This stores and reads the channel_announcements in the wrapping message which
allows us to store associated data with the raw channel_announcements.
The gossip_store applies channel_announcements directly but it also returns it,
and it gets discarded as a duplicate. In the next commit we'll have gossip_store
apply all changes, bypassing verification, so the duplication is only temporary.
Signed-off-by: Christian Decker <decker.christian@gmail.com>
Since we now store additional data along with the original messages they exceed
the length of the peer wire protocol messages.
Signed-off-by: Christian Decker <decker.christian@gmail.com>
If we have a non-empty file and the version doesn't match, then we truncate and
write our own version. If the file is empty we write our version and the
truncate becomes a no-op
Signed-off-by: Christian Decker <decker.christian@gmail.com>
As proposed by @rustyrussell this makes it a bit easier to truncate and sync on
read errors.
Signed-off-by: Christian Decker <decker.christian@gmail.com>