proxmox-backup/pbs-datastore/src/checksum_writer.rs

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use std::sync::Arc;
use std::io::Write;
use anyhow::{Error};
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use pbs_tools::borrow::Tied;
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use super::CryptConfig;
pub struct ChecksumWriter<W> {
writer: W,
hasher: crc32fast::Hasher,
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signer: Option<Tied<Arc<CryptConfig>, openssl::sign::Signer<'static>>>,
}
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impl <W: Write> ChecksumWriter<W> {
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pub fn new(writer: W, config: Option<Arc<CryptConfig>>) -> Self {
let hasher = crc32fast::Hasher::new();
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let signer = match config {
Some(config) => {
let tied_signer = Tied::new(config, |config| {
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Box::new(unsafe { (*config).data_signer() })
});
Some(tied_signer)
}
None => None,
};
Self { writer, hasher, signer }
}
pub fn finish(mut self) -> Result<(W, u32, Option<[u8; 32]>), Error> {
let crc = self.hasher.finalize();
if let Some(ref mut signer) = self.signer {
let mut tag = [0u8; 32];
signer.sign(&mut tag)?;
Ok((self.writer, crc, Some(tag)))
} else {
Ok((self.writer, crc, None))
}
}
}
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impl <W: Write> Write for ChecksumWriter<W> {
fn write(&mut self, buf: &[u8]) -> Result<usize, std::io::Error> {
self.hasher.update(buf);
if let Some(ref mut signer) = self.signer {
signer.update(buf)
.map_err(|err| {
std::io::Error::new(
std::io::ErrorKind::Other,
format!("hmac update failed - {}", err))
})?;
}
self.writer.write(buf)
}
fn flush(&mut self) -> Result<(), std::io::Error> {
self.writer.flush()
}
}