channeld: implement pending_updates()

Says if we have started an update which is still pending somewhere.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

channeld/full_channel.c

@@ -1252,6 +1252,34 @@ static bool adjust_balance(struct balance view_owed[NUM_SIDES][NUM_SIDES],
 	return true;
 }
 
+bool pending_updates(const struct channel *channel, enum side side)
+{
+	struct htlc_map_iter it;
+	const struct htlc *htlc;
+
+	/* Initiator might have fee changes in play. */
+	if (side == channel->opener) {
+		if (!feerate_changes_done(channel->fee_states))
+			return true;
+	}
+
+	for (htlc = htlc_map_first(channel->htlcs, &it);
+	     htlc;
+	     htlc = htlc_map_next(channel->htlcs, &it)) {
+		/* If it's still being added, it's owner added it. */
+		if (htlc_state_flags(htlc->state) & HTLC_ADDING) {
+			if (htlc_owner(htlc) == side)
+				return true;
+		/* If it's being removed, non-owner removed it */
+		} else if (htlc_state_flags(htlc->state) & HTLC_REMOVING) {
+			if (htlc_owner(htlc) != side)
+				return true;
+		}
+	}
+
+	return false;
+}
+
 bool channel_force_htlcs(struct channel *channel,
 			 const struct existing_htlc **htlcs)
 {

channeld/full_channel.h

@@ -254,6 +254,13 @@ bool channel_force_htlcs(struct channel *channel,
  */
 void dump_htlcs(const struct channel *channel, const char *prefix);
 
+/**
+ * pending_updates: does this side have updates pending in channel?
+ * @channel: the channel
+ * @side: the side who is offering or failing/fulfilling HTLC, or feechange
+ */
+bool pending_updates(const struct channel *channel, enum side side);
+
 const char *channel_add_err_name(enum channel_add_err e);
 const char *channel_remove_err_name(enum channel_remove_err e);