backup: remove AsyncIndexReader
superseded by CachedChunkReader, with less code and more speed Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
This commit is contained in:
Stefan Reiter
Wolfgang Bumiller
parent
1ef6e8b6a7
commit
da78b90f9c
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@ -257,8 +257,5 @@ pub use verify::*;
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mod catalog_shell;
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pub use catalog_shell::*;
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mod async_index_reader;
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pub use async_index_reader::*;
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mod cached_chunk_reader;
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pub use cached_chunk_reader::*;
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@ -1,215 +0,0 @@
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use std::future::Future;
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use std::task::{Poll, Context};
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use std::pin::Pin;
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use std::io::SeekFrom;
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use anyhow::Error;
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use futures::future::FutureExt;
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use futures::ready;
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use tokio::io::{AsyncRead, AsyncSeek, ReadBuf};
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use proxmox::sys::error::io_err_other;
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use proxmox::io_format_err;
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use super::IndexFile;
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use super::read_chunk::AsyncReadChunk;
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use super::index::ChunkReadInfo;
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type ReadFuture<S> = dyn Future<Output = Result<(S, Vec<u8>), Error>> + Send + 'static;
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// FIXME: This enum may not be required?
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// - Put the `WaitForData` case directly into a `read_future: Option<>`
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// - make the read loop as follows:
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// * if read_buffer is not empty:
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// use it
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// * else if read_future is there:
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// poll it
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// if read: move data to read_buffer
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// * else
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// create read future
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#[allow(clippy::enum_variant_names)]
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enum AsyncIndexReaderState<S> {
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NoData,
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WaitForData(Pin<Box<ReadFuture<S>>>),
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HaveData,
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}
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pub struct AsyncIndexReader<S, I: IndexFile> {
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store: Option<S>,
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index: I,
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read_buffer: Vec<u8>,
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current_chunk_offset: u64,
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current_chunk_idx: usize,
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current_chunk_info: Option<ChunkReadInfo>,
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position: u64,
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seek_to_pos: i64,
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state: AsyncIndexReaderState<S>,
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}
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// ok because the only public interfaces operates on &mut Self
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unsafe impl<S: Sync, I: IndexFile + Sync> Sync for AsyncIndexReader<S, I> {}
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impl<S: AsyncReadChunk, I: IndexFile> AsyncIndexReader<S, I> {
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pub fn new(index: I, store: S) -> Self {
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Self {
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store: Some(store),
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index,
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read_buffer: Vec::with_capacity(1024 * 1024),
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current_chunk_offset: 0,
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current_chunk_idx: 0,
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current_chunk_info: None,
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position: 0,
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seek_to_pos: 0,
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state: AsyncIndexReaderState::NoData,
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}
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}
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}
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impl<S, I> AsyncRead for AsyncIndexReader<S, I>
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where
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S: AsyncReadChunk + Unpin + Sync + 'static,
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I: IndexFile + Unpin,
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{
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fn poll_read(
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self: Pin<&mut Self>,
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cx: &mut Context,
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buf: &mut ReadBuf,
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) -> Poll<tokio::io::Result<()>> {
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let this = Pin::get_mut(self);
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loop {
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match &mut this.state {
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AsyncIndexReaderState::NoData => {
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let (idx, offset) = if this.current_chunk_info.is_some() &&
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this.position == this.current_chunk_info.as_ref().unwrap().range.end
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{
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// optimization for sequential chunk read
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let next_idx = this.current_chunk_idx + 1;
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(next_idx, 0)
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} else {
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match this.index.chunk_from_offset(this.position) {
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Some(res) => res,
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None => return Poll::Ready(Ok(()))
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}
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};
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if idx >= this.index.index_count() {
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return Poll::Ready(Ok(()));
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}
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let info = this
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.index
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.chunk_info(idx)
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.ok_or_else(|| io_format_err!("could not get digest"))?;
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this.current_chunk_offset = offset;
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this.current_chunk_idx = idx;
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let old_info = this.current_chunk_info.replace(info.clone());
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if let Some(old_info) = old_info {
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if old_info.digest == info.digest {
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// hit, chunk is currently in cache
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this.state = AsyncIndexReaderState::HaveData;
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continue;
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}
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}
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// miss, need to download new chunk
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let store = match this.store.take() {
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Some(store) => store,
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None => {
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return Poll::Ready(Err(io_format_err!("could not find store")));
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}
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};
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let future = async move {
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store.read_chunk(&info.digest)
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.await
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.map(move |x| (store, x))
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};
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this.state = AsyncIndexReaderState::WaitForData(future.boxed());
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}
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AsyncIndexReaderState::WaitForData(ref mut future) => {
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match ready!(future.as_mut().poll(cx)) {
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Ok((store, chunk_data)) => {
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this.read_buffer = chunk_data;
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this.state = AsyncIndexReaderState::HaveData;
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this.store = Some(store);
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}
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Err(err) => {
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return Poll::Ready(Err(io_err_other(err)));
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}
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};
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}
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AsyncIndexReaderState::HaveData => {
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let offset = this.current_chunk_offset as usize;
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let len = this.read_buffer.len();
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let n = if len - offset < buf.remaining() {
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len - offset
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} else {
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buf.remaining()
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};
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buf.put_slice(&this.read_buffer[offset..(offset + n)]);
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this.position += n as u64;
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if offset + n == len {
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this.state = AsyncIndexReaderState::NoData;
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} else {
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this.current_chunk_offset += n as u64;
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this.state = AsyncIndexReaderState::HaveData;
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}
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return Poll::Ready(Ok(()));
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}
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}
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}
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}
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}
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impl<S, I> AsyncSeek for AsyncIndexReader<S, I>
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where
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S: AsyncReadChunk + Unpin + Sync + 'static,
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I: IndexFile + Unpin,
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{
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fn start_seek(
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self: Pin<&mut Self>,
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pos: SeekFrom,
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) -> tokio::io::Result<()> {
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let this = Pin::get_mut(self);
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this.seek_to_pos = match pos {
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SeekFrom::Start(offset) => {
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offset as i64
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},
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SeekFrom::End(offset) => {
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this.index.index_bytes() as i64 + offset
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},
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SeekFrom::Current(offset) => {
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this.position as i64 + offset
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}
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};
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Ok(())
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}
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fn poll_complete(
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self: Pin<&mut Self>,
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_cx: &mut Context<'_>,
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) -> Poll<tokio::io::Result<u64>> {
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let this = Pin::get_mut(self);
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let index_bytes = this.index.index_bytes();
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if this.seek_to_pos < 0 {
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return Poll::Ready(Err(io_format_err!("cannot seek to negative values")));
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} else if this.seek_to_pos > index_bytes as i64 {
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this.position = index_bytes;
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} else {
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this.position = this.seek_to_pos as u64;
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}
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// even if seeking within one chunk, we need to go to NoData to
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// recalculate the current_chunk_offset (data is cached anyway)
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this.state = AsyncIndexReaderState::NoData;
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Poll::Ready(Ok(this.position))
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}
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}
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