src/backup/checksum_reader.rs

   1 use anyhow::{Error};
   2 use std::sync::Arc;
   3 use std::io::Read;
   4
   5 use super::CryptConfig;
   6 use crate::tools::borrow::Tied;
   7
   8 pub struct ChecksumReader<R> {
   9     reader: R,
  10     hasher: crc32fast::Hasher,
  11     signer: Option<Tied<Arc<CryptConfig>, openssl::sign::Signer<'static>>>,
  12 }
  13
  14 impl <R: Read> ChecksumReader<R> {
  15
  16     pub fn new(reader: R, config: Option<Arc<CryptConfig>>) -> Self {
  17         let hasher = crc32fast::Hasher::new();
  18         let signer = match config {
  19             Some(config) => {
  20                 let tied_signer = Tied::new(config, |config| {
  21                     Box::new(unsafe { (*config).data_signer() })
  22                 });
  23                 Some(tied_signer)
  24             }
  25             None => None,
  26         };
  27
  28         Self { reader, hasher, signer }
  29     }
  30
  31     pub fn finish(mut self) -> Result<(R, u32, Option<[u8; 32]>), Error> {
  32         let crc = self.hasher.finalize();
  33
  34         if let Some(ref mut signer) = self.signer {
  35             let mut tag = [0u8; 32];
  36             signer.sign(&mut tag)?;
  37             Ok((self.reader, crc, Some(tag)))
  38         } else {
  39             Ok((self.reader, crc, None))
  40         }
  41     }
  42 }
  43
  44 impl <R: Read> Read for ChecksumReader<R> {
  45
  46     fn read(&mut self, buf: &mut [u8]) -> Result<usize, std::io::Error> {
  47         let count = self.reader.read(buf)?;
  48         if count > 0 {
  49             self.hasher.update(&buf[..count]);
  50             if let Some(ref mut signer) = self.signer {
  51                 signer.update(&buf[..count])
  52                     .map_err(|err| {
  53                         std::io::Error::new(
  54                             std::io::ErrorKind::Other,
  55                             format!("hmac update failed - {}", err))
  56                     })?;
  57             }
  58         }
  59         Ok(count)
  60     }
  61 }