* elmo.el (elmo-folder-append-msgdb): Rewrite and define as an inline
[elisp/wanderlust.git] / elmo / elmo.el
index b2a437c..cb66c79 100644 (file)
@@ -124,8 +124,7 @@ If a folder name begins with PREFIX, use BACKEND."
 ;;;###autoload
 (defun elmo-make-folder (name &optional non-persistent)
   "Make an ELMO folder structure specified by NAME.
-If optional argument NON-PERSISTENT is non-nil, folder is treated as
- non-persistent."
+If optional argument NON-PERSISTENT is non-nil, the folder msgdb is not saved."
   (let ((type (elmo-folder-type name))
        prefix split class folder original)
     (setq original (elmo-string name))
@@ -141,23 +140,27 @@ If optional argument NON-PERSISTENT is non-nil, folder is treated as
     (setq class (format "elmo-%s" (symbol-name type)))
     (require (intern class))
     (setq folder (luna-make-entity (intern (concat class "-folder"))
-                                  :type   type
+                                  :type type
                                   :prefix prefix
                                   :name original
                                   :persistent (not non-persistent)))
     (save-match-data
       (elmo-folder-send folder 'elmo-folder-initialize name))))
 
-(defmacro elmo-folder-msgdb (folder)
-  "Return the msgdb of FOLDER (on-demand loading)."
-  (` (or (elmo-folder-msgdb-internal (, folder))
-        (elmo-folder-set-msgdb-internal (, folder)
-                                        (elmo-msgdb-load (, folder))))))
+;; Note that this function is for internal use only.
+(luna-define-generic elmo-folder-msgdb (folder)
+  "Return the msgdb of FOLDER (on-demand loading).
+\(For internal use only.\)")
+
+(luna-define-method elmo-folder-msgdb ((folder elmo-folder))
+  (or (elmo-folder-msgdb-internal folder)
+      (elmo-folder-set-msgdb-internal folder
+                                     (elmo-msgdb-load folder))))
 
 (luna-define-generic elmo-folder-open (folder &optional load-msgdb)
   "Open and setup (load saved status) FOLDER.
 If optional LOAD-MSGDB is non-nil, msgdb is loaded.
-(otherwise, msgdb is loaded on-demand)")
+\(otherwise, msgdb is loaded on-demand)")
 
 (luna-define-generic elmo-folder-open-internal (folder)
   "Open FOLDER (without loading saved folder status).")
@@ -190,13 +193,11 @@ If optional KEEP-KILLED is non-nil, killed-list is not cleared.")
 (luna-define-generic elmo-folder-use-flag-p (folder)
   "Returns t if FOLDER treats unread/important flag itself.")
 
-(luna-define-generic elmo-folder-diff (folder &optional numbers)
+(luna-define-generic elmo-folder-diff (folder)
   "Get diff of FOLDER.
-If optional NUMBERS is set, it is used as current NUMBERS.
-Otherwise, saved status for folder is used for comparison.
 Return value is cons cell or list:
- - a cons cell (NEWS . MESSAGES)
- - a list (RECENT UNSEEN MESSAGES) ; RECENT means NEWS, UNSEEN means UNREAD.")
+ - a cons cell (new . all)
+ - a list (new unread all)")
 
 (luna-define-generic elmo-folder-status (folder)
   "Returns a cons cell of (MAX-NUMBER . MESSAGES) in the FOLDER.")
@@ -204,56 +205,83 @@ Return value is cons cell or list:
 (luna-define-generic elmo-folder-reserve-status-p (folder)
   "If non-nil, the folder should not close folder after `elmo-folder-status'.")
 
-(defun elmo-folder-list-messages (folder &optional visible-only)
+(luna-define-generic elmo-folder-set-message-modified (folder modified)
+  "Set FOLDER as modified.")
+(luna-define-method elmo-folder-set-message-modified ((folder elmo-folder)
+                                                     modified)
+  (elmo-folder-set-message-modified-internal folder modified))
+
+(luna-define-generic elmo-folder-list-messages (folder &optional visible-only
+                                                      in-msgdb)
   "Return a list of message numbers contained in FOLDER.
-If optional VISIBLE-ONLY is non-nil, killed messages are not listed."
-  (let ((list (elmo-folder-list-messages-internal folder visible-only))
-       (killed (elmo-folder-killed-list-internal folder))
-       numbers)
-    (setq numbers
+If optional VISIBLE-ONLY is non-nil, killed messages are not listed.
+If second optional IN-MSGDB is non-nil, only messages in the msgdb are listed.")
+(luna-define-method elmo-folder-list-messages ((folder elmo-folder)
+                                              &optional visible-only in-msgdb)
+  (let ((list (if in-msgdb
+                 t
+               (elmo-folder-list-messages-internal folder visible-only))))
+    (setq list
          (if (listp list)
              list
-           ;; Not available, use current list.
-           (mapcar
-            'car
-            (elmo-msgdb-get-number-alist (elmo-folder-msgdb folder)))))
-    (elmo-living-messages numbers killed)))
-
-(defun elmo-folder-list-unreads (folder unread-marks)
-  "Return a list of unread message numbers contained in FOLDER.
-UNREAD-MARKS is the unread marks."
-  (let ((list (elmo-folder-list-unreads-internal folder
-                                                unread-marks)))
-    (if (listp list)
-       list
-      ;; Not available, use current mark.
-      (delq nil
-           (mapcar
-            (function
-             (lambda (x)
-               (if (member (cadr x) unread-marks)
-                   (car x))))
-            (elmo-msgdb-get-mark-alist (elmo-folder-msgdb folder)))))))
-
-(defun elmo-folder-list-importants (folder important-mark)
-  "Returns a list of important message numbers contained in FOLDER.
-IMPORTANT-MARK is the important mark."
-  (let ((importants (elmo-folder-list-importants-internal folder important-mark))
-       (number-alist (elmo-msgdb-get-number-alist
-                      (elmo-folder-msgdb folder)))
-       num-pair result)
+           ;; Use current list.
+           (elmo-msgdb-list-messages (elmo-folder-msgdb folder))))
+    (if visible-only
+       (elmo-living-messages list (elmo-folder-killed-list-internal folder))
+      list)))
+
+(luna-define-generic elmo-folder-list-unreads (folder)
+  "Return a list of unread message numbers contained in FOLDER.")
+(luna-define-generic elmo-folder-list-importants (folder)
+  "Return a list of important message numbers contained in FOLDER.")
+(luna-define-generic elmo-folder-list-answereds (folder)
+  "Return a list of answered message numbers contained in FOLDER.")
+
+;; TODO: Should reconsider the structure of global mark.
+(defun elmo-folder-list-messages-with-global-mark (folder mark)
+  (let (entity msgs)
     (dolist (mark-pair (or elmo-msgdb-global-mark-alist
                           (setq elmo-msgdb-global-mark-alist
                                 (elmo-object-load
                                  (expand-file-name
                                   elmo-msgdb-global-mark-filename
                                   elmo-msgdb-directory)))))
-      (if (and (string= important-mark (cdr mark-pair))
-              (setq num-pair (rassoc (car mark-pair) number-alist)))
-         (setq result (cons (car num-pair) result))))
-    (if (listp importants)
-       (elmo-uniq-list (nconc result importants))
-      result)))
+      (if (and (string= mark (cdr mark-pair))
+              (setq entity
+                    (elmo-msgdb-overview-get-entity (car mark-pair)
+                                                    (elmo-folder-msgdb
+                                                     folder))))
+         (setq msgs (cons (elmo-msgdb-overview-entity-get-number entity)
+                          msgs))))
+    msgs))
+
+(luna-define-generic elmo-folder-list-flagged (folder flag &optional in-msgdb)
+  "List messages in the FOLDER with FLAG.
+FLAG is a symbol which is one of the following:
+  `new'        (new messages)
+  `unread'     (unread messages (new messages are included))
+  `answered'   (answered or forwarded)
+  `important'  (marked as important)
+'sugar' flags:
+  `read'       (not unread)
+  `digest'     (unread + important)
+  `any'        (digest + answered)
+
+If optional IN-MSGDB is non-nil, retrieve flag information from msgdb.")
+
+(luna-define-method elmo-folder-list-flagged ((folder elmo-folder) flag
+                                             &optional in-msgdb)
+  ;; Currently, only in-msgdb is implemented.
+  (elmo-msgdb-list-flagged (elmo-folder-msgdb folder) flag))
+
+(luna-define-method elmo-folder-list-unreads ((folder elmo-folder))
+  (elmo-folder-list-flagged folder 'unread))
+
+(luna-define-method elmo-folder-list-importants ((folder elmo-folder))
+  (elmo-folder-list-flagged folder 'important))
+
+(luna-define-method elmo-folder-list-answereds ((folder elmo-folder))
+  (elmo-folder-list-flagged folder 'answered))
 
