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mod bmap;
pub use crate::bmap::*;
mod discarder;
pub use crate::discarder::*;
use async_trait::async_trait;
use futures::io::{AsyncRead, AsyncReadExt, AsyncSeek, AsyncSeekExt, AsyncWrite, AsyncWriteExt};
use futures::TryFutureExt;
use sha2::{Digest, Sha256};
use thiserror::Error;
use std::io::Result as IOResult;
use std::io::{Read, Seek, SeekFrom, Write};
pub trait SeekForward {
fn seek_forward(&mut self, offset: u64) -> IOResult<()>;
}
impl<T: Seek> SeekForward for T {
fn seek_forward(&mut self, forward: u64) -> IOResult<()> {
self.seek(SeekFrom::Current(forward as i64))?;
Ok(())
}
}
#[async_trait(?Send)]
pub trait AsyncSeekForward {
async fn async_seek_forward(&mut self, offset: u64) -> IOResult<()>;
}
#[async_trait(?Send)]
impl<T: AsyncSeek + Unpin + Send> AsyncSeekForward for T {
async fn async_seek_forward(&mut self, forward: u64) -> IOResult<()> {
self.seek(SeekFrom::Current(forward as i64)).await?;
Ok(())
}
}
#[derive(Debug, Error)]
pub enum CopyError {
#[error("Failed to Read: {0}")]
ReadError(std::io::Error),
#[error("Failed to Write: {0}")]
WriteError(std::io::Error),
#[error("Checksum error")]
ChecksumError,
#[error("Unexpected EOF on input")]
UnexpectedEof,
}
pub fn copy<I, O>(input: &mut I, output: &mut O, map: &Bmap) -> Result<(), CopyError>
where
I: Read + SeekForward,
O: Write + SeekForward,
{
let mut hasher = match map.checksum_type() {
HashType::Sha256 => Sha256::new(),
};
let mut v = Vec::new();
v.resize(8 * 1024 * 1024, 0);
let buf = v.as_mut_slice();
let mut position = 0;
for range in map.block_map() {
let forward = range.offset() - position;
input.seek_forward(forward).map_err(CopyError::ReadError)?;
output
.seek_forward(forward)
.map_err(CopyError::WriteError)?;
let mut left = range.length() as usize;
while left > 0 {
let toread = left.min(buf.len());
let r = input
.read(&mut buf[0..toread])
.map_err(CopyError::ReadError)?;
if r == 0 {
return Err(CopyError::UnexpectedEof);
}
hasher.update(&buf[0..r]);
output
.write_all(&buf[0..r])
.map_err(CopyError::WriteError)?;
left -= r;
}
let digest = hasher.finalize_reset();
if range.checksum().as_slice() != digest.as_slice() {
return Err(CopyError::ChecksumError);
}
position = range.offset() + range.length();
}
Ok(())
}
pub async fn copy_async<I, O>(input: &mut I, output: &mut O, map: &Bmap) -> Result<(), CopyError>
where
I: AsyncRead + AsyncSeekForward + Unpin,
O: AsyncWrite + AsyncSeekForward + Unpin,
{
let mut hasher = match map.checksum_type() {
HashType::Sha256 => Sha256::new(),
};
let mut v = Vec::new();
v.resize(8 * 1024 * 1024, 0);
let buf = v.as_mut_slice();
let mut position = 0;
for range in map.block_map() {
let forward = range.offset() - position;
input
.async_seek_forward(forward)
.map_err(CopyError::ReadError)
.await?;
output.flush().map_err(CopyError::WriteError).await?;
output
.async_seek_forward(forward)
.map_err(CopyError::WriteError)
.await?;
let mut left = range.length() as usize;
while left > 0 {
let toread = left.min(buf.len());
let r = input
.read(&mut buf[0..toread])
.map_err(CopyError::ReadError)
.await?;
if r == 0 {
return Err(CopyError::UnexpectedEof);
}
hasher.update(&buf[0..r]);
output
.write_all(&buf[0..r])
.await
.map_err(CopyError::WriteError)?;
left -= r;
}
let digest = hasher.finalize_reset();
if range.checksum().as_slice() != digest.as_slice() {
return Err(CopyError::ChecksumError);
}
position = range.offset() + range.length();
}
Ok(())
}