# HG changeset patch
# User Matt Mackall <mpm@selenic.com>
# Date 2014-04-07 19:18:10
# Node ID 469d949a7cb8d20e0fee7464c3b12dcac1e55d4c
# Parent  e9725e18bdf8eaebbdd3a5a4b4dba66e615d5574

revlog: deal with chunk ranges over 2G on Windows (issue4215)

Python uses a C long (32 bits on Windows 64) rather than an ssize_t in
read(), and thus has a 2G size limit. Work around this by falling back
to reading one chunk at a time on overflow. This approximately doubles
our headroom until we run back into the size limit on single reads.

diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -909,8 +909,13 @@ class revlog(object):
         ladd = l.append
 
         # preload the cache
-        self._chunkraw(revs[0], revs[-1])
-        offset, data = self._chunkcache
+        try:
+            self._chunkraw(revs[0], revs[-1])
+            offset, data = self._chunkcache
+        except OverflowError:
+            # issue4215 - we can't cache a run of chunks greater than
+            # 2G on Windows
+            return [self._chunk(rev) for rev in revs]
 
         for rev in revs:
             chunkstart = start(rev)