Enum Preference

pub enum Preference<T> {
    Any,
    Specific(T),
}

A wrapper for types used in header values where wildcard (*) items are allowed but the underlying type does not support them.

For example, we use the language-tags crate for the AcceptLanguage typed header but it does not parse * successfully. On the other hand, the mime crate, used for Accept, has first-party support for wildcard items so this wrapper is not used in those header types.

Variants

Any

A wildcard value.

Specific(T)

A valid T.

Implementations

impl<T> Preference<T>

pub fn is_any(&self) -> bool

Returns true if preference is the any/wildcard (*) value.

pub fn is_specific(&self) -> bool

Returns true if preference is the specific item (T) variant.

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

Returns reference to value in Specific variant, if it is set.

pub fn into_item(self) -> Option<T>

Consumes the container, returning the value in the Specific variant, if it is set.

Trait Implementations

impl<T: Clone> Clone for Preference<T>

fn clone(&self) -> Preference<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for Preference<T>

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

Formats the value using the given formatter.

impl<T: Display> Display for Preference<T>

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

Formats the value using the given formatter.

impl<T: FromStr> FromStr for Preference<T>

type Err = <T as FromStr>::Err

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl<T: Hash> Hash for Preference<T>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

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

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T: PartialEq> PartialEq for Preference<T>

fn eq(&self, other: &Preference<T>) -> 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<T: PartialOrd> PartialOrd for Preference<T>

fn partial_cmp(&self, other: &Preference<T>) -> 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<T: Copy> Copy for Preference<T>

impl<T: Eq> Eq for Preference<T>

impl<T> StructuralPartialEq for Preference<T>