Struct salsa::Durability [−][src]
pub struct Durability(_);
Expand description
Describes how likely a value is to change – how “durable” it is.
By default, inputs have Durability::LOW
and interned values have
Durability::HIGH
. But inputs can be explicitly set with other
durabilities.
We use durabilities to optimize the work of “revalidating” a query after some input has changed. Ordinarily, in a new revision, queries have to trace all their inputs back to the base inputs to determine if any of those inputs have changed. But if we know that the only changes were to inputs of low durability (the common case), and we know that the query only used inputs of medium durability or higher, then we can skip that enumeration.
Typically, one assigns low durabilites to inputs that the user is frequently editing. Medium or high durabilities are used for configuration, the source from library crates, or other things that are unlikely to be edited.
Implementations
Low durability: things that change frequently.
Example: part of the crate being edited
Medium durability: things that change sometimes, but rarely.
Example: a Cargo.toml file
High durability: things that are not expected to change under common usage.
Example: the standard library or something from crates.io
Trait Implementations
This method tests for self
and other
values to be equal, and is used
by ==
. Read more
This method tests for !=
.
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
Auto Trait Implementations
impl RefUnwindSafe for Durability
impl Send for Durability
impl Sync for Durability
impl Unpin for Durability
impl UnwindSafe for Durability
Blanket Implementations
Mutably borrows from an owned value. Read more
Compare self to key
and return true
if they are equal.