src/backup/checksum_reader.rs

   1 use failure::*;
   2 use std::io::Read;
   3
   4 pub struct ChecksumReader<'a, R> {
   5     reader: R,
   6     hasher: crc32fast::Hasher,
   7     signer: Option<openssl::sign::Signer<'a>>,
   8 }
   9
  10 impl <'a, R: Read> ChecksumReader<'a, R> {
  11
  12     pub fn new(reader: R, signer: Option<openssl::sign::Signer<'a>>) -> Self {
  13         let hasher = crc32fast::Hasher::new();
  14         Self { reader, hasher, signer }
  15     }
  16
  17     pub fn finish(mut self) -> Result<(R, u32, Option<[u8; 32]>), Error> {
  18         let crc = self.hasher.finalize();
  19
  20         if let Some(ref mut signer) = self.signer {
  21             let mut tag = [0u8; 32];
  22             signer.sign(&mut tag)?;
  23             Ok((self.reader, crc, Some(tag)))
  24         } else {
  25             Ok((self.reader, crc, None))
  26         }
  27     }
  28 }
  29
  30 impl <'a, R: Read> Read for ChecksumReader<'a, R> {
  31
  32     fn read(&mut self, buf: &mut [u8]) -> Result<usize, std::io::Error> {
  33         let count = self.reader.read(buf)?;
  34         if count > 0 {
  35             self.hasher.update(&buf[..count]);
  36             if let Some(ref mut signer) = self.signer {
  37                 signer.update(&buf[..count])
  38                     .map_err(|err| {
  39                         std::io::Error::new(
  40                             std::io::ErrorKind::Other,
  41                             format!("hmac update failed - {}", err))
  42                     })?;
  43             }
  44         }
  45         Ok(count)
  46     }
  47 }