Merge from 2.7 branch:

- Add "instance-local" "period" to TransientObjectContainer.  This allows
  users to dial a knob which may (or may not) reduce the number of conflicts
  that happen during heavy sessioning usage by reducing the frequency at
  which buckets potentially expire at the cost of expiration time
  accuracy.  Previously, this setting was hardcoded to 20 (seconds) at
  module scope.

- Add 'session-resolution-seconds' to zope.conf.in/zopeschema.xml to
  control instance-local period for /temp_folder/session_data.

- Update TOC UI, interface, and help files to deal with instance-local
  period.

- Update OFS/Application to deal with instance-local period for default
  /temp/session_data TOC.

- Use __setstate__ for TOC upgrade instead of a dedicated _upgrade method
  (it was too hard to figure out where to call _upgrade from and when to
  call it).

- Perform a few formatting changes that should make it easier to merge the 2.7
  branch with the HEAD going forward.  I beseech those who make formatting
  changes to a branch or the HEAD make them to the other at that time
  as well, especially with the SVN/CVS split it's very painful to do merging
  when there are non-substantive differences between HEAD/maint.  When I was
  a child, I never thought I would need to use the word "beseech", however, it
  has indeed happened.

lib/python/OFS/Application.py

-############################################################################
+##############################################################################
 #
 # Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
 #
@@ -375,9 +375,15 @@ class AppInitializer:
             delnotify = getattr(config, 'session_delete_notify_script_path',
                                 None)
             default_limit = 1000
+            default_period_secs = 20
+            default_timeout_mins = 20
+            
             limit = (getattr(config, 'maximum_number_of_session_objects', None)
                      or default_limit)
-            timeout_spec = getattr(config, 'session_timeout_minutes', None)
+            timeout_spec = getattr(config, 'session_timeout_minutes',
+                                   default_timeout_mins)
+            period_spec = getattr(config, 'session_resolution_seconds',
+                                  default_period_secs)
 
             if addnotify and app.unrestrictedTraverse(addnotify, None) is None:
                 LOG('Zope Default Object Creation', WARNING,
@@ -395,7 +401,8 @@ class AppInitializer:
                 'session_data', 'Session Data Container',
                 addNotification = addnotify,
                 delNotification = delnotify,
-                limit=limit)
+                limit=limit,
+                period_secs=period_spec)
 
             if timeout_spec is not None:
                 toc = TransientObjectContainer('session_data',
@@ -403,7 +410,8 @@ class AppInitializer:
                                                timeout_mins = timeout_spec,
                                                addNotification = addnotify,
                                                delNotification = delnotify,
-                                               limit=limit)
+                                               limit=limit,
+                                               period_secs = period_spec)
 
             tf._setObject('session_data', toc)
             tf_reserved = getattr(tf, '_reserved_names', ())

lib/python/Products/Transience/dtml/addTransientObjectContainer.dtml

@@ -62,7 +62,7 @@ the Zope physical path to the method to be invoked to receive the notification
 <TR>
   <TD ALIGN="LEFT" VALIGN="TOP">
     <div class="form-label">
-      Data object timeout in minutes
+      Data object timeout (in minutes)
    </div>
     <div class="form-help">
       ("0" means no expiration)
@@ -73,6 +73,20 @@ the Zope physical path to the method to be invoked to receive the notification
   </TD>
 </TR>
 
+<TR>
+  <TD ALIGN="LEFT" VALIGN="TOP">
+    <div class="form-label">
+      Timeout resolution (in seconds)
+   </div>
+    <div class="form-help">
+      (accept the default if you're not sure)
+    </div>
+  </TD>
+  <TD ALIGN="LEFT" VALIGN="TOP">
+    <INPUT TYPE="TEXT" NAME="period_secs:int" SIZE="10" value="20">
+  </TD>
+</TR>
+
 <TR>
   <TD ALIGN="LEFT" VALIGN="TOP">
     <div class="form-label">

lib/python/Products/Transience/dtml/manageTransientObjectContainer.dtml

@@ -5,7 +5,6 @@
            help_topic='Transience-change.stx'
 	   )">
 
-
 <form action="manage_changeTransientObjectContainer" method="post">
 
 <p class="form-help">
@@ -13,7 +12,9 @@ Transient Object Containers are used to store transient data.
 Transient data will persist, but only for a user-specified period of time
 (the "data object timeout") after which it will be flushed.
 </p>
+
 <dtml-call nudge><!-- turn the buckets if necessary -->
+
 <p class="form-label">
 <font color="green">
 <dtml-let l=getLen>
@@ -43,7 +44,7 @@ Transient data will persist, but only for a user-specified period of time
 <tr>
   <td align="left" valign="top">
     <div class="form-label">
-     Data object timeout value in minutes
+     Data object timeout value (in minutes)
     </div>
     <div class="form-help">
       ("0" means no expiration)
@@ -55,6 +56,26 @@ Transient data will persist, but only for a user-specified period of time
   </td>
 </tr>
 
