Struct autoken::PotentialImmutableBorrow

pub struct PotentialImmutableBorrow<T: ?Sized>(/* private fields */);

A variant of ImmutableBorrow which represents an immutable borrow which can gracefully recover from borrow errors if they end up occurring.

Unlike an ImmutableBorrow, this token will not trigger a warning if a confounding borrow is potentially alive at the same time as it since, if the dynamic borrow this borrow guard backs ends up aliasing with something else, the error is assumed to be handled gracefully.

As with borrow_immutably and friends, setting T to Nothing causes this guard to have no effect on the statically-analyzed borrow counts.

If the error cannot be handled gracefully, one may construct an ImmutableBorrow and downgrade it to a PotentialImmutableBorrow so that the static analyzer will start reporting these potentially aliasing borrows again.

See the Potential Borrows section of the crate documentation for more details.

Implementations

impl<T: ?Sized> PotentialImmutableBorrow<T>

pub fn new() -> Self

Constructs a new PotentialImmutableBorrow guard.

This function has no runtime cost but will cause the AuToken static analyzer to increment the number of immutable borrows of type T in scope. Note, however, that it will not cause the static analyzer to report aliases with potentially confounding borrow tokens. See the structure documentation for details.

Internally, this function calls:

autoken::assume_no_alias(|| ImmutableBorrow::<T>::new());

pub const fn loan(&self) -> ImmutableBorrow<Nothing<'_>>

Creates a loaned ImmutableBorrow of this guard which has no effect on the static analysis borrow counters by itself, making it safe to use in conditional code.

This is typically used to construct the ImmutableBorrow guard for runtime borrow guards which were successfully created in fallible code.

See the Making Sense of Control Flow Errors section of the crate documentation for more details on loans.

pub fn strip_lifetime_analysis( self ) -> PotentialImmutableBorrow<Nothing<'static>>

Transforms the type of T into Nothing, effectively making it as if this borrow guard no longer exists.

See the Making Sense of Control Flow Errors section of the crate documentation for more details on the utility of strip_lifetime_analysis.

Trait Implementations

impl<T: ?Sized> Clone for PotentialImmutableBorrow<T>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: ?Sized> Debug for PotentialImmutableBorrow<T>

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

Formats the value using the given formatter.

impl<T: ?Sized> Default for PotentialImmutableBorrow<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T: ?Sized> Ord for PotentialImmutableBorrow<T>

fn cmp(&self, _other: &Self) -> 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 + PartialOrd,

Restrict a value to a certain interval.

impl<T: ?Sized> PartialEq for PotentialImmutableBorrow<T>

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

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

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

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

impl<T: ?Sized> PartialOrd for PotentialImmutableBorrow<T>

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

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

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

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

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

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

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

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

impl<T: ?Sized> Eq for PotentialImmutableBorrow<T>