 (luna-define-generic elmo-folder-list-messages-internal (folder &optional
                                                                visible-only)
@@ -261,24 +289,10 @@ IMPORTANT-MARK is the important mark."
   ;; Return t if the message list is not available.
   )
 
-(luna-define-generic elmo-folder-list-unreads-internal (folder
-                                                       unread-marks
-                                                       &optional mark-alist)
-  ;; Return a list of unread message numbers contained in FOLDER.
-  ;; If optional MARK-ALIST is set, it is used as mark-alist.
-  ;; Return t if this feature is not available.
-  )
-
-(luna-define-generic elmo-folder-list-importants-internal (folder
-                                                          important-mark)
-  ;; Return a list of important message numbers contained in FOLDER.
-  ;; Return t if this feature is not available.
-  )
-
 (luna-define-generic elmo-folder-list-subfolders (folder &optional one-level)
   "Returns a list of subfolders contained in FOLDER.
 If optional argument ONE-LEVEL is non-nil, only children of FOLDER is returned.
-(a folder which have children is returned as a list)
+\(a folder which have children is returned as a list\)
 Otherwise, all descendent folders are returned.")
 
 (luna-define-generic elmo-folder-have-subfolder-p (folder)
@@ -328,46 +342,63 @@ CONDITION is a condition structure for testing.
 NUMBERS is a list of message numbers,
 use to be test for \"last\" and \"first\" predicates.")
 
-(luna-define-generic elmo-folder-msgdb-create
-  (folder numbers new-mark already-mark seen-mark important-mark seen-list)
+(luna-define-generic elmo-folder-msgdb-create (folder numbers flag-table)
   "Create a message database (implemented in each backends).
 FOLDER is the ELMO folder structure.
 NUMBERS is a list of message numbers to create msgdb.
-NEW-MARK, ALREADY-MARK, SEEN-MARK, and IMPORTANT-MARK are mark string for
-new message, unread but cached message, read message and important message.
-SEEN-LIST is a list of message-id string which should be treated as read.")
+FLAG-TABLE is a hashtable of message-id and flag.")
 
-(luna-define-generic elmo-folder-unmark-important (folder numbers)
+(luna-define-generic elmo-folder-unmark-important (folder
+                                                  numbers
+                                                  &optional ignore-flags)
   "Un-mark messages as important.
 FOLDER is the ELMO folder structure.
-NUMBERS is a list of message numbers to be processed.")
+NUMBERS is a list of message numbers to be processed.
+If IGNORE-FLAGS is non-nil, folder flags are not updated.")
 
-(luna-define-generic elmo-folder-mark-as-important (folder numbers)
+(luna-define-generic elmo-folder-mark-as-important (folder
+                                                   numbers
+                                                   &optional ignore-flags)
   "Mark messages as important.
 FOLDER is the ELMO folder structure.
-NUMBERS is a list of message numbers to be processed.")
+NUMBERS is a list of message numbers to be processed.
+If IGNORE-FLAGS is non-nil, folder flags are not updated.")
 
-(luna-define-generic elmo-folder-unmark-read (folder numbers)
+(luna-define-generic elmo-folder-unmark-read (folder numbers
+                                                    &optional ignore-flags)
   "Un-mark messages as read.
 FOLDER is the ELMO folder structure.
-NUMBERS is a list of message numbers to be processed.")
+NUMBERS is a list of message numbers to be processed.
+If IGNORE-FLAGS is non-nil, folder flags are not updated.")
 
-(luna-define-generic elmo-folder-mark-as-read (folder numbers)
+(luna-define-generic elmo-folder-mark-as-read (folder numbers
+                                                     &optional ignore-flags)
   "Mark messages as read.
 FOLDER is the ELMO folder structure.
+NUMBERS is a list of message numbers to be processed.
+If IGNORE-FLAGS is non-nil, folder flags are not updated.")
+
+(luna-define-generic elmo-folder-unmark-answered (folder numbers)
+  "Un-mark messages as answered.
+FOLDER is the ELMO folder structure.
 NUMBERS is a list of message numbers to be processed.")
 
