* lib/db, lib/protocol: Compact FileInfo and BlockInfo alignment
This fixes the following two lint warnings
FileInfo: struct of size 160 bytes could be of size 136 bytes
BlockInfo: struct of size 48 bytes could be of size 40 bytes
by reordering fields in alignment order (64 bit fields, then 32 bit
fields, then 16 bit fields (if any), then small ones). The end result is
a slightly less aesthetically pleasing struct field order, but since
these are the objects we often juggle in bulk and keep large queues of I
think it's worth it.
It's a micro optimization, but a cheap one.
This adds error returns to model methods called by the protocol layer.
Returning an error will cause the connection to be torn down as the
message couldn't be handled. Using this to signal that a folder isn't
currently available will then cause a reconnection a few moments later,
when it'll hopefully work better.
Tested manually by running with STRECHECKDBEVERY=0 on a nontrivially
sized setup. This panics reliably before this patch, but just causes a
disconnect/reconnect now.
As foretold by the prophecy, "once the database refactor is merged, then
shall appear a request to propagate errors from the store known
throughout the land as the NamedspacedKV, and it shall be good".
This PR does two things, because one lead to the other:
- Move the leveldb specific stuff into a small "backend" package that
defines a backend interface and the leveldb implementation. This allows,
potentially, in the future, switching the db implementation so another
KV store should we wish to do so.
- Add proper error handling all along the way. The db and backend
packages are now errcheck clean. However, I drew the line at modifying
the FileSet API in order to keep this manageable and not continue
refactoring all of the rest of Syncthing. As such, the FileSet methods
still panic on database errors, except for the "database is closed"
error which is instead handled by silently returning as quickly as
possible, with the assumption that we're anyway "on the way out".
Since we've taken upon ourselves to create a log file by default on
Windows, this adds proper management of that log file. There are two new
options:
-log-max-old-files="3" Number of old files to keep (zero to keep only current).
-log-max-size="10485760" Maximum size of any file (zero to disable log rotation).
The default values result in four files (syncthing.log, synchting.0.log,
..., syncthing.3.log) each up to 10 MiB in size. To not use log rotation
at all, the user can say --log-max-size=0.
