *);
const CallFn call;
const DtorFn destroy;
const MoveCtrFn moveConstruct;
const qsizetype size;
template<typename Callable, typename PropertyType=void>
static constexpr BindingFunctionVTable createFor()
{
static_assert (alignof(Callable) <= alignof(std::max_align_t), "Bindings do not support overaligned functors!");
return {
/*call=*/[](QMetaType metaType, QUntypedPropertyData *dataPtr, void *f){
if constexpr (!std::is_invocable_v<Callable>) {
// we got an untyped callable
static_assert (std::is_invocable_r_v<bool, Callable, QMetaType, QUntypedPropertyData *> );
auto untypedEvaluationFunction = static_cast<Callable *>(f);
return std::invoke(*untypedEvaluationFunction, metaType, dataPtr);
} else {
Q_UNUSED(metaType);
QPropertyData<PropertyType> *propertyPtr = static_cast<QPropertyData<PropertyType> *>(dataPtr);
// That is allowed by POSIX even if Callable is a function pointer
auto evaluationFunction = static_cast<Callable *>(f);
PropertyType newValue = std::invoke(*evaluationFunction);
if constexpr (QTypeTraits::has_operator_equal_v<PropertyType>) {
if (newValue == propertyPtr->valueBypassingBindings())
return false;
}
propertyPtr->setValueBypassingBindings(std::move(newValue));
return true;
}
},
/*destroy*/[](void *f){ static_cast<Callable *>(f)->~Callable(); },
/*moveConstruct*/[](void *addr, void *other){
new (addr) Callable(std::move(*static_cast<Callable *>(other)));
},
/*size*/sizeof(Callable)
};
}
};
template<typename Callable, typename PropertyType=void>
inline constexpr BindingFunctionVTable bindingFunctionVTable = BindingFunctionVTable::createFor<Callable, PropertyType>();
// writes binding result into dataPtr
struct QPropertyBindingFunction {
const QtPrivate::BindingFunctionVTable *vtable;
void *functor;
};
using QPropertyObserverCallback = void (*)(QUntypedPropertyData *);
using QPropertyBindingWrapper = bool(*)(QMetaType, QUntypedPropertyData *dataPtr, QPropertyBindingFunction);
class Q_CORE_EXPORT QPropertyBindingData
{
// Mutable because the address of the observer of the currently evaluating binding is stored here, for
// notification later when the value changes.
mutable quintptr d_ptr = 0;
friend struct QT_PREPEND_NAMESPACE(QPropertyBindingDataPointer);
Q_DISABLE_COPY(QPropertyBindingData)
public:
QPropertyBindingData() = default;
QPropertyBindingData(QPropertyBindingData &&other);
QPropertyBindingData &operator=(QPropertyBindingData &&other) = delete;
~QPropertyBindingData();
bool hasBinding() const { return d_ptr & BindingBit; }
QUntypedPropertyBinding setBinding(const QUntypedPropertyBinding &newBinding,
QUntypedPropertyData *propertyDataPtr,
QPropertyObserverCallback staticObserverCallback = nullptr,
QPropertyBindingWrapper bindingWrapper = nullptr);
QPropertyBindingPrivate *binding() const;
void evaluateIfDirty(const QUntypedPropertyData *property) const;
void removeBinding();
void registerWithCurrentlyEvaluatingBinding() const;
void notifyObservers(QUntypedPropertyData *propertyDataPtr) const;
void setExtraBit(bool b)
{
if (b)
d_ptr |= ExtraBit;
else
d_ptr &= ~ExtraBit;
}
bool extraBit() const { return d_ptr & ExtraBit; }
static const quintptr ExtraBit = 0x1; // Used for QProperty<bool> specialization
static const quintptr BindingBit = 0x2; // Is d_ptr pointing to a binding (1) or list of notifiers (0)?
static const quintptr FlagMask = BindingBit | ExtraBit;
};
template <typename T, typename Tag>
class QTagPreservingPointerToPointer
{
public:
constexpr QTagPreservingPointerToPointer() = default;
QTagPreservingPointerToPointer(T **ptr)
: d(reinterpret_cast<quintptr*>(ptr))
{}
QTagPreservingPointerToPointer<T, Tag> &operator=(T **ptr)
{
d = reinterpret_cast<quintptr *>(ptr);
return *this;
}
QTagPreservingPointerToPointer<T, Tag> &operator=(QTaggedPointer<T, Tag> *ptr)
{
d = reinterpret_cast<quintptr *>(ptr);
return *this;
}
void clear()
{
d = nullptr;
}
void setPointer(T *ptr)
{
*d = reinterpret_cast<quintptr>(ptr) | (*d & QTaggedPointer<T, Tag>::tagMask());
}
T *get() const
{
return reinterpret_cast<T*>(*d & QTaggedPointer<T, Tag>::pointerMask());
}
explicit operator bool() const
{
return d != nullptr;
}
private:
quintptr *d = nullptr;
};
namespace detail {
template <typename F>
struct ExtractClassFromFunctionPointer;
template<typename T, typename C>
struct ExtractClassFromFunctionPointer<T C::*> { using Class = C; };
constexpr size_t getOffset(size_t o)
{
return o;
}
constexpr size_t getOffset(size_t (*offsetFn)())
{
return offsetFn();
}
}
} // namespace QtPrivate
QT_END_NAMESPACE
#endif // QPROPERTYPRIVATE_H