-(luna-define-generic elmo-folder-append-buffer (folder unread &optional number)
+(luna-define-generic elmo-folder-mark-as-answered (folder numbers)
+  "Mark messages as answered.
+FOLDER is the ELMO folder structure.
+NUMBERS is a list of message numbers to be processed.")
+
+(luna-define-generic elmo-folder-append-buffer (folder &optional flag
+                                                      number)
   "Append current buffer as a new message.
 FOLDER is the destination folder(ELMO folder structure).
-If UNREAD is non-nil, message is appended as unread.
+FLAG is the status of appended message.
 If optional argument NUMBER is specified, the new message number is set
-(if possible).")
+\(if possible\).")
 
 (luna-define-generic elmo-folder-append-messages (folder
                                                  src-folder
                                                  numbers
-                                                 unread-marks
                                                  &optional
                                                  same-number)
   "Append messages from folder.
@@ -376,7 +407,6 @@ Caller should make sure 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.
-UNREAD-MARKS is a list of unread mark string.
 If second optional argument SAME-NUMBER is specified,
 message number is preserved (if possible).")
 
@@ -485,6 +515,8 @@ Return newly created temporary directory name which contains temporary files.")
     (setq message-id (elmo-msgdb-overview-entity-get-id entity))
     (setq number (elmo-msgdb-overview-entity-get-number entity))
     (setq cache-file (elmo-file-cache-get message-id))
+    (setq ignore-cache (or ignore-cache
+                          (null (elmo-message-use-cache-p folder number))))
     (if (or ignore-cache
            (null (elmo-file-cache-status cache-file)))
        ;; No cache or ignore-cache.
@@ -519,14 +551,6 @@ Return newly created temporary directory name which contains temporary files.")
   ((folder elmo-folder) &optional visible-only)
   t)
 
-(luna-define-method elmo-folder-list-unreads-internal
-  ((folder elmo-folder) unread-marks &optional mark-alist)
-  t)
-
-(luna-define-method elmo-folder-list-importants-internal
-  ((folder elmo-folder) important-mark)
-  t)
-
 (defun elmo-folder-encache (folder numbers &optional unread)
   "Encache messages in the FOLDER with NUMBERS.
 If UNREAD is non-nil, messages are not marked as read."
@@ -601,19 +625,29 @@ FIELD is a symbol of the field name.")
 (luna-define-generic elmo-message-folder (folder number)
   "Get primitive folder of the message.")
 
-(luna-define-generic elmo-folder-process-crosspost (folder
-                                                   &optional
-                                                   number-alist)
+(luna-define-generic elmo-folder-process-crosspost (folder)
   "Process crosspost for FOLDER.
-If NUMBER-ALIST is set, it is used as number-alist.
 Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
 
-(luna-define-generic elmo-folder-append-msgdb (folder append-msgdb)
-  "Append  APPEND-MSGDB to the current msgdb of the folder.")
-
 (luna-define-generic elmo-folder-newsgroups (folder)
   "Return list of newsgroup name of FOLDER.")
 
+(luna-define-generic elmo-folder-search-requires-msgdb-p (folder condition)
+  "Return non-nil if searching in FOLDER by CONDITION requires msgdb fetch.")
+
+(defun elmo-folder-search-requires-msgdb-p-internal (folder condition)
+  (if (listp condition)
+      (or (elmo-folder-search-requires-msgdb-p-internal
+          folder (nth 1 condition))
+         (elmo-folder-search-requires-msgdb-p-internal
+          folder (nth 2 condition)))
+    (and (not (string= (elmo-filter-key condition) "last"))
+        (not (string= (elmo-filter-key condition) "first")))))
+
+(luna-define-method elmo-folder-search-requires-msgdb-p ((folder elmo-folder)
+                                                        condition)
+  (elmo-folder-search-requires-msgdb-p-internal folder condition))
+
 (luna-define-method elmo-folder-newsgroups ((folder elmo-folder))
   nil)
 
@@ -623,8 +657,7 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
 
 (defun elmo-generic-folder-open (folder load-msgdb)
   (let ((inhibit-quit t))
-    (if load-msgdb
-       (elmo-folder-set-msgdb-internal folder (elmo-msgdb-load folder)))
+    (if load-msgdb (elmo-folder-msgdb folder))
     (elmo-folder-set-killed-list-internal
      folder
      (elmo-msgdb-killed-list-load (elmo-folder-msgdb-path folder))))
@@ -651,9 +684,8 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
        (elmo-msgdb-get-number-alist (elmo-folder-msgdb folder)))
       (elmo-folder-set-info-max-by-numdb
        folder
-       (elmo-msgdb-get-number-alist
-       (elmo-folder-msgdb folder)))
-      (elmo-folder-set-message-modified-internal folder nil)
+       (elmo-folder-list-messages folder nil 'in-msgdb))
+      (elmo-folder-set-message-modified folder nil)
       (elmo-msgdb-killed-list-save
        (elmo-folder-msgdb-path folder)
        (elmo-folder-killed-list-internal folder)))
@@ -690,13 +722,16 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
   (elmo-folder-persistent-internal folder))
 
 (luna-define-method elmo-folder-creatable-p ((folder elmo-folder))
-  t) ; default is creatable.
+  nil) ; default is not creatable.
 
 (luna-define-method elmo-folder-writable-p ((folder elmo-folder))
   nil) ; default is not writable.
 
 (luna-define-method elmo-folder-delete ((folder elmo-folder))
-  (elmo-msgdb-delete-path folder))
+  (when (yes-or-no-p (format "Delete msgdb of \"%s\"? "
+                            (elmo-folder-name-internal folder)))
+    (elmo-msgdb-delete-path folder)
+    t))
 
 (luna-define-method elmo-folder-rename ((folder elmo-folder) new-name)
   (let* ((new-folder (elmo-make-folder new-name)))
@@ -710,54 +745,83 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
     (elmo-msgdb-rename-path folder new-folder)))
 
