CollapseDrafts

Inside Macintosh: OpenDoc Class Reference /: Part 1 - Classes and Methods / ODDocument

CollapseDrafts
Document Shell
The CollapseDrafts method removes the specified range of empty drafts from this document.
ODDocument CollapseDrafts (in ODDraft from, 
                           in ODDraft to);
from
A reference to the first (most recent) draft in the range.
to
A reference to the last (oldest) draft in the range.
return value
A reference to this document with the specified drafts removed.

DISCUSSION
If the to parameter is kODNULL, it is set to the draft immediately previous to (below) the from draft. When successful, this method removes all the drafts between the from draft (inclusive) and the to draft (exclusive), and returns a reference to the amended document object. This method maintains the appropriate draft topology for this document. After successful execution, the from draft is no longer a valid draft object.
For this method to be successful, the following conditions must all be met:

The from draft itself must have a reference count of 1, meaning that only the caller has a reference to that draft object.
The from draft must not be this document's base draft and must be more recent than (above) the to draft in this document's draft history.
All the drafts targeted for removal must be empty. A draft is empty if it contains no changes from its previous draft.
There must be no outstanding drafts between the from draft (exclusive) and the to draft (exclusive). An outstanding draft has a reference count greater than 0, meaning that it is being used by some object.

Before calling this method, the document shell or container application can call the SaveToAPrevDraft method to consolidate the changes in a range of drafts.

EXCEPTIONS

kODErrCannotCollapseDrafts
The from draft is not a more recent draft than the to draft.
kODErrNonEmptyDraft
There are non-empty draft(s) between the from draft (inclusive) and the to draft (exclusive).
kODErrOutstandingDraft
There are outstanding drafts between the from draft (exclusive) and the to draft (exclusive) or the from draft has a reference count greater than 1.

SEE ALSO
The ODDocument::SaveToAPrevDraft method (page 144).