Files
mxaccess/design
Joseph Doherty a2b8989cbf [M5] mxaccess-asb: F25 step 2 — per-operation request body codecs
Adds the IAsbCustomSerializableType binary fast-path + per-operation
request-body NBFX-token builders. RegisterItems and UnregisterItems
now compose end-to-end through SoapEnvelope + encode_envelope to a
byte stream that round-trips back to the original ItemIdentity array.

Three pieces:

1. F21 NBFX gains `Bytes8/16/32` text records (records 0x9E/0xA0/0xA2
   plus +1 WithEndElement variants). WCF's `XmlDictionaryWriter.
   WriteBase64` emits these in binary form — not actual base64 text —
   so they're required for the `<ASBIData>` content.

2. `mxaccess-asb::contracts::ItemIdentity` ports `AsbContracts.cs:533-633`:
   * Wire layout: u16 kind + u16 reference_type +
     AsbBinary.WriteUnicodeString(Name) + AsbBinary.WriteUnicodeString
     (ContextName) + u64 Id + u8 IdSpecified.
   * `AsbBinary.WriteUnicodeString` per cs:1622-1633: u32 byte-length
     + UTF-16LE bytes; null/empty collapse to a 4-byte zero header.
   * `encode_item_identity_array` / `decode_item_identity_array`
     mirror `WriteArrayToStream` — 4-byte int32 count + each
     element's `WriteToStream` output. Per `AsbDataCustomSerializer`
     at cs:1583-1591.
   * `absolute_by_name(...)` convenience constructor matching
     `MxAsbDataClient.CreateAbsoluteItem` at cs:172-194.

3. `mxaccess-asb::operations` builds SOAP body NBFX token streams:
   * `build_register_items_request_body(items, require_id, register_only)`
     — RegisterItems contract per cs:119-143.
   * `build_unregister_items_request_body(items)` — UnregisterItems
     per cs:145-159.
   * Internal `BodyField` helper assembles the wire shape:
     `<RegisterItemsRequest xmlns="urn:msg.data.asb.iom:2">
        <Items><ASBIData>{Bytes(payload)}</ASBIData></Items>
        <RequireId>true|false</RequireId>
        <RegisterOnly>true|false</RegisterOnly>
      </RegisterItemsRequest>`

15 new tests cover:
* ItemIdentity round-trip (default, with id, unicode name).
* AsbBinary unicode-string null/empty/value semantics.
* Byte-layout pinning (21 bytes for default ItemIdentity, le-int32
  array count).
* ItemIdentity array round-trip.
* `<ASBIData>` Bytes record round-trip across NBFX widths
  (Bytes8/16/32 selected by length).
* RegisterItems body → SoapEnvelope → encode → decode → recover the
  ItemIdentity array end-to-end.
* RequireId / RegisterOnly Bool wire form.
* UnregisterItems body uses correct outer element name and omits
  the RegisterItems-only fields.

Stubbed for next F25 iteration: per-operation Read / Write /
PublishWriteComplete / CreateSubscription / AddMonitoredItems /
DeleteMonitoredItems / Publish builders, response decoders, and the
`AsbClient` network loop.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-05 11:24:19 -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).