Struct windows::core::Borrowed

#[repr(transparent)]
pub struct Borrowed<'a, T: Abi> { /* private fields */ }

Expand description

A logically borrowed type that still retains the in-memory representation of the underlying type.

Note: this type is normally only used as a field to a struct. For function parameters, the Param type, which builds on top of Borrowed is used.

Borroweds can be thought of much like an Option<&T>. The reason Borrowed must be used instead of Option<&T> is because Borrowed has the same in-memory layout as Option<T>. This is necessary for FFI calls that expect a logically borrowed type that, in-memory, looks like an owned type.

It’s important to note that owned values cannot be turn into Borroweds. After all, Borrowed types are borrowed and not owned. Just as you cannot turn pass a T into function and get a &T back, you cannot pass a T into a function that ultimately expects a Borrowed<'a, T>.

Implementations

impl<'a, T: Abi> Borrowed<'a, T>

pub fn new(item: Option<&'a T>) -> Self

Create a new Borrowed value.

Normally, it is not necessary to use this function. Generally, there is a From implementation that allows you to call .into to safely create a Borrowed value.

pub fn none() -> Self

Create a new null Borrowed value.

pub fn abi(&self) -> T::Abi

Get the abi representation for this param

Note: the return value is only guranteed to be valid for the lifetime of &self

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

Get an optional reference to the underlying value

Trait Implementations

impl<'a, T: Abi> Clone for Borrowed<'a, T>

fn clone(&self) -> Self

Returns a copy of the value. Read more

1.0.0 · source

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more

impl<'a, T: Abi + Debug> Debug for Borrowed<'a, T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

impl<'a, T: 'a, U> From<&'a U> for Borrowed<'a, T> where
T: Abi,
&'a U: Into<&'a T>,

fn from(item: &'a U) -> Self

Converts to this type from the input type.

impl<'a, T: Abi> From<Option<&'a T>> for Borrowed<'a, T> where
&'a T: Into<Borrowed<'a, T>>,

fn from(item: Option<&'a T>) -> Self

Converts to this type from the input type.

impl<'a> From<bool> for Borrowed<'a, bool>

fn from(item: bool) -> Self

Converts to this type from the input type.

impl<'a> From<f32> for Borrowed<'a, f32>

fn from(item: f32) -> Self

Converts to this type from the input type.

impl<'a> From<f64> for Borrowed<'a, f64>

fn from(item: f64) -> Self

Converts to this type from the input type.

impl<'a> From<i16> for Borrowed<'a, i16>

fn from(item: i16) -> Self

Converts to this type from the input type.

impl<'a> From<i32> for Borrowed<'a, i32>

fn from(item: i32) -> Self

Converts to this type from the input type.

impl<'a> From<i64> for Borrowed<'a, i64>

fn from(item: i64) -> Self

Converts to this type from the input type.

impl<'a> From<i8> for Borrowed<'a, i8>

fn from(item: i8) -> Self

Converts to this type from the input type.

impl<'a> From<isize> for Borrowed<'a, isize>

fn from(item: isize) -> Self

Converts to this type from the input type.

impl<'a> From<u16> for Borrowed<'a, u16>

fn from(item: u16) -> Self

Converts to this type from the input type.

impl<'a> From<u32> for Borrowed<'a, u32>

fn from(item: u32) -> Self

Converts to this type from the input type.

impl<'a> From<u64> for Borrowed<'a, u64>

fn from(item: u64) -> Self

Converts to this type from the input type.

impl<'a> From<u8> for Borrowed<'a, u8>

fn from(item: u8) -> Self

Converts to this type from the input type.

impl<'a> From<usize> for Borrowed<'a, usize>

fn from(item: usize) -> Self

Converts to this type from the input type.

Auto Trait Implementations

impl<'a, T> RefUnwindSafe for Borrowed<'a, T> where
<T as Abi>::Abi: RefUnwindSafe,

impl<'a, T> Send for Borrowed<'a, T> where
<T as Abi>::Abi: Send,

impl<'a, T> Sync for Borrowed<'a, T> where
<T as Abi>::Abi: Sync,

impl<'a, T> Unpin for Borrowed<'a, T> where
<T as Abi>::Abi: Unpin,

impl<'a, T> UnwindSafe for Borrowed<'a, T> where
<T as Abi>::Abi: UnwindSafe,

Blanket Implementations

impl<T> Any for T where
T: 'static + ?Sized,

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

impl<T> Borrow<T> for T where
T: ?Sized,

const: unstable · source

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

impl<T> BorrowMut<T> for T where
T: ?Sized,

const: unstable · source

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

impl<T> From<T> for T

const: unstable · source

fn from(t: T) -> T

Returns the argument unchanged.

impl<T, U> Into<U> for T where
U: From<T>,

const: unstable · source

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

impl<T> ToOwned for T where
T: Clone,

type Owned = T

The resulting type after obtaining ownership.

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more

impl<T, U> TryFrom<U> for T where
U: Into<T>,

type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.

impl<T, U> TryInto<U> for T where
U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

const: unstable · source

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.