revlog: fix reading of larger revlog indices on Windows

mercurial/revlog.py

@@ -322,7 +322,7 b' class revlogoldio(object):'
         index = []
         nodemap =  {nullid: nullrev}
         n = off = 0
-        if len(data) < _prereadsize:
+        if len(data) == _prereadsize:
             data += fp.read() # read the rest
         l = len(data)
         while off + s <= l:
@@ -362,14 +362,8 b' class revlogio(object):'
         self.size = struct.calcsize(indexformatng)
 
     def parseindex(self, fp, data, inline):
-        try:
-            size = len(data)
-            if size == _prereadsize:
-                size = util.fstat(fp).st_size
-        except AttributeError:
-            size = 0
-
-        if util.openhardlinks() and not inline and size > _prereadsize:
+        if len(data) == _prereadsize:
+            if util.openhardlinks() and not inline:
             # big index, let's parse it on demand
             parser = lazyparser(fp, size)
             index = lazyindex(parser)
@@ -379,6 +373,8 b' class revlogio(object):'
             e[0] = offset_type(0, type)
             index[0] = e
             return index, nodemap, None
+            else:
+                data += fp.read()
 
         # call the C implementation to parse the index data
         index, nodemap, cache = parsers.parse_index(data, inline)