Struct ProcStack 

pub struct ProcStack { /* private fields */ }

The records whose dbProcess frame is live on the current chain.

C keeps this marker on the record — processTarget claims dbRec2Pvt(pdst)->procThread before dbProcess(pdst) (dbDbLink.c:500-503) and the frame that claimed it clears it on unwind (:523-526). The port cannot put it there: its frame has released the record lock by the time it unwinds, and re-taking it to clear a flag would cost more than the marker saves. So the marker travels with the chain.

What it travelled in was a HashSet<Arc<str>>, which hashed the record name on the way in and again on the way out and allocated a table to hold, at the depth a scan cycle actually reaches, one entry. The depth is the point: a scan of a record whose links are unwired is depth one, so the first claim lives in a field and only a real cascade allocates.

The entry is the record cell’s identity, as C’s marker is on the record itself: an alias claims the same entry as its target, and a claim costs no name clone or compare.

Implementations

impl ProcStack

pub fn new() -> Self

pub fn claim(&mut self, rec: &Arc<RecordCell>) -> bool

Claim name for the calling frame. false when it is already on the chain — C’s cycle — and then the caller has claimed nothing and must not release anything.

pub fn len(&self) -> usize

How many frames are live on this chain.

pub fn is_empty(&self) -> bool

Whether no frame is live on this chain — the entry is the outermost.

pub fn holds(&self, rec: &Arc<RecordCell>) -> bool

Whether a frame for rec is live on this chain.

Trait Implementations

impl Debug for ProcStack

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

Formats the value using the given formatter.

impl Default for ProcStack

fn default() -> Self

Returns the “default value” for a type.