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Author	SHA1	Message	Date
andodeki	e0aab74452	feat(pdf): page operations — insert, reorder, duplicate, delete, import ... Phase 5's page management, matching dart-pdf's `page_ops_test.dart`, `page_index_map_test.dart` and `import_source_test.dart`. A reader sees "page 3"; the file holds a tree of /Pages nodes with /Kids and /Count and /Parent back-pointers, any of which can be left stale. So the writer **flattens to a single level**: a one-level /Pages node with every page as a direct kid is valid, is what most producers emit, and removes the entire class of bug where an intermediate node's /Count no longer matches what is under it. Preserving an arbitrary tree shape through arbitrary reordering is far more code for nothing a reader can see. `PagePlan` accumulates operations and applies them together, so intermediate states never have to be valid — delete page 0 and insert a new one at 0 without the document momentarily having no first page. `PageIndexMap` reports where every page went, which is the only way to fix an outline entry, named destination or link annotation afterwards. What each operation carries matters and differs: - Reorder and delete rewrite only the kid array, so page objects and their resources are untouched. - Duplicate writes a new page dictionary that **shares** the original's resource references. Two pages naming one font object is normal; deep-copying would double the file and change nothing visible. - Import must deep-copy the page and everything it reaches, renumbered, because source object numbers mean nothing in the destination. /Parent is deliberately not followed — it leads back to the source's page tree and from there to every other page in that file. Inheritable attributes are resolved *before* a page is imported. /Resources, /MediaBox, /CropBox and /Rotate may live on an ancestor (Table 30) that is not coming with it, so a page imported without them renders at the wrong size with no fonts, and nothing reports an error. **Round-trip tested through the saved file**, which is Phase 5's exit criterion: 20 tests that save, re-parse, and assert on what a reader actually gets. Pages are identified by /MediaBox width rather than object number, because object numbers are exactly what a page-tree bug scrambles. Mutation testing changed two things. Seven defects injected: /Count left stale 1 fail /Count omitted entirely 1 fail imported /Parent not rewritten 1 fail inherited attributes not resolved 1 fail import does not deep-copy 3 fail duplicate loses /Contents 1 fail re-parenting skipped 1 fail The last two only fail because of tests the mutations forced: - **A stale /Count passed everything.** Our own parser walks /Kids and never reads /Count, so it cannot see the disagreement — but other readers trust /Count, and a document where the two differ opens with a different page count in different viewers. The test now reads the raw page-tree node instead of asking the document. - **Re-parenting could be deleted with every test still green**, because the flat fixture's pages already parent to the root. Added a nested fixture with an intermediate /Pages node supplying an inherited /MediaBox — the case where leaving /Parent stale means a page keeps inheriting from a node it is no longer under. Externally verified: a generated sample with pages swapped and duplicated passes `qpdf --check` with no warnings, and poppler reads 4 pages with the reordering visible in extracted text. Engine suite 1039 -> 1075. Remaining in Phase 5: flatten, object compaction, redaction, and outline and struct-tree editing.	2026-08-17 10:38:55 +00:00