[Modeling-cvs] ProjectModeling/Modeling DatabaseChannel.py,1.18,1.19

[Sebastien B. <sbi...@us...>]

Update of /cvsroot/modeling/ProjectModeling/Modeling
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv26330/Modeling

Modified Files:
	DatabaseChannel.py 
Log Message:
* Fixed: DatabaseChannel.fetchObject(): it was possible for a snapshot to
  be cleared from the cache while initializeObject() was in progress (this
  could happen when another EC was garbage-collected in another thread e.g.)
  This happened because at this point, the database's lock is released. To
  prevent the problem, the snapshot's count is incremented before releasing
  the database's lock, and decremented only after initialzeObject() has
  returned.


Index: DatabaseChannel.py
===================================================================
RCS file: /cvsroot/modeling/ProjectModeling/Modeling/DatabaseChannel.py,v
retrieving revision 1.18
retrieving revision 1.19
diff -C2 -d -r1.18 -r1.19
*** DatabaseChannel.py	20 Jul 2004 06:21:36 -0000	1.18
--- DatabaseChannel.py	25 Feb 2006 12:32:33 -0000	1.19
***************
*** 133,143 ****
      import time
      currentTimestamp=time.time() # for snapshots
!     dict=self._adaptorChannel.fetchRow()
  
!     if dict is None:
        self.cancelFetch() # No more objects
        return None
  
!     globalID=self._currentEntity.globalIDForRow(dict)
  
      if self.fetchesRawRows():
--- 133,143 ----
      import time
      currentTimestamp=time.time() # for snapshots
!     raw_row=self._adaptorChannel.fetchRow()
  
!     if raw_row is None:
        self.cancelFetch() # No more objects
        return None
  
!     globalID=self._currentEntity.globalIDForRow(raw_row)
  
      if self.fetchesRawRows():
***************
*** 153,163 ****
              return registeredSnapshot
            else:
!             return dict
        else:
!         return dict
  
      # Get snapshot
!     #snapshot=self._currentEntity.snapshotForRow(dict)
!     snapshot=dict
      database=self.databaseContext().database()
  
--- 153,163 ----
              return registeredSnapshot
            else:
!             return raw_row
        else:
!         return raw_row
  
      # Get snapshot
!     #snapshot=self._currentEntity.snapshotForRow(raw_row)
!     snapshot=raw_row
      database=self.databaseContext().database()
  
***************
*** 189,192 ****
--- 189,193 ----
      # since the corresponding snapshot has been thrown away.
      #
+     snapshot_refcount_incremented = False
      database.lock()
      try:
***************
*** 260,272 ****
            ec.recordObject(object, globalID)
        
!       # Initialize the new object or the cleared fault
!       try:
!         object.clearFault()
!       except:
!         pass
!       ec.initializeObject(object, globalID, ec)
      finally:
        database.unlock()
        
      return object
    
--- 261,282 ----
            ec.recordObject(object, globalID)
        
! 
!       database.incrementSnapshotCountForGlobalID(globalID)
!       snapshot_refcount_incremented = True
      finally:
        database.unlock()
        
+     # Initialize the new object or the cleared fault
+     try:
+       object.clearFault()
+     except:
+       pass
+ 
+     try:
+       ec.initializeObject(object, globalID, ec)
+     finally:
+       if snapshot_refcount_incremented:
+         database.decrementSnapshotCountForGlobalID(globalID)
+ 
      return object