Struct owning_ref::OwningRef[][src]

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>
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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);
}

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 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);
}

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);
}

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 OwningRef<O, T> to a OwningRef<Box<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::{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);
}

Important traits for &'a mut R

A reference to the underlying owner.

Discards the reference and retrieves the owner.

Trait Implementations

impl<O, T: ?Sized> Deref for OwningRef<O, T>
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The resulting type after dereferencing.

Important traits for &'a mut R

Dereferences the value.

impl<O, T: ?Sized> StableAddress for OwningRef<O, T>
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impl<O, T: ?Sized> AsRef<T> for OwningRef<O, T>
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Important traits for &'a mut R

Performs the conversion.

impl<O, T: ?Sized> Borrow<T> for OwningRef<O, T>
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Important traits for &'a mut R

Immutably borrows from an owned value. Read more

impl<O, T: ?Sized> From<O> for OwningRef<O, T> where
    O: StableAddress,
    O: Deref<Target = T>, 
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Performs the conversion.

impl<O, T: ?Sized> From<OwningRefMut<O, T>> for OwningRef<O, T> where
    O: StableAddress,
    O: DerefMut<Target = T>, 
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Performs the conversion.

impl<O, T: ?Sized> Debug for OwningRef<O, T> where
    O: Debug,
    T: Debug
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Formats the value using the given formatter. Read more

impl<O, T: ?Sized> Clone for OwningRef<O, T> where
    O: CloneStableAddress
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Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

impl<O, T: ?Sized> CloneStableAddress for OwningRef<O, T> where
    O: CloneStableAddress
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impl<O, T: ?Sized> Send for OwningRef<O, T> where
    O: Send,
    &'a T: Send
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impl<O, T: ?Sized> Sync for OwningRef<O, T> where
    O: Sync,
    &'a T: Sync
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impl<O, T: ?Sized> PartialEq for OwningRef<O, T> where
    T: PartialEq
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This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

impl<O, T: ?Sized> Eq for OwningRef<O, T> where
    T: Eq
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impl<O, T: ?Sized> PartialOrd for OwningRef<O, T> where
    T: PartialOrd
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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

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

impl<O, T: ?Sized> Hash for OwningRef<O, T> where
    T: Hash
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Feeds this value into the given [Hasher]. Read more

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