122 lines
3.9 KiB
Rust
122 lines
3.9 KiB
Rust
use std::future::Future;
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use std::collections::HashMap;
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use std::pin::Pin;
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use std::sync::{Arc, Mutex};
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use anyhow::{bail, Error};
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use super::BackupReader;
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use crate::backup::{AsyncReadChunk, CryptConfig, CryptMode, DataBlob, ReadChunk};
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use crate::tools::runtime::block_on;
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/// Read chunks from remote host using ``BackupReader``
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#[derive(Clone)]
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pub struct RemoteChunkReader {
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client: Arc<BackupReader>,
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crypt_config: Option<Arc<CryptConfig>>,
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crypt_mode: CryptMode,
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cache_hint: Arc<HashMap<[u8; 32], usize>>,
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cache: Arc<Mutex<HashMap<[u8; 32], Vec<u8>>>>,
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}
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impl RemoteChunkReader {
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/// Create a new instance.
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///
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/// Chunks listed in ``cache_hint`` are cached and kept in RAM.
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pub fn new(
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client: Arc<BackupReader>,
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crypt_config: Option<Arc<CryptConfig>>,
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crypt_mode: CryptMode,
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cache_hint: HashMap<[u8; 32], usize>,
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) -> Self {
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Self {
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client,
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crypt_config,
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crypt_mode,
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cache_hint: Arc::new(cache_hint),
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cache: Arc::new(Mutex::new(HashMap::new())),
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}
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}
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/// Downloads raw chunk. This only verifies the (untrusted) CRC32, use
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/// DataBlob::verify_unencrypted or DataBlob::decode before storing/processing further.
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pub async fn read_raw_chunk(&self, digest: &[u8; 32]) -> Result<DataBlob, Error> {
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let mut chunk_data = Vec::with_capacity(4 * 1024 * 1024);
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self.client
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.download_chunk(&digest, &mut chunk_data)
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.await?;
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let chunk = DataBlob::load_from_reader(&mut &chunk_data[..])?;
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match self.crypt_mode {
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CryptMode::Encrypt => {
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match chunk.crypt_mode()? {
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CryptMode::Encrypt => Ok(chunk),
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CryptMode::SignOnly | CryptMode::None => bail!("Index and chunk CryptMode don't match."),
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}
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},
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CryptMode::SignOnly | CryptMode::None => {
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match chunk.crypt_mode()? {
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CryptMode::Encrypt => bail!("Index and chunk CryptMode don't match."),
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CryptMode::SignOnly | CryptMode::None => Ok(chunk),
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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 ReadChunk for RemoteChunkReader {
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fn read_raw_chunk(&self, digest: &[u8; 32]) -> Result<DataBlob, Error> {
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block_on(Self::read_raw_chunk(self, digest))
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}
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fn read_chunk(&self, digest: &[u8; 32]) -> Result<Vec<u8>, Error> {
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if let Some(raw_data) = (*self.cache.lock().unwrap()).get(digest) {
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return Ok(raw_data.to_vec());
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}
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let chunk = ReadChunk::read_raw_chunk(self, digest)?;
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let raw_data = chunk.decode(self.crypt_config.as_ref().map(Arc::as_ref), Some(digest))?;
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let use_cache = self.cache_hint.contains_key(digest);
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if use_cache {
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(*self.cache.lock().unwrap()).insert(*digest, raw_data.to_vec());
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}
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Ok(raw_data)
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}
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}
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impl AsyncReadChunk for RemoteChunkReader {
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fn read_raw_chunk<'a>(
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&'a self,
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digest: &'a [u8; 32],
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) -> Pin<Box<dyn Future<Output = Result<DataBlob, Error>> + Send + 'a>> {
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Box::pin(Self::read_raw_chunk(self, digest))
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}
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fn read_chunk<'a>(
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&'a self,
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digest: &'a [u8; 32],
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) -> Pin<Box<dyn Future<Output = Result<Vec<u8>, Error>> + Send + 'a>> {
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Box::pin(async move {
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if let Some(raw_data) = (*self.cache.lock().unwrap()).get(digest) {
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return Ok(raw_data.to_vec());
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}
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let chunk = Self::read_raw_chunk(self, digest).await?;
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let raw_data = chunk.decode(self.crypt_config.as_ref().map(Arc::as_ref), Some(digest))?;
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let use_cache = self.cache_hint.contains_key(digest);
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if use_cache {
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(*self.cache.lock().unwrap()).insert(*digest, raw_data.to_vec());
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}
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Ok(raw_data)
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})
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}
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}
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