Remove Option<BF> to just BF

crates/librqbit/src/peer_state.rs

@@ -223,10 +223,24 @@ pub struct LivePeerState {
     pub peer_id: Id20,
     pub i_am_choked: bool,
     pub peer_interested: bool,
+
+    // This is used to limit the number of requests we send to a peer at a time.
     pub requests_sem: Arc<Semaphore>,
+
+    // This is used to unpause processes after we were choked.
     pub have_notify: Arc<Notify>,
-    pub bitfield: Option<BF>,
+
+    // This is used to track the pieces the peer has.
+    pub bitfield: BF,
+
+    // This is used to only request a piece from a peer once when stealing from others.
+    // So that you don't steal then re-steal the same piece in a loop.
+    pub previously_requested_pieces: BF,
+
+    // When the peer sends us data this is used to track if we asked for it.
     pub inflight_requests: HashSet<InflightRequest>,
+
+    // The main channel to send requests to peer.
     pub tx: PeerTx,
 }
 
@@ -236,7 +250,8 @@ impl LivePeerState {
             peer_id,
             i_am_choked: true,
             peer_interested: false,
-            bitfield: None,
+            bitfield: BF::new(),
+            previously_requested_pieces: BF::new(),
             have_notify: Arc::new(Notify::new()),
             requests_sem: Arc::new(Semaphore::new(0)),
             inflight_requests: Default::default(),
@@ -245,10 +260,8 @@ impl LivePeerState {
     }
 
     pub fn has_full_torrent(&self, total_pieces: usize) -> bool {
-        let bf = match self.bitfield.as_ref() {
-            Some(bf) => bf,
-            None => return false,
-        };
-        bf.get(0..total_pieces).map_or(false, |s| s.all())
+        self.bitfield
+            .get(0..total_pieces)
+            .map_or(false, |s| s.all())
     }
 }

crates/librqbit/src/torrent_state.rs

@@ -168,16 +168,11 @@ impl PeerStates {
             prev
         })
     }
-    pub fn update_bitfield_from_vec(
-        &self,
-        handle: PeerHandle,
-        bitfield: Vec<u8>,
-    ) -> Option<Option<BF>> {
+    pub fn update_bitfield_from_vec(&self, handle: PeerHandle, bitfield: Vec<u8>) -> Option<()> {
         self.with_live_mut(handle, "update_bitfield_from_vec", |live| {
             let bitfield = BF::from_vec(bitfield);
-            let prev = live.bitfield.take();
-            live.bitfield = Some(bitfield);
-            prev
+            live.previously_requested_pieces = BF::with_capacity(bitfield.len());
+            live.bitfield = bitfield;
         })
     }
     pub fn mark_peer_connecting(&self, h: PeerHandle) -> anyhow::Result<PeerRx> {
@@ -543,7 +538,7 @@ impl TorrentState {
         self.peers
             .with_live_mut(peer_handle, "l(get_next_needed_piece)", |live| {
                 let g = self.lock_read("g(get_next_needed_piece)");
-                let bf = live.bitfield.as_ref()?;
+                let bf = &live.bitfield;
                 for n in g.chunks.iter_needed_pieces() {
                     if bf.get(n).map(|v| *v) == Some(true) {
                         // in theory it should be safe without validation, but whatever.
@@ -567,9 +562,10 @@ impl TorrentState {
                     return None;
                 }
                 let mut g = self.lock_write("reserve_next_needed_piece");
+
                 let n = {
                     let mut n_opt = None;
-                    let bf = live.bitfield.as_ref()?;
+                    let bf = &live.bitfield;
                     for n in g.chunks.iter_needed_pieces() {
                         if bf.get(n).map(|v| *v) == Some(true) {
                             n_opt = Some(n);
@@ -627,6 +623,7 @@ impl TorrentState {
         None
     }
 
+    // TODO: need to throttle this or make it smarter as it may loop and steal pieces forever from each other.
     fn try_steal_piece(&self, handle: PeerHandle) -> Option<ValidPieceIndex> {
         let mut rng = rand::thread_rng();
         use rand::seq::IteratorRandom;
@@ -782,8 +779,8 @@ impl TorrentState {
 
                     if live
                         .bitfield
-                        .as_ref()
-                        .and_then(|b| b.get(index.get() as usize).map(|v| *v))
+                        .get(index.get() as usize)
+                        .map(|v| *v)
                         .unwrap_or(false)
                     {
                         continue;
@@ -986,10 +983,8 @@ impl PeerHandler {
 
     fn on_have(&self, handle: PeerHandle, have: u32) {
         self.state.peers.with_live_mut(handle, "on_have", |live| {
-            if let Some(bitfield) = live.bitfield.as_mut() {
-                bitfield.set(have as usize, true);
-                debug!("updated bitfield with have={}", have);
-            }
+            live.bitfield.set(have as usize, true);
+            debug!("updated bitfield with have={}", have);
         });
     }
 
@@ -1081,6 +1076,7 @@ impl PeerHandler {
                 None => return Ok(()),
             }
 
+            // Try steal a pice from a very slow peer first.
             let next = match self.state.try_steal_old_slow_piece(handle) {
                 Some(next) => next,
                 None => match self.state.reserve_next_needed_piece(handle) {