treemanifest: add local pack store to unionstore

Summary:
In a future patch we will start writing user local tree data into a local
directory. This patches add the local store to the union store so the contents
will be accessible once we start writing it.

It also renames manifest to manifests for consistency with the other store names
(like 'packs').

Test Plan: Ran the tests

Reviewers: #mercurial, quark

Reviewed By: quark

Subscribers: mjpieters

Differential Revision: https://phabricator.intern.facebook.com/D4055827

Signature: t1:4055827:1477059457:0d5b0d999b47d88c73f5ab2721d8d27deacc01bc

remotefilelog/shallowutil.py

@@ -68,6 +68,9 @@ def getcachepackpath(repo, category):
     else:
         return os.path.join(cachepath, repo.name, 'packs')
 
+def getlocalpackpath(base, category):
+    return os.path.join(base, 'packs', category)
+
 def createrevlogtext(text, copyfrom=None, copyrev=None):
     """returns a string that matches the revlog contents in a
     traditional revlog

treemanifest/__init__.py

@@ -26,7 +26,7 @@ import struct
 cmdtable = {}
 command = cmdutil.command(cmdtable)
 
-PACK_CATEGORY='manifest'
+PACK_CATEGORY='manifests'
 
 def extsetup(ui):
     extensions.wrapfunction(changegroup.cg1unpacker, '_unpackmanifests',
@@ -39,11 +39,17 @@ def wraprepo(repo):
     if not isinstance(repo, localrepo.localrepository):
         return
 
+    usecdatapack = repo.ui.configbool('remotefilelog', 'fastdatapack')
+
     packpath = shallowutil.getcachepackpath(repo, PACK_CATEGORY)
-    datastore = datapackstore(
-        packpath,
-        usecdatapack=repo.ui.configbool('remotefilelog', 'fastdatapack'))
-    repo.svfs.manifestdatastore = unioncontentstore(datastore)
+    datastore = datapackstore(packpath, usecdatapack=usecdatapack)
+
+    localpackpath = shallowutil.getlocalpackpath(repo.svfs.vfs.base,
+                                                 PACK_CATEGORY)
+    localdatastore = datapackstore(localpackpath, usecdatapack=usecdatapack)
+
+    repo.svfs.manifestdatastore = unioncontentstore(localdatastore, datastore,
+        writestore=localdatastore)
 
 def _unpackmanifests(orig, self, repo, *args, **kwargs):
     mf = repo.manifest