 (defsubst elmo-folder-search-fast (folder condition numbers)
-  (when (and numbers
-            (vectorp condition)
-            (member (elmo-filter-key condition) '("first" "last")))
-    (let ((len (length numbers))
-         (lastp (string= (elmo-filter-key condition) "last"))
-         (value (string-to-number (elmo-filter-value condition))))
-      (when (eq (elmo-filter-type condition) 'unmatch)
-       (setq lastp (not lastp)
-             value  (- len value)))
-      (if lastp
-         (nthcdr (max (- len value) 0) numbers)
-       (when (> value 0)
-         (let ((last (nthcdr (1- value) numbers)))
-           (when last
-             (setcdr last nil))
-           numbers))))))
+  "Search and return list of message numbers.
+Return t if CONDITION is not treated.
+FOLDER is the ELMO folder structure.
+CONDITION is a condition structure for searching.
+NUMBERS is a list of message numbers, messages are searched from the list."
+  (if (and numbers
+          (vectorp condition))
+      (cond
+       ((string= (elmo-filter-key condition) "flag")
+       (let ((msgdb (elmo-folder-msgdb folder)))
+         ;; msgdb should be synchronized at this point.
+         (cond
+          ((string= (elmo-filter-value condition) "unread")
+           (elmo-folder-list-unreads folder))
+          ((string= (elmo-filter-value condition) "important")
+           (elmo-folder-list-importants folder))
+          ((string= (elmo-filter-value condition) "answered")
+           (elmo-folder-list-answereds folder))
+          ((string= (elmo-filter-value condition) "digest")
+           (nconc (elmo-folder-list-unreads folder)
+                  (elmo-folder-list-importants folder)))
+          ((string= (elmo-filter-value condition) "any")
+           (nconc (elmo-folder-list-unreads folder)
+                  (elmo-folder-list-importants folder)
+                  (elmo-folder-list-answereds folder))))))
+       ((member (elmo-filter-key condition) '("first" "last"))
+       (let ((len (length numbers))
+             (lastp (string= (elmo-filter-key condition) "last"))
+             (value (string-to-number (elmo-filter-value condition))))
+         (when (eq (elmo-filter-type condition) 'unmatch)
+           (setq lastp (not lastp)
+                 value  (- len value)))
+         (if lastp
+             (nthcdr (max (- len value) 0) numbers)
+           (when (> value 0)
+             (let* ((numbers (copy-sequence numbers))
+                    (last (nthcdr (1- value) numbers)))
+               (when last
+                 (setcdr last nil))
+               numbers)))))
+       (t
+       t))
+    t))
 
 (luna-define-method elmo-folder-search ((folder elmo-folder)
                                        condition
                                        &optional numbers)
-  (let ((numbers (or numbers (elmo-folder-list-messages folder))))
-    (or (elmo-folder-search-fast folder condition numbers)
-       (let ((msgdb (elmo-folder-msgdb folder))
-             (len (length numbers))
-             matched)
-         (when (> len elmo-display-progress-threshold)
-           (elmo-progress-set 'elmo-folder-search len "Searching..."))
-         (unwind-protect
-             (dolist (number numbers)
-               (let ((entity (elmo-msgdb-overview-get-entity number msgdb))
-                     result)
-                 (if entity
-                     (setq result (elmo-msgdb-match-condition
-                                   condition
-                                   entity
-                                   numbers))
-                   (setq result condition))
-                 (when (elmo-filter-condition-p result)
-                   (setq result (elmo-message-match-condition
-                                 folder
-                                 number
-                                 condition
-                                 numbers)))
-                 (when result
-                   (setq matched (cons number matched))))
-               (elmo-progress-notify 'elmo-folder-search))
-           (elmo-progress-clear 'elmo-folder-search))
-         (nreverse matched)))))
+  (let ((numbers (or numbers (elmo-folder-list-messages folder)))
+       results)
+    (if (listp (setq results (elmo-folder-search-fast folder
+                                                     condition
+                                                     numbers)))
+       results
+      (let ((msgdb (elmo-folder-msgdb folder))
+           (len (length numbers))
+           matched)
+       (when (> len elmo-display-progress-threshold)
+         (elmo-progress-set 'elmo-folder-search len "Searching..."))
+       (unwind-protect
+           (dolist (number numbers)
+             (let (result)
+               (setq result (elmo-msgdb-match-condition
+                             msgdb
+                             condition
+                             number
+                             numbers))
+               (when (elmo-filter-condition-p result)
+                 (setq result (elmo-message-match-condition
+                               folder
+                               number
+                               condition
+                               numbers)))
+               (when result
+                 (setq matched (cons number matched))))
+             (elmo-progress-notify 'elmo-folder-search))
+         (elmo-progress-clear 'elmo-folder-search))
+       (nreverse matched)))))
 
 (luna-define-method elmo-message-match-condition ((folder elmo-folder)
                                                  number condition
@@ -824,14 +888,13 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
                       (list new unread numbers max)
                       elmo-folder-info-hashtb)))
 
-(defun elmo-folder-set-info-max-by-numdb (folder msgdb-number)
+(defun elmo-folder-set-info-max-by-numdb (folder numbers)
   "Set FOLDER info by MSGDB-NUMBER in msgdb."
-  (let ((num-db (sort (mapcar 'car msgdb-number) '<)))
-    (elmo-folder-set-info-hashtb
-     folder
-     (or (nth (max 0 (1- (length num-db))) num-db) 0)
-     nil ;;(length num-db)
-     )))
+  (elmo-folder-set-info-hashtb
+   folder
+   (or (car (sort numbers '>)) 0)
+   nil ;;(length num-db)
+   ))
 
 (defun elmo-folder-get-info-max (folder)
   "Return max number of FODLER from folder info."
@@ -876,17 +939,13 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
 
 (defsubst elmo-strict-folder-diff (folder)
   "Return folder diff information strictly from FOLDER."
-  (let* ((dir (elmo-folder-msgdb-path folder))
-        (nalist (elmo-msgdb-get-number-alist (elmo-folder-msgdb folder)))
-        (in-db (sort (mapcar 'car nalist) '<))
-        (in-folder  (elmo-folder-list-messages folder))
-        append-list delete-list diff)
+  (let ((in-db (sort (elmo-msgdb-list-messages (elmo-folder-msgdb folder))
+                    '<))
+       (in-folder  (elmo-folder-list-messages folder))
+       append-list delete-list diff)
     (cons (if (equal in-folder in-db)
              0
-           (setq diff (elmo-list-diff
-                       in-folder in-db
-                       nil
-                       ))
+           (setq diff (elmo-list-diff in-folder in-db nil))
            (setq append-list (car diff))
            (setq delete-list (cadr diff))
            (if append-list
@@ -896,11 +955,10 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
                0)))
          (length in-folder))))
 
-(luna-define-method elmo-folder-diff ((folder elmo-folder)
-                                     &optional numbers)
-  (elmo-generic-folder-diff folder numbers))
+(luna-define-method elmo-folder-diff ((folder elmo-folder))
+  (elmo-generic-folder-diff folder))
 
