46 lines
1.1 KiB
Rust
46 lines
1.1 KiB
Rust
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use std::{fs::File, task::Waker, io::Write, path::PathBuf};
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pub trait LiveWriter: Write {
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fn add_waker(&mut self, waker: Waker);
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}
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/// A simple wrapper for a file that can be read while we're still appending data
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pub struct LiveFileWriter {
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file: File,
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/// Wake handles for contexts that are waiting for us to write more
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wakers: Vec<Waker>,
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}
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impl LiveFileWriter {
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pub fn new(path: &PathBuf) -> std::io::Result<Self> {
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Ok(Self {
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file: File::options().write(true).create_new(true).open(path)?,
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wakers: Vec::new(),
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})
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}
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}
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impl LiveWriter for LiveFileWriter {
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fn add_waker(&mut self, waker: Waker) {
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self.wakers.push(waker);
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}
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}
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impl Write for LiveFileWriter {
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fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
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let result = self.file.write(buf);
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if let Ok(n) = result {
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if n > 0 {
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for waker in self.wakers.drain(..) {
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waker.wake();
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}
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}
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}
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result
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}
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fn flush(&mut self) -> std::io::Result<()> {
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self.file.flush()
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}
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}
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