# dude-on-disk profile — The Dude `objs.obj` blobs
#
# A per-row object blob from `dude.db`. Same physical nv::message TLV grammar
# as winbox-ipc, but the profile-specific rules differ: byte 2 is a marker,
# compactness is signaled by that marker instead of the low tcode bit, and the
# object class is chosen from the range of the leading section-1 tag.
---
m2ir-version: 0.1
schema-version: 0.1

id: dude-on-disk
title: The Dude on-disk object blob
maturity: exploratory
description: |
  The Dude stores each object row as a Nova / nv::message blob in `dude.db`
  table `objs`, column `obj`. Donny's decoder treats the blob as an 8-byte
  constant preamble, a 4-byte LE declared-field-count, then TLV entries until
  end-of-buffer. The same physical TLV grammar as winbox-ipc applies, but this
  profile renames byte 2 to `marker`, uses marker 0x11 for compact-width
  payloads, and dispatches objects by the leading section-1 tag's numeric range.

physical-ref: ../../physical/nv-message.yaml
magic: [0x4d, 0x32, 0x01, 0x00, 0xff, 0x88, 0x01, 0x00]

structure:
  root:
    seq:
      - { name: preamble, size: 8, role: "constant Nova prefix; bytes 4-7 also resemble the header of a one-element u32 array" }
      - { name: declared-field-count, width: u32le, role: "section-1 field count as consumed by donny's decoder" }
      - { name: fields, kind: tlv-entry, repeat: eos }

byte-2-as: marker
markers:
  0x10:
    name: standard
    width-rule: from-tcode
    confidence: documented
  0x11:
    name: compact
    width-rule: always-1-byte
    confidence: documented
    notes: "Donny short-circuits marker 0x11 to a one-byte value regardless of tcode."
  0xfe:
    name: alternate
    width-rule: from-tcode
    confidence: documented
    notes: |
      Alternate standard marker. Used for the continuation separator
      (`SELF_ID`, tag 0x0001) and trailing `NAME` field in donny's writers.

compact-rule: marker-byte
continuation:
  separator:
    tag: 0x0001
    canonical-name: SELF_ID
    marker: 0xfe
    tcode: 0x08
    role: "section boundary between the main body and the trailing NAME field"
  trailing-field:
    tag: 0x0010
    canonical-name: NAME
    marker: 0xfe
    role: "last field emitted by donny's object builders"

classification:
  kind: by-leading-tag-range
  skip-leading-tags: [0x0001]
  refs:
    object-classes: ./object-classes.yaml
  notes: |
    Donny classifies objects by the first section-1 tag, except when that tag is
    SELF_ID (0x0001). In that case the next tag is the real discriminator.
    Overlapping ranges exist; prefer the narrower/special-case bands before
    the wider ranges around them (for example syslog-rule before network-scanner).

refs:
  object-classes: ./object-classes.yaml
  fields: ./fields.yaml

evidence:
  - source: code
    ref: "tikoci/donny src/lib/nova.ts:1-248"
    url: "https://github.com/tikoci/donny/blob/main/src/lib/nova.ts#L1-L248"
  - source: code
    ref: "german77/TheDudeToHuman src/the_dude_to_human/database/dude_field_parser.cpp:1-438"
    url: "https://github.com/german77/TheDudeToHuman/blob/master/src/the_dude_to_human/database/dude_field_parser.cpp#L1-L438"

investigation-trail:
  - date: 2026-05-03
    finding: |
      Donny's comments call the first 8 bytes a constant magic, while the local
      design notes observe that bytes 4-7 also parse as the header of a
      one-element u32 array. Keep both interpretations visible until fixture
      work decides whether a more structured prefix model is useful downstream.