[][src]Struct owning_ref::OwningRef

pub struct OwningRef<O, T: ?Sized> { /* fields omitted */ }

An owning reference.

This wraps an owner O and a reference &T pointing at something reachable from O::Target while keeping the ability to move self around.

The owner is usually a pointer that points at some base type.

For more details and examples, see the module and method docs.

Methods

impl<O, T: ?Sized> OwningRef<O, T>[src]

pub fn new(o: O) -> Self where
    O: StableAddress,
    O: Deref<Target = T>, 
[src]

Creates a new owning reference from a owner initialized to the direct dereference of it.

Example

extern crate owning_ref;
use owning_ref::OwningRef;

fn main() {
    let owning_ref = OwningRef::new(Box::new(42));
    assert_eq!(*owning_ref, 42);
}

pub unsafe fn new_assert_stable_address(o: O) -> Self where
    O: Deref<Target = T>, 
[src]

Like new, but doesn’t require O to implement the StableAddress trait. Instead, the caller is responsible to make the same promises as implementing the trait.

This is useful for cases where coherence rules prevents implementing the trait without adding a dependency to this crate in a third-party library.

pub fn map<F, U: ?Sized>(self, f: F) -> OwningRef<O, U> where
    O: StableAddress,
    F: FnOnce(&T) -> &U, 
[src]

Converts self into a new owning reference that points at something reachable from the previous one.

This can be a reference to a field of U, something reachable from a field of U, or even something unrelated with a 'static lifetime.

Example

extern crate owning_ref;
use owning_ref::OwningRef;

fn main() {
    let owning_ref = OwningRef::new(Box::new([1, 2, 3, 4]));

    // create a owning reference that points at the
    // third element of the array.
    let owning_ref = owning_ref.map(|array| &array[2]);
    assert_eq!(*owning_ref, 3);
}

pub fn try_map<F, U: ?Sized, E>(self, f: F) -> Result<OwningRef<O, U>, E> where
    O: StableAddress,
    F: FnOnce(&T) -> Result<&U, E>, 
[src]

Tries to convert self into a new owning reference that points at something reachable from the previous one.

This can be a reference to a field of U, something reachable from a field of U, or even something unrelated with a 'static lifetime.

Example

extern crate owning_ref;
use owning_ref::OwningRef;

fn main() {
    let owning_ref = OwningRef::new(Box::new([1, 2, 3, 4]));

    // create a owning reference that points at the
    // third element of the array.
    let owning_ref = owning_ref.try_map(|array| {
        if array[2] == 3 { Ok(&array[2]) } else { Err(()) }
    });
    assert_eq!(*owning_ref.unwrap(), 3);
}

pub unsafe fn map_owner<F, P>(self, f: F) -> OwningRef<P, T> where
    O: StableAddress,
    P: StableAddress,
    F: FnOnce(O) -> P, 
[src]

Converts self into a new owning reference with a different owner type.

The new owner type needs to still contain the original owner in some way so that the reference into it remains valid. This function is marked unsafe because the user needs to manually uphold this guarantee.

pub fn map_owner_box(self) -> OwningRef<Box<O>, T>[src]

Converts self into a new owning reference where the owner is wrapped in an additional Box<O>.

This can be used to safely erase the owner of any OwningRef<O, T> to a OwningRef<Box<Erased>, T>.

pub fn erase_owner<'a>(self) -> OwningRef<O::Erased, T> where
    O: IntoErased<'a>, 
[src]

Erases the concrete base type of the owner with a trait object.

This allows mixing of owned references with different owner base types.

