sshpeer: use peer interface

sshpeer: use peer interface

We need the same @property conversion of ui like we did for localpeer.
We renamed _capabilities() to capabilities() to satisfy the new
naming requirement.

However, since we're inheriting from wireproto.wirepeer which inherits
from peer.peerrepository and provides its own code accessing
_capabilities(), we need to keep the old alias around. This wonkiness
will disappear once wirepeer is cleaned up in subsequent commits.

We also implement methods for basepeer that are identical to the
defaults in peer.peerrepository in preparation for the removal of
peerrepository.

Differential Revision: https://phab.mercurial-scm.org/D336

--- a/mercurial/sshpeer.py	Wed Aug 09 23:52:25 2017 -0700
+++ b/mercurial/sshpeer.py	Sun Aug 06 17:59:48 2017 -0700
@@ -13,6 +13,7 @@
 from . import (
     error,
     pycompat,
+    repository,
     util,
     wireproto,
 )
@@ -114,10 +115,10 @@
     def flush(self):
         return self._main.flush()
 
-class sshpeer(wireproto.wirepeer):
+class sshpeer(wireproto.wirepeer, repository.legacypeer):
     def __init__(self, ui, path, create=False):
         self._url = path
-        self.ui = ui
+        self._ui = ui
         self._pipeo = self._pipei = self._pipee = None
 
         u = util.url(path, parsequery=False, parsefragment=False)
@@ -150,9 +151,39 @@
 
         self._validaterepo(sshcmd, args, remotecmd)
 
+        # TODO remove this alias once peerrepository inheritance is removed.
+        self._capabilities = self.capabilities
+
+    # Begin of _basepeer interface.
+
+    @util.propertycache
+    def ui(self):
+        return self._ui
+
     def url(self):
         return self._url
 
+    def local(self):
+        return None
+
+    def peer(self):
+        return self
+
+    def canpush(self):
+        return True
+
+    def close(self):
+        pass
+
+    # End of _basepeer interface.
+
+    # Begin of _basewirecommands interface.
+
+    def capabilities(self):
+        return self._caps
+
+    # End of _basewirecommands interface.
+
     def _validaterepo(self, sshcmd, args, remotecmd):
         # cleanup up previous run
         self._cleanup()
@@ -200,9 +231,6 @@
                 self._caps.update(l[:-1].split(":")[1].split())
                 break
 
-    def _capabilities(self):
-        return self._caps
-
     def _readerr(self):
         _forwardoutput(self.ui, self._pipee)