75 lines
2.0 KiB
Rust
75 lines
2.0 KiB
Rust
use std::collections::HashMap;
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use std::sync::Arc;
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use failure::*;
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use super::BackupReader;
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use crate::backup::{ReadChunk, DataBlob, CryptConfig};
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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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pub struct RemoteChunkReader {
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client: Arc<BackupReader>,
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crypt_config: Option<Arc<CryptConfig>>,
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cache_hint: HashMap<[u8; 32], usize>,
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cache: 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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cache_hint: HashMap<[u8; 32], usize>,
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) -> Self {
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Self { client, crypt_config, cache_hint, cache: HashMap::new() }
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}
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}
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impl ReadChunk for RemoteChunkReader {
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fn read_raw_chunk(&mut 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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//tokio::task::block_in_place(|| futures::executor::block_on(self.client.download_chunk(&digest, &mut chunk_data)))?;
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block_on(async {
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// download_chunk returns the writer back to us, but we need to return a 'static value
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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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.map(drop)
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})?;
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let chunk = DataBlob::from_raw(chunk_data)?;
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chunk.verify_crc()?;
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Ok(chunk)
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}
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fn read_chunk(&mut self, digest:&[u8; 32]) -> Result<Vec<u8>, Error> {
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if let Some(raw_data) = self.cache.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(digest)?;
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let raw_data = chunk.decode(self.crypt_config.as_ref().map(Arc::as_ref))?;
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// fixme: verify 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.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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