rqbit/crates/librqbit/src/chunk_tracker.rs
2024-04-15 23:41:47 +04:00

598 lines
20 KiB
Rust

use std::collections::HashSet;
use anyhow::Context;
use librqbit_core::lengths::{ChunkInfo, Lengths, ValidPieceIndex};
use peer_binary_protocol::Piece;
use tracing::{debug, trace};
use crate::type_aliases::{FilePriorities, OpenedFiles, BF};
pub struct ChunkTracker {
// This forms the basis of a "queue" to pull from.
// It's set to 1 if we need a piece, but the moment we start requesting a peer,
// it's set to 0.
//
// Initially this is the opposite of "have", until we start making requests.
// An in-flight request is not in in the queue, and not in "have".
//
// needed initial value = selected & !have
queue_pieces: BF,
// This has a bit set per each chunk (block) that we have written to the output file.
// It doesn't mean it's valid yet. Used to track how much is left in each piece.
chunk_status: BF,
// These are the pieces that we actually have, fully checked and downloaded.
have: BF,
// The pieces that the user selected. This doesn't change unless update_only_files
// was called.
selected: BF,
lengths: Lengths,
// Quick to retrieve stats, that MUST be in sync with the BFs
// above (have/selected).
hns: HaveNeededSelected,
}
#[derive(Default, Debug, PartialEq, Eq, Clone, Copy)]
pub struct HaveNeededSelected {
// How many bytes we have downloaded and verified.
pub have_bytes: u64,
// How many bytes do we need to download for selected to be
// a subset of have.
pub needed_bytes: u64,
// How many bytes the user selected (by picking files).
pub selected_bytes: u64,
}
impl HaveNeededSelected {
pub const fn progress(&self) -> u64 {
self.selected_bytes - self.needed_bytes
}
pub const fn total(&self) -> u64 {
self.selected_bytes
}
pub const fn finished(&self) -> bool {
self.needed_bytes == 0
}
}
// Comput the have-status of chunks.
//
// Save as "have_pieces", but there's one bit per chunk (not per piece).
fn compute_chunk_have_status(lengths: &Lengths, have_pieces: &BF) -> anyhow::Result<BF> {
if have_pieces.len() < lengths.total_pieces() as usize {
anyhow::bail!(
"bug: have_pieces.len() < lengths.total_pieces(); {} < {}",
have_pieces.len(),
lengths.total_pieces()
);
}
let required_size = lengths.chunk_bitfield_bytes();
let vec = vec![0u8; required_size];
let mut chunk_bf = BF::from_boxed_slice(vec.into_boxed_slice());
for piece in lengths.iter_piece_infos() {
let chunks = lengths.chunks_per_piece(piece.piece_index) as usize;
let offset = (lengths.default_chunks_per_piece() * piece.piece_index.get()) as usize;
let range = offset..(offset + chunks);
if have_pieces[piece.piece_index.get() as usize] {
chunk_bf
.get_mut(range.clone())
.with_context(|| {
format!("bug in bitvec: error getting range {range:?} from chunk_bf")
})?
.fill(true);
}
}
Ok(chunk_bf)
}
fn compute_queued_pieces_unchecked(have_pieces: &BF, selected_pieces: &BF) -> BF {
// it's needed ONLY if it's selected and we don't have it.
use core::ops::BitAnd;
use core::ops::Not;
have_pieces.clone().not().bitand(selected_pieces)
}
fn compute_queued_pieces(have_pieces: &BF, selected_pieces: &BF) -> anyhow::Result<BF> {
if have_pieces.len() != selected_pieces.len() {
anyhow::bail!(
"have_pieces.len() != selected_pieces.len(), {} != {}",
have_pieces.len(),
selected_pieces.len()
);
}
Ok(compute_queued_pieces_unchecked(
have_pieces,
selected_pieces,
))
}
pub enum ChunkMarkingResult {
PreviouslyCompleted,
NotCompleted,
Completed,
}
impl ChunkTracker {
pub fn new(
// Have pieces are the ones we have already downloaded and verified.
have_pieces: BF,
// Selected pieces are the ones the user has selected
selected_pieces: BF,
lengths: Lengths,
) -> anyhow::Result<Self> {
let needed_pieces = compute_queued_pieces(&have_pieces, &selected_pieces)
.context("error computing needed pieces")?;
// TODO: ideally this needs to be a list based on needed files, e.g.
