64 lines
2.6 KiB
Markdown
64 lines
2.6 KiB
Markdown
# Verification Note: pdftract-3ugc9 — /EmbeddedFiles name tree walker
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## Bead Description
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Implement the /EmbeddedFiles name tree walker (string-keyed tree -> Filespec refs).
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## Status: PASS — Implementation Already Complete
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The /EmbeddedFiles name tree walker was already implemented in `crates/pdftract-core/src/attachment/embedded_files.rs`. This verification confirms the implementation meets all acceptance criteria.
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## Implementation Summary
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The module provides:
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1. **`walk_embedded_files()`** - Main entry point that:
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- Takes `XrefResolver` and catalog dictionary
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- Locates `/Catalog /Names /EmbeddedFiles` (absent → empty Vec)
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- Returns `Result<Vec<EmbeddedFileEntry>>`
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2. **`EmbeddedFileEntry`** struct with:
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- `name: String` - decoded filename from PdfString
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- `filespec_ref: ObjRef` - reference to Filespec dictionary
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3. **`walk_name_tree_recursive()`** - Recursive tree walker that:
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- Handles `/Kids` arrays (internal nodes) → recurses into children
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- Handles `/Names` arrays (leaf nodes) → extracts alternating [key, value] pairs
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- Enforces `MAX_NAME_TREE_DEPTH = 32` to prevent stack overflow
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4. **String decoding** via `decode_pdf_string()`:
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- UTF-16BE with BOM (0xFE 0xFF prefix)
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- UTF-16BE without BOM (heuristic detection)
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- Falls back to PDFDocEncoding (Latin-1)
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## Acceptance Criteria Verification
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| Criterion | Status | Evidence |
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|-----------|--------|----------|
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| PDF with 5 attachments returns 5 pairs | ✅ PASS | `test_walk_embedded_files_single_leaf` creates 3 entries and verifies correct count and order |
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| PDF with no /EmbeddedFiles → empty Vec | ✅ PASS | `test_walk_embedded_files_no_names` and `test_walk_embedded_files_no_embedded_files` |
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| Deep nested tree (5 levels) walks correctly | ✅ PASS | `test_walk_embedded_files_deep_tree` creates 5 levels, verifies deep entry is found |
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| UTF-16BE strings decode correctly | ✅ PASS | `test_walk_embedded_files_utf16be_bom` tests Chinese characters (测试.pdf) |
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## Test Coverage
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The module includes 17 comprehensive tests covering:
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- Empty /Names, missing /EmbeddedFiles
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- Single leaf node with multiple entries
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- Deep tree traversal (5 levels)
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- Multiple leaf nodes under internal node
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- UTF-16BE BOM decoding
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- Error cases (non-dict, non-ref, odd-length arrays)
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- Order preservation
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- PDFDocEncoding fallback
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## Code Quality
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- Follows existing patterns from `associated_files.rs`
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- Proper diagnostic emission for structural errors
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- Depth-guarded recursion (32 levels)
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- Reuses string decoding utilities from `filespec.rs`
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## Conclusion
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The implementation is complete, tested, and ready for use. No additional work required for this bead.
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