Marco/with after func (#763)

refactor: if the conn has a context, use context.AfterFunc for cleanup
---------

Co-authored-by: Marco Munizaga <git@marcopolo.io>

Author: gammazero

CHANGELOG.md

@@ -27,11 +27,11 @@ The following emojis are used to highlight certain changes:
 
 * 🛠 `blockstore` and `blockservice`'s `WriteThrough()` option now takes an "enabled" parameter: `WriteThrough(enabled bool)`.
 * Replaced unmaintained mock time implementation uses in tests: [from](github.com/benbjohnson/clock) => [to](github.com/filecoin-project/go-clock)
+* `bitswap/client`: if a libp2p connection has a context, use `context.AfterFunc` to cleanup the connection.
 
 ### Removed
 
 
-
 ### Fixed
 
 * `mfs`: directory cache is now cleared on Flush(), liberating the memory used by the otherwise ever-growing cache. References to directories and sub-directories should be renewed after flushing.

bitswap/network/ipfs_impl.go

@@ -82,9 +82,32 @@ type impl struct {
 	receivers []Receiver
 }
 
+// interfaceWrapper is concrete type that wraps an interface. Necessary because
+// atomic.Value needs the same type and can not Store(nil). This indirection
+// allows us to store nil.
+type interfaceWrapper[T any] struct {
+	t T
+}
+type atomicInterface[T any] struct {
+	iface atomic.Value
+}
+
+func (a *atomicInterface[T]) Load() T {
+	var v T
+	x := a.iface.Load()
+	if x != nil {
+		return x.(interfaceWrapper[T]).t
+	}
+	return v
+}
+
+func (a *atomicInterface[T]) Store(v T) {
+	a.iface.Store(interfaceWrapper[T]{v})
+}
+
 type streamMessageSender struct {
 	to     peer.ID
-	stream network.Stream
+	stream atomicInterface[network.Stream]
 	bsnet  *impl
 	opts   *MessageSenderOpts
 }
@@ -95,7 +118,7 @@ type HasContext interface {
 
 // Open a stream to the remote peer
 func (s *streamMessageSender) Connect(ctx context.Context) (network.Stream, error) {
-	stream := s.stream
+	stream := s.stream.Load()
 	if stream != nil {
 		return stream, nil
 	}
@@ -111,36 +134,41 @@ func (s *streamMessageSender) Connect(ctx context.Context) (network.Stream, erro
 	if err != nil {
 		return nil, err
 	}
+	if withCtx, ok := stream.Conn().(HasContext); ok {
+		context.AfterFunc(withCtx.Context(), func() {
+			s.stream.Store(nil)
+		})
+	}
 
-	s.stream = stream
+	s.stream.Store(stream)
 	return stream, nil
 }
 
 // Reset the stream
 func (s *streamMessageSender) Reset() error {
-	stream := s.stream
+	stream := s.stream.Load()
 	if stream != nil {
 		err := stream.Reset()
-		s.stream = nil
+		s.stream.Store(nil)
 		return err
 	}
 	return nil
 }
 
 // Close the stream
 func (s *streamMessageSender) Close() error {
-	stream := s.stream
+	stream := s.stream.Load()
 	if stream != nil {
 		err := stream.Close()
-		s.stream = nil
+		s.stream.Store(nil)
 		return err
 	}
 	return nil
 }
 
 // Indicates whether the peer supports HAVE / DONT_HAVE messages
 func (s *streamMessageSender) SupportsHave() bool {
-	stream := s.stream
+	stream := s.stream.Load()
 	if stream == nil {
 		return false
 	}