Struct salsa::Cycle

pub struct Cycle { /* private fields */ }

Captures the participants of a cycle that occurred when executing a query.

This type is meant to be used to help give meaningful error messages to the user or to help salsa developers figure out why their program is resulting in a computation cycle.

It is used in a few ways:

• During cycle recovery, where it is given to the fallback function.
• As the panic value when an unexpected cycle (i.e., a cycle where one or more participants lacks cycle recovery information) occurs.

You can read more about cycle handling in the salsa book.

Implementations

impl Cycle

pub fn participant_keys(&self) -> impl Iterator<Item = DatabaseKeyIndex> + '_

Iterate over the DatabaseKeyIndex for each query participating in the cycle. The start point of this iteration within the cycle is arbitrary but deterministic, but the ordering is otherwise determined by the execution.

pub fn all_participants<DB: ?Sized + Database>(&self, db: &DB) -> Vec<String>

Returns a vector with the debug information for all the participants in the cycle.

pub fn unexpected_participants<DB: ?Sized + Database>( &self, db: &DB ) -> Vec<String>

Returns a vector with the debug information for those participants in the cycle that lacked recovery information.

pub fn debug<'me, DB: ?Sized + Database>( &'me self, db: &'me DB ) -> impl Debug + 'me

Returns a “debug” view onto this strict that can be used to print out information.

Trait Implementations

impl Clone for Cycle

fn clone(&self) -> Cycle

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Cycle

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

Formats the value using the given formatter.

impl Hash for Cycle

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 Ord for Cycle

fn cmp(&self, other: &Cycle) -> 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 PartialEq for Cycle

fn eq(&self, other: &Cycle) -> 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 PartialOrd for Cycle

fn partial_cmp(&self, other: &Cycle) -> 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 Eq for Cycle

impl StructuralPartialEq for Cycle