// last needed piece for each file. But let's keep simple for now.
let mut ct = Self {
chunk_status: compute_chunk_have_status(&lengths, &have_pieces)
.context("error computing chunk status")?,
queue_pieces: needed_pieces,
selected: selected_pieces,
lengths,
have: have_pieces,
hns: HaveNeededSelected::default(),
};
ct.hns = ct.calc_hns();
Ok(ct)
}
pub fn get_lengths(&self) -> &Lengths {
&self.lengths
}
pub fn get_have_pieces(&self) -> &BF {
&self.have
}
pub fn get_selected_pieces(&self) -> &BF {
&self.selected
}
pub fn reserve_needed_piece(&mut self, index: ValidPieceIndex) {
self.queue_pieces.set(index.get() as usize, false)
}
pub fn get_hns(&self) -> &HaveNeededSelected {
&self.hns
}
fn calc_hns(&self) -> HaveNeededSelected {
let mut hns = HaveNeededSelected::default();
for piece in self.lengths.iter_piece_infos() {
let id = piece.piece_index.get() as usize;
let len = piece.len as u64;
let is_have = self.have[id];
let is_selected = self.selected[id];
let is_needed = is_selected && !is_have;
hns.have_bytes += len * (is_have as u64);
hns.selected_bytes += len * (is_selected as u64);
hns.needed_bytes += len * (is_needed as u64);
}
hns
}
pub(crate) fn iter_queued_pieces<'a>(
&'a self,
file_priorities: &'a FilePriorities,
opened_files: &'a OpenedFiles,
) -> impl Iterator<Item = usize> + 'a {
file_priorities
.iter()
.filter_map(|p| opened_files.get(*p))
.filter(|f| !f.approx_is_finished())
.flat_map(|f| f.iter_piece_priorities())
.filter(|id| self.queue_pieces[*id])
}
// None if wrong chunk
// true if did something
// false if didn't do anything
pub fn mark_chunk_request_cancelled(
&mut self,
index: ValidPieceIndex,
_chunk: u32,
) -> Option<bool> {
if *self.have.get(index.get() as usize)? {
return Some(false);
}
// This will trigger the requesters to re-check each chunk in this piece.
let chunk_range = self.lengths.chunk_range(index);
if !self.chunk_status.get(chunk_range)?.all() {
self.queue_pieces.set(index.get() as usize, true);
}
Some(true)
}
pub fn mark_piece_broken_if_not_have(&mut self, index: ValidPieceIndex) {
if self
.have
.get(index.get() as usize)
.map(|r| *r)
.unwrap_or_default()
{
return;
}
debug!("remarking piece={} as broken", index);
self.queue_pieces.set(index.get() as usize, true);
if let Some(s) = self.chunk_status.get_mut(self.lengths.chunk_range(index)) {
s.fill(false);
}
}
pub fn mark_piece_downloaded(&mut self, idx: ValidPieceIndex) {
let id = idx.get() as usize;
if !self.have[id] {
self.have.set(id, true);
let len = self.lengths.piece_length(idx) as u64;
self.hns.have_bytes += len;
if self.selected[id] {
self.hns.needed_bytes -= len;
}
}
}
pub fn is_chunk_ready_to_upload(&self, chunk: &ChunkInfo) -> bool {
self.have
.get(chunk.piece_index.get() as usize)
.map(|b| *b)
.unwrap_or(false)
}
pub fn get_remaining_bytes(&self) -> u64 {
self.hns.needed_bytes
}
// return true if the whole piece is marked downloaded
pub fn mark_chunk_downloaded<ByteBuf>(
&mut self,
piece: &Piece<ByteBuf>,
) -> Option<ChunkMarkingResult>
where
ByteBuf: AsRef<[u8]>,
{
let chunk_info = self.lengths.chunk_info_from_received_data(
self.lengths.validate_piece_index(piece.index)?,
piece.begin,
piece.block.as_ref().len() as u32,
)?;
let chunk_range = self.lengths.chunk_range(chunk_info.piece_index);
let chunk_range = self.chunk_status.get_mut(chunk_range).unwrap();
if chunk_range.all() {
return Some(ChunkMarkingResult::PreviouslyCompleted);
}
chunk_range.set(chunk_info.chunk_index as usize, true);
trace!(
"piece={}, chunk_info={:?}, bits={:?}",
piece.index,
chunk_info,
chunk_range,
);
if chunk_range.all() {
return Some(ChunkMarkingResult::Completed);
}
Some(ChunkMarkingResult::NotCompleted)
}
// NOTE: this doesn't validate new_only_files.
