ExternalMethod.__call__(): Fixed DevelopmentMode behavior so it didn't

reload extenal method files every time.

The problem was that the entire os.stat() record was being compared,
and that includes the access time, which of course changes every time
the method is loaded - self fulfilling prophecy, and all.

Instead, we now just stash and compare the modification time
(ST_MTIME) field, and get rid of the extraneous (expensive) reloads.

lib/python/Products/ExternalMethod/ExternalMethod.py

@@ -88,12 +88,12 @@
 This product provides support for external methods, which allow
 domain-specific customization of web environments.
 """
-__version__='$Revision: 1.31 $'[11:-2]
+__version__='$Revision: 1.32 $'[11:-2]
 from Acquisition import Explicit
 from Globals import Persistent, HTMLFile, MessageDialog, HTML
 import OFS.SimpleItem
 from string import split, join, find, lower
-import AccessControl.Role, sys, os, traceback
+import AccessControl.Role, sys, os, stat, traceback
 from OFS.SimpleItem import pretty_tb
 from App.Extensions import getObject, getPath, FuncCode
 from Globals import DevelopmentMode
@@ -231,9 +231,10 @@ class ExternalMethod(OFS.SimpleItem.Item, Persistent, Explicit,
         """
 
         if DevelopmentMode:
-            ts=os.stat(self.filepath())
-            if not hasattr(self, '_v_last_read') or \
-               (ts != self._v_last_read):
+            # If the file has been modified since last loaded, force a reload.
+            ts=os.stat(self.filepath())[stat.ST_MTIME]
+            if (not hasattr(self, '_v_last_read') or 
+                (ts != self._v_last_read)):
                 self._v_f=self.getFunction(1,1)
                 self._v_last_read=ts