matcher: make e.g. 'relpath:.' lead to fast paths
Several commands take the fast path when match.always() is
true. However, when the user passes "." on the command line, that
results in a matcher for which match.always() == False. Let's make it
so such matchers return True, and have an empty list of .files(). This
makes e.g. "hg log ." as fast as "hg log" and "hg revert ." as fast as
"hg revert --all" (when run from repo root).
$ cat > engine.py << EOF
>
> from mercurial import templater
>
> class mytemplater(object):
> def __init__(self, loader, filters, defaults):
> self.loader = loader
>
> def process(self, t, map):
> tmpl = self.loader(t)
> for k, v in map.iteritems():
> if k in ('templ', 'ctx', 'repo', 'revcache', 'cache'):
> continue
> if hasattr(v, '__call__'):
> v = v(**map)
> v = templater.stringify(v)
> tmpl = tmpl.replace('{{%s}}' % k, v)
> yield tmpl
>
> templater.engines['my'] = mytemplater
> EOF
$ hg init test
$ echo '[extensions]' > test/.hg/hgrc
$ echo "engine = `pwd`/engine.py" >> test/.hg/hgrc
$ cd test
$ cat > mymap << EOF
> changeset = my:changeset.txt
> EOF
$ cat > changeset.txt << EOF
> {{rev}} {{node}} {{author}}
> EOF
$ hg ci -Ama
adding changeset.txt
adding mymap
$ hg log --style=./mymap
0 97e5f848f0936960273bbf75be6388cd0350a32b test
$ cat > changeset.txt << EOF
> {{p1rev}} {{p1node}} {{p2rev}} {{p2node}}
> EOF
$ hg ci -Ama
$ hg log --style=./mymap
0 97e5f848f0936960273bbf75be6388cd0350a32b -1 0000000000000000000000000000000000000000
-1 0000000000000000000000000000000000000000 -1 0000000000000000000000000000000000000000
$ cd ..