[PATCH 3 of 6] shrink-revlog: add --sort option for user-selectable toposort algorithm

[Greg Ward]

# HG changeset patch
# User Greg Ward <greg-hg at gerg.ca>
# Date 1267107399 18000
# Node ID c0411bca1d9814aec5fe6869da5ecaed32997484
# Parent  f57e0059b98dc348537b0470f1a9d5880658ea04
shrink-revlog: add --sort option for user-selectable toposort algorithm.

diff --git a/contrib/shrink-revlog.py b/contrib/shrink-revlog.py
old mode 100755
new mode 100644
--- a/contrib/shrink-revlog.py
+++ b/contrib/shrink-revlog.py
@@ -24,7 +24,7 @@
 from mercurial import changegroup
 from mercurial.i18n import _
 
-def toposort(ui, rl):
+def toposort_branchsort(ui, rl):
 
     children = {}
     root = []
@@ -131,9 +131,18 @@
              % (shrink_percent, shrink_factor))
 
 def shrink(ui, repo, **opts):
+    """shrink a revlog by reordering revisions
+
+    Rewrites all the entries in some revlog of the current repository
+    (by default, the manifest log) to save space.
+
+    Different sort algorithms have different performance
+    characteristics.  Use ``--sort`` to select a sort algorithm so you
+    can determine which works best for your data.  The default
+    algorithm, ``branchsort``, works well for workflows with lots of
+    active (unmerged) branches, but not so well when all branches have
+    been merged and there is only one repository head.
     """
-    Shrink revlog by re-ordering revisions. Will operate on manifest for
-    the given repository if no other revlog is specified."""
 
     if not repo.local():
         raise util.Abort(_('not a local repository: %s') % repo.root)
@@ -152,6 +161,12 @@
             raise util.Abort(_('--revlog option must specify a revlog in %s, '
                                'not %s') % (store, indexfn))
 
+    sortname = opts['sort']
+    try:
+        toposort = globals()['toposort_' + sortname]
+    except KeyError:
+        raise util.Abort(_('no such toposort algorithm: %s') % sortname)
+
     if not os.path.exists(indexfn):
         raise util.Abort(_('no such file: %s') % indexfn)
     if '00changelog' in indexfn:
@@ -242,6 +257,7 @@
     'shrink': (shrink,
                [('', 'revlog', '', _('index (.i) file of the revlog to shrink')),
                 ('n', 'dry-run', None, _('do not shrink, simulate only')),
+                ('', 'sort', 'branchsort', 'name of sort algorithm to use'),
                 ],
                _('hg shrink [--revlog PATH]'))
 }