-(defun elmo-generic-folder-diff (folder numbers)
+(defun elmo-generic-folder-diff (folder)
   (if (elmo-string-match-member (elmo-folder-name-internal folder)
                                elmo-strict-diff-folder-list)
       (elmo-strict-folder-diff folder)
@@ -909,27 +967,20 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
          (in-db t)
          unsync messages
          in-db-max)
-      (if numbers
-         (setq in-db-max (or (nth (max 0 (1- (length numbers))) numbers)
-                             0))
-       (if (not cached-in-db-max)
-           (let ((number-list (mapcar 'car
-                                      (elmo-msgdb-number-load
-                                       (elmo-folder-msgdb-path folder)))))
-             ;; No info-cache.
-             (setq in-db (sort number-list '<))
-             (setq in-db-max (or (nth (max 0 (1- (length in-db))) in-db)
-                                 0))
-             (elmo-folder-set-info-hashtb folder in-db-max nil))
-         (setq in-db-max cached-in-db-max)))
-      (setq unsync (if (and in-db
-                           (car in-folder))
+      (if (not cached-in-db-max)
+         (let ((number-list (elmo-folder-list-messages folder
+                                                       nil 'in-msgdb)))
+           ;; No info-cache.
+           (setq in-db (sort number-list '<))
+           (setq in-db-max (or (nth (max 0 (1- (length in-db))) in-db)
+                               0))
+           (elmo-folder-set-info-hashtb folder in-db-max nil))
+       (setq in-db-max cached-in-db-max))
+      (setq unsync (if (and in-db (car in-folder))
                       (- (car in-folder) in-db-max)
-                    (if (and in-folder
-                             (null in-db))
+                    (if (and in-folder (null in-db))
                         (cdr in-folder)
-                      (if (null (car in-folder))
-                          nil))))
+                      (car in-folder))))
       (setq messages (cdr in-folder))
       (if (and unsync messages (> unsync messages))
          (setq unsync messages))
@@ -953,24 +1004,36 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
 (luna-define-method elmo-folder-append-messages ((folder elmo-folder)
                                                 src-folder
                                                 numbers
-                                                unread-marks
                                                 &optional
                                                 same-number)
   (elmo-generic-folder-append-messages folder src-folder numbers
-                                      unread-marks same-number))
+                                      same-number))
 
 (defun elmo-generic-folder-append-messages (folder src-folder numbers
-                                                  unread-marks same-number)
-  (let (unseen seen-list succeed-numbers failure cache)
+                                                  same-number)
+  (let ((src-msgdb-exists (not (zerop (elmo-folder-length src-folder))))
+       unseen table flag mark
+       succeed-numbers failure cache id)
+    (setq table (elmo-flag-table-load (elmo-folder-msgdb-path folder)))
     (with-temp-buffer
       (set-buffer-multibyte nil)
       (while numbers
-       (setq failure nil)
+       (setq failure nil
+             id (and src-msgdb-exists
+                     (elmo-message-field src-folder (car numbers)
+                                         'message-id))
+             mark (and src-msgdb-exists
+                       (elmo-message-mark src-folder (car numbers)))
+             flag (and id
+                       (cond
+                        ((null mark) 'read)
+                        ((member mark (elmo-msgdb-answered-marks))
+                         'answered)
+                        ;;
+                        ((not (member mark (elmo-msgdb-unread-marks)))
+                         'read))))
        (condition-case nil
-           (setq cache (elmo-file-cache-get
-                        (elmo-message-field src-folder
-                                            (car numbers)
-                                            'message-id))
+           (setq cache (elmo-file-cache-get id)
                  failure
                  (not
                   (and
@@ -992,26 +1055,18 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
                    (> (buffer-size) 0)
                    (elmo-folder-append-buffer
                     folder
-                    (setq unseen (member (elmo-message-mark
-                                          src-folder (car numbers))
-                                         unread-marks))
+                    flag
                     (if same-number (car numbers))))))
          (error (setq failure t)))
        ;; FETCH & APPEND finished
        (unless failure
-         (unless unseen
-           (setq seen-list (cons (elmo-message-field
-                                  src-folder (car numbers)
-                                  'message-id)
-                                 seen-list)))
+         (when id
+           (elmo-flag-table-set table id flag))
          (setq succeed-numbers (cons (car numbers) succeed-numbers)))
        (elmo-progress-notify 'elmo-folder-move-messages)
        (setq numbers (cdr numbers)))
-      (if (and seen-list (elmo-folder-persistent-p folder))
-         (elmo-msgdb-seen-save (elmo-folder-msgdb-path folder)
-                               (nconc (elmo-msgdb-seen-load
-                                       (elmo-folder-msgdb-path folder))
-                                      seen-list)))
+      (when (elmo-folder-persistent-p folder)
+       (elmo-flag-table-save (elmo-folder-msgdb-path folder) table))
       succeed-numbers)))
 
 ;; Arguments should be reduced.
@@ -1020,7 +1075,6 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
                                             no-delete-info
                                             no-delete
                                             same-number
-                                            unread-marks
                                             save-unread)
   (save-excursion
     (let* ((messages msgs)
@@ -1038,39 +1092,22 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
          (unless (setq succeeds (elmo-folder-append-messages dst-folder
                                                              src-folder
                                                              messages
-                                                             unread-marks
                                                              same-number))
            (error "move: append message to %s failed"
                   (elmo-folder-name-internal dst-folder)))
-         (elmo-folder-close dst-folder))
-       (when (and (elmo-folder-persistent-p dst-folder)
-                  save-unread)
-         ;; Save to seen list.
-         (let* ((dir (elmo-folder-msgdb-path dst-folder))
-                (seen-list (elmo-msgdb-seen-load dir)))
-           (setq seen-list
-                 (elmo-msgdb-add-msgs-to-seen-list
-                  msgs (elmo-folder-msgdb src-folder)
-                  unread-marks seen-list))
-           (elmo-msgdb-seen-save dir seen-list))))
+         (elmo-folder-close dst-folder)))
       (if (and (not no-delete) succeeds)
          (progn
-           (if (not no-delete-info)
-               (message "Cleaning up src folder..."))
            (if (and (elmo-folder-delete-messages src-folder succeeds)
-                    (elmo-msgdb-delete-msgs
-                     (elmo-folder-msgdb src-folder) succeeds))
+                    (elmo-folder-detach-messages src-folder succeeds))
                (setq result t)
              (message "move: delete messages from %s failed."
                       (elmo-folder-name-internal src-folder))
              (setq result nil))
-           (if (and result
-                    (not no-delete-info))
-               (message "Cleaning up src folder...done"))
            result)
        (if no-delete
            (progn
-             (message "Copying messages...done")
+             ;; (message "Copying messages...done")
              t)
          (if (eq len 0)
              (message "No message was moved.")
@@ -1085,54 +1122,147 @@ Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).")
        folder
        (elmo-folder-expand-msgdb-path folder))))
 
-(defun elmo-message-mark (folder number)
+(defun elmo-message-accessible-p (folder number)
+  "Get accessibility of the message.
+Return non-nil when message is accessible."
+  (or (elmo-folder-plugged-p folder)
+      (elmo-folder-local-p folder)
+      (elmo-msgdb-get-cached (elmo-folder-msgdb folder) number)))
+
+(luna-define-generic elmo-message-set-cached (folder number cached)
+  "Set cache status of the message in the msgdb.
+FOLDER is the ELMO folder structure.
+NUMBER is a number of the message.
+If CACHED is t, message is set as cached.")
+
+(luna-define-method elmo-message-set-cached ((folder elmo-folder)
+                                            number cached)
+  (when (elmo-msgdb-set-cached (elmo-folder-msgdb folder)
+                              number
+                              cached
+                              (elmo-message-use-cache-p folder number))
+    (elmo-folder-set-mark-modified-internal folder t)))
+
+(defun elmo-message-copy-entity (entity)
+  ;; 
+  (elmo-msgdb-copy-overview-entity entity))
+
+(defun elmo-message-entity-set-number (entity number)
+  (elmo-msgdb-overview-entity-set-number entity number))
+
+(luna-define-generic elmo-message-entity (folder key)
+  "Return the message-entity structure which matches to the KEY.
+KEY is a number or a string.
+A number is for message number in the FOLDER.
+A string is for message-id of the message.")
+
+(luna-define-method elmo-message-entity ((folder elmo-folder) key)
+  (elmo-msgdb-message-entity (elmo-folder-msgdb folder) key))
+
+(luna-define-generic elmo-message-entity-parent (folder entity)
+  "Return the parent message-entity structure in the FOLDER.
+ENTITY is the message-entity to get the parent.")
+
+(luna-define-method elmo-message-entity-parent ((folder elmo-folder) entity)
+  (elmo-msgdb-get-parent-entity entity (elmo-folder-msgdb folder)))
+
+(put 'elmo-folder-do-each-message-entity 'lisp-indent-function '1)
+(def-edebug-spec elmo-folder-do-each-message-entity
+  ((symbolp form &rest form) &rest form))
+
+(defsubst elmo-folder-list-message-entities (folder)
+  ;; List all message entities in the FOLDER.
+  (mapcar
+   (lambda (number) (elmo-message-entity folder number))
+   (elmo-folder-list-messages folder nil t))) ; XXX killed-list is not used.
+
+(defmacro elmo-folder-do-each-message-entity (spec &rest form)
+  "Iterator for message entity in the folder.
+\(elmo-folder-do-each-message-entity \(entity folder\)
+ ... do the process using entity...
+\)"
+  `(dolist (,(car spec) (elmo-folder-list-message-entities ,(car (cdr spec))))
+     ,@form))
+
+(defmacro elmo-message-entity-number (entity)
+  `(elmo-msgdb-overview-entity-get-number ,entity))
+
+(defun elmo-message-entity-field (entity field &optional decode)
+  "Get message entity field value.
+ENTITY is the message entity structure obtained by `elmo-message-entity'.
+FIELD is the symbol of the field name.
+if optional DECODE is non-nil, returned value is decoded."
+  (elmo-msgdb-message-entity-field entity field decode))
+
+(defun elmo-message-entity-set-field (entity field value)
+  "Set message entity field value.
+ENTITY is the message entity structure.
+FIELD is the symbol of the field name.
+VALUE is the field value (raw)."
+  (elmo-msgdb-message-entity-set-field entity field value))
+
+(luna-define-generic elmo-folder-count-flags (folder)
+  "Count flagged message number in the msgdb of the FOLDER.
+Return a list of numbers (`new' `unread' `answered')")
+
+(luna-define-method elmo-folder-count-flags ((folder elmo-folder))
+  (let ((new 0)
+       (unreads 0)
+       (answered 0))
+    (dolist (elem (elmo-msgdb-get-mark-alist (elmo-folder-msgdb folder)))
+      (cond
+       ((string= (cadr elem) elmo-msgdb-new-mark)
+       (incf new))
+       ((member (cadr elem) (elmo-msgdb-unread-marks))
+       (incf unreads))
+       ((member (cadr elem) (elmo-msgdb-answered-marks))
+       (incf answered))))
+    (list new unreads answered)))
+
+(defun elmo-message-set-flag (folder number flag)
+  "Set message flag.
+FOLDER is a ELMO folder structure.
+NUMBER is a message number to set flag.
+
+FLAG is a symbol which is one of the following:
+  `unread'    (set the message as unread)
+  `answered'  (set the message as answered)
+  `important' (set the message as important)
+'sugar' flag:
+  `read'      (remove new and unread flags)")
+
+(defun elmo-message-unset-flag (folder number flag)
+  "Unset message flag.
+FOLDER is a ELMO folder structure.
+NUMBER is a message number to set flag.
+
+FLAG is a symbol which is one of the following:
+  `unread'    (remove unread and new flag)
+  `answered'  (remove answered flag)
+  `important' (remove important flag)
+'sugar' flag:
+  `read'      (set unread flag)")
+
+(luna-define-generic elmo-message-mark (folder number)
   "Get mark of the message.
 FOLDER is the ELMO folder structure.
-NUMBER is a number of the message."
-  (cadr (assq number (elmo-msgdb-get-mark-alist (elmo-folder-msgdb folder)))))
-
-(defun elmo-folder-list-messages-mark-match (folder mark-regexp)
-  "List messages in the FOLDER which have a mark that matches MARK-REGEXP"
-  (let ((case-fold-search nil)
-       matched)
-    (if mark-regexp
-       (dolist (elem (elmo-msgdb-get-mark-alist (elmo-folder-msgdb folder)))
-         (if (string-match mark-regexp (cadr elem))
-             (setq matched (cons (car elem) matched)))))
-    matched))
-
-(defun elmo-message-field (folder number field)
+NUMBER is a number of the message.")
+
+(luna-define-method elmo-message-mark ((folder elmo-folder) number)
+  (when (zerop (elmo-folder-length folder))
+    (error "Cannot treat this folder correctly."))
+  (elmo-msgdb-get-mark (elmo-folder-msgdb folder) number))
+
+(luna-define-generic elmo-message-field (folder number field)
   "Get message field value in the msgdb.
 FOLDER is the ELMO folder structure.
 NUMBER is a number of the message.
-FIELD is a symbol of the field."
-  (case field
-    (message-id (elmo-msgdb-overview-entity-get-id
-                (elmo-msgdb-overview-get-entity
-                 number (elmo-folder-msgdb folder))))
-    (subject (elmo-msgdb-overview-entity-get-subject
-             (elmo-msgdb-overview-get-entity
-              number (elmo-folder-msgdb folder))))
-    (size (elmo-msgdb-overview-entity-get-size
-          (elmo-msgdb-overview-get-entity
-           number (elmo-folder-msgdb folder))))
-    (date (elmo-msgdb-overview-entity-get-date
-          (elmo-msgdb-overview-get-entity
-           number (elmo-folder-msgdb folder))))
-    (to (elmo-msgdb-overview-entity-get-to
-        (elmo-msgdb-overview-get-entity
-         number (elmo-folder-msgdb folder))))
-    (cc (elmo-msgdb-overview-entity-get-cc
-        (elmo-msgdb-overview-get-entity
-         number (elmo-folder-msgdb folder))))))
-
-(defun elmo-message-set-mark (folder number mark)
-  "Set mark for the message in the FOLDER with NUMBER as MARK."
-  (elmo-msgdb-set-mark-alist
-   (elmo-folder-msgdb folder)
-   (elmo-msgdb-mark-set
-    (elmo-msgdb-get-mark-alist (elmo-folder-msgdb folder))
-    number mark)))
+FIELD is a symbol of the field.")
+
+(luna-define-method elmo-message-field ((folder elmo-folder) number field)
+  (when (zerop (elmo-folder-length folder))
+    (error "Cannot treat this folder correctly."))
+  (elmo-msgdb-get-field (elmo-folder-msgdb folder) number field))
 
