Module render_workers 

Process-parallel page rendering for pass B of the post pipeline (docs/performance/STREAMING_POST_DESIGN_2026-07-06.md §6).

In-process page threads are blocked twice (ObjectDB is !Send; libxslt serializes every transform behind a process-wide lock), so the chosen shape is process-level page-range workers: the parent saves the completed ObjectDB as a SQLite file, partitions the spilled pages into contiguous chunks, and re-invokes its own binary once per chunk with LATEXML_RENDER_WORKER=<manifest.json>. Each child attaches the db readonly (WAL — N readers share one page cache via mmap), runs the SAME per-page pipeline as the serial driver (crate::post::render_spilled_page), and reports its diagnostic tally as trailing Status: lines on stderr. The parent folds child logs and counts deterministically, in chunk order, into its own LOG_BUFFER / REPORT — so the combined verdict and the persisted --log stay lossless (canvas signal-integrity rule: a child that dies without a status line is folded as FATAL, never as success).

Env knob: LATEXML_RENDER_JOBS (usize). Default 1 = the serial path, byte-identical to before this module existed.

Structs

PageJob

One spilled page for a worker to render: the spill path plus the metadata that does not survive the XML round-trip (mirrors post::SpilledPage minus the parent-only placeholder flags).

PageOpts

The serializable subset of PostDocumentOptions a worker needs to reconstruct the page parse — ALL of its fields, since even destination (later overridden per page) feeds the site-directory fallback inside PostDocument::new.

RenderManifest

Everything a page-render worker needs to rebuild the pass-B processor set exactly as the parent would have, plus its page range. Written as render-manifest-{i}.json beside the saved render.db.

Functions

worker_main

Entry point of the hidden worker mode (LATEXML_RENDER_WORKER=<manifest>), dispatched from the binary’s main before any CLI handling. Renders the manifest’s page range and ALWAYS ends its stderr with the status report — even when the manifest cannot be read — so the parent never mistakes a broken worker for a clean one.