End-to-end unit test (#90)

* First implementation of create_torrent_file

* Test harness for e2e preparing

* Saving

* Continuing test harness

* Continuing test harness

* Continuing test harness

* All servers are running

* Full e2e harness done

* Test e2e harness working fine

* Remove lints

* injecting faults

* The e2e test runs continuously

* e2e test

* Add a test for create_torrent

* Nothing

* Nothing, just tweaking the numberes

* Update tokio, remove custom tempfile shim

Cargo.lock

@@ -1292,6 +1292,7 @@ dependencies = [
  "serde_with",
  "sha1",
  "size_format",
+ "tempfile",
  "tokio",
  "tokio-stream",
  "tokio-test",
@@ -2483,9 +2484,9 @@ checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
 
 [[package]]
 name = "tokio"
-version = "1.35.1"
+version = "1.36.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c89b4efa943be685f629b149f53829423f8f5531ea21249408e8e2f8671ec104"
+checksum = "61285f6515fa018fb2d1e46eb21223fff441ee8db5d0f1435e8ab4f5cdb80931"
 dependencies = [
  "backtrace",
  "bytes",

crates/librqbit/Cargo.toml

@@ -75,3 +75,4 @@ async-stream = "0.3.5"
 futures = {version = "0.3"}
 tracing-subscriber = "0.3"
 tokio-test = "0.4"
+tempfile = "3"

crates/librqbit/src/chunk_tracker.rs

@@ -41,7 +41,7 @@ fn compute_chunk_status(lengths: &Lengths, needed_pieces: &BF) -> BF {
         .unwrap()
         .iter_zeros()
     {
-        let offset = piece_index * lengths.default_chunks_per_piece() as usize;
+        let offset = piece_index * lengths.default_max_chunks_per_piece() as usize;
         let chunks_per_piece = lengths
             .chunks_per_piece(lengths.validate_piece_index(piece_index as u32).unwrap())
             as usize;