// E.g. if there are indices there that don't make
// sense, they will be ignored.
pub fn update_only_files(
&mut self,
file_lengths_iterator: impl IntoIterator<Item = u64>,
// TODO: maybe make this a BF
new_only_files: &HashSet<usize>,
) -> anyhow::Result<HaveNeededSelected> {
let mut piece_it = self.lengths.iter_piece_infos();
let mut current_piece = piece_it
.next()
.context("bug: iter_piece_infos() returned empty iterator")?;
let mut current_piece_selected = false;
let mut current_piece_remaining = current_piece.len;
let mut have_bytes = 0u64;
let mut selected_bytes = 0u64;
let mut needed_bytes = 0u64;
for (idx, len) in file_lengths_iterator.into_iter().enumerate() {
let file_required = new_only_files.contains(&idx);
let mut remaining_file_len = len;
while remaining_file_len > 0 {
current_piece_selected |= len > 0 && file_required;
let shift = std::cmp::min(current_piece_remaining as u64, remaining_file_len);
if shift == 0 {
anyhow::bail!("bug: shift = 0, this shouldn't have happened")
}
remaining_file_len -= shift;
current_piece_remaining -= shift as u32;
if current_piece_remaining == 0 {
let current_piece_have = self.have[current_piece.piece_index.get() as usize];
if current_piece_have {
have_bytes += current_piece.len as u64;
}
if current_piece_selected {
selected_bytes += current_piece.len as u64;
}
if current_piece_selected && !current_piece_have {
needed_bytes += current_piece.len as u64;
}
self.selected.set(
current_piece.piece_index.get() as usize,
current_piece_selected,
);
match (current_piece_selected, current_piece_have) {
(true, true) => {}
(true, false) => {
self.mark_piece_broken_if_not_have(current_piece.piece_index)
}
(false, true) => {}
(false, false) => {
// don't need the piece, and don't have it - cancel downloading it
self.queue_pieces
.set(current_piece.piece_index.get() as usize, false);
}
}
if current_piece.piece_index != self.lengths.last_piece_id() {
current_piece = piece_it.next().context(
"bug: iter_piece_infos() pieces ended earlier than expected",
)?;
current_piece_selected = false;
current_piece_remaining = current_piece.len;
}
}
}
}
let res = HaveNeededSelected {
have_bytes,
needed_bytes,
selected_bytes,
};
self.hns = res;
Ok(res)
}
}
#[cfg(test)]
mod tests {
use std::collections::HashSet;
use librqbit_core::{constants::CHUNK_SIZE, lengths::Lengths};
use crate::{chunk_tracker::HaveNeededSelected, type_aliases::BF};
use super::{compute_chunk_have_status, ChunkTracker};
#[test]
fn test_compute_chunk_status() {
// Create the most obnoxious lenghts, and ensure it doesn't break in that case.
let piece_length = CHUNK_SIZE * 2 + 1;
let l = Lengths::new(piece_length as u64 * 2 + 1, piece_length).unwrap();
assert_eq!(l.total_pieces(), 3);
assert_eq!(l.default_chunks_per_piece(), 3);
assert_eq!(l.total_chunks(), 7);
{
let mut have_pieces =
BF::from_boxed_slice(vec![u8::MAX; l.piece_bitfield_bytes()].into_boxed_slice());
have_pieces.set(0, false);
let chunks = compute_chunk_have_status(&l, &have_pieces).unwrap();
assert_eq!(chunks[0], false);
assert_eq!(chunks[1], false);
assert_eq!(chunks[2], false);
assert_eq!(chunks[3], true);
assert_eq!(chunks[4], true);
assert_eq!(chunks[5], true);
assert_eq!(chunks[6], true);
}
{
let mut have_pieces =
BF::from_boxed_slice(vec![u8::MAX; l.piece_bitfield_bytes()].into_boxed_slice());
have_pieces.set(1, false);
let chunks = compute_chunk_have_status(&l, &have_pieces).unwrap();
dbg!(&chunks);
assert_eq!(chunks[0], true);
assert_eq!(chunks[1], true);
assert_eq!(chunks[2], true);
assert_eq!(chunks[3], false);
assert_eq!(chunks[4], false);
assert_eq!(chunks[5], false);
assert_eq!(chunks[6], true);
}
{
let mut have_pieces =
BF::from_boxed_slice(vec![u8::MAX; l.piece_bitfield_bytes()].into_boxed_slice());
have_pieces.set(2, false);
let chunks = compute_chunk_have_status(&l, &have_pieces).unwrap();
dbg!(&chunks);
assert_eq!(chunks[0], true);
assert_eq!(chunks[1], true);
assert_eq!(chunks[2], true);
assert_eq!(chunks[3], true);
assert_eq!(chunks[4], true);
assert_eq!(chunks[5], true);
assert_eq!(chunks[6], false);
}
{
// A more reasonable case.
