Struct obstack::Ref

pub struct Ref<'a, T: 'a + ?Sized> { /* fields omitted */ }

A wrapper referencing a value in an Obstack.

A Ref value owns the value it references, and will invoke drop on the value when the Ref goes out of scope. Effectively a Ref is a Box that uses an Obstack rather than the heap.

The inherent methods of Ref are all associated functions, which means you have to call them as e.g. Ref::unwrap(value) instead of value.unwrap(). This avoids conflicts with methods of the inner type T.

Implementations

impl<'a, T: ?Sized> Ref<'a, T>

pub fn unwrap(this: Self) -> T where
    T: Sized, 

Returns the owned value, consuming the Ref.

This allows the value to taken out of the Obstack and used even after it goes out of scope:

fn f() -> String {
    let stack = Obstack::new();
    let r = stack.push(String::from("foo"));

    Ref::unwrap(r)
}

assert_eq!(f(), "foo");

Since obstacks only free memory when they go out of scope, the bytes_used remains unchanged:

let r = stack.push(String::new());

let used = stack.bytes_used();
let inner = Ref::unwrap(r);

assert_eq!(used, stack.bytes_used());

Trait Implementations

impl<'a, T> AsMut<T> for Ref<'a, T>

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

Performs the conversion.

impl<'a, T> AsRef<T> for Ref<'a, T>

fn as_ref(&self) -> &T

Performs the conversion.

impl<'a, T> Borrow<T> for Ref<'a, T>

fn borrow(&self) -> &T

Immutably borrows from an owned value.

impl<'a, T> BorrowMut<T> for Ref<'a, T>

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

Mutably borrows from an owned value.

impl<'a, T> Debug for Ref<'a, T> where
    T: Debug, 

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

Formats the value using the given formatter.

impl<'a, T> Deref for Ref<'a, T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<'a, T> DerefMut for Ref<'a, T>

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

Mutably dereferences the value.

impl<'a, T> Display for Ref<'a, T> where
    T: Display, 

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

Formats the value using the given formatter.

impl<'a, T: ?Sized> Drop for Ref<'a, T>

fn drop(&mut self)

Executes the destructor for this type.

impl<'a, T> Eq for Ref<'a, T> where
    T: Eq, 

impl<'a, T> Ord for Ref<'a, T> where
    T: Ord, 

fn cmp(&self, other: &Ref<'a, T>) -> Ordering

This method returns an [Ordering] between self and other.

#[must_use]fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]fn clamp(self, min: Self, max: Self) -> Self

🔬 This is a nightly-only experimental API. (clamp)

Restrict a value to a certain interval.

impl<'a, T> PartialEq<Ref<'a, T>> for Ref<'a, T> where
    T: PartialEq<T>, 

fn eq(&self, other: &Ref<'a, T>) -> bool

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

fn ne(&self, other: &Ref<'a, T>) -> bool

This method tests for !=.

impl<'a, T> PartialOrd<Ref<'a, T>> for Ref<'a, T> where
    T: PartialOrd, 

fn partial_cmp(&self, other: &Ref<'a, T>) -> Option<Ordering>

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

fn le(&self, other: &Ref<'a, T>) -> bool

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

fn lt(&self, other: &Ref<'a, T>) -> bool

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

fn gt(&self, other: &Ref<'a, T>) -> bool

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

fn ge(&self, other: &Ref<'a, T>) -> bool

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

impl<'a, T> Pointer for Ref<'a, T>

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

Formats the value using the given formatter.