b8a1b8f193
This commit fixes a compilation error in the javascript tests that were using PageDict::default(). The JBIG2 decoder module was already fully implemented; this change only enables the tests to compile and run. Changes: - Add Default impl for PageDict in parser/pages.rs - Verify all 11 JBIG2-related tests pass The JBIG2Decode passthrough filter implementation is complete: - Passthrough of raw JBIG2 bytes - /JBIG2Globals reference recording for downstream consumers - OCR_JBIG2_UNSUPPORTED diagnostic emission when full-render disabled Co-Authored-By: Claude Code <noreply@anthropic.com>
83 lines
4.1 KiB
Markdown
83 lines
4.1 KiB
Markdown
# pdftract-2sswr: JBIG2Decode passthrough + /JBIG2Globals reference recording + OCR_JBIG2_UNSUPPORTED diagnostic
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## Summary
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Verified that the JBIG2Decode passthrough filter implementation is complete and functional. The JBIG2 decoder module (`crates/pdftract-core/src/decoder/jbig2.rs`) was already implemented with all required functionality.
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## Acceptance Criteria Status
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### PASS
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- JBIG2 stream with full-render feature → pass-through, no diagnostic (stream.rs:3542-3548)
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- JBIG2 stream WITHOUT full-render → OCR_JBIG2_UNSUPPORTED diagnostic; pass-through anyway (stream.rs:3542-3548)
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- /JBIG2Globals reference recorded on StreamMeta (stream.rs:3550-3556)
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- Self-contained JBIG2 (no globals): StreamMeta.jbig2_globals_ref is None (field defaults to None)
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### WARN
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- Round-trip test with reference JBIG2 fixture: Unit tests in stream.rs (test_jbig2_passthrough, test_jbig2_extract_globals_ref, etc.) verify the passthrough and globals extraction functionality with mock data. No actual JBIG2 PDF fixture exists in the test suite.
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## Changes Made
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### Fixed compilation error in `parser/pages.rs`
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- Added `Default` implementation for `PageDict` struct to fix compilation errors in `javascript.rs` tests
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- The `PageDict::default()` method is used in javascript detection tests
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### Verified existing implementation
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The following components were already implemented and verified working:
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**`crates/pdftract-core/src/decoder/jbig2.rs`** (225 lines):
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- `Jbig2GlobalsRef` struct - captures ObjRef to globals stream
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- `Jbig2Decoder` struct - handles passthrough and diagnostic emission
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- `extract_globals_ref()` - extracts /JBIG2Globals reference from stream dict
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- `emit_unsupported_diagnostic()` - emits OCR_JBIG2_UNSUPPORTED when full-render not available
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- `has_full_render()` - checks cfg!(feature = "full-render") at compile time
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- Read trait implementation for passthrough compatibility
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- 6 unit tests (all passing)
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**`crates/pdftract-core/src/parser/stream.rs`** (integration):
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- Lines 3542-3548: Emit OCR_JBIG2_UNSUPPORTED diagnostic when full-render disabled
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- Lines 3550-3556: Extract /JBIG2Globals reference and store in stream_meta
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- Lines 5742-5831: 5 integration tests for JBIG2 passthrough (all passing)
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**`crates/pdftract-core/src/diagnostics.rs`**:
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- `DiagCode::OcrJbig2Unsupported` defined at line 633
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- Diagnostic info at line 1951-1955 (Warning severity, recoverable)
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## Test Results
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All 11 JBIG2-related tests pass:
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```
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test decoder::jbig2::tests::test_emit_unsupported_diagnostic_when_feature_disabled ... ok
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test decoder::jbig2::tests::test_extract_globals_ref_with_valid_ref ... ok
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test decoder::jbig2::tests::test_extract_globals_ref_with_invalid_type ... ok
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test decoder::jbig2::tests::test_extract_globals_ref_without_globals ... ok
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test decoder::jbig2::tests::test_jbig2_decoder_const ... ok
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test decoder::jbig2::tests::test_jbig2_globals_ref_const ... ok
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test parser::stream::source_tests::test_jbig2_bomb_limit ... ok
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test parser::stream::source_tests::test_jbig2_extract_globals_ref ... ok
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test parser::stream::source_tests::test_jbig2_extract_globals_ref_invalid_type ... ok
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test parser::stream::source_tests::test_jbig2_extract_globals_ref_missing ... ok
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test parser::stream::source_tests::test_jbig2_passthrough ... ok
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```
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## Implementation Details
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Per PDF spec 7.4.7:
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- JBIG2Decode is a lossless compression format for bitonal images
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- /JBIG2Globals is an indirect reference to a globally-shared symbol dictionary
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- Without globals, the stream is self-contained (still decodable)
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Passthrough behavior (EC-11):
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- With full-render feature: Passthrough only, no diagnostic
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- Without full-render: Emit OCR_JBIG2_UNSUPPORTED diagnostic, still passthrough
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## Files Modified
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- `crates/pdftract-core/src/parser/pages.rs` - Added Default impl for PageDict
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## Files Verified (no changes needed)
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- `crates/pdftract-core/src/decoder/jbig2.rs` - Complete implementation
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- `crates/pdftract-core/src/decoder/mod.rs` - Module exports
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- `crates/pdftract-core/src/parser/stream.rs` - Integration and diagnostics
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- `crates/pdftract-core/src/diagnostics.rs` - Diagnostic code definition
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- `crates/pdftract-core/src/lib.rs` - Public module export
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