On Mon, May 9, 2011 at 8:26 AM, Laurence Rowe <l...@lrowe.co.uk> wrote: > While looking at the Plone versioning code the other day, it struck me > that it would be much more efficient to implement file versioning if > we could rely on blobs never changing after their first commit, as a > copy of the file data would not need to be made proactively in the > versioning repository incase the blob was changed in a future > transaction. > > Subclassing of blobs is not supported, but looking at the code I > didn't see anything that actively prevented this other than the > Blob.__init__ itself. Is there something I've missed here?
Nope. Subclassing blobs is *explicitly* not supported. > I had > thought that an ImmutableBlob could be implemented by overriding the > open and consumeFile methods of Blob to prevent modification after > first commit. If you want to implement a restriction like this, do it in a wrapper class. Jim -- Jim Fulton http://www.linkedin.com/in/jimfulton _______________________________________________ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev