Replaces TUniMessage's 13-field flat record with a strict two-area
model: Body holds only the message text; Attributes holds everything
else (from/to/subject/dates/addresses/MSGID/SEEN-BY/PATH/format-
specific fields) as namespaced key/value pairs.
Why this fix is required NOW: the previous JAM adapter dropped
MSGID, ReplyID, PID, Flags, SEEN-BY and PATH on every Read/Write
through the unified API. A NetReader parity test surfaced it (17/21
pass with 4 kludge failures). All 9 adapters had the same bug. For
tossers and scanners the impact is silent corruption: dropped MSGID
→ dupe storms, dropped PATH → mail loops, dropped SEEN-BY → broken
routing. Three downstream consumers (Fimail's codex-transport branch,
NetReader, future Allfix) had halted integration work pending this
fix. Without it, anyone vendoring fpc-msgbase 0.1 ships with a
known-corrupting adapter.
Design choice: per Ken's call, "message is just the message text;
everything else is an attribute, including from/to/subject/dates."
Same architecture as RFC 822 email (headers + body). Each backend
fills attributes it knows on Read; reads attributes it understands
on Write; ignores unknown attributes silently (RFC 822 X-header
semantics). Forward-compatible -- a new backend (e.g. a planned SQL
message store) just adds its own attribute keys; old backends ignore
them.
Composition is the consumer's job. The library never reassembles
Body + Attributes into kludge-laden display text. A BBS that wants
inline kludges walks Attributes and prepends ^aMSGID etc. to its
own display. A tosser that needs MSGID for dupe detection reads
Attributes.Get('msgid') directly -- no body parsing required.
src/ma.types.pas:
- New TMsgAttribute / TMsgAttributes records with Get/SetValue,
typed accessors (GetInt/GetBool/GetDate/GetAddr), Has/Remove,
iteration. Linear-search lookup, fine for the ~30-50 keys per
message. Switch to hash later if profiling shows need.
- Replaced TUniMessage with the minimal Body + Attributes record.
- New UniAttrBitsToAttributes / UniAttrBitsFromAttributes helpers
to bridge the canonical MSG_ATTR_* cardinal bitset to/from
individual `attr.*` boolean keys.
- {$modeswitch advancedrecords} added so records have methods.
src/ma.api.pas:
- New capabilities API: TStringDynArray return type,
ClassSupportedAttributes (virtual class fn, default empty),
SupportedAttributes (instance sugar), SupportsAttribute (per-key
query). Each backend overrides ClassSupportedAttributes with the
static list of keys it knows. Callers query before setting so a
BBS UI can hide controls the underlying backend has no slot for.
src/formats/ma.fmt.*.uni.pas (all 9):
- Rewrote each XxxToUni and XxxFromUni for the new model. Read
populates Attributes with universal/FTSC/format-specific keys per
the attribute registry (to be published in phase 5). Write reads
attributes back and writes native form.
- JAM walks SubFields[] for SEEN-BY/PATH/TZUTC/TRACE plus passthrough
of unknown subfield IDs as `jam.subfield.<id>` for round-trip
safety. Squish parses CtrlInfo (NUL-separated ^A lines) into
individual attributes, rebuilds on Write. MSG and PKT (which keep
kludges inline in body per FTS-1) parse leading ^A lines and
trailing SEEN-BY/PATH out of the body so TUniMessage.Body is
always plain user text; on Write they reassemble the on-disk form.
- Each backend ships ClassSupportedAttributes with its key list.
src/ma.batch.pas: PktToUni signature updated to (in,out var) form.
tests/* + examples/*: migrated all callers from Msg.WhoFrom (etc.)
to Msg.Attributes.Get('from'). MakeMsg helpers now use SetValue/
SetBool/SetAddr.
Verified: 24/24 tests pass across all 7 test programs (read,
roundtrip, lock, batch, wildcat, write_existing, pack). Wildcat
walks all 7 vendored conferences clean.
Out of scope (next phases):
- docs/attributes-registry.md publishing the full key list with
per-format support matrix
- cross-format round-trip + capabilities-driven copy test
- update architecture.md / PROPOSAL.md to reflect the new model
