Crate moq_pattern 

Exact path patterns for Media over QUIC.

A Pattern describes a set of broadcast paths. Patterns is an unordered union reduced by exact containment. Matching is linear. Pattern::literal rejects * because it is reserved for pattern syntax.

moq-net and moq-auth re-export this crate. The TypeScript twin is @moq/pattern.

Grammar

A pattern is canonical /-separated segments:

• a literal;
• *, matching one complete segment;
• lit*lit, with one * matching bytes inside one segment;
• **, matching zero or more complete segments, at most once per pattern.

Patterns are exact: foo matches only foo, foo/** matches its subtree including foo, ** matches every path, and the empty pattern matches only the current root. Parse rejects leading, trailing, or repeated /, more than one * in a segment, ** mixed with literal bytes, more than one **, and more than Pattern::MAX_SEGMENTS (32) segments. Construction moves ** before adjacent * segments, so */** is **/*.

Algebra

Pattern::matches, Pattern::overlaps, Pattern::contains, Pattern::head, Pattern::specificity, set-valued Pattern::rebase and Pattern::intersect, and Pattern::captures. A rebase never picks one lossy residual: **/a at a is both the empty pattern and **/a, and an intersection never picks one lossy overlap: a/** with **/a is both a and a/**/a. A union reduces per member; a candidate covered only jointly by several members is refused.

CAT / C4M

Common Access Token and draft-ietf-moq-c4m-01 match namespace fields positionally: exact, prefix, or suffix per field, with a trailing nil for exact depth. Without nil, longer namespaces that start with the matching fields are in scope.

That common subset is:

Pattern	C4M
foo/bar	exact foo, exact bar, nil
foo/bar/**	exact foo, exact bar (no nil)
foo*	prefix foo on that field
*foo	suffix foo on that field
*	prefix of the empty byte string (any field)
pid/*/chat	exact pid, any field, exact chat, nil

Richer MoQ forms, kept explicit rather than claimed as CAT gaps:

• ** not at the end (**/a, a/**/b): C4M is positional from the front.
• foo*bar: C4M’s match object is exact, prefix, or suffix, not both.

Literal paths

Path stays a coordinate. Roots, joins, exact names, URL paths, and object-store keys keep their own types. Pattern::literal rejects *; literal Path construction and wire decoding retain their existing behavior.

Structs

Pattern

A pattern over broadcast paths: literal segments, * for one segment, prefix*suffix for one segment with a known start and end, and at most one ** for any run of segments. Every segment kind matches whole segments, and a pattern is exact: foo matches only foo, and a subtree is foo/**.

Patterns

A union of patterns, reduced so no member is contained by another.

Specificity

How much of a path a pattern pins down, for ranking the patterns that match one path.

Enums

IntersectionError

Why an exact pattern intersection could not be represented safely.

InvalidPattern

Why a string or a segment list is not a valid Pattern.

Segment

One segment of a Pattern.