the thing actually works pretty good now

TODO.md

@@ -8,5 +8,27 @@
 - [ ] per-file stats
 - [ ] per-peer stats
 
+- [ ] slow peers cause slowness in the end, need the "end of game" algorithm
+  - [ ] will require implementing cancel message
+
 someday:
-- [ ] cancellation
+- [ ] cancellation from the client-side for the lib (i.e. stop the torrent manager)
+
+
+# concurrency
+it's fucked up now, so need to rethink.
+
+Sequencing:
+- when the peer sends bitfield
+  - update its bitfield
+  - this can only happen at the start. But it can also NOT happen at all (if the peer wants to download)
+    - so we actually cannot use it as a trigger to start the "uploader" of it (where we upload to it)
+  - however both this and "have" we can use as a trigger to start the "downloader" part of it
+- when the peer sends "interested"
+- when the peer sends "have"
+  - update its bitfield
+
+"peer downloader":
+- if started, means there was some initial interest
+- if we are unchoked:
+  - fetch new pieces forever from the queue, send requests

crates/librqbit/src/torrent_manager.rs

@@ -791,11 +791,11 @@ impl TorrentManager {
             .peers
             .update_bitfield_from_vec(handle, bitfield.0);
         if !self.am_i_interested_in_peer(handle) {
-            self.inner.locked.write().peers.drop_peer(handle);
+            // self.inner.locked.write().peers.drop_peer(handle);
             return;
         }
 
-        // Additional spawn per peer.
+        // Additional spawn per peer, not good.
         spawn(
             format!("peer_chunk_requester({})", handle),
             self.clone().task_peer_chunk_requester(handle),
@@ -1375,8 +1375,7 @@ impl TorrentManager {
                     match tokio::time::timeout(keep_alive_interval, outgoing_chan.recv()).await {
                         Ok(Some(msg)) => msg,
                         Ok(None) => {
-                            // we were closed
-                            return Ok(());
+                            anyhow::bail!("closing writer, channel closed")
                         }
                         Err(_) => MessageOwned::KeepAlive,
                     };