Struct Boundary 

struct Boundary<'a> {
    scope: Scope,
    block: Option<&'a Block>,
    occupied: HashSet<PinSlot>,
    last: Option<PinSlot>,
}

The boundary a paste slots pins onto: the slots the owner’s pins hold, plus the ones this gesture has handed out, and the growth that keeps the block tall enough for them — the 10c policy (first_free_slot, grown_to_fit) driven by a whole group rather than one stamp. A block the document does not hold, or one whose interface is frozen, offers no slots at all.

Fields

scope: Scope

block: Option<&'a Block>

occupied: HashSet<PinSlot>

last: Option<PinSlot>

Implementations

impl<'a> Boundary<'a>

fn of(indexed: &'a IndexedDocument<'a>, scope: Scope) -> Self

fn fresh(scope: Scope, block: &'a Block) -> Self

The boundary of a block this same commit is creating: it has no row in the index to be found by, and nothing stands on it yet.

fn take(&mut self) -> Option<PinSlot>

fn push_growth(&self, builder: &mut CommitBuilder)

The growth rider, once for the whole group: the search hands out slots in ascending order, so the last one taken is the lowest the block has to reach.