wireproto: use CBOR for command requests
Now that we're using CBOR in the new wire protocol, let's convert
command requests to it.
Before I wrote this patch and was even thinking about CBOR, I was
thinking about how commands should be issued and came to the
conclusion that we didn't need separate frames to represent the
command name from its arguments. I already had a partially
completed patch prepared to merge the frames.
But with CBOR, it makes the implementation a bit simpler because
we don't need to roll our own serialization.
The changes here are a bit invasive. I tried to split this into
multiple commits to make it easier to review. But it was just too
hard.
* "command name" and "command argument" frames have been collapsed
into a "command request" frame.
* The flags for this new frame are totally different.
* Frame processing has been overhauled to reflect the new order
of things.
* Test fallout was significant. A handful of tests were removed.
Altogether, I think the new code is simpler. We don't have
complicated state around receiving commands. We're either receiving
command request frames or command data frames. We /could/
potentially collapse command data frames into command request
frames. Although I'd have to think a bit more about this before
I do it.
Differential Revision: https://phab.mercurial-scm.org/D2951
#if no-windows no-osx
$ mkdir -p xdgconf/hg
$ echo '[ui]' > xdgconf/hg/hgrc
$ echo 'username = foobar' >> xdgconf/hg/hgrc
$ XDG_CONFIG_HOME="`pwd`/xdgconf" ; export XDG_CONFIG_HOME
$ unset HGRCPATH
$ hg config ui.username 2>/dev/null
foobar
#endif