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35 lines
868 B
Rust
35 lines
868 B
Rust
//! Prints a file given as an argument to stdout.
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#![feature(async_await)]
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use std::env::args;
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use async_std::{fs, io, prelude::*, task};
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const LEN: usize = 4 * 1024 * 1024; // 4 Mb
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fn main() -> io::Result<()> {
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let path = args().nth(1).expect("missing path argument");
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task::block_on(async {
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let mut file = fs::File::open(&path).await?;
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let mut stdout = io::stdout();
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let mut buf = vec![0u8; LEN];
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loop {
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// Read a buffer from the file.
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let n = file.read(&mut buf).await?;
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// If this is the end of file, clean up and return.
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if n == 0 {
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stdout.flush().await?;
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file.close().await?;
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return Ok(());
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}
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// Write the buffer into stdout.
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stdout.write_all(&buf[..n]).await?;
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}
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})
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}
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