+<tr>
+  <td align="left" valign="top">
+    <div class="form-label">
+     Timeout resolution (in seconds)
+    </div>
+    <div class="form-help">
+      Defines what the "resolution" of item timeout is. Setting this higher
+      allows the transience machinery to do fewer "writes" at the expense of
+      causing items to time out later than the "Data object timeout value" by
+      a factor of (at most) this many seconds.  This number must divide evenly
+      into the number of timeout seconds ("Data object timeout value" * 60)
+      and cannot be set higher than the timeout value in seconds.
+    </div>
+  </td>
+  <td align="left" valign="top">
+    <input type="text" name="period_secs:int" size=10
+     value=&dtml-getPeriodSeconds;>
+  </td>
+</tr>
+
 <tr>
   <td align="left" valign="top">
     <div class="form-label">
@@ -100,6 +121,22 @@ Transient data will persist, but only for a user-specified period of time
   </td>
 </tr>
 
+<dtml-let l=getLen>
+<dtml-if l>
+<tr>
+<td colspan=2>
+<br/>
+<p class="form-label">
+<font color="red">WARNING!</font>
+All data objects existing in this transient object container
+will be deleted when the data object timeout or expiration resolution
+is changed.
+</p>
+</tr>
+</td>
+</dtml-if>
+</dtml-let>
+
 <tr>
   <td></td>
   <td>
@@ -109,12 +146,5 @@ Transient data will persist, but only for a user-specified period of time
 </table>
 </form>
 
-<p class="form-label">
-<font color="red">WARNING!</font>
-The data objects existing in this transient object container
-will be deleted when the data object timeout is changed.
-</p>
-
-
 
 <dtml-var manage_page_footer>

lib/python/Products/Transience/help/Transience-add.stx

@@ -23,13 +23,23 @@ TransientObjectContainer - Add
 
        The title of the object.
 
-     - **Data object timeout in minutes**
+     - **Data object timeout (in minutes)**
 
        The minimum number of minutes that objects in the container will
        persist for.  Objects in the container are passively deleted, so
        they may not be deleted exactly after this number of minutes elapses.
        A setting of "0" indicates that objects should not expire.
 
+     - **Timeout resolution (in seconds)**
+
+       Defines what the "resolution" of item timeout is. Setting this
+       higher allows the transience machinery to do fewer "writes" at
+       the expense of causing items to time out later than the "Data
+       object timeout value" by a factor of (at most) this many
+       seconds. This number must divide evenly into the number of
+       timeout seconds ("Data object timeout value" * 60) and cannot
+       be set higher than the timeout value in seconds.
+       
      - **Maximum number of subobjects **
 
        The maximum number of subobjects that this container may

lib/python/Products/Transience/help/Transience-change.stx

@@ -23,7 +23,7 @@ TransientObjectContainer - Manage
 
        The title of the object.
 
-     - **Data object timeout in minutes**
+     - **Data object timeout (in minutes)**
 
        The minimum number of minutes that objects in the container will
        persist for.  Objects in the container are passively deleted, so
@@ -34,6 +34,16 @@ TransientObjectContainer - Manage
 
        If the timeout value is "0", objects will not time out.
 
+     - **Timeout resolution (in seconds)**
+
+       Defines what the "resolution" of item timeout is. Setting this
+       higher allows the transience machinery to do fewer "writes" at
+       the expense of causing items to time out later than the "Data
+       object timeout value" by a factor of (at most) this many
+       seconds. This number must divide evenly into the number of
+       timeout seconds ("Data object timeout value" * 60) and cannot
+       be set higher than the timeout value in seconds.
+
      - **Maximum number of subobjects **
 
        The maximum number of subobjects that this container may
@@ -92,11 +102,6 @@ TransientObjectContainer - Manage
                  from zLOG import LOG
                  LOG(100, 'test', 'id: %s' % item.getId())
 
-  Environment Variables
-
-    You can control some transient object settings with environment
-    variables. See 'doc/ENVIORNMENT.txt' for more informatin.
-
   See Also
 
      - "Transience API":TransienceInterfaces.py

lib/python/Products/Transience/help/TransienceInterfaces.py

@@ -80,10 +80,12 @@ class TransientObjectContainer:
         Permission -- 'Create Transient Objects'
         """
 
-    def setTimeoutMinutes(self, timeout_mins):
+    def setTimeoutMinutes(self, timeout_mins, period=20):
         """
         Set the number of minutes of inactivity allowable for subobjects
-        before they expire.
+        before they expire (timeout_mins) as well as the 'timeout resolution'
+        in seconds (period).  'timeout_mins' * 60 must be evenly divisible
+        by the period.  Period must be less than 'timeout_mins' * 60.
 
