leave all the hard work to OpenSSL. this has several consequences:
- certificate chain validation actually works instead of throwing
around error 20
- the interactive approval is gone. i don't expect it to be useful
anyway, as mbsync is mostly a batch tool
- the code is much shorter
this removes the pathological O(<number of sync records> * <number of
new messages>) case at the cost of being a bit more cpu-intensive (but
O(<number of all messages>)) for old messages.
when we find that the store is incompatible with in-store sync state,
we want to fail the whole channel. however, we must not claim that the
store died, otherwise it won't be disposed of properly.
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.
- introduce sys_error() and use it instead of perror() and
error(strerror()) in all expected error conditions
- perror() is used only for "something's really wrong with the system"
kind of errors
- file names, etc. are quoted if they are not validated yet, so e.g. an
empty string becomes immediately obvious
- improve and unify language
- add missing newlines
- asynchronous sockets using an event loop
- connect & starttls have completion callback parameters
- callbacks for notification about filled input buffer and emptied
output buffer
- unsent imap command queue
- used when
- socket output buffer is non-empty
- number of commands in flight exceeds limit
- last sent command requires round-trip
- command has a dependency on completion of previous command
- trashnc is tri-state so only a single "scout" trash APPEND/COPY is
sent at first. a possibly resulting CREATE is injected in front of
the remaining trash commands, so they can succeed (or be cancel()d
if it fails).
- queue's presence necessitates imap_cancel implementation
this prepares the code for being called from a callback.
notably, this makes the imap list parser have a "soft stack", so the
recursion can be suspended at any time.
synchronous error codes which are passed through callbacks aren't a
particularly good idea, after all: latest when the callback does stuff
which does not concern the caller, the return code becomes ambiguous.
instead, protect the sync_vars object with a refcount when invoking
driver functions from loops, as the callbacks they call could invalidate
the object and we would have no way of knowing that the loop should be
aborted prematurely. the upcoming async imap driver will also need a
refcount to protect the cancelation marker of the imap socket dispatcher
loop.
that way we don't have to piggy-back (possibly asynchronous) fatal
errors to particular commands.
internally, the drivers still use synchronous return values as well,
so they don't try to access the invalidated store after calling back.
imap may very well store messages with LF line endings. only RFC2822
requires CRLF.
consequently, preserve the line endings as much as possible unless the
mailbox format does not support it (this would be the case for unix mbox
- i actually have no idea about maildir).
- wrap message (un)expirations into transactions
- no redundand flag propagations in conjunction with expirations
- better prepared for the upcoming async operation
