+(luna-define-method elmo-folder-next-message-number ((folder elmo-folder))
+ (+ 1 (elmo-max-of-list (or (elmo-folder-list-messages folder)
+ '(0)))))
+
+(eval-and-compile
+ (luna-define-class elmo-file-tag))
+
+(defconst elmo-append-messages-dispatch-table
+ '(((nil . null) . elmo-folder-append-messages-*-null)
+ ((filter . nil) . elmo-folder-append-messages-filter-*)
+ ((nil . filter) . elmo-folder-append-messages-*-filter)
+ ((pipe . nil) . elmo-folder-append-messages-pipe-*)
+ ((nil . pipe) . elmo-folder-append-messages-*-pipe)
+ ((multi . nil) . elmo-folder-append-messages-multi-*)
+ ((nil . flag) . elmo-folder-append-messages-*-flag)
+ ((imap4 . imap4) . elmo-folder-append-messages-imap4-imap4)
+ ((elmo-file-tag . localdir) . elmo-folder-append-messages-*-localdir)
+ ((elmo-file-tag . maildir) . elmo-folder-append-messages-*-maildir)
+ ((nil . archive) . elmo-folder-append-messages-*-archive)
+ ((nil . nil) . elmo-generic-folder-append-messages)))
+
+(defun elmo-folder-type-p (folder type)
+ (or (null type)
+ (eq (elmo-folder-type-internal folder) type)
+ (labels ((member-if (predicate list)
+ (and list
+ (or (funcall predicate (car list))
+ (member-if predicate (cdr list)))))
+ (subtypep (name type)
+ (or (eq name type)
+ (let ((class (luna-find-class name)))
+ (and class
+ (member-if (lambda (name)
+ (subtypep name type))
+ (luna-class-parents class)))))))
+ (subtypep (luna-class-name folder)
+ (or (intern-soft (format "elmo-%s-folder" type))
+ type)))))
+
+(defun elmo-folder-append-messages (dst-folder src-folder numbers
+ &optional same-number caller)
+ "Append messages from folder.
+DST-FOLDER is the ELMO folder structure.
+Caller should make sure DST-FOLDER is `writable'.
+\(Can be checked with `elmo-folder-writable-p'\).
+SRC-FOLDER is the source ELMO folder structure.
+NUMBERS is the message numbers to be appended in the SRC-FOLDER.
+If second optional argument SAME-NUMBER is specified,
+message number is preserved \(if possible\).
+Returns a list of message numbers successfully appended."
+ (let ((rest (if caller
+ (cdr (memq (rassq caller elmo-append-messages-dispatch-table)
+ elmo-append-messages-dispatch-table))
+ elmo-append-messages-dispatch-table))
+ result)
+ (while rest
+ (let ((types (car (car rest))))
+ (if (and (elmo-folder-type-p src-folder (car types))
+ (elmo-folder-type-p dst-folder (cdr types)))
+ (setq result (funcall (cdr (car rest))
+ dst-folder src-folder numbers same-number)
+ rest nil)
+ (setq rest (cdr rest)))))
+ result))