matthew
5380edd737
Introduces the SequentialSink / RandomAccessSink trait pair under io::sink and an open_for_mkv dispatch helper that picks WritebackFile on Linux+NFS and LocalFileSink everywhere else. LocalFileSink wraps BufWriter<File> with a 4 MiB buffer and exposes a per-OS preallocate path (fallocate on Linux, F_PREALLOCATE on macOS, no-op fallback). Adds platform::fs_type::detect with a per-OS split (statfs on Linux / macOS, UNC heuristic on Windows, Unknown elsewhere) so construction- site dispatch has a single primitive to call. Blanket impls cover the common shapes: any Write+Send is a SequentialSink, and any SequentialSink+Seek is a RandomAccessSink. WritebackFile satisfies the random-access trait via the blanket impl without needing an explicit per-type impl. No callers wired yet — the mux::resolve construction sites stay on WritebackFile pending Phase 3. Tests: 5 new sink/preallocate tests + 3 fs_type tests (1 ignored, needs a real NFS mount). cargo +1.86 fmt + clippy + tests all green.
47 lines
2.0 KiB
Rust
47 lines
2.0 KiB
Rust
//! File I/O helpers that bound kernel cache pressure on big writes.
|
|
//!
|
|
//! `WritebackFile` is a drop-in wrapper around `std::fs::File` for any
|
|
//! call site that performs large sequential writes (sweep, patch, mux,
|
|
//! etc.). It implements `Write` and `Seek` so existing code paths can
|
|
//! swap `File` for `WritebackFile` with no body changes. Internally it
|
|
//! drives a `WritebackPipeline` that, on Linux, drains dirty pages
|
|
//! continuously at 32 MB granularity to avoid the kernel's
|
|
//! accumulate-then-burst flush behaviour. macOS and Windows use a
|
|
//! no-op pipeline — their default cache policies have not been shown
|
|
//! to exhibit the same pathology for this access pattern.
|
|
//!
|
|
//! `FileSectorSource` is the read-side dual — it implements
|
|
//! [`crate::sector::SectorSource`] for an ISO file with an internal
|
|
//! 32 MiB read-ahead buffer that amortises NFS round-trip latency
|
|
//! across thousands of sector reads.
|
|
//!
|
|
//! `Pipeline` + `Sink` (0.18) is the generic producer/consumer primitive
|
|
//! used by sweep, patch, and mux to overlap reads with writes via a
|
|
//! bounded channel + dedicated consumer thread.
|
|
//!
|
|
//! `byte_channel` is a byte-sized producer/consumer channel for the
|
|
//! mux pipeline, sized to absorb worst-case input read stalls (see
|
|
//! `freemkv-private/memory/project_buffering_architecture.md`).
|
|
|
|
pub(crate) mod bounded;
|
|
pub mod byte_channel;
|
|
pub mod file_sector_source;
|
|
pub mod sink;
|
|
mod writeback;
|
|
mod writeback_file;
|
|
|
|
pub mod pipeline;
|
|
|
|
pub(crate) use writeback_file::WritebackFile;
|
|
|
|
// Re-exports for the 0.18 redesign. Sweep + patch are both wired up
|
|
// (disc/sweep.rs, disc/patch.rs); mux migrates separately in autorip.
|
|
// `WRITE_THROUGH_DEPTH` is patch-specific and has no other in-tree
|
|
// caller — the targeted `#[allow]` keeps the re-export visible without
|
|
// dragging the rest of the module under `dead_code`.
|
|
#[allow(unused_imports)]
|
|
pub use pipeline::{
|
|
DEFAULT_PIPELINE_DEPTH, Flow, Pipeline, READ_PIPELINE_DEPTH, Sink, WRITE_PIPELINE_DEPTH,
|
|
WRITE_THROUGH_DEPTH,
|
|
};
|