crates/librqbit/src/create_torrent_file.rs

@@ -0,0 +1,238 @@
+use std::borrow::Cow;
+use std::io::{BufWriter, Read};
+use std::os::unix::ffi::OsStrExt;
+use std::path::Path;
+
+use anyhow::Context;
+use bencode::bencode_serialize_to_writer;
+use buffers::ByteString;
+use librqbit_core::torrent_metainfo::{TorrentMetaV1File, TorrentMetaV1Info, TorrentMetaV1Owned};
+use librqbit_core::Id20;
+use sha1w::{ISha1, Sha1};
+
+use crate::spawn_utils::BlockingSpawner;
+
+#[derive(Debug, Clone, Default)]
+pub struct CreateTorrentOptions<'a> {
+    pub name: Option<&'a str>,
+    pub piece_length: Option<u32>,
+}
+
+fn walk_dir_find_paths(dir: &Path, out: &mut Vec<Cow<'_, Path>>) -> anyhow::Result<()> {
+    let mut stack = vec![Cow::Borrowed(dir)];
+    while let Some(dir) = stack.pop() {
+        let rd = std::fs::read_dir(&dir).with_context(|| format!("error reading {:?}", dir))?;
+        for element in rd {
+            let element =
+                element.with_context(|| format!("error reading DirEntry from {:?}", dir))?;
+            let ft = element.file_type().with_context(|| {
+                format!(
+                    "error determining filetype of DirEntry {:?} while reading {:?}",
+                    element.file_name(),
+                    dir
+                )
+            })?;
+
+            let full_path = Cow::Owned(dir.join(element.file_name()));
+            if ft.is_dir() {
+                stack.push(full_path);
+            } else {
+                out.push(full_path);
+            }
+        }
+    }
+    Ok(())
+}
+
+fn compute_info_hash(t: &TorrentMetaV1Info<ByteString>) -> anyhow::Result<Id20> {
+    struct W {
+        hash: sha1w::Sha1,
+    }
+    impl std::io::Write for W {
+        fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+            self.hash.update(buf);
+            Ok(buf.len())
+        }
+
+        fn flush(&mut self) -> std::io::Result<()> {
+            Ok(())
+        }
+    }
+    let mut writer = BufWriter::new(W { hash: Sha1::new() });
+    bencode_serialize_to_writer(t, &mut writer)?;
+    let hash = writer
+        .into_inner()
+        .map_err(|_| anyhow::anyhow!("into_inner errored"))?
+        .hash;
+    Ok(Id20::new(hash.finish()))
+}
+
+fn choose_piece_length(_input_files: &[Cow<'_, Path>]) -> u32 {
+    // TODO: make this smarter or smth
+    2 * 1024 * 1024
+}
+
+async fn create_torrent_raw<'a>(
+    path: &'a Path,
+    options: CreateTorrentOptions<'a>,
+) -> anyhow::Result<TorrentMetaV1Info<ByteString>> {
+    path.try_exists()
+        .with_context(|| format!("path {:?} doesn't exist", path))?;
+    let basename = path
+        .file_name()
+        .ok_or_else(|| anyhow::anyhow!("cannot determine basename of {:?}", path))?;
+    let is_dir = path.is_dir();
+    let single_file_mode = !is_dir;
+    let name: ByteString = match options.name {
+        Some(name) => name.as_bytes().into(),
+        None => basename.as_bytes().into(),
+    };
+
+    let mut input_files: Vec<Cow<'a, Path>> = Default::default();
+    if is_dir {
+        walk_dir_find_paths(path, &mut input_files)
+            .with_context(|| format!("error walking {:?}", path))?;
+    } else {
+        input_files.push(Cow::Borrowed(path));
+    }
+
+    let piece_length = options
+        .piece_length
+        .unwrap_or_else(|| choose_piece_length(&input_files));
+
+    // Calculate hashes etc.
+    const READ_SIZE: u32 = 8192; // todo: twea
+    let mut read_buf = vec![0; READ_SIZE as usize];
+
+    let mut length = 0;
+    let mut remaining_piece_length = piece_length;
+    let mut piece_checksum = sha1w::Sha1::new();
+    let mut piece_hashes = Vec::<u8>::new();
+    let mut output_files: Vec<TorrentMetaV1File<ByteString>> = Vec::new();
+
+    let spawner = BlockingSpawner::default();
+
+    'outer: for file in input_files {
+        let filename = &*file;
+        length = 0;
+        let mut fd = std::io::BufReader::new(
+            std::fs::File::open(&file).with_context(|| format!("error opening {:?}", filename))?,
+        );
+
+        loop {
+            let max_bytes_to_read = remaining_piece_length.min(READ_SIZE) as usize;
+            let size = spawner
+                .spawn_block_in_place(|| fd.read(&mut read_buf[..max_bytes_to_read]))
+                .with_context(|| format!("error reading {:?}", filename))?;
+
+            // EOF: swap file
+            if size == 0 {
+                let filename = filename
+                    .strip_prefix(path)
+                    .context("internal error, can't strip prefix")?;
+                let path = filename
+                    .components()
+                    .map(|c| c.as_os_str().as_bytes().into())
+                    .collect();
+                output_files.push(TorrentMetaV1File { length, path });
+                continue 'outer;
+            }
+
+            length += size as u64;
+            piece_checksum.update(&read_buf[..size]);
+
+            remaining_piece_length -= size as u32;
+            if remaining_piece_length == 0 {
+                remaining_piece_length = piece_length;
+                piece_hashes.extend_from_slice(&piece_checksum.finish());
+                piece_checksum = sha1w::Sha1::new();
+            }
+        }
+    }
+
+    if remaining_piece_length > 0 && length > 0 {
+        piece_hashes.extend_from_slice(&piece_checksum.finish());
+    }
+    Ok(TorrentMetaV1Info {
+        name: Some(name),
+        pieces: piece_hashes.into(),
+        piece_length,
+        length: if single_file_mode { Some(length) } else { None },
+        md5sum: None,
+        files: if single_file_mode {
+            None
+        } else {
+            Some(output_files)
+        },
+    })
+}
+
+#[derive(Debug)]
+pub struct CreateTorrentResult {
+    meta: TorrentMetaV1Owned,
+}
+
+impl CreateTorrentResult {
+    pub fn as_info(&self) -> &TorrentMetaV1Owned {
+        &self.meta
+    }
+
+    pub fn info_hash(&self) -> Id20 {
+        self.meta.info_hash
+    }
+
+    pub fn as_bytes(&self) -> anyhow::Result<Vec<u8>> {
+        let mut b = Vec::new();
+        bencode_serialize_to_writer(&self.meta, &mut b).context("error serializing torrent")?;
+        Ok(b)
+    }
+}
+
+pub async fn create_torrent<'a>(
+    path: &'a Path,
+    options: CreateTorrentOptions<'a>,
+) -> anyhow::Result<CreateTorrentResult> {
+    let info = create_torrent_raw(path, options).await?;
+    let info_hash = compute_info_hash(&info).context("error computing info hash")?;
+    Ok(CreateTorrentResult {
+        meta: TorrentMetaV1Owned {
+            announce: b""[..].into(),
+            announce_list: Vec::new(),
+            info,
+            comment: None,
+            created_by: None,
+            encoding: Some(b"utf-8"[..].into()),
+            publisher: None,
+            publisher_url: None,
+            creation_date: None,
+            info_hash,
+        },
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use buffers::ByteBuf;
+    use librqbit_core::torrent_metainfo::torrent_from_bytes;
+
+    use crate::create_torrent;
+
+    #[tokio::test]
+    async fn test_create_torrent() {
+        use crate::tests::test_util;
+
+        let dir = test_util::create_default_random_dir_with_torrents(
+            3,
+            1000 * 1000,
+            Some("rqbit_test_create_torrent"),
+        );
+        let torrent = create_torrent(dir.path(), Default::default())
+            .await
+            .unwrap();
+
+        let bytes = torrent.as_bytes().unwrap();
+
+        let deserialized = torrent_from_bytes::<ByteBuf>(&bytes).unwrap();
+        assert_eq!(torrent.info_hash(), deserialized.info_hash);
+    }
+}

