Struct owning_ref::OwningRefMut

source · [−]
pub struct OwningRefMut<O, T: ?Sized> { /* private fields */ }
Expand description

An mutable owning reference.

This wraps an owner O and a reference &mut 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.

Implementations

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

Example
extern crate owning_ref;
use owning_ref::OwningRefMut;

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

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.

Converts self into a new shared 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::OwningRefMut;

fn main() {
    let owning_ref_mut = OwningRefMut::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_mut.map(|array| &array[2]);
    assert_eq!(*owning_ref, 3);
}

Converts self into a new mutable 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::OwningRefMut;

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

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

Tries to convert self into a new shared 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::OwningRefMut;

fn main() {
    let owning_ref_mut = OwningRefMut::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_mut.try_map(|array| {
        if array[2] == 3 { Ok(&array[2]) } else { Err(()) }
    });
    assert_eq!(*owning_ref.unwrap(), 3);
}

Tries to convert self into a new mutable 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::OwningRefMut;

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

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

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.

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 OwningRefMut<O, T> to a OwningRefMut<Box<dyn Erased>, T>.

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::{OwningRefMut, Erased};

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

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

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

    let owning_ref_mut_a: OwningRefMut<Box<[i32; 4]>, i32>
        = owning_ref_mut_a.map_mut(|a| &mut a[0]);

    let owning_ref_mut_b: OwningRefMut<Box<Vec<(i32, bool)>>, i32>
        = owning_ref_mut_b.map_mut(|a| &mut a[1].0);

    let owning_refs_mut: [OwningRefMut<Box<dyn Erased>, i32>; 2]
        = [owning_ref_mut_a.erase_owner(), owning_ref_mut_b.erase_owner()];

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

A reference to the underlying owner.

A mutable reference to the underlying owner.

Discards the reference and retrieves the owner.

Trait Implementations

Performs the conversion.

Performs the conversion.

Formats the value using the given formatter. Read more

The resulting type after dereferencing.

Dereferences the value.

Mutably dereferences the value.

Performs the conversion.

Performs the conversion.

Feeds this value into the given Hasher. Read more

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

This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

Restrict a value to a certain interval. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method returns an ordering between self and other values if one exists. Read more

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

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

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

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

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

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

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.