view contrib/plan9/proto @ 40589:054d0fcba2c4

commandserver: add experimental option to use separate message channel

This is loosely based on the idea of the TortoiseHg's pipeui extension,
which attaches ui.label to message text so the command-server client can
capture prompt text, for example.

https://bitbucket.org/tortoisehg/thg/src/4.7.2/tortoisehg/util/pipeui.py

I was thinking that this functionality could be generalized to templating,
but changed mind as doing template stuff would be unnecessarily complex.
It's merely a status message, a simple serialization option should suffice.

Since this slightly changes the command-server protocol, it's gated by a
config knob. If the config is enabled, and if it's supported by the server,
"message-encoding: <name>" is advertised so the client can stop parsing
'o'/'e' channel data and read encoded messages from the 'm' channel. As we
might add new message encodings in future releases, client can specify a list
of encoding names in preferred order.

This patch includes 'cbor' encoding as example. Perhaps, 'json' should be
supported as well.

lib	- sys sys
	mercurial	- sys sys
		hgrc.d	- sys sys
			9diff.rc	- sys sys
			factotum.rc	- sys sys
rc	- sys sys
	bin	- sys sys
		9diff	- sys sys
		hg	- sys sys
sys	- sys sys
	lib	- sys sys
		python	- sys sys
			lib	- sys sys
				python2.5	- sys sys
					site-packages	- sys sys
						hgext	- sys sys
							+	- sys sys
						mercurial	- sys sys
							+	- sys sys
						mercurial-VERSION-py2.5.egg-info	- sys sys
	src	- sys sys
		cmd	- sys sys
			hg	- sys sys
				+	- sys sys