crates/librqbit/src/lib.rs

@@ -25,6 +25,7 @@
 pub mod api;
 mod api_error;
 mod chunk_tracker;
+mod create_torrent_file;
 mod dht_utils;
 mod file_ops;
 pub mod http_api;
@@ -40,6 +41,7 @@ mod type_aliases;
 
 pub use api::Api;
 pub use api_error::ApiError;
+pub use create_torrent_file::{create_torrent, CreateTorrentOptions};
 pub use dht;
 pub use peer_connection::PeerConnectionOptions;
 pub use session::{
@@ -55,6 +57,9 @@ pub use librqbit_core::magnet::*;
 pub use librqbit_core::peer_id::*;
 pub use librqbit_core::torrent_metainfo::*;
 
+#[cfg(test)]
+mod tests;
+
 /// The cargo version of librqbit.
 pub fn version() -> &'static str {
     env!("CARGO_PKG_VERSION")

crates/librqbit/src/peer_connection.rs

@@ -181,7 +181,10 @@ impl<H: PeerConnectionHandler> PeerConnection<H> {
             .await
             .context("error reading handshake")?;
         let h_supports_extended = h.supports_extended();
-        trace!("connected: id={:?}", try_decode_peer_id(Id20::new(h.peer_id)));
+        trace!(
+            "connected: id={:?}",
+            try_decode_peer_id(Id20::new(h.peer_id))
+        );
         if h.info_hash != self.info_hash.0 {
             anyhow::bail!("info hash does not match");
         }
@@ -269,6 +272,22 @@ impl<H: PeerConnectionHandler> PeerConnection<H> {
                             .and_then(|e| e.ut_metadata())
                     })?,
                     WriterRequest::ReadChunkRequest(chunk) => {
+                        #[cfg(test)]
+                        {
+                            // This is poor-mans fault injection for running e2e tests.
+                            use crate::tests::test_util::TestPeerMetadata;
+                            let tpm = TestPeerMetadata::from_peer_id(self.peer_id);
+                            use rand::Rng;
+                            if rand::thread_rng().gen_bool(tpm.disconnect_probability()) {
+                                bail!("disconnecting, to simulate failure in tests");
+                            }
+
+                            let sleep_ms = (rand::thread_rng().gen::<f64>()
+                                * (tpm.max_random_sleep_ms as f64))
+                                as u64;
+                            tokio::time::sleep(Duration::from_millis(sleep_ms)).await;
+                        }
+
                         // this whole section is an optimization
                         write_buf.resize(PIECE_MESSAGE_DEFAULT_LEN, 0);
                         let preamble_len = serialize_piece_preamble(chunk, &mut write_buf);

