Fixup names and comments

src/github.com/matrix-org/dendrite/syncapi/sync/notifier.go

@@ -106,9 +106,13 @@ func (n *Notifier) OnNewEvent(ev *gomatrixserverlib.Event, userID string, pos ty
 	}
 }
 
-// WaitForEvents returns a channel that produces a single stream position when
+// GetNotifyChannel returns a channel that produces a single stream position when
 // a new event *may* be available to return to the client.
-func (n *Notifier) WaitForEvents(req syncRequest, sincePos types.StreamPosition) <-chan types.StreamPosition {
+// sincePos specifies from which point we want to be notified about, i.e. don't
+// notify for anything before sincePos
+func (n *Notifier) GetNotifyChannel(
+	req syncRequest, sincePos types.StreamPosition,
+) <-chan types.StreamPosition {
 	// Do what synapse does: https://github.com/matrix-org/synapse/blob/v0.20.0/synapse/notifier.py#L298
 	// - Bucket request into a lookup map keyed off a list of joined room IDs and separately a user ID
 	// - Incoming events wake requests for a matching room ID
@@ -123,7 +127,7 @@ func (n *Notifier) WaitForEvents(req syncRequest, sincePos types.StreamPosition)
 
 	n.removeEmptyUserStreams()
 
-	return n.fetchUserStream(req.userID, true).Wait(req.ctx, sincePos)
+	return n.fetchUserStream(req.userID, true).GetNotifyChannel(req.ctx, sincePos)
 }
 
 // Load the membership states required to notify users correctly.

src/github.com/matrix-org/dendrite/syncapi/sync/notifier_test.go

@@ -261,7 +261,7 @@ func waitForEvents(n *Notifier, req syncRequest) (types.StreamPosition, error) {
 		return types.StreamPosition(0), fmt.Errorf(
 			"waitForEvents timed out waiting for %s (pos=%d)", req.userID, req.since,
 		)
-	case p := <-n.WaitForEvents(req, req.since):
+	case p := <-n.GetNotifyChannel(req, req.since):
 		return p, nil
 	}
 }

src/github.com/matrix-org/dendrite/syncapi/sync/requestpool.go

@@ -85,7 +85,7 @@ func (rp *RequestPool) OnIncomingSyncRequest(req *http.Request, device *authtype
 	for {
 		select {
 		// Wait for notifier to wake us up
-		case currPos = <-rp.notifier.WaitForEvents(*syncReq, currPos):
+		case currPos = <-rp.notifier.GetNotifyChannel(*syncReq, currPos):
 		// Or for timeout to expire
 		case <-timer.C:
 			return util.JSONResponse{

src/github.com/matrix-org/dendrite/syncapi/sync/userstream.go

@@ -27,10 +27,10 @@ import (
 // goroutines can Broadcast(streamPosition) to other goroutines.
 type UserStream struct {
 	UserID string
-	// The waiting channels....... TODO
-	waitingChannels []chan<- types.StreamPosition
-	// The lock that protects pos
+	// The lock that protects changes to this struct
 	lock sync.Mutex
+	// The channels waiting for updates for this user
+	waitingChannels []chan<- types.StreamPosition
 	// The position to broadcast to callers of Wait().
 	pos types.StreamPosition
 	// The time when waitingChannels was last non-empty
@@ -46,19 +46,22 @@ func NewUserStream(userID string, currPos types.StreamPosition) *UserStream {
 	}
 }
 
-// Wait returns a channel that produces a single stream position when
+// GetNotifyChannel returns a channel that produces a single stream position when
 // a new event *may* be available to return to the client.
-func (s *UserStream) Wait(ctx context.Context, waitAtPos types.StreamPosition) <-chan types.StreamPosition {
+// sincePos specifies from which point we want to be notified about
+func (s *UserStream) GetNotifyChannel(
+	ctx context.Context, sincePos types.StreamPosition,
+) <-chan types.StreamPosition {
 	posChannel := make(chan types.StreamPosition, 1)
 
 	s.lock.Lock()
 	defer s.lock.Unlock()
 
 	// Before we start blocking, we need to make sure that we didn't race with a call
-	// to Broadcast() between calling Wait() and actually sleeping. We check the last
+	// to Broadcast() between calling Wait() and getting the lock. We check the last
 	// broadcast pos to see if it is newer than the pos we are meant to wait at. If it
 	// is newer, something has Broadcast to this stream more recently so return immediately.
-	if s.pos > waitAtPos {
+	if s.pos > sincePos {
 		posChannel <- s.pos
 		close(posChannel)
 		return posChannel