dirstate: add a function to compute non-normal entries from the dmap

This patch adds a new python function in the dirstate to compute the set of
non-normal files from the dmap. These files are useful to compute the repository
status.

mercurial/dirstate.py

@@ -49,6 +49,11 b' def _getfsnow(vfs):'
         os.close(tmpfd)
         vfs.unlink(tmpname)
 
+def nonnormalentries(dmap):
+    '''Compute the nonnormal dirstate entries from the dmap'''
+    return set(fname for fname, e in dmap.iteritems()
+           if e[0] != 'n' or e[3] == -1)
+
 def _trypending(root, vfs, filename):
     '''Open  file to be read according to HG_PENDING environment variable