[PATCH 2 of 5] revlog: support closing files via a caller-specified mechanism

[Gregory Szorc]

# HG changeset patch
# User Gregory Szorc <gregory.szorc at gmail.com>
# Date 1443487562 25200
#      Mon Sep 28 17:46:02 2015 -0700
# Node ID 6433c97a719dec3532379deec5cc178270b0cdc6
# Parent  f578fedbeb3ce63fff0e3fdbe7b2424e9cdd399a
revlog: support closing files via a caller-specified mechanism

This patch allows addgroup() to receive a function that will be called
in lieu of closing the handles within addgroup(). We will soon hook this
up to the file closer utility that was just introduced.

diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -1441,9 +1441,10 @@ class revlog(object):
             ifh.write(data[0])
             ifh.write(data[1])
             self.checkinlinesize(transaction, ifh)
 
-    def addgroup(self, bundle, linkmapper, transaction, addrevisioncb=None):
+    def addgroup(self, bundle, linkmapper, transaction, addrevisioncb=None,
+                 closecb=None):
         """
         add a delta group
 
         given a set of deltas, add them to the revision log. the
@@ -1451,8 +1452,12 @@ class revlog(object):
         log, the rest are against the previous delta.
 
         If ``addrevisioncb`` is defined, it will be called with arguments of
         this revlog and the node that was added.
+
+        If ``closecb`` is defined, it will be called with open file handles
+        that will no longer be used and the file handles will not be closed
+        by this function.
         """
 
         # track the base of the current delta log
         content = []
@@ -1540,11 +1545,16 @@ class revlog(object):
                     ifh.close()
                     dfh = self.opener(self.datafile, "a+")
                     ifh = self.opener(self.indexfile, "a+")
         finally:
-            if dfh:
-                dfh.close()
-            ifh.close()
+            if closecb:
+                if dfh:
+                    closecb(dfh)
+                closecb(ifh)
+            else:
+                if dfh:
+                    dfh.close()
+                ifh.close()
 
         return content
 
     def iscensored(self, rev):