         Permission -- 'Manage Transient Object Container'
         """
@@ -96,6 +98,13 @@ class TransientObjectContainer:
         Permission -- 'View management screens'
         """
 
+    def getPeriodSeconds(self):
+        """
+        Return the 'timeout resolution' in seconds.
+
+        Permission -- 'View management screens'
+        """
+
     def getAddNotificationTarget(self):
         """
         Returns the current 'after add' function, or None.

lib/python/Products/Transience/tests/testTransientObjectContainer.py

@@ -34,7 +34,9 @@ class TestBase(TestCase):
                                           
         self.errmargin = .20
         self.timeout = 120
-        self.t = TransientObjectContainer('sdc', timeout_mins=self.timeout/60)
+        self.period = 20
+        self.t = TransientObjectContainer('sdc', timeout_mins=self.timeout/60,
+                                          period_secs=self.period)
 
     def tearDown(self):
         self.t = None
@@ -267,7 +269,7 @@ class TestTransientObjectContainer(TestBase):
         self.assertEqual(len(self.t.keys()), 0)
 
         # 2 minutes
-        self.t._setTimeout(self.timeout/60*2)
+        self.t._setTimeout(self.timeout/60*2, self.period)
         self.t._reset()
         for x in range(10, 110):
             self.t[x] = x
@@ -279,7 +281,7 @@ class TestTransientObjectContainer(TestBase):
         self.assertEqual(len(self.t.keys()), 0)
 
         # 3 minutes
-        self.t._setTimeout(self.timeout/60*3)
+        self.t._setTimeout(self.timeout/60*3, self.period)
         self.t._reset()
         for x in range(10, 110):
             self.t[x] = x
@@ -318,7 +320,8 @@ class TestTransientObjectContainer(TestBase):
 
     def testLen(self):
         # This test must not time out else it will fail.
-        self.t._setTimeout(self.timeout)  # make timeout extremely unlikely
+        # make timeout extremely unlikely by setting it very high
+        self.t._setTimeout(self.timeout, self.period)
         added = {}
         r = range(10, 1010)
         for x in r:
@@ -340,8 +343,9 @@ class TestTransientObjectContainer(TestBase):
 
     def testGetTimeoutMinutesWorks(self):
         self.assertEqual(self.t.getTimeoutMinutes(), self.timeout / 60)
-        self.t._setTimeout(10)
+        self.t._setTimeout(10, 30)
         self.assertEqual(self.t.getTimeoutMinutes(), 10)
+        self.assertEqual(self.t.getPeriodSeconds(), 30)
 
     def test_new(self):
         t = self.t.new('foobieblech')
@@ -369,7 +373,7 @@ class TestTransientObjectContainer(TestBase):
         self.assertRaises(MaxTransientObjectsExceeded, self._maxOut)
 
     def testZeroTimeoutMeansPersistForever(self):
-        self.t._setTimeout(0)
+        self.t._setTimeout(0, self.period)
         self.t._reset()
         for x in range(10, 110):
             self.t[x] = x

lib/python/Zope/Startup/zopeschema.xml

@@ -627,6 +627,16 @@
      <metadefault>20</metadefault>
   </key>
 
+  <key name="session-resolution-seconds" datatype="integer"
+       default="20">
+     <description>
+     An integer value representing the number of seconds to be used as the
+     "timeout resolution" of the '/temp_folder/session_data' transient
+     object container in Zope's object database.
+     </description>
+     <metadefault>20</metadefault>
+  </key>
+
   <key name="suppress-all-access-rules" datatype="boolean"
        default="off" handler="suppress_all_access_rules">
      <description>

skel/etc/zope.conf.in

@@ -548,6 +548,20 @@ instancehome $INSTANCE
 #    session-timeout-minutes 30
 
 
+# Directive: session-resolution-seconds
+#
+# Description:
+#    An integer value representing the number of seconds to be used as the
+#    "timeout resolution" of the '/temp_folder/session_data' transient
+#    object container.
+#
+# Default: 20
+#
+# Example:
+#
+#    session-resolution-seconds 60
+
+
 # Directive: suppress-all-access-rules
 #
 # Description: