Struct AliasCatalog 

pub struct AliasCatalog { /* private fields */ }

The per-leg alias index the ChainFetch carries so normalization does not discard the identifiers needed to subscribe, resubscribe, and join later updates (docs/01-domain-model.md §6, docs/03-data-providers.md §4).

It maps the provider-agnostic InstrumentKey to each feed’s Instrument (native + stream symbol plus its ContractSpecFingerprint), holding no raw upstream DTO. One key can map to several Instruments — one per feed that knows this leg (a source chain plus, e.g., a DXLink overlay) — which is how a cross-provider overlay joins a chain seeded by a different provider.

The per-leg fingerprint is what the cross-provider overlay merge compares to refuse an economically non-equivalent leg (overlay_compatible).

Implementations

impl AliasCatalog

pub fn new() -> Self

An empty catalog. Adapters populate it with insert during chain normalization.

pub fn insert(&mut self, instrument: Instrument)

Register a feed’s view of a leg. Multiple feeds can register the same InstrumentKey — each becomes a distinct alias entry under that key.

Re-inserting the same (key, provider) replaces the prior entry in place rather than appending a duplicate, so the catalog stays a function of (key, provider) and instrument returns the current view, never a stale first match.

pub fn is_empty(&self) -> bool

True when no leg has been registered.

pub fn len(&self) -> usize

The number of distinct InstrumentKeys the catalog knows (not the number of feed aliases).

pub fn instruments(&self) -> impl Iterator<Item = &Instrument>

Every feed alias the catalog holds, across all keys — the enumeration a provider adapter uses to resubscribe off the fresh aliases after a reconnect re-fetch (docs/03-data-providers.md §5), so it never re-derives symbols from strikes. The iteration order is unspecified (the backing map is unordered); a caller that needs the legs for one feed filters on Instrument::provider.

pub fn instrument( &self, key: &InstrumentKey, provider: &ProviderId, ) -> Option<&Instrument>

The native/stream symbols (and spec fingerprint) to (re)subscribe for one leg on a given feed, or None when that feed does not know the leg.

pub fn resolve_symbol(&self, symbol: &str) -> Option<&InstrumentKey>

Resolve an incoming stream/native symbol back to the shared InstrumentKey — the reverse join the DXLink overlay and the poll→stream merge both use (docs/03-data-providers.md §4). Matches a leg’s native_symbol or its stream_symbol.

pub fn overlay_compatible( &self, key: &InstrumentKey, source: &ProviderId, overlay: &ProviderId, ) -> Result<(), OverlayError>

The cross-provider overlay gate (docs/01-domain-model.md §4): the two feeds’ Instruments for one key may merge only when their ContractSpecFingerprints are equal.

The InstrumentKey 4-tuple proves the two feeds name the same option; this compares the economic-equivalence fingerprint before a live overlay quote is allowed to overwrite a source-chain leg. The within-provider poll→stream merge passes the same provider for source and overlay, so it compares one fingerprint against itself — a no-op that always succeeds.

The store-level invocation of this gate during the merge lands with the ChainStore in issue #7; this is the comparison primitive it calls, with the full fingerprint comparison already wired here.

Errors

OverlayError::SpecMismatch naming the first fingerprint dimension that disagrees (multiplier / settlement / exercise / quote currency / venue product code) — never a raw payload or credential.

OverlayError::MissingAlias when either feed does not know the leg: there is no fingerprint pair to compare, so the gate fails CLOSED (naming the absent feed) rather than admitting an unverified overlay. The caller (gate_overlay) treats only Ok(()) as permission to merge, so a missing alias refuses the merge instead of resurrecting an unchecked leg.

Trait Implementations

impl Clone for AliasCatalog

fn clone(&self) -> AliasCatalog

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for AliasCatalog

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

Formats the value using the given formatter.

impl Default for AliasCatalog

fn default() -> AliasCatalog

Returns the “default value” for a type.