// Atomic allows a transactional change of tags to the message.
func (m *Message) Atomic(callback func(*Message)) error {
if err := statusErr(C.notmuch_message_freeze(m.toC())); err != nil {
return err
}
callback(m)
return statusErr(C.notmuch_message_thaw(m.toC()))
}
/* Freeze the current state of 'message' within the database.
*
* This means that changes to the message state, (via
* notmuch_message_add_tag, notmuch_message_remove_tag, and
* notmuch_message_remove_all_tags), will not be committed to the
* database until the message is thawed with notmuch_message_thaw.
*
* Multiple calls to freeze/thaw are valid and these calls will
* "stack". That is there must be as many calls to thaw as to freeze
* before a message is actually thawed.
*
* The ability to do freeze/thaw allows for safe transactions to
* change tag values. For example, explicitly setting a message to
* have a given set of tags might look like this:
*
* notmuch_message_freeze (message);
*
* notmuch_message_remove_all_tags (message);
*
* for (i = 0; i < NUM_TAGS; i++)
* notmuch_message_add_tag (message, tags[i]);
*
* notmuch_message_thaw (message);
*
* With freeze/thaw used like this, the message in the database is
* guaranteed to have either the full set of original tag values, or
* the full set of new tag values, but nothing in between.
*
* Imagine the example above without freeze/thaw and the operation
* somehow getting interrupted. This could result in the message being
* left with no tags if the interruption happened after
* notmuch_message_remove_all_tags but before notmuch_message_add_tag.
*
* Return value:
*
* NOTMUCH_STATUS_SUCCESS: Message successfully frozen.
*
* NOTMUCH_STATUS_READ_ONLY_DATABASE: Database was opened in read-only
* mode so message cannot be modified.
*/
func (self *Message) Freeze() Status {
if self.message == nil {
return STATUS_NULL_POINTER
}
return Status(C.notmuch_message_freeze(self.message))
}
