# HG changeset patch
# User Eamonn Kent <ekent@fb.com>
# Date 1507568976 25200
# Node ID b79f59425964aa67c382f20557cef9ddc176e394
# Parent  1faa34347b247d710b4207ad8a95d744c5c9b3ea
fsmonitor: change the distance calculation

Change the distance calculation in the fsmonitor extension. It is done
in a method since anticipated changes will need to use this logic as well.

Test Plan:
Tested on development server.

Differential Revision: https://phab.mercurial-scm.org/D988

diff -r 1faa34347b24 -r b79f59425964 hgext/fsmonitor/__init__.py
--- a/hgext/fsmonitor/__init__.py	Mon Oct 09 16:31:43 2017 +0200
+++ b/hgext/fsmonitor/__init__.py	Mon Oct 09 10:09:36 2017 -0700
@@ -660,6 +660,14 @@
                 'watchman', 'Exception %s while running %s\n', e, cmd)
             return False
 
+# Estimate the distance between two nodes
+def calcdistance(repo, oldnode, newnode):
+    anc = repo.changelog.ancestor(oldnode, newnode)
+    ancrev = repo[anc].rev()
+    distance = (abs(repo[oldnode].rev() - ancrev)
+        + abs(repo[newnode].rev() - ancrev))
+    return distance
+
 # Bracket working copy updates with calls to the watchman state-enter
 # and state-leave commands.  This allows clients to perform more intelligent
 # settling during bulk file change scenarios
@@ -671,14 +679,8 @@
     partial = True
     if matcher is None or matcher.always():
         partial = False
-        wc = repo[None]
-        parents = wc.parents()
-        if len(parents) == 2:
-            anc = repo.changelog.ancestor(parents[0].node(), parents[1].node())
-            ancrev = repo[anc].rev()
-            distance = abs(repo[node].rev() - ancrev)
-        elif len(parents) == 1:
-            distance = abs(repo[node].rev() - parents[0].rev())
+        distance = calcdistance(repo.unfiltered(), repo['.'].node(),
+                                repo[node].node())
 
     with state_update(repo, node, distance, partial):
         return orig(