[PATCH 1 of 6 V2 RFC] localrepo: introduce shared method to check if a repository is shared

[Angel Ezquerra]

# HG changeset patch
# User Angel Ezquerra <angel.ezquerra at gmail.com>
# Date 1419117550 -3600
#      Sun Dec 21 00:19:10 2014 +0100
# Node ID b213f4439d5427cfff6c7fa28927c25e4422a948
# Parent  67d63ec85eb72187508692e52f14be46101707a5
localrepo: introduce shared method to check if a repository is shared

Up until now we compared the "path" and "sharedpath" repository properties to
check if a repository is shared. This was relying an implementation detail of
shared repositories. In order to make it possible to change the way shared
repositories are implemented, we encapsulate this check into its own localrepo
method, called shared.

This new method returns None if the repository is shared, and something else
(for now a string describing the short of share) otherwise.

The reason why I did not call this method "isshared" and made it return a
boolean is that I plan to introduce a new type of shared repository soon.

# NOTES:

This is the first patch in a series whose purpose is to add support for
creating "full repository shares", which are repositories that share everything
with the repository source except their current revision, branch and bookmark.

This series is RFC because I am not very sure of some of the solutions I took.
Comments are welcome!

diff --git a/hgext/share.py b/hgext/share.py
--- a/hgext/share.py
+++ b/hgext/share.py
@@ -46,7 +46,7 @@
     Copy the store data to the repo and remove the sharedpath data.
     """
 
-    if repo.sharedpath == repo.path:
+    if not repo.shared():
         raise util.Abort(_("this is not a shared repo"))
 
     destlock = lock = None
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -758,6 +758,12 @@
         # if publishing we can't copy if there is filtered content
         return not self.filtered('visible').changelog.filteredrevs
 
+    def shared(self):
+        '''the type of shared repository (None if not shared)'''
+        if self.sharedpath != self.path:
+            return 'store'
+        return None
+
     def join(self, f, *insidef):
         return os.path.join(self.path, f, *insidef)
 
diff --git a/mercurial/subrepo.py b/mercurial/subrepo.py
--- a/mercurial/subrepo.py
+++ b/mercurial/subrepo.py
@@ -302,7 +302,7 @@
             return repo.ui.config('paths', 'default-push')
         if repo.ui.config('paths', 'default'):
             return repo.ui.config('paths', 'default')
-        if repo.sharedpath != repo.path:
+        if repo.shared():
             # chop off the .hg component to get the default path form
             return os.path.dirname(repo.sharedpath)
     if abort: