use std::{collections::HashMap, path::Path};
use anyhow::Context;
use librqbit_core::lengths::{Lengths, ValidPieceIndex};
use parking_lot::RwLock;
use crate::type_aliases::FileInfos;
use crate::storage::{StorageFactory, StorageFactoryExt, TorrentStorage};
struct InMemoryPiece {
bytes: Box<[u8]>,
}
impl InMemoryPiece {
fn new(l: &Lengths) -> Self {
let v = vec![0; l.default_piece_length() as usize].into_boxed_slice();
Self { bytes: v }
}
}
#[derive(Default, Clone)]
pub struct InMemoryExampleStorageFactory {}
impl StorageFactory for InMemoryExampleStorageFactory {
type Storage = InMemoryExampleStorage;
fn create(
&self,
info: &crate::torrent_state::ManagedTorrentShared,
) -> anyhow::Result<InMemoryExampleStorage> {
InMemoryExampleStorage::new(info.lengths, info.file_infos.clone())
}
fn clone_box(&self) -> crate::storage::BoxStorageFactory {
self.clone().boxed()
}
}
pub struct InMemoryExampleStorage {
lengths: Lengths,
file_infos: FileInfos,
map: RwLock<HashMap<ValidPieceIndex, InMemoryPiece>>,
}
impl InMemoryExampleStorage {
fn new(lengths: Lengths, file_infos: FileInfos) -> anyhow::Result<Self> {
let max_pieces = 128 * 1024 * 1024 / lengths.default_piece_length();
if max_pieces == 0 {
anyhow::bail!("pieces too large");
}
Ok(Self {
lengths,
file_infos,
map: RwLock::new(HashMap::new()),
})
}
}
impl TorrentStorage for InMemoryExampleStorage {
fn pread_exact(&self, file_id: usize, offset: u64, buf: &mut [u8]) -> anyhow::Result<()> {
let fi = &self.file_infos[file_id];
let abs_offset = fi.offset_in_torrent + offset;
let piece_id: u32 = (abs_offset / self.lengths.default_piece_length() as u64).try_into()?;
let piece_offset: usize =
(abs_offset % self.lengths.default_piece_length() as u64).try_into()?;
let piece_id = self.lengths.validate_piece_index(piece_id).context("bug")?;
let g = self.map.read();
let inmp = g.get(&piece_id).context("piece expired")?;
buf.copy_from_slice(&inmp.bytes[piece_offset..(piece_offset + buf.len())]);
Ok(())
}
fn pwrite_all(&self, file_id: usize, offset: u64, buf: &[u8]) -> anyhow::Result<()> {
let fi = &self.file_infos[file_id];
let abs_offset = fi.offset_in_torrent + offset;
let piece_id: u32 = (abs_offset / self.lengths.default_piece_length() as u64).try_into()?;
let piece_offset: usize =
(abs_offset % self.lengths.default_piece_length() as u64).try_into()?;
let piece_id = self.lengths.validate_piece_index(piece_id).context("bug")?;
let mut g = self.map.write();
let inmp = g
.entry(piece_id)
.or_insert_with(|| InMemoryPiece::new(&self.lengths));
inmp.bytes[piece_offset..(piece_offset + buf.len())].copy_from_slice(buf);
Ok(())
}
fn remove_file(&self, _file_id: usize, _filename: &Path) -> anyhow::Result<()> {
Ok(())
}
fn ensure_file_length(&self, _file_id: usize, _length: u64) -> anyhow::Result<()> {
Ok(())
}
fn take(&self) -> anyhow::Result<Box<dyn TorrentStorage>> {
let map = {
let mut g = self.map.write();
let mut repl = HashMap::new();
std::mem::swap(&mut *g, &mut repl);
repl
};
Ok(Box::new(Self {
lengths: self.lengths,
map: RwLock::new(map),
file_infos: self.file_infos.clone(),
}))
}
fn init(&mut self, _meta: &crate::ManagedTorrentShared) -> anyhow::Result<()> {
Ok(())
}
fn remove_directory_if_empty(&self, _path: &Path) -> anyhow::Result<()> {
Ok(())
}
}