Files
mxaccess/design
Joseph Doherty 5f985588f7 [M5] mxaccess-asb-nettcp: F21 [MC-NBFX] binary XML token codec
Ports the proven subset of `[MC-NBFX]` to `mxaccess-asb-nettcp::nbfx`.

Token model: Element { prefix, name } / EndElement / Attribute /
DefaultNamespace / NamespaceDeclaration / Text. Element + attribute
names can be inline UTF-8, an `[MC-NBFS]` static-dictionary id (via
F22's `lookup_static`), or a per-session `DynamicDictionary` id.

Text records covered: Empty (0xA8), Zero (0x80), One (0x82), Bool
(0x84/0x86 + 0xB4), Int8 (0x88), Int16 (0x8A), Int32 (0x8C), Int64
(0x8E), Chars (0x98/0x9A/0x9C — width variant chosen automatically by
payload length), DictionaryText (0xAA — both static and dynamic refs).

`*WithEndElement` collapse is automatic: a `Text → EndElement` pair
encodes as the `+1` record byte (e.g. `EmptyTextWithEndElement = 0xA9`,
`TrueTextWithEndElement = 0x87`). The decoder splits the implicit
EndElement back out so consumers see the same token stream regardless
of which wire form was used.

Element variants covered: ShortElement (0x40), Element (0x41 with
prefix string), ShortDictionaryElement (0x42), DictionaryElement
(0x43). Prefix-letter family (0x44-0x77) deferred — emit the long
form for now.

Attribute variants covered: ShortAttribute (0x04), Attribute (0x05),
ShortDictionaryAttribute (0x06), DictionaryAttribute (0x07), plus
xmlns variants (0x08/0x09).

15 new unit tests cover the dynamic dictionary, every supported
element/attribute/xmlns/text record form (including round-trip),
explicit byte pinning for the collapse behavior, Chars width-variant
selection, unknown-record rejection, and truncated-payload rejection.

Records left for follow-up: Decimal, UniqueId, TimeSpan, Float/Double
text, DateTime text, Bytes8/16/32, QNameDictionary, the 0x0C-0x25
prefix-dict-attribute / 0x26-0x3F prefix-attribute / 0x44-0x77
prefix-element families. None of these are on the proven ASB path.

With F21 landed, the M5 framing + encoder layer (streams A+B+C+D and
the F24 codec) is complete. F25 (mxaccess-asb IASBIDataV2 client) and
F26 (Session over AsbTransport) remain.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-05 11:10:50 -04:00
..

design/ — Rust port architectural plan

This folder is the design contract for the Rust replacement of AVEVA/Wonderware MXAccess. It is the gap between the .NET reference in src/ and the Rust crates that will be written under a sibling rust/ workspace (per CLAUDE.md).

The folder is structured as a small set of focused documents. Read in order; each builds on the previous.

File Purpose
00-overview.md Mission, two-layer goal, architectural principles, non-goals
10-raw-layer.md Byte-accurate raw MXAccess layer (codec + transport + session)
20-async-layer.md Idiomatic Tokio async layer on top of the raw layer
30-crate-topology.md Cargo workspace, crates, dependencies, build/test commands
40-protocol-invariants.md Bill of materials: IIDs, opnums, envelope/handle bytes
50-error-model.md MxStatus, error types, panic/cancellation policy
60-roadmap.md Milestones M0..M6, validation strategy
70-risks-and-open-questions.md Parity gaps, unproven flows, cross-platform constraints
dependencies.md Cross- and within-milestone parallelism map; agent budget per phase
review.md Adversarial review log (BLOCKER/MAJOR/MINOR/NIT findings, all resolved)
prompt.md /loop driver prompt for autonomous M2M6 execution
followups.md Open / resolved deferred work items; auto-triaged by prompt.md Step 0 (created on first /loop run if missing)

The design is grounded in the .NET reference at src/ and the protocol artifacts in docs/, analysis/, and captures/. Do not introduce protocol behavior in these documents that is not already proven in the reference. When adding a new claim about wire format, cite either:

  • a .cs file path in src/MxNativeCodec/, src/MxNativeClient/, or src/MxAsbClient/, or
  • a docs/*.md spec file, or
  • a captures/0NN-frida-* directory or analysis/frida/*.tsv row.

This folder is documentation, not code. When the Rust workspace is created, the design here is the contract it must satisfy. When evidence in captures/ invalidates a design decision here, update the design first, then the code.

Reading order

  • New contributor: 00 → 30 → 10 → 40 → 20 → 50 → 60 → 70.
  • Protocol question: 40 first, then the relevant section of 10.
  • API question: 20 first, then 50.
  • Planning a milestone: 60 first, cross-reference 70 for blockers.
  • Scheduling concurrent work: dependencies.md for the per-phase parallelism map.
  • Driving M2M6 autonomously via /loop: prompt.md (and the followups.md triage log it maintains).