From 92b891bee3759c206e27057d3558ebb08062c852 Mon Sep 17 00:00:00 2001
From: Christian Decker <decker.christian@gmail.com>
Date: Fri, 6 May 2022 15:38:34 +0200
Subject: [PATCH] ld: Add function to retrieve either the scid or the local
 alias

We use this in a couple of places, when we want to refer to a channel
by its `short_channel_id`, I'm moving this into a separate function
primarily to have a way to mark places where we do that.
---
 lightningd/channel.c | 10 ++++++++++
 lightningd/channel.h | 10 ++++++++++
 2 files changed, 20 insertions(+)

diff --git a/lightningd/channel.c b/lightningd/channel.c
index 123ca84a5..e0bffb768 100644
--- a/lightningd/channel.c
+++ b/lightningd/channel.c
@@ -956,3 +956,13 @@ void channel_fail_reconnect(struct channel *channel, const char *fmt, ...)
 	err_and_reconnect(channel, tal_vfmt(tmpctx, fmt, ap), 1);
 	va_end(ap);
 }
+
+const struct short_channel_id *
+channel_scid_or_local_alias(const struct channel *chan)
+{
+	assert(chan->scid != NULL || chan->alias[LOCAL] != NULL);
+	if (chan->scid != NULL)
+		return chan->scid;
+	else
+		return chan->alias[LOCAL];
+}
diff --git a/lightningd/channel.h b/lightningd/channel.h
index aabbcf1ff..afd72e4a7 100644
--- a/lightningd/channel.h
+++ b/lightningd/channel.h
@@ -476,6 +476,16 @@ static inline bool channel_has(const struct channel *channel, int f)
 	return channel_type_has(channel->type, f);
 }
 
+/**
+ * Either returns the short_channel_id if it is known or the local alias.
+ *
+ * This is used to refer to a channel by its scid. But sometimes we
+ * don't have a scid yet, e.g., for `zeroconf` channels, so we resort
+ * to referencing it by the local alias, which we have in that case.
+ */
+const struct short_channel_id *
+channel_scid_or_local_alias(const struct channel *chan);
+
 void get_channel_basepoints(struct lightningd *ld,
 			    const struct node_id *peer_id,
 			    const u64 dbid,