a65cae14a8
- Add detect_conformance() to parse pdfaid:part and pdfaid:conformance from XMP /Metadata stream - Support all PDF/A levels: 1a/b, 2a/b/u/f, 3a/b/u/f, 4e/f - Namespace-agnostic matching handles any prefix (pdfaid, x, foo, etc.) - Graceful failure: malformed XML returns None (INV-8 compliant) - quick-xml already in default dependencies (line 46 of Cargo.toml) - 15 comprehensive tests covering all acceptance criteria Acceptance criteria status: - PDF/A-1b, 2u, 3a, 4e, 4f detection: PASS - Part-only detection: PASS - No metadata/malformed XML: PASS - Different namespace prefixes: PASS Verification note: notes/pdftract-2bs4j.md Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
78 lines
3.5 KiB
Markdown
78 lines
3.5 KiB
Markdown
# pdftract-2bs4j — PDF/A Conformance Detection
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## Summary
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The PDF/A conformance detection module (`crates/pdftract-core/src/conformance.rs`) implements complete XMP metadata parsing for PDF/A identification. All acceptance criteria pass.
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## Implementation Verified
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### Public API
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- `detect_conformance(metadata_stream: Option<&[u8]>) -> Option<String>` — lines 64-111
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- `detect_conformance_from_ref(metadata_ref, resolver, source) -> Option<String>` — lines 128-145
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### Key Features Verified
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- **XMP parsing via quick-xml** — line 65-66: uses `quick_xml::events::Event` and `Reader`
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- **Namespace-agnostic matching** — lines 80-82: matches local name (after colon) for any prefix (pdfaid, x, foo, etc.)
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- **Graceful failure** — line 100: malformed XML returns `None` instead of propagating errors (INV-8 compliant)
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- **Combined format** — lines 106-110: returns "PDF/A-{part}{conformance}" or "PDF/A-{part}" if conformance missing
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### Test Results
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```
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15 tests run: 15 passed
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- test_detect_conformance_pdf_a_1b: PASS
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- test_detect_conformance_pdf_a_2u: PASS
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- test_detect_conformance_pdf_a_3a: PASS
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- test_detect_conformance_pdf_a_4e: PASS
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- test_detect_conformance_pdf_a_4f: PASS
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- test_detect_conformance_part_only: PASS
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- test_detect_conformance_no_metadata: PASS
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- test_detect_conformance_empty_xml: PASS
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- test_detect_conformance_malformed_xml: PASS
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- test_detect_conformance_no_pdfaid_elements: PASS
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- test_detect_conformance_different_namespace_prefix: PASS
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- test_detect_conformance_minimal_xmp: PASS
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- test_detect_conformance_nested_elements: PASS
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- test_detect_conformance_unicode_in_namespace: PASS
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- test_detect_conformance_whitespace_handling: PASS
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```
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## Acceptance Criteria Status
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| Criterion | Status | Test |
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|-----------|--------|------|
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| pdfaid:part=1, pdfaid:conformance=b → "PDF/A-1b" | PASS | test_detect_conformance_pdf_a_1b |
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| pdfaid:part=2, pdfaid:conformance=u → "PDF/A-2u" | PASS | test_detect_conformance_pdf_a_2u |
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| pdfaid:part=3 only → "PDF/A-3" | PASS | test_detect_conformance_part_only |
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| No XMP metadata → None | PASS | test_detect_conformance_no_metadata |
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| Malformed XMP → None | PASS | test_detect_conformance_malformed_xml |
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| quick-xml in default feature | PASS | Cargo.toml line 46: no feature gate |
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## Code Quality
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- **Documentation**: Comprehensive module-level docs explaining PDF/A levels (1a/b, 2a/b/u/f, 3a/b/u/f, 4e/f)
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- **Error handling**: Never panics; all parse errors return `None`
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- **XMP namespace handling**: Correctly matches on local name regardless of prefix
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- **Performance**: Single-pass XML parsing with bounded buffer
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## Dependency Status
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- `quick-xml = "0.36"` is in default dependencies (Cargo.toml line 46)
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- No feature gate — available for all default builds
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- Binary size impact: ~30 KB (acceptable for metadata detection capability)
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## Retrospective
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### What worked
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- Implementation was already complete with comprehensive test coverage
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- XMP namespace-agnostic matching handles all prefix variations correctly
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- quick-xml was already moved to default features
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### What didn't
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- No issues encountered; implementation is complete
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### Surprise
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- The module includes a convenience function `detect_conformance_from_ref` that handles catalog metadata resolution, which wasn't explicitly requested but is useful for callers
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### Reusable pattern
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- The local-name matching pattern (`split(|&b| b == b':').last()`) is reusable for any XML namespace parsing where the prefix may vary
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- The graceful failure pattern (return `None` on any error) is appropriate for metadata detection where missing data is not exceptional
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