Example

extern crate owning_ref;
use owning_ref::{OwningRef, Erased};

fn main() {
    // NB: Using the concrete types here for explicitnes.
    // For less verbose code type aliases like `BoxRef` are provided.

    let owning_ref_a: OwningRef<Box<[i32; 4]>, [i32; 4]>
        = OwningRef::new(Box::new([1, 2, 3, 4]));

    let owning_ref_b: OwningRef<Box<Vec<(i32, bool)>>, Vec<(i32, bool)>>
        = OwningRef::new(Box::new(vec![(0, false), (1, true)]));

    let owning_ref_a: OwningRef<Box<[i32; 4]>, i32>
        = owning_ref_a.map(|a| &a[0]);

    let owning_ref_b: OwningRef<Box<Vec<(i32, bool)>>, i32>
        = owning_ref_b.map(|a| &a[1].0);

    let owning_refs: [OwningRef<Box<Erased>, i32>; 2]
        = [owning_ref_a.erase_owner(), owning_ref_b.erase_owner()];

    assert_eq!(*owning_refs[0], 1);
    assert_eq!(*owning_refs[1], 1);
}

pub fn as_owner(&self) -> &O[src]

A reference to the underlying owner.

pub fn into_owner(self) -> O[src]

Discards the reference and retrieves the owner.

Trait Implementations

impl<O, T: ?Sized> Send for OwningRef<O, T> where
    O: Send,
    &'a T: Send
[src]

impl<O, T: ?Sized> Sync for OwningRef<O, T> where
    O: Sync,
    &'a T: Sync
[src]

impl<O, T: ?Sized> Clone for OwningRef<O, T> where
    O: CloneStableAddress
[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

Performs copy-assignment from source. Read more

impl<O, T: ?Sized> Ord for OwningRef<O, T> where
    T: Ord
[src]

fn max(self, other: Self) -> Self1.21.0[src]

Compares and returns the maximum of two values. Read more

fn min(self, other: Self) -> Self1.21.0[src]

Compares and returns the minimum of two values. Read more

fn clamp(self, min: Self, max: Self) -> Self[src]

🔬 This is a nightly-only experimental API. (clamp)

Restrict a value to a certain interval. Read more

impl<O, T: ?Sized> From<O> for OwningRef<O, T> where
    O: StableAddress,
    O: Deref<Target = T>, 
[src]

impl<O, T: ?Sized> From<OwningRefMut<O, T>> for OwningRef<O, T> where
    O: StableAddress,
    O: DerefMut<Target = T>, 
[src]

impl<O, T: ?Sized> Eq for OwningRef<O, T> where
    T: Eq
[src]

impl<O, T: ?Sized> PartialOrd<OwningRef<O, T>> for OwningRef<O, T> where
    T: PartialOrd
[src]

#[must_use]
fn lt(&self, other: &Rhs) -> bool
1.0.0[src]

This method tests less than (for self and other) and is used by the < operator. Read more

#[must_use]
fn le(&self, other: &Rhs) -> bool
1.0.0[src]

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

#[must_use]
fn gt(&self, other: &Rhs) -> bool
1.0.0[src]

This method tests greater than (for self and other) and is used by the > operator. Read more

#[must_use]
fn ge(&self, other: &Rhs) -> bool
1.0.0[src]

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

impl<O, T: ?Sized> PartialEq<OwningRef<O, T>> for OwningRef<O, T> where
    T: PartialEq
[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0[src]

This method tests for !=.

impl<O, T: ?Sized> AsRef<T> for OwningRef<O, T>[src]

impl<O, T: ?Sized> Debug for OwningRef<O, T> where
    O: Debug,
    T: Debug
[src]

impl<O, T: ?Sized> Deref for OwningRef<O, T>[src]

type Target = T

The resulting type after dereferencing.

impl<O, T: ?Sized> Hash for OwningRef<O, T> where
    T: Hash
[src]

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher
1.3.0[src]

Feeds a slice of this type into the given [Hasher]. Read more

impl<O, T: ?Sized> Borrow<T> for OwningRef<O, T>[src]

impl<O, T: ?Sized> StableDeref for OwningRef<O, T>[src]

impl<O, T: ?Sized> CloneStableDeref for OwningRef<O, T> where
    O: CloneStableAddress
[src]

Blanket Implementations

impl<T> Erased for T[src]

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 
[src]

impl<T> ToOwned for T where
    T: Clone
[src]

type Owned = T

The resulting type after obtaining ownership.

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 
[src]

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 
[src]

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

The type returned in the event of a conversion error.

impl<T> BorrowMut<T> for T where
    T: ?Sized
[src]

impl<T> Borrow<T> for T where
    T: ?Sized
[src]

impl<T> Any for T where
    T: 'static + ?Sized
[src]