Enum When 

pub enum When {
    Always,
    Unset,
    AlreadySet,
    Later,
    Earlier,
    EarlierAndAlreadySet,
}

Whether a deadline is allowed to move, which is EXPIRE’s NX, XX, GT and LT.

The condition is checked before the moment is, so a deadline that has already gone and a condition that says no leaves the key alone rather than deleting it.

Variants

Always

Whatever is there now. Plain EXPIRE.

Unset

Only if the key has no deadline yet. NX.

AlreadySet

Only if it already has one. XX.

Later

Only if this pushes the deadline further out. GT.

A key with no deadline is refused, because no deadline reads as infinitely far away and nothing is further out than that.

Earlier

Only if this brings the deadline in. LT.

A key with no deadline is accepted, by the same reading.

EarlierAndAlreadySet

Only if there is one now and this brings it in. XX LT.

The one combination the other five cannot say. XX GT is just GT, since GT already refuses a key with no deadline.

Trait Implementations

impl Clone for When

fn clone(&self) -> When

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for When

impl Debug for When

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

Formats the value using the given formatter.

impl Default for When

fn default() -> When

Returns the “default value” for a type.

impl Eq for When

impl From<When> for Cond

fn from(when: When) -> Cond

Converts to this type from the input type.

impl PartialEq for When

fn eq(&self, other: &When) -> bool

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for When