crates/librqbit/src/session.rs

@@ -1136,6 +1136,10 @@ impl Session {
         handle.start(peer_rx, false, self.cancellation_token.child_token())?;
         Ok(())
     }
+
+    pub fn tcp_listen_port(&self) -> Option<u16> {
+        self.tcp_listen_port
+    }
 }
 
 // Ad adapter for converting stats into the format that tracker_comms accepts.

crates/librqbit/src/tests/e2e.rs

@@ -0,0 +1,271 @@
+use std::{
+    borrow::Cow,
+    net::{Ipv4Addr, SocketAddr},
+    time::Duration,
+};
+
+use anyhow::bail;
+use futures::{stream::FuturesUnordered, StreamExt};
+use rand::Rng;
+use tokio::{
+    spawn,
+    time::{interval, timeout},
+};
+use tracing::{error_span, info, Instrument};
+
+use crate::{
+    create_torrent,
+    tests::test_util::{create_default_random_dir_with_torrents, TestPeerMetadata},
+    AddTorrentOptions, AddTorrentResponse, Session, SessionOptions,
+};
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 64)]
+async fn test_e2e() {
+    let _ = tracing_subscriber::fmt::try_init();
+
+    // 1. Create a torrent
+    // Ideally (for a more complicated test) with N files, and at least N pieces that span 2 files.
+
+    let piece_length: u32 = 16384 * 2; // TODO: figure out if this should be multiple of chunk size or not
+    let file_length: usize = 1000 * 1000;
+    let num_files: usize = 64;
+
+    let tempdir =
+        create_default_random_dir_with_torrents(num_files, file_length, Some("rqbit_e2e"));
+    let torrent_file = create_torrent(
+        dbg!(tempdir.path()),
+        crate::CreateTorrentOptions {
+            piece_length: Some(piece_length),
+            ..Default::default()
+        },
+    )
+    .await
+    .unwrap();
+
+    let num_servers = 128;
+
+    let torrent_file_bytes = torrent_file.as_bytes().unwrap();
+    let mut futs = FuturesUnordered::new();
+
+    // 2. Start N servers that are serving that torrent, and return their IP:port combos.
+    //    Disable DHT on each.
+    for i in 0u8..num_servers {
+        let torrent_file_bytes = torrent_file_bytes.clone();
+        let (tx, rx) = tokio::sync::oneshot::channel();
+        let tempdir = tempdir.path().to_owned();
+        spawn(
+            async move {
+                let peer_id = TestPeerMetadata {
+                    server_id: i,
+                    max_random_sleep_ms: rand::thread_rng().gen_range(0u8..128),
+                }
+                .as_peer_id();
+                let session = crate::Session::new_with_opts(
+                    std::env::temp_dir().join("does_not_exist"),
+                    SessionOptions {
+                        disable_dht: true,
+                        disable_dht_persistence: true,
+                        dht_config: None,
+                        persistence: false,
+                        persistence_filename: None,
+                        peer_id: Some(peer_id),
+                        peer_opts: None,
+                        listen_port_range: Some(15100..17000),
+                        enable_upnp_port_forwarding: false,
+                    },
+                )
+                .await
+                .unwrap();
+
+                info!("started session");
+
+                let handle = session
+                    .add_torrent(
+                        crate::AddTorrent::TorrentFileBytes(Cow::Owned(torrent_file_bytes)),
+                        Some(AddTorrentOptions {
+                            overwrite: true,
+                            output_folder: Some(tempdir.to_str().unwrap().to_owned()),
+                            ..Default::default()
+                        }),
+                    )
+                    .await
+                    .unwrap();
+                let h = handle.into_handle().unwrap();
+                let mut interval = interval(Duration::from_millis(100));
+
+                info!("added torrent");
+                loop {
+                    interval.tick().await;
+                    let is_live = h
+                        .with_state(|s| match s {
+                            crate::ManagedTorrentState::Initializing(_) => Ok(false),
+                            crate::ManagedTorrentState::Live(l) => {
+                                if !l.is_finished() {
+                                    bail!("torrent went live, but expected it to be finished");
+                                }
+                                Ok(true)
+                            }
+                            _ => bail!("broken state"),
+                        })
+                        .unwrap();
+                    if is_live {
+                        break;
+                    }
+                }
+                info!("torrent is live");
+                tx.send(SocketAddr::new(
+                    std::net::IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)),
+                    session.tcp_listen_port().unwrap(),
+                ))
+            }
+            .instrument(error_span!("server", server = i)),