 (luna-define-method elmo-message-use-cache-p ((folder elmo-folder) number)
   nil) ; default is not use cache.
@@ -1140,72 +1270,90 @@ FIELD is a symbol of the field."
 (luna-define-method elmo-message-folder ((folder elmo-folder) number)
   folder) ; default is folder
 
-(luna-define-method elmo-folder-unmark-important ((folder elmo-folder) numbers)
-  t)
+(luna-define-method elmo-folder-unmark-important ((folder elmo-folder)
+                                                 numbers
+                                                 &optional ignore-flags)
+  (when (elmo-folder-msgdb-internal folder)
+    (dolist (number numbers)
+      (elmo-msgdb-unset-flag (elmo-folder-msgdb folder)
+                            folder
+                            number
+                            'important))))
 
 (luna-define-method elmo-folder-mark-as-important ((folder elmo-folder)
-                                                  numbers)
-  t)
-
-(luna-define-method elmo-folder-unmark-read ((folder elmo-folder) numbers)
-  t)
-
-(luna-define-method elmo-folder-mark-as-read ((folder elmo-folder) numbers)
-  t)
-
-(luna-define-method elmo-folder-process-crosspost ((folder elmo-folder)
-                                                  &optional
-                                                  number-alist)
+                                                  numbers
+                                                  &optional ignore-flags)
+  (when (elmo-folder-msgdb-internal folder)
+    (dolist (number numbers)
+      (elmo-msgdb-set-flag (elmo-folder-msgdb folder)
+                          folder
+                          number
+                          'important))))
+
+(luna-define-method elmo-folder-unmark-read ((folder elmo-folder)
+                                            numbers
+                                            &optional ignore-flags)
+  (when (elmo-folder-msgdb-internal folder)
+    (dolist (number numbers)
+      (elmo-msgdb-unset-flag (elmo-folder-msgdb folder)
+                            folder
+                            number
+                            'read))))
+
+(luna-define-method elmo-folder-mark-as-read ((folder elmo-folder)
+                                             numbers
+                                             &optional ignore-flag)
+  (when (elmo-folder-msgdb-internal folder)
+    (dolist (number numbers)
+      (elmo-msgdb-set-flag (elmo-folder-msgdb folder)
+                          folder
+                          number
+                          'read))))
+
+(luna-define-method elmo-folder-unmark-answered ((folder elmo-folder) numbers)
+  (when (elmo-folder-msgdb-internal folder)
+    (dolist (number numbers)
+      (elmo-msgdb-unset-flag (elmo-folder-msgdb folder)
+                            folder
+                            number
+                            'answered))))
+
+(luna-define-method elmo-folder-mark-as-answered ((folder elmo-folder) numbers)
+  (when (elmo-folder-msgdb-internal folder)
+    (dolist (number numbers)
+      (elmo-msgdb-set-flag (elmo-folder-msgdb folder)
+                          folder
+                          number
+                          'answered))))
+
+(luna-define-method elmo-folder-process-crosspost ((folder elmo-folder))
   ;; Do nothing.
   )
 
-(defun elmo-generic-folder-append-msgdb (folder append-msgdb)
+;;(luna-define-generic elmo-folder-append-message-entity (folder entity
+;;                                                            &optional
+;;                                                            flag-table)
+;;  "Append ENTITY to the folder.")
+
+(defsubst elmo-folder-append-msgdb (folder append-msgdb)
   (if append-msgdb
-      (let* ((number-alist (elmo-msgdb-get-number-alist append-msgdb))
-            (all-alist (copy-sequence (append
-                                       (elmo-msgdb-get-number-alist
-                                        (elmo-folder-msgdb folder))
-                                       number-alist)))
-            (cur number-alist)
-            pair overview
-            to-be-deleted
-            mark-alist)
-       (while cur
-         (setq all-alist (delq (car cur) all-alist))
-         ;; same message id exists.
-         (if (setq pair (rassoc (cdr (car cur)) all-alist))
-             (setq to-be-deleted (nconc to-be-deleted (list (car pair)))))
-         (setq cur (cdr cur)))
+      (let ((duplicates (elmo-msgdb-merge folder append-msgdb)))
        (cond ((eq (elmo-folder-process-duplicates-internal folder)
                   'hide)
-              ;; Hide duplicates.
-              (setq overview (elmo-delete-if
-                              (lambda (x)
-                                (memq (elmo-msgdb-overview-entity-get-number
-                                       x)
-                                      to-be-deleted))
-                              (elmo-msgdb-get-overview append-msgdb)))
+              ;; Let duplicates be a temporary killed message.
+              (elmo-folder-kill-messages folder duplicates)
               ;; Should be mark as read.
-              (elmo-folder-mark-as-read folder to-be-deleted)
-              (elmo-msgdb-set-overview append-msgdb overview))
+              (elmo-folder-mark-as-read folder duplicates))
              ((eq (elmo-folder-process-duplicates-internal folder)
                   'read)
               ;; Mark as read duplicates.
-              (elmo-folder-mark-as-read folder to-be-deleted))
+              (elmo-folder-mark-as-read folder duplicates))
              (t
               ;; Do nothing.
-              (setq to-be-deleted nil)))
-       (elmo-folder-set-msgdb-internal folder
-                                       (elmo-msgdb-append
-                                        (elmo-folder-msgdb folder)
-                                        append-msgdb t))
-       (length to-be-deleted))
+              (setq duplicates nil)))
+       (length duplicates))
     0))
 
