Struct Takeable

pub struct Takeable<T> { /* private fields */ }

A wrapper-type that always holds a single T value.

This type is implemented using an Option<T>, however, the wrapper requires the Option<T> to always contain a value.

Panics

If the closure given to borrow or borrow_result panics, then the Takeable is left in an invalid state without holding a T. Calling any method on the object besides is_usable when in this state will result in a panic. This includes trying to dereference the object. The object will also be permanently invalidated if the value is moved out manually using take.

It is always safe to drop the Takeable even when invalidated.

Implementations

impl<T> Takeable<T>

pub fn new(value: T) -> Takeable<T>

Constructs a new Takeable<T> value.

pub fn into_inner(self) -> T

Takes ownership of the inner value.

pub fn borrow<F>(&mut self, f: F)

where F: FnOnce(T) -> T,

Updates the inner value using the provided closure.

pub fn borrow_result<F, R>(&mut self, f: F) -> R

where F: FnOnce(T) -> (T, R),

Updates the inner value using the provided closure, which also returns a result.

pub fn take(&mut self) -> T

Moves out the inner value and invalidates the object.

Subsequent calls to any methods except is_usable will panic, including attempts to deference the object.

pub fn is_usable(&self) -> bool

Check if the object is still usable.

The object will always start out as usable, and can only enter an unusable state if the methods borrow or borrow_result are called with closures that panic, or if the value is explicitly moved out permanently with take.

Trait Implementations

impl<T> AsMut<T> for Takeable<T>

fn as_mut(&mut self) -> &mut T

Gets a mutable reference to the underlying value.

impl<T> AsRef<T> for Takeable<T>

fn as_ref(&self) -> &T

Gets a reference to the underlying value.

impl<T: Clone> Clone for Takeable<T>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for Takeable<T>

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

Formats the value using the given formatter.

impl<T: Default> Default for Takeable<T>

fn default() -> Takeable<T>

Returns the “default value” for a type.

impl<T> Deref for Takeable<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<T> DerefMut for Takeable<T>

fn deref_mut(&mut self) -> &mut T

Mutably dereferences the value.

impl<T: Display> Display for Takeable<T>

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

Formats the value using the given formatter.

impl<T> From<T> for Takeable<T>

fn from(value: T) -> Self

Converts a T value into a Takeable<T>.

impl<T: Hash> Hash for Takeable<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: Ord> Ord for Takeable<T>

fn cmp(&self, other: &Takeable<T>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

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

where Self: Sized,

Restrict a value to a certain interval.

impl<T: PartialEq> PartialEq for Takeable<T>

fn eq(&self, other: &Takeable<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 Takeable<T>

fn partial_cmp(&self, other: &Takeable<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 Takeable<T>

impl<T: Eq> Eq for Takeable<T>

impl<T> StructuralPartialEq for Takeable<T>