This has the following upsides:
- We can now routes WHO replies to the correct client, without
broadcasting them to everybody.
- We are less likely to hit server rate limits when multiple downstreams
are issuing WHO commands at the same time.
The message stores don't need to access the internal network
struct, they just need network metadata such as ID and name.
This can ease moving message stores into a separate package in the
future.
This is a mecanical change, which just lifts up the context.TODO()
calls from inside the DB implementations to the callers.
Future work involves properly wiring up the contexts when it makes
sense.
This allows users to set a default realname used if the per-network
realname isn't set.
A new "user update" command is introduced and can be extended to edit
other user properties and other users in the future.
Typically done via:
/notice $<bouncer> <message>
Or, for a connection not bound to a specific network:
/notice $* <message>
The message is broadcast as BouncerServ, because that's the only
user that can be trusted to belong to the bouncer by users. Any
other prefix would conflict with the upstream network.
Instead of ignoring detached channels wehn replaying backlog,
process them as usual and relay messages as BouncerServ NOTICEs
if necessary. Advance the delivery receipts as if the channel was
attached.
Closes: https://todo.sr.ht/~emersion/soju/98
TL;DR: supports for casemapping, now logs are saved in
casemapped/canonical/tolower form
(eg. in the #channel directory instead of #Channel... or something)
== What is casemapping? ==
see <https://modern.ircdocs.horse/#casemapping-parameter>
== Casemapping and multi-upstream ==
Since each upstream does not necessarily use the same casemapping, and
since casemappings cannot coexist [0],
1. soju must also update the database accordingly to upstreams'
casemapping, otherwise it will end up inconsistent,
2. soju must "normalize" entity names and expose only one casemapping
that is a subset of all supported casemappings (here, ascii).
[0] On some upstreams, "emersion[m]" and "emersion{m}" refer to the same
user (upstreams that advertise rfc1459 for example), while on others
(upstreams that advertise ascii) they don't.
Once upstream's casemapping is known (default to rfc1459), entity names
in map keys are made into casemapped form, for upstreamConn,
upstreamChannel and network.
downstreamConn advertises "CASEMAPPING=ascii", and always casemap map
keys with ascii.
Some functions require the caller to casemap their argument (to avoid
needless calls to casemapping functions).
== Message forwarding and casemapping ==
downstream message handling (joins and parts basically):
When relaying entity names from downstreams to upstreams, soju uses the
upstream casemapping, in order to not get in the way of the user. This
does not brings any issue, as long as soju replies with the ascii
casemapping in mind (solves point 1.).
marshalEntity/marshalUserPrefix:
When relaying entity names from upstreams with non-ascii casemappings,
soju *partially* casemap them: it only change the case of characters
which are not ascii letters. ASCII case is thus kept intact, while
special symbols like []{} are the same every time soju sends them to
downstreams (solves point 2.).
== Casemapping changes ==
Casemapping changes are not fully supported by this patch and will
result in loss of history. This is a limitation of the protocol and
should be solved by the RENAME spec.
... so that the JOIN/history batch takes into account all capabilities.
Without this commit for example, enabling multi-prefix after the batch
makes the client send NAMES requests for all channels, which generate
needless traffic.
This uses the fields added previously to the Channel struct to implement
the actual detaching/reattaching/relaying logic.
The `FilterDefault` values of the messages filters are currently
hardcoded.
The values of the message filters are not currently user-settable.
This introduces a new user event, eventChannelDetach, which stores an
upstreamConn (which might become invalid at the time of processing), and
a channel name, used for auto-detaching. Every time the channel detach
timer is refreshed (by receveing a message, etc.), a new timer is
created on the upstreamChannel, which will dispatch this event after the
duration (and discards the previous timer, if any).
Introduce a messageStore type, which will allow for multiple
implementations (e.g. in the DB or in-memory instead of on-disk).
The message store is per-user so that we don't need to deal with locking
and it's easier to implement per-user limits.
Instead, always read chat history from logs. Unify the implicit chat
history (pushing history to clients) and explicit chat history
(via the CHATHISTORY command).
Instead of keeping track of ring buffer cursors for each client, use
message IDs.
If necessary, the ring buffer could be re-introduced behind a
common MessageStore interface (could be useful when on-disk logs are
disabled).
References: https://todo.sr.ht/~emersion/soju/80
Keep the ring buffer alive even if all clients are connected. Keep the
ID of the latest delivered message even for online clients.
As-is, this is a net downgrade: memory usage increases because ring
buffers aren't free'd anymore. However upcoming commits will replace the
ring buffer with log files. This change makes reading from log files
easier.
