D3256: httppeer: basic implementation of capabilities interface

indygreg (Gregory Szorc) phabricator at mercurial-scm.org
Wed Apr 11 23:43:03 UTC 2018


indygreg created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  This is a bit crude. The capabilities mechanism for version 2 of
  the wire protocol is a bit different from version 1. And code
  in core is relying on strings passed to capable() matching strings
  advertised by the "capabilities" wire protocol command. I may
  refactor the internal checking mechanism to be a bit more
  abstract or based on interfaces. Time will tell...

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D3256

AFFECTED FILES
  mercurial/httppeer.py
  tests/test-check-interfaces.py

CHANGE DETAILS

diff --git a/tests/test-check-interfaces.py b/tests/test-check-interfaces.py
--- a/tests/test-check-interfaces.py
+++ b/tests/test-check-interfaces.py
@@ -94,6 +94,8 @@
 
     ziverify.verifyClass(repository.ipeerconnection,
                          httppeer.httpv2peer)
+    ziverify.verifyClass(repository.ipeercapabilities,
+                         httppeer.httpv2peer)
     checkzobject(httppeer.httpv2peer(None, '', None, None, None, None))
 
     ziverify.verifyClass(repository.ipeerbase,
diff --git a/mercurial/httppeer.py b/mercurial/httppeer.py
--- a/mercurial/httppeer.py
+++ b/mercurial/httppeer.py
@@ -517,7 +517,7 @@
         raise exception
 
 # TODO implement interface for version 2 peers
- at zi.implementer(repository.ipeerconnection)
+ at zi.implementer(repository.ipeerconnection, repository.ipeercapabilities)
 class httpv2peer(object):
     def __init__(self, ui, repourl, apipath, opener, requestbuilder,
                  apidescriptor):
@@ -552,6 +552,33 @@
 
     # End of ipeerconnection.
 
+    # Start of ipeercapabilities.
+
+    def capable(self, name):
+        # The capabilities used internally historically map to capabilities
+        # advertised from the "capabilities" wire protocol command. However,
+        # version 2 of that command works differently.
+
+        # Maps to commands that are available.
+        if name in ('branchmap', 'getbundle', 'known', 'lookup', 'pushkey'):
+            return True
+
+        # Other concepts.
+        if name in ('bundle2',):
+            return True
+
+        return False
+
+    def requirecap(self, name, purpose):
+        if self.capable(name):
+            return
+
+        raise error.CapabilityError(
+            _('cannot %s; client or remote repository does not support the %r '
+              'capability') % (purpose, name))
+
+    # End of ipeercapabilities.
+
     # TODO require to be part of a batched primitive, use futures.
     def _call(self, name, **args):
         """Call a wire protocol command with arguments."""



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