pub struct QBox<T: StaticUpcast<QObject> + CppDeletable>(/* private fields */);Expand description
An owning pointer for QObject-based objects.
QBox will delete its object on drop if it has no parent. If the object has a parent,
it’s assumed that the parent is responsible for deleting the object, as per Qt ownership system.
Additionally, QBox will be automatically set to null when the object is deleted, similar
to QPtr (or QPointer<T> in C++). QBox will not attempt to delete null pointers.
Note that dereferencing a null QBox will panic, so if it’s known that the object may
already have been deleted, you should use is_null(), as_ref(),
or a similar method to check
if the object is still alive before calling its methods.
Unlike CppBox (which is non-nullable), QBox is permitted to contain a null pointer because
even if a non-null pointer is provided when constructing QBox, it will become null
automatically if the object is deleted.
To prevent the object from being deleted, convert QBox to another type of pointer using
into_q_ptr() or into_ptr(). Alternatively, setting a parent for the object will prevent
QBox from deleting it.
To make sure the object is deleted regardless of its parent, convert QBox to CppBox using
into_box().
§Safety
QBox has the same safety issues as QPtr. See QPtr documentation.
Implementations§
Source§impl<T: StaticUpcast<QObject> + CppDeletable> QBox<T>
impl<T: StaticUpcast<QObject> + CppDeletable> QBox<T>
Sourcepub unsafe fn from_q_ptr(target: QPtr<T>) -> Self
pub unsafe fn from_q_ptr(target: QPtr<T>) -> Self
Sourcepub unsafe fn new(target: impl CastInto<Ptr<T>>) -> Self
pub unsafe fn new(target: impl CastInto<Ptr<T>>) -> Self
Creates a QBox from a Ptr.
§Safety
target must be either a valid pointer to an object or a null pointer.
See type level documentation.
Sourcepub unsafe fn from_raw(target: *const T) -> Self
pub unsafe fn from_raw(target: *const T) -> Self
Creates a QBox from a raw pointer.
§Safety
target must be either a valid pointer to an object or a null pointer.
See type level documentation.
Sourcepub unsafe fn null() -> Self
pub unsafe fn null() -> Self
Creates a null pointer.
Note that you can also use NullPtr to specify a null pointer to a function accepting
impl CastInto<Ptr<_>>. Unlike Ptr, NullPtr is not a generic type, so it will
not cause type inference issues.
Note that accessing the content of a null QBox through Deref will result
in a panic.
§Safety
Null pointers must not be dereferenced. See type level documentation.
Sourcepub unsafe fn as_raw_ptr(&self) -> *const T
pub unsafe fn as_raw_ptr(&self) -> *const T
Sourcepub unsafe fn as_mut_raw_ptr(&self) -> *mut T
pub unsafe fn as_mut_raw_ptr(&self) -> *mut T
Sourcepub unsafe fn as_ref(&self) -> Option<Ref<T>>
pub unsafe fn as_ref(&self) -> Option<Ref<T>>
Returns the content as a const Ref. Returns None if self is a null pointer.
§Safety
See type level documentation.
Sourcepub unsafe fn as_raw_ref<'a>(&self) -> Option<&'a T>
pub unsafe fn as_raw_ref<'a>(&self) -> Option<&'a T>
Returns a reference to the value. Returns None if the pointer is null.
§Safety
self must be valid.
The content must not be read or modified through other ways while the returned reference
exists.See type level documentation.
Sourcepub unsafe fn as_mut_raw_ref<'a>(&self) -> Option<&'a mut T>
pub unsafe fn as_mut_raw_ref<'a>(&self) -> Option<&'a mut T>
Returns a mutable reference to the value. Returns None if the pointer is null.
§Safety
self must be valid.
The content must not be read or modified through other ways while the returned reference
exists.See type level documentation.
Sourcepub unsafe fn static_upcast<U>(&self) -> QPtr<U>
pub unsafe fn static_upcast<U>(&self) -> QPtr<U>
Converts the pointer to the base class type U.
§Safety
This operation is safe as long as self is valid or null. See type level documentation.
Sourcepub unsafe fn static_downcast<U>(&self) -> QPtr<U>
pub unsafe fn static_downcast<U>(&self) -> QPtr<U>
Converts the pointer to the derived class type U.
It’s recommended to use dynamic_cast instead because it performs a checked conversion.
§Safety
This operation is safe as long as self is valid and it’s type is U or inherits from U,
of if self is a null pointer. See type level documentation.
Sourcepub unsafe fn dynamic_cast<U>(&self) -> QPtr<U>
pub unsafe fn dynamic_cast<U>(&self) -> QPtr<U>
Converts the pointer to the derived class type U. Returns None if the object’s type
is not U and doesn’t inherit U.
§Safety
This operation is safe as long as self is valid or null. See type level documentation.
Sourcepub unsafe fn into_box(self) -> Option<CppBox<T>>
pub unsafe fn into_box(self) -> Option<CppBox<T>>
Converts this pointer to a CppBox. Returns None if self
is a null pointer.
Unlike QBox, CppBox will always delete the object when dropped.
§Safety
CppBox will attempt to delete the object on drop. If something else also tries to
delete this object before or after that, the behavior is undefined.
See type level documentation.
Sourcepub unsafe fn into_q_ptr(self) -> QPtr<T>
pub unsafe fn into_q_ptr(self) -> QPtr<T>
Converts this QBox into a QPtr.
Unlike QBox, QPtr will never delete the object when dropped.
§Safety
See type level documentation.
Sourcepub unsafe fn into_ptr(self) -> Ptr<T>
pub unsafe fn into_ptr(self) -> Ptr<T>
Converts this QBox into a Ptr.
Unlike QBox, Ptr will never delete the object when dropped.
§Safety
See type level documentation.
Sourcepub unsafe fn into_raw_ptr(self) -> *mut T
pub unsafe fn into_raw_ptr(self) -> *mut T
Converts this QBox into a raw pointer without deleting the object.
§Safety
See type level documentation.
Trait Implementations§
Source§impl<'a, T> AsReceiver for &'a QBox<T>
impl<'a, T> AsReceiver for &'a QBox<T>
Source§type Arguments = <T as AsReceiver>::Arguments
type Arguments = <T as AsReceiver>::Arguments
Source§fn as_receiver(&self) -> Receiver<Self::Arguments>
fn as_receiver(&self) -> Receiver<Self::Arguments>
Source§impl<T: StaticUpcast<QObject> + CppDeletable> Debug for QBox<T>
impl<T: StaticUpcast<QObject> + CppDeletable> Debug for QBox<T>
Source§impl<T: StaticUpcast<QObject> + CppDeletable> Deref for QBox<T>
Allows to call member functions of T and its base classes directly on the pointer.
impl<T: StaticUpcast<QObject> + CppDeletable> Deref for QBox<T>
Allows to call member functions of T and its base classes directly on the pointer.
Panics if the pointer is null.