jedarden 43d31f8dfc docs(pdftract-dejqs): update verification note with 2026-05-22 test results

Re-verified per-page Resource dictionary inheritance implementation:
- All 33 tests pass (resources + pages)
- Arc sharing optimization confirmed (Arc::ptr_eq test)
- INV-8 maintained (proptests pass)

Acceptance criteria:
- ✅ 3-level resource inheritance
- ✅ Per-key override semantics
- ✅ Arc sharing when no merge needed
- ✅ ColorSpace inline arrays preserved
- ✅ Empty root /Resources propagation

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

2026-05-22 19:21:39 -04:00

3.1 KiB

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pdftract-dejqs: Per-page Resource Dictionary Inheritance

Summary

Implemented per-page Resource dictionary inheritance as specified in PDF 1.7 Section 7.7.3.3. The implementation was already complete in resources.rs and pages.rs; this task verified the implementation and added missing test coverage for Arc sharing.

Changes Made

Added Arc sharing test (test_resource_inheritance_page_without_resources):
- Modified existing test to verify that when multiple pages have no /Resources, they share the same Arc<ResourceDict> instance
- Uses Arc::ptr_eq to verify pointer equality (memory efficiency)
Added public API exports in parser/mod.rs:
- pub use resources::{ResourceDict, merge_resources, extract_resources};
- pub use pages::{PageDict, flatten_page_tree, DEFAULT_MEDIABOX};

Acceptance Criteria Status

Criterion	Status	Test
3-level resource inheritance	✅ PASS	`test_resource_inheritance_three_level`
Per-key override (page's /F1 wins)	✅ PASS	`test_merge_fonts_last_write_wins`
Arc sharing when /Resources missing	✅ PASS	`test_resource_inheritance_page_without_resources` (new `Arc::ptr_eq` check)
ColorSpace inline array preserved	✅ PASS	`test_merge_colorspace_inline_array`
Empty root /Resources propagates	✅ PASS	`test_resource_inheritance_empty_root`
INV-8 maintained (no panics)	✅ PASS	`proptests::fuzz_*` tests verify no panics on arbitrary input

Implementation Details

The merge_resources function in resources.rs implements per-namespace merging:

Font namespace: IndexMap<Arc, ObjRef> - per-key last-write-wins
XObject namespace: IndexMap<Arc, ObjRef>
ExtGState namespace: IndexMap<Arc, ObjRef>
ColorSpace namespace: IndexMap<Arc, PdfObject> - preserves inline arrays
Shading namespace: IndexMap<Arc, ObjRef>
Pattern namespace: IndexMap<Arc, ObjRef>
Properties namespace: IndexMap<Arc, ObjRef>
ProcSet: Vec<Arc> - deprecated, informational only

The flatten_page_tree function in pages.rs calls merge_resources during traversal:

Ancestor resources are accumulated in InheritedAttrs.resources
Each leaf page merges its own /Resources with inherited resources
When a page has no /Resources, it directly clones the Arc (pointer-sharing, not deep copy)

Files Modified

crates/pdftract-core/src/parser/pages.rs: Enhanced Arc sharing test
crates/pdftract-core/src/parser/mod.rs: Added public API exports
notes/pdftract-dejqs.md: This verification note

Test Results (2026-05-22 verification)

All tests pass:

cargo test --lib -- parser::resources parser::pages
test result: ok. 33 passed; 0 failed; 0 ignored

Breakdown:

9 tests in parser::resources::tests
20 tests in parser::pages::tests (excluding 4 proptests)
4 proptests for INV-8 compliance (no panics on arbitrary input)

No Breaking Changes

The implementation was already complete and tested. This task only added:

One additional test assertion for Arc sharing
Public API exports that were previously internal

3.1 KiB Raw Blame History