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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
1.3 KiB
Markdown
35 lines
1.3 KiB
Markdown
# `LocalFileSink`
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`BufWriter<File>`-backed sink for the common local-disk case
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(`src/io/sink/local_file.rs`).
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## Buffering
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4 MiB internal `BufWriter`. Sized to coalesce the small per-PES writes
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that come out of the muxer into kernel-page-aligned flushes without
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making the buffer big enough to matter for memory pressure on a single
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concurrent rip.
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## Seek-flush ordering
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`Seek` flushes the underlying `BufWriter` first; otherwise a seek could
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leapfrog buffered data and silently corrupt the file. This is the same
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shape `BufWriter` itself uses when it impls `Seek` in stdlib, and is
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necessary for MKV's seek-back operations (cluster size patch, Cues
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index, segment header backpatch) to land on the right offset.
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## Trait wiring
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[`SequentialSink`](../src/io/sink/mod.rs) is implemented explicitly
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(not via a blanket impl) so its `finish()` flushes the `BufWriter` and
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`fsync`s the file even when called through a `dyn` trait object;
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`RandomAccessSink` is implemented over the `Seek` impl.
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## Construction contract
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Construction always opens the file `create + truncate + read + write`.
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`read` is enabled so the same handle can be reused for a verification
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re-read after the mux (the existing `FileSectorSink::create` pattern).
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On Linux, `with_size_hint` additionally calls
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`fallocate(FALLOC_FL_KEEP_SIZE)` to pre-reserve extents.
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