let piece_length = CHUNK_SIZE * 2;
let l = Lengths::new(piece_length as u64 * 2 + 1, piece_length).unwrap();
assert_eq!(l.total_pieces(), 3);
assert_eq!(l.default_chunks_per_piece(), 2);
assert_eq!(l.total_chunks(), 5);
{
let mut have_pieces = BF::from_boxed_slice(
vec![u8::MAX; l.piece_bitfield_bytes()].into_boxed_slice(),
);
have_pieces.set(1, false);
let chunks = compute_chunk_have_status(&l, &have_pieces).unwrap();
dbg!(&chunks);
assert_eq!(chunks[0], true);
assert_eq!(chunks[1], true);
assert_eq!(chunks[2], false);
assert_eq!(chunks[3], false);
assert_eq!(chunks[4], true);
}
{
let mut have_pieces = BF::from_boxed_slice(
vec![u8::MAX; l.piece_bitfield_bytes()].into_boxed_slice(),
);
have_pieces.set(2, false);
let chunks = compute_chunk_have_status(&l, &have_pieces).unwrap();
dbg!(&chunks);
assert_eq!(chunks[0], true);
assert_eq!(chunks[1], true);
assert_eq!(chunks[2], true);
assert_eq!(chunks[3], true);
assert_eq!(chunks[4], false);
}
}
}
#[test]
fn test_update_only_files() {
let piece_len = CHUNK_SIZE * 2 + 1;
let total_len = piece_len as u64 * 2 + 1;
let l = Lengths::new(total_len, piece_len).unwrap();
assert_eq!(l.total_pieces(), 3);
assert_eq!(l.total_chunks(), 7);
let all_files = [
piece_len as u64, // piece 0 and boundary
1, // piece 1
0, // piece 1 (or none)
piece_len as u64, // piece 1 and 2
];
let bf_len = l.piece_bitfield_bytes();
let initial_have = BF::from_boxed_slice(vec![0u8; bf_len].into_boxed_slice());
let initial_selected = BF::from_boxed_slice(vec![u8::MAX; bf_len].into_boxed_slice());
// Initially, we need all files and all pieces.
let mut ct = ChunkTracker::new(initial_have.clone(), initial_selected.clone(), l).unwrap();
// Select all file, no changes.
assert_eq!(
ct.update_only_files(all_files.into_iter(), &HashSet::from_iter([0, 1, 2, 3]))
.unwrap(),
HaveNeededSelected {
have_bytes: 0,
selected_bytes: total_len,
needed_bytes: total_len,
}
);
assert_eq!(ct.have, initial_have);
assert_eq!(ct.queue_pieces, initial_selected);
// Select only the first file.
println!("Select only the first file.");
assert_eq!(
ct.update_only_files(all_files, &HashSet::from_iter([0]))
.unwrap(),
HaveNeededSelected {
have_bytes: 0,
selected_bytes: all_files[0],
needed_bytes: all_files[0],
}
);
assert_eq!(ct.queue_pieces[0], true);
assert_eq!(ct.queue_pieces[1], false);
assert_eq!(ct.queue_pieces[2], false);
// Select only the second file.
assert_eq!(
ct.update_only_files(all_files, &HashSet::from_iter([1]))
.unwrap(),
HaveNeededSelected {
have_bytes: 0,
selected_bytes: piece_len as u64,
needed_bytes: piece_len as u64,
}
);
assert_eq!(ct.queue_pieces[0], false);
assert_eq!(ct.queue_pieces[1], true);
assert_eq!(ct.queue_pieces[2], false);
// Select only the third file (zero sized one!).
assert_eq!(
ct.update_only_files(all_files, &HashSet::from_iter([2]))
.unwrap(),
HaveNeededSelected {
have_bytes: 0,
selected_bytes: 0,
needed_bytes: 0,
}
);
assert_eq!(ct.queue_pieces[0], false);
assert_eq!(ct.queue_pieces[1], false);
assert_eq!(ct.queue_pieces[2], false);
// Select only the fourth file.
assert_eq!(
ct.update_only_files(all_files, &HashSet::from_iter([3]))
.unwrap(),
HaveNeededSelected {
have_bytes: 0,
selected_bytes: (piece_len + 1) as u64,
needed_bytes: (piece_len + 1) as u64,
}
);
assert_eq!(ct.queue_pieces[0], false);
assert_eq!(ct.queue_pieces[1], true);
assert_eq!(ct.queue_pieces[2], true);
// Select first and last file
assert_eq!(
ct.update_only_files(all_files.clone(), &HashSet::from_iter([0, 3]))
.unwrap(),
HaveNeededSelected {
have_bytes: 0,
selected_bytes: all_files[0] + all_files[3] + 1,
needed_bytes: all_files[0] + all_files[3] + 1,
}
);
assert_eq!(ct.queue_pieces[0], true);
assert_eq!(ct.queue_pieces[1], true);
assert_eq!(ct.queue_pieces[2], true);
// Select all files
assert_eq!(
ct.update_only_files(all_files.clone(), &HashSet::from_iter([0, 1, 2, 3]))
.unwrap(),
HaveNeededSelected {
have_bytes: 0,
selected_bytes: total_len,
needed_bytes: total_len
}
);
assert_eq!(ct.queue_pieces[0], true);
assert_eq!(ct.queue_pieces[1], true);
assert_eq!(ct.queue_pieces[2], true);
}
}