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https://github.com/freemkv/libfreemkv.git
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Matthew Jackson
6e14fc0c0c
Security - Remove the unsafe Vec::set_len over recycled sector buffers — UB reachable from safe code (GHSA-j8ww-f5fg-9pmh, low). Uses Vec::resize; pooling unchanged. CI / tooling - clippy on stable with the MSRV single-sourced from Cargo.toml; cargo-deny dependency-audit gate with first-party git sources allowed (#15); audience-based comment-guard (#17). Docs - README (keydb ownership, BD-J parser count), drive-access transport/reset notes, mux timeline module-doc links.
35 lines
1.4 KiB
Markdown
35 lines
1.4 KiB
Markdown
# `src/io/mod.rs` — background
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## `WritebackFile`
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Drop-in wrapper around `std::fs::File` for any call site that performs
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large sequential writes (sweep, patch, mux, etc.). It implements `Write`
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and `Seek` so existing code paths can swap `File` for `WritebackFile`
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with no body changes. Internally it drives a `WritebackPipeline` that,
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on Linux, drains dirty pages continuously at 32 MB granularity to avoid
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the kernel's accumulate-then-burst flush behaviour. macOS and Windows
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use a no-op pipeline — their default cache policies have not been shown
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to exhibit the same pathology for this access pattern.
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## `FileSectorSource`
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The read-side dual of `WritebackFile` — it implements
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[`crate::sector::SectorSource`] for an ISO file using direct
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`pread`-equivalent calls so the kernel's own readahead policy runs
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(which interleaves naturally with the concurrent writeback). It pairs
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that with periodic `posix_fadvise(DONTNEED)` drops on the consumed
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window so an 85 GB streaming ISO read doesn't fill the page cache and
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starve the concurrent MKV write.
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## `Pipeline` + `Sink`
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The generic producer/consumer primitive used by sweep, patch, and mux
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to overlap reads with writes via a bounded channel + dedicated consumer
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thread.
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## `byte_prefetcher`
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The read-ahead producer feeding the mux pipeline for `io::Read`-backed
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sources: a worker thread fills a recycled pool of buffers and ships
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them through a channel, exposing `BytePrefetcher` / `PrefetchShell`.
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