+        );
+        futs.push(timeout(Duration::from_secs(10), rx));
+    }
+
+    let mut peers = Vec::new();
+    while let Some(addr) = futs.next().await {
+        peers.push(addr.unwrap().unwrap());
+    }
+
+    info!("started all servers, starting client");
+
+    let client_iters = std::env::var("E2E_CLIENT_ITERS")
+        .ok()
+        .and_then(|v| v.parse().ok())
+        .unwrap_or(1usize);
+
+    // 3. Start a client with the initial peers, and download the file.
+    for _ in 0..client_iters {
+        let outdir = tempfile::TempDir::with_prefix("rqbit_e2e_client").unwrap();
+        let session = Session::new_with_opts(
+            outdir.path().to_owned(),
+            SessionOptions {
+                disable_dht: true,
+                disable_dht_persistence: true,
+                dht_config: None,
+                persistence: false,
+                persistence_filename: None,
+                listen_port_range: None,
+                enable_upnp_port_forwarding: false,
+                ..Default::default()
+            },
+        )
+        .await
+        .unwrap();
+
+        info!("started client session");
+
+        let (id, handle) = {
+            let r = session
+                .add_torrent(
+                    crate::AddTorrent::TorrentFileBytes(Cow::Owned(torrent_file_bytes.clone())),
+                    Some(AddTorrentOptions {
+                        initial_peers: Some(peers.clone()),
+                        overwrite: false,
+                        ..Default::default()
+                    }),
+                )
+                .await
+                .unwrap();
+
+            match r {
+                AddTorrentResponse::AlreadyManaged(_, _) => todo!(),
+                AddTorrentResponse::ListOnly(_) => todo!(),
+                AddTorrentResponse::Added(id, h) => (id, h),
+            }
+        };
+
+        info!("added handle");
+
+        {
+            let stats_printer = {
+                let handle = handle.clone();
+                async move {
+                    let mut interval = interval(Duration::from_millis(100));
+
+                    loop {
+                        interval.tick().await;
+                        let stats = handle.stats();
+                        let live = match &stats.live {
+                            Some(live) => live,
+                            None => continue,
+                        };
+                        let pstats = &live.snapshot.peer_stats;
+
+                        info!(
+                            progress_percent =
+                                format!("{}", stats.progress_percent_human_readable()),
+                            peers = format!("{:?}", pstats),
+                        );
+                    }
+                }
+            }
+            .instrument(error_span!("stats_printer"));
+
+            let timeout = timeout(Duration::from_secs(60), handle.wait_until_completed());
+
+            tokio::pin!(stats_printer);
+            tokio::pin!(timeout);
+
+            let mut stats_finished = false;
+            loop {
+                tokio::select! {
+                    r = &mut timeout => {
+                        r.unwrap().unwrap();
+                        break;
+                    }
+                    _ = &mut stats_printer, if !stats_finished => {
+                        stats_finished = true;
+                    }
+                }
+            }
+        }
+
+        info!("handle is completed");
+        session.delete(id, false).unwrap();
+
+        info!("deleted handle");
+
+        // 4. After downloading, recheck its integrity.
+        let handle = session
+            .add_torrent(
+                crate::AddTorrent::TorrentFileBytes(Cow::Owned(torrent_file_bytes.clone())),
+                Some(AddTorrentOptions {
+                    paused: true,
+                    overwrite: true,
+                    ..Default::default()
+                }),
+            )
+            .await
+            .unwrap()
+            .into_handle()
+            .unwrap();
+
+        info!("re-added handle");
+
+        timeout(Duration::from_secs(10), async {
+            let mut interval = interval(Duration::from_millis(100));
+            loop {
+                interval.tick().await;
+                let b = handle
+                    .with_state(|s| match s {
+                        crate::ManagedTorrentState::Initializing(_) => Ok(false),
+                        crate::ManagedTorrentState::Paused(p) => {
+                            assert_eq!(p.needed_bytes, 0);
+                            Ok(true)
+                        }
+                        _ => bail!("bugged state"),
+                    })
+                    .unwrap();
+                if b {
+                    break;
+                }
+            }
+        })
+        .await
+        .unwrap();
+
+        info!("all good");
+    }
+}

