Enum MaybeOwned 

pub enum MaybeOwned<'a, TOwned, TBorrowed: ?Sized = TOwned> {
    Owned(TOwned),
    Borrowed(&'a TBorrowed),
}

A value that may be owned or not. Similar to std::borrow::Cow but does not require Clone.

Variants

Owned(TOwned)

An owned value.

Borrowed(&'a TBorrowed)

A borrowed value.

Trait Implementations

impl<'a, TOwned, TBorrowed> Borrow<TBorrowed> for MaybeOwned<'a, TOwned, TBorrowed>

where TOwned: Borrow<TBorrowed>, TBorrowed: ?Sized,

fn borrow(&self) -> &TBorrowed

Immutably borrows from an owned value.

impl<'a, TOwned, TBorrowed> Clone for MaybeOwned<'a, TOwned, TBorrowed>

where TOwned: Clone, TBorrowed: ?Sized,

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a, TOwned: Debug, TBorrowed: Debug + ?Sized> Debug for MaybeOwned<'a, TOwned, TBorrowed>

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

Formats the value using the given formatter.

impl<'a, TOwned, TBorrowed> Deref for MaybeOwned<'a, TOwned, TBorrowed>

where TOwned: Borrow<TBorrowed>, TBorrowed: ?Sized,

type Target = TBorrowed

The resulting type after dereferencing.

fn deref(&self) -> &TBorrowed

Dereferences the value.

impl<'a, 'k, TOwned, TBorrowed> Key<'k> for MaybeOwned<'a, TOwned, TBorrowed>

where TBorrowed: KeyEncoding<TOwned, Error = TOwned::Error> + PartialEq + ?Sized, TOwned: Key<'k> + PartialEq<TBorrowed>,

const CAN_OWN_BYTES: bool = TOwned::CAN_OWN_BYTES

If true, this type can benefit from an owned Vec<u8>. This flag is used as a hint of whether to attempt to do memcpy operations in some decoding operations to avoid extra allocations.

fn from_ord_bytes<'e>(bytes: ByteSource<'k, 'e>) -> Result<Self, Self::Error>

Deserialize a sequence of bytes previously encoded with KeyEncoding::as_ord_bytes.

fn first_value() -> Result<Self, NextValueError>

Return the first value in sequence for this type. Not all types implement this.

fn next_value(&self) -> Result<Self, NextValueError>

Return the next value in sequence for this type. Not all types implement this. Instead of wrapping/overflowing, None should be returned.

impl<'a, 'k, TOwned, TBorrowed> KeyEncoding for MaybeOwned<'a, TOwned, TBorrowed>

where TBorrowed: KeyEncoding<TOwned, Error = TOwned::Error> + PartialEq + ?Sized, TOwned: Key<'k> + PartialEq<TBorrowed>,

const LENGTH: Option<usize> = TBorrowed::LENGTH

The size of the key, if constant. If this type doesn’t produce the same number of bytes for each value, this should be None.

type Error = <TOwned as KeyEncoding>::Error

The error type that can be produced by either serialization or deserialization.

fn describe<Visitor>(visitor: &mut Visitor)

where Visitor: KeyVisitor,

Describes this type by invoking functions on visitor describing the key being encoded.

fn as_ord_bytes(&self) -> Result<Cow<'_, [u8]>, Self::Error>

Convert self into a Cow<'_, [u8]> containing bytes that are able to be compared via memcmp in a way that is comptaible with its own Ord implementation.

impl<'a, TOwned, TBorrowed> PartialEq<TBorrowed> for MaybeOwned<'a, TOwned, TBorrowed>

where TOwned: Borrow<TBorrowed>, TBorrowed: PartialEq + ?Sized,

fn eq(&self, other: &TBorrowed) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a, TOwned, TBorrowed> PartialEq for MaybeOwned<'a, TOwned, TBorrowed>

where TOwned: Borrow<TBorrowed>, TBorrowed: PartialEq + ?Sized,

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a, TOwned, TBorrowed> PartialOrd<TBorrowed> for MaybeOwned<'a, TOwned, TBorrowed>

where TOwned: Borrow<TBorrowed>, TBorrowed: PartialOrd + ?Sized,

fn partial_cmp(&self, other: &TBorrowed) -> Option<Ordering>

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

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'a, TOwned, TBorrowed> PartialOrd for MaybeOwned<'a, TOwned, TBorrowed>

where TOwned: Borrow<TBorrowed>, TBorrowed: PartialOrd + ?Sized,

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

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

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.