delay the creation of the new state and journal until there is actually
something interesting to write. this saves some cpu cycles and prolongs
ssd life a whee bit.
now that expiration order is determined by a single loop ordered by
far-side UIDs, it is no longer necessary to accurately track the highest
seen UID.
as a side effect, this fixes a problem reported (way too long ago) by
Yuri D'Elia: we failed to up newmaxuid for messages we produced
ourselves, so we would keep enumerating the same messages until we also
propagated externally generated messages from that mailbox - which might
have been never for the server side of archive/trash mailboxes.
the underlying metaphor refers to an inhumane practice, so using it
casually is rightfully offensive to many people. it isn't even a
particularly apt metaphor, as it suggests a strict hierarchy that is
counter to mbsync's highly symmetrical mode of operation.
the far/near terminology has been chosen as the replacement, as it is a
natural fit for the push/pull terminology. on the downside, due to these
not being nouns, a few uses are a bit awkward, and several others had to
be amended to include 'side'. also, it's conceptually quite close to
remote/local, which matches the typical use case, but is maybe a bit too
suggestive of actually non-existing limitations.
the new f/n suffixes of the -C/-R/-X options clash with pre-existing
options, so direct concatenation of short options is even less practical
than before (some suffixes of -D already clashed), but doing that leads
to unreadable command lines anyway.
as with previous deprecations, all pre-existing command line and config
options keep working, but yield a warning. the state files are silently
upgraded.
an effect of 7ce658d is that we can index messages by UID rather than
content (or more specifically, subject). apart from being cleaner, it
allows duplicated subjects.
on modern systems, this makes it likely to end up on tmpfs, which is a
lot faster and ssd-friendlier.
the symlink is not deleted at the end, to minimize fs churn. that means
it will be dangling after a reboot, which gets fixed in the next run.
the only legitimate "deviant" UID is zero, meaning "no message". this
can be futher qualified by additional flags in the sync record, rather
than using magic values for the UID. in fact, the zero UID (so far
meaning only "expunged") was already optionally qualifed with "expired".
as a side effect, driver->store_msg() now returns 0 instead of -2 for
unknown UIDs. this was a hack to avoid translating the value later
on, but it made the api horrible, and now it's superflous in the first
place.
this ensures stable results when the boxes are used with different
OPEN_FLAGS (which will happen in a subsequent commit), at the negligible
cost of removing the implicit test of the maildir driver's ability to
enumerate new messages.
introduce recognition of $USE_VALGRIND to run all mbsync invocations
through valgrind.
this also removes the seemingly purposeless --log-fd=3 indirection.
this helps enormously on the first sync of a 100k message box with a
limit of 1k messages. it also happens to make the syncing idempotent.
in a few conditionals we now explicitly test for max_messages being
enabled, not smaxxuid != 0, as after the initial fetch with no important
messages smaxxuid is zero, but we still have to skip over 99k messages
in the above case.
the removed code would only ever trigger if a) we were after a journal
replay or b) something external expunged the expired messages - both are
corner cases not worth the extra code.
however, this means that the syncing code further down now needs to take
care of these zombies.
in the end, the normal cleanup will take care of all expired entries,
new and old.
the header is not space-critical, so use proper name-value pairs.
this has the additional advantage that subsequent format changes can be
done much easier.
this value is only ever used to find just pushed messages by TUID, so we
can simply use the UIDNEXT value from before we started pushing - and of
course, we need to record that in the journal. it makes no sense to log
the new value after completing a search, as there won't be a next search
before we push the next messages.
files may be renamed (due to new -> cur transition or flag changes),
which may lead to two effects if ignored:
- we see both the old and the new name, so we report a spurious
duplicate UID
- we see neither name, so we report a spurious deletion
as countermeasure, record and compare directory modification times. upon
mismatch, we just start over - as usual.
instead of SEARCHing every single message (which is slow and happens to
be unreliabe with M$ Exchange 2010), just FETCH the new messages from
the mailbox - the ones we just appended will be amongst them.