crates/librqbit/src/tests/mod.rs

@@ -0,0 +1,2 @@
+mod e2e;
+pub mod test_util;

crates/librqbit/src/tests/test_util.rs

@@ -0,0 +1,66 @@
+use std::{io::Write, path::Path};
+
+use librqbit_core::Id20;
+use rand::RngCore;
+use tempfile::TempDir;
+
+pub fn create_new_file_with_random_content(path: &Path, mut size: usize) {
+    let mut file = std::fs::OpenOptions::new()
+        .create_new(true)
+        .write(true)
+        .open(path)
+        .unwrap();
+
+    eprintln!("creating temp file {:?}", path);
+
+    const BUF_SIZE: usize = 8192 * 16;
+    let mut rng = rand::rngs::OsRng;
+    let mut write_buf = [0; BUF_SIZE];
+    while size > 0 {
+        rng.fill_bytes(&mut write_buf[..]);
+        let written = file.write(&write_buf[..size.min(BUF_SIZE)]).unwrap();
+        size -= written;
+    }
+}
+
+pub fn create_default_random_dir_with_torrents(
+    num_files: usize,
+    file_size: usize,
+    tempdir_prefix: Option<&str>,
+) -> TempDir {
+    let dir = TempDir::with_prefix(tempdir_prefix.unwrap_or("rqbit_test")).unwrap();
+    dbg!(dir.path());
+    for f in 0..num_files {
+        create_new_file_with_random_content(&dir.path().join(&format!("{f}.data")), file_size);
+    }
+    dir
+}
+
+#[derive(Debug)]
+pub struct TestPeerMetadata {
+    pub server_id: u8,
+    pub max_random_sleep_ms: u8,
+}
+
+impl TestPeerMetadata {
+    pub fn as_peer_id(&self) -> Id20 {
+        let mut peer_id = Id20::default();
+        peer_id.0[0] = self.server_id;
+        peer_id.0[1] = self.max_random_sleep_ms;
+        peer_id
+    }
+
+    pub fn from_peer_id(peer_id: Id20) -> Self {
+        Self {
+            server_id: peer_id.0[0],
+            max_random_sleep_ms: peer_id.0[1],
+        }
+    }
+
+    pub fn disconnect_probability(&self) -> f64 {
+        if self.server_id % 2 == 0 {
+            return 0.05f64;
+        }
+        0f64
+    }
+}

