unbundle20: retrieve unbundler instances through a factory function

To support multiple bundle2 formats, we will need a function returning
the proper unbundler according to the header. We introduce such aa
function and change the usage in the code base. The function will get
smarter in later changesets.

This is somewhat similar to the dispatching we do for 'HG10' and 'HG11'.

The main target is to allow HG2Y support in an extension to ease transition of
companies using the experimental protocol in production (yeah...) But I've no
doubt this will be useful when playing with a future HG21.

mercurial/bundle2.py

@@ -521,6 +521,10 b' class unpackermixin(object):'
         if util.safehasattr(self._fp, 'close'):
             return self._fp.close()
 
+def getunbundler(ui, fp, header=None):
+    """return a valid unbundler object for a given header"""
+    return unbundle20(ui, fp, header)
+
 class unbundle20(unpackermixin):
     """interpret a bundle2 stream
 

mercurial/exchange.py

@@ -33,7 +33,7 b' def readbundle(ui, fh, fname, vfs=None):'
             alg = changegroup.readexactly(fh, 2)
         return changegroup.cg1unpacker(fh, alg)
     elif version == '2Y':
-        return bundle2.unbundle20(ui, fh, header=magic + version)
+        return bundle2.getunbundler(ui, fh, header=magic + version)
     else:
         raise util.Abort(_('%s: unknown bundle version %s') % (fname, version))
 

mercurial/localrepo.py

@@ -114,7 +114,7 b' class localpeer(peer.peerrepository):'
             # When requesting a bundle2, getbundle returns a stream to make the
             # wire level function happier. We need to build a proper object
             # from it in local peer.
-            cg = bundle2.unbundle20(self.ui, cg)
+            cg = bundle2.getunbundler(self.ui, cg)
         return cg
 
     # TODO We might want to move the next two calls into legacypeer and add
@@ -132,7 +132,7 b' class localpeer(peer.peerrepository):'
                 # This little dance should be dropped eventually when the API
                 # is finally improved.
                 stream = util.chunkbuffer(ret.getchunks())
-                ret = bundle2.unbundle20(self.ui, stream)
+                ret = bundle2.getunbundler(self.ui, stream)
             return ret
         except error.PushRaced, exc:
             raise error.ResponseError(_('push failed:'), str(exc))

mercurial/wireproto.py

@@ -364,7 +364,7 b' class wirepeer(peer.peerrepository):'
         f = self._callcompressable("getbundle", **opts)
         bundlecaps = kwargs.get('bundlecaps')
         if bundlecaps is not None and 'HG2Y' in bundlecaps:
-            return bundle2.unbundle20(self.ui, f)
+            return bundle2.getunbundler(self.ui, f)
         else:
             return changegroupmod.cg1unpacker(f, 'UN')
 
@@ -401,7 +401,7 b' class wirepeer(peer.peerrepository):'
         else:
             # bundle2 push. Send a stream, fetch a stream.
             stream = self._calltwowaystream('unbundle', cg, heads=heads)
-            ret = bundle2.unbundle20(self.ui, stream)
+            ret = bundle2.getunbundler(self.ui, stream)
         return ret
 
     def debugwireargs(self, one, two, three=None, four=None, five=None):

tests/test-bundle2-format.t

@@ -157,7 +157,7 b' Create an extension to test bundle2 API'
   >         lock = repo.lock()
   >         tr = repo.transaction('processbundle')
   >         try:
-  >             unbundler = bundle2.unbundle20(ui, sys.stdin)
+  >             unbundler = bundle2.getunbundler(ui, sys.stdin)
   >             op = bundle2.processbundle(repo, unbundler, lambda: tr)
   >             tr.close()
   >         except error.BundleValueError, exc:
@@ -183,7 +183,7 b' Create an extension to test bundle2 API'
   > @command('statbundle2', [], '')
   > def cmdstatbundle2(ui, repo):
   >     """print statistic on the bundle2 container read from stdin"""
-  >     unbundler = bundle2.unbundle20(ui, sys.stdin)
+  >     unbundler = bundle2.getunbundler(ui, sys.stdin)
   >     try:
   >         params = unbundler.params
   >     except error.BundleValueError, exc: