Struct mesh::payload::inplace::InplaceOption

pub struct InplaceOption<'a, T> { /* private fields */ }

A type with methods like Option but that operates on a mutable reference to possibly-initialized data.

This is used to initialize data in place without copying to/from Option types.

Implementations

impl<'a, T> InplaceOption<'a, T>

pub fn uninit(val: &'a mut MaybeUninit<T>) -> InplaceOption<'a, T>

Creates an option in the uninitialized state.

pub unsafe fn new_init_unchecked( val: &'a mut MaybeUninit<T>, ) -> InplaceOption<'a, T>

Creates an option in the initialized state.

Safety

The caller must guarantee that the value referenced by val is initialized.

pub unsafe fn set_init_unchecked(&mut self) -> &mut T

Sets the value to the initialized state.

Safety

The caller must guarantee that the underlying data has been fully initialized.

pub fn take(&mut self) -> Option<T>

Takes the value, returning Some(_) if the value is initialized and None otherwise.

pub fn as_ref(&self) -> Option<&T>

Returns a reference to the data if it’s initialized.

pub fn as_mut(&mut self) -> Option<&mut T>

Returns a mutable reference to the data if it’s initialized.

pub fn clear(&mut self)

Clears the data to the uninitialized state.

pub fn forget(&mut self) -> bool

Resets the data to the uninitialized state without dropping any initialized value.

pub fn set(&mut self, v: T) -> &mut T

Initializes the value to v, dropping any existing value first.

pub fn get_or_insert(&mut self, v: T) -> &mut T

Gets a mutable reference to the value, setting it to v first if it’s not initialized.

pub fn get_or_insert_with(&mut self, f: impl FnOnce() -> T) -> &mut T

Gets a mutable reference to the value, setting it to f() first if it’s not initialized.

pub fn is_some(&self) -> bool

Returns whether the value is initialized.

pub fn is_none(&self) -> bool

Returns whether the value is uninitialized.

pub fn as_ptr(&self) -> *const T

Returns a const pointer to the underlying value (initialized or not).

pub fn as_mut_ptr(&mut self) -> *mut T

Returns a mut pointer to the underlying value (initialized or not).

impl<'a, T> InplaceOption<'a, Box<T>>

pub fn update_box<F, R>(&mut self, f: F) -> R

where F: FnOnce(&mut InplaceOption<'_, T>) -> R,

Updates a boxed value in place.

N.B. This will allocate space for a value if one is not already present, which is wasteful if f does not actually initialize the value.

impl<'a, T> InplaceOption<'a, Arc<T>>

where T: Clone,

pub fn update_arc<F, R>(&mut self, f: F) -> R

where F: FnOnce(&mut InplaceOption<'_, T>) -> R,

Updates a reference counted value in place.

N.B. This will allocate space for a value if one is not already present, which is wasteful if f does not actually initialize the value.

Trait Implementations

impl<T> Drop for InplaceOption<'_, T>

fn drop(&mut self)

Executes the destructor for this type.