crates/librqbit_core/src/lengths.rs

@@ -38,7 +38,7 @@ pub struct Lengths {
     piece_length: u32,
     last_piece_id: u32,
     last_piece_length: u32,
-    chunks_per_piece: u32,
+    max_chunks_per_piece: u32,
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
@@ -84,7 +84,7 @@ impl Lengths {
         }
         if chunk_length > piece_length {
             anyhow::bail!(
-                "chunk length {} should be smaller than or equal to piece length {}",
+                "chunk length {} should be >= piece length {}",
                 chunk_length,
                 piece_length
             );
@@ -97,7 +97,7 @@ impl Lengths {
             chunk_length,
             piece_length,
             total_length,
-            chunks_per_piece: ceil_div_u64(piece_length as u64, chunk_length as u64) as u32,
+            max_chunks_per_piece: ceil_div_u64(piece_length as u64, chunk_length as u64) as u32,
             last_piece_id: total_pieces - 1,
             last_piece_length: last_element_size_u64(total_length, piece_length as u64) as u32,
         })
@@ -123,8 +123,8 @@ impl Lengths {
     pub const fn default_chunk_length(&self) -> u32 {
         self.chunk_length
     }
-    pub const fn default_chunks_per_piece(&self) -> u32 {
+    pub const fn default_max_chunks_per_piece(&self) -> u32 {
-        self.chunks_per_piece
+        self.max_chunks_per_piece
     }
     pub const fn total_chunks(&self) -> u32 {
         ceil_div_u64(self.total_length, self.chunk_length as u64) as u32
@@ -161,7 +161,7 @@ impl Lengths {
     pub fn iter_chunk_infos(&self, index: ValidPieceIndex) -> impl Iterator<Item = ChunkInfo> {
         let mut remaining = self.piece_length(index);
         let chunk_size = self.chunk_length;
-        let absolute_offset = index.0 * self.chunks_per_piece;
+        let absolute_offset = index.0 * self.max_chunks_per_piece;
         (0u32..).scan(0, move |offset, idx| {
             if remaining == 0 {
                 return None;
@@ -195,7 +195,7 @@ impl Lengths {
         if expected_chunk_size != chunk_size {
             return None;
         }
-        let absolute_index = self.chunks_per_piece * piece_index.get() + index;
+        let absolute_index = self.max_chunks_per_piece * piece_index.get() + index;
         Some(ChunkInfo {
             piece_index,
             chunk_index: index,
@@ -214,7 +214,7 @@ impl Lengths {
         self.chunk_info_from_received_data(self.validate_piece_index(index)?, begin, block_len)
     }
     pub const fn chunk_range(&self, index: ValidPieceIndex) -> std::ops::Range<usize> {
-        let start = index.0 * self.chunks_per_piece;
+        let start = index.0 * self.max_chunks_per_piece;
         let end = start + self.chunks_per_piece(index);
         start as usize..end as usize
     }
@@ -222,7 +222,7 @@ impl Lengths {
         if index.0 == self.last_piece_id {
             return (self.last_piece_length + self.chunk_length - 1) / self.chunk_length;
         }
-        self.chunks_per_piece
+        self.max_chunks_per_piece
     }
     pub const fn chunk_offset_in_piece(
         &self,

crates/librqbit_core/src/torrent_metainfo.rs

@@ -27,20 +27,27 @@ pub fn torrent_from_bytes<'de, ByteBuf: Deserialize<'de>>(
 }
 
 /// A parsed .torrent file.
-#[derive(Deserialize, Debug, Clone)]
+#[derive(Serialize, Deserialize, Debug, Clone)]
 pub struct TorrentMetaV1<BufType> {
     pub announce: BufType,
-    #[serde(rename = "announce-list", default = "Vec::new")]
+    #[serde(
+        rename = "announce-list",
+        default = "Vec::new",
+        skip_serializing_if = "Vec::is_empty"
+    )]
     pub announce_list: Vec<Vec<BufType>>,
     pub info: TorrentMetaV1Info<BufType>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub comment: Option<BufType>,
-    #[serde(rename = "created by")]
+    #[serde(rename = "created by", skip_serializing_if = "Option::is_none")]
     pub created_by: Option<BufType>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub encoding: Option<BufType>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub publisher: Option<BufType>,
-    #[serde(rename = "publisher-url")]
+    #[serde(rename = "publisher-url", skip_serializing_if = "Option::is_none")]
     pub publisher_url: Option<BufType>,
-    #[serde(rename = "creation date")]
+    #[serde(rename = "creation date", skip_serializing_if = "Option::is_none")]
     pub creation_date: Option<usize>,
 
     #[serde(skip)]

desktop/src-tauri/Cargo.lock

@@ -3958,9 +3958,9 @@ checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
 
 [[package]]
 name = "tokio"
-version = "1.34.0"
+version = "1.36.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d0c014766411e834f7af5b8f4cf46257aab4036ca95e9d2c144a10f59ad6f5b9"
+checksum = "61285f6515fa018fb2d1e46eb21223fff441ee8db5d0f1435e8ab4f5cdb80931"
 dependencies = [
  "backtrace",
  "bytes",