Module watch 

Local change detection — the snapshot/diff engine behind dbmd watch.

Poll-based and dependency-free by design: a snapshot stats the store’s emit membership (every content file plus DB.md — emit::walk_rels, so watch and emit can never disagree about what is observable), and a diff of two snapshots yields the created / modified / removed set in deterministic path order. No OS file-event API is used — kernel watchers differ per platform, mis-report on network filesystems, and would be the toolkit’s first such dependency; a bounded stat sweep per tick is simple, portable, and honest about cost (the caller narrows big stores with a prefix). Modification is detected by (byte length, mtime) — the standard watcher tradeoff: a same-length rewrite inside one mtime granule is invisible.

Everything here is pure observation: no locks are taken and nothing is written, so a watcher never blocks a writer.

Structs

Change

One observed change.

FileSig

One observed file’s cheap identity: byte length plus mtime (absent where the filesystem reports none).

Enums

ChangeKind

What happened to one path between two snapshots.

Functions

diff

Diff two snapshots into the created / modified / removed set, in deterministic store-path order.

snapshot

Snapshot the watched membership, optionally narrowed to a store-relative prefix. A file that vanishes between the walk and its stat is simply absent from this snapshot (the next diff reports it removed) — a benign race, not an error.

Type Aliases

Snapshot

A point-in-time view of the watched membership: store-relative path → signature, path-ordered.