-(luna-define-method elmo-folder-append-msgdb ((folder elmo-folder)
-                                             append-msgdb)
-  (elmo-generic-folder-append-msgdb folder append-msgdb))
-
 (defun elmo-folder-confirm-appends (appends)
   (let ((len (length appends))
        in)
@@ -1222,8 +1370,9 @@ FIELD is a symbol of the field."
                    in (string-to-int in))
              (if (< len in)
                  (throw 'end len))
-             (if (y-or-n-p (format "%d messages are not appeared.  OK? "
-                                   (max (- len in) 0)))
+             (if (y-or-n-p (format
+                            "%d messages are killed (not appeared). OK? "
+                            (max (- len in) 0)))
                  (throw 'end in))))
          (nthcdr (max (- len in) 0) appends))
       (if (and elmo-folder-update-threshold
@@ -1284,78 +1433,74 @@ FIELD is a symbol of the field."
     (or result
        (and err (signal (car err) (cdr err))))))
 
+(defun elmo-folder-kill-messages-before (folder msg)
+  (elmo-folder-set-killed-list-internal
+   folder
+   (list (cons 1 msg))))
+
+(defun elmo-folder-kill-messages (folder numbers)
+  "Kill(hide) messages in the FOLDER with NUMBERS."
+  (elmo-folder-set-killed-list-internal
+   folder
+   (elmo-number-set-append-list (elmo-folder-killed-list-internal
+                                folder) numbers)))
+
+
 (luna-define-method elmo-folder-clear ((folder elmo-folder)
                                       &optional keep-killed)
   (unless keep-killed
     (elmo-folder-set-killed-list-internal folder nil))
   (elmo-folder-set-msgdb-internal folder (elmo-msgdb-clear)))
 
-(defun elmo-folder-synchronize (folder
-                               new-mark             ;"N"
-                               unread-uncached-mark ;"U"
-                               unread-cached-mark   ;"!"
-                               read-uncached-mark   ;"u"
-                               important-mark       ;"$"
-                               &optional ignore-msgdb
-                               no-check)
+(luna-define-generic elmo-folder-synchronize (folder
+                                             &optional
+                                             disable-killed
+                                             ignore-msgdb
+                                             no-check)
   "Synchronize the folder data to the newest status.
 FOLDER is the ELMO folder structure.
-NEW-MARK, UNREAD-CACHED-MARK, READ-UNCACHED-MARK, and IMPORTANT-MARK
-are mark strings for new messages, unread but cached messages,
-read but not cached messages, and important messages.
+
+If optional DISABLE-KILLED is non-nil, killed messages are also synchronized.
 If optional IGNORE-MSGDB is non-nil, current msgdb is thrown away except
-read mark status. If IGNORE-MSGDB is 'visible-only, only visible messages
-\(the messages which are not in the killed-list\) are thrown away and
-synchronized.
+flag status.
 If NO-CHECK is non-nil, rechecking folder is skipped.
-
-Return a list of
-\(NEW-MSGDB DELETE-LIST CROSSED\)
-NEW-MSGDB is the newly appended msgdb.
-DELETE-LIST is a list of deleted message number.
-CROSSED is cross-posted message number.
-If update process is interrupted, return nil."
+Return a list of a cross-posted message number.
+If update process is interrupted, return nil.")
+
+(luna-define-method elmo-folder-synchronize ((folder elmo-folder)
+                                            &optional
+                                            disable-killed
+                                            ignore-msgdb
+                                            no-check)
   (let ((killed-list (elmo-folder-killed-list-internal folder))
        (before-append t)
-       number-alist mark-alist
        old-msgdb diff diff-2 delete-list new-list new-msgdb mark
-       seen-list crossed after-append)
+       flag-table crossed after-append)
     (setq old-msgdb (elmo-folder-msgdb folder))
-    ;; Load seen-list.
-    (setq seen-list (elmo-msgdb-seen-load (elmo-folder-msgdb-path folder)))
-    (setq number-alist (elmo-msgdb-get-number-alist
-                       (elmo-folder-msgdb folder)))
-    (setq mark-alist (elmo-msgdb-get-mark-alist
-                     (elmo-folder-msgdb folder)))
-    (if ignore-msgdb
-       (progn
-         (setq seen-list (nconc
-                          (elmo-msgdb-mark-alist-to-seen-list
-                           number-alist mark-alist
-                           (concat important-mark read-uncached-mark))
-                          seen-list))
-         (elmo-folder-clear folder (eq ignore-msgdb 'visible-only))))
+    (setq flag-table (elmo-flag-table-load (elmo-folder-msgdb-path folder)))
+    (when ignore-msgdb
+      (elmo-msgdb-flag-table (elmo-folder-msgdb folder) flag-table)
+      (elmo-folder-clear folder (not disable-killed)))
     (unless no-check (elmo-folder-check folder))
     (condition-case nil
        (progn
          (message "Checking folder diff...")
-         ;; TODO: killed list is loaded in elmo-folder-open and
-         ;; list-messages use internal killed-list-folder.
          (setq diff (elmo-list-diff (elmo-folder-list-messages
                                      folder
-                                     (eq 'visible-only ignore-msgdb))
-                                    (unless ignore-msgdb
-                                      (sort (mapcar
-                                             'car
-                                             number-alist)
-                                            '<))))
+                                     (not disable-killed))
+                                    (elmo-folder-list-messages
+                                     folder
+                                     (not disable-killed)
+                                     'in-msgdb)))
          (message "Checking folder diff...done")
          (setq new-list (elmo-folder-confirm-appends (car diff)))
-         ;; Set killed list.
+         ;; Set killed list as ((1 . MAX-OF-DISAPPEARED))
          (when (and (not (eq (length (car diff))
                              (length new-list)))
                     (setq diff-2 (elmo-list-diff (car diff) new-list)))
-           (elmo-msgdb-append-to-killed-list folder (car diff-2)))
+           (elmo-folder-kill-messages-before folder
+                                             (nth (- (length (car diff-2)) 1)
+                                                  (car diff-2))))
          (setq delete-list (cadr diff))
          (if (or (equal diff '(nil nil))
                  (equal diff '(nil))
@@ -1364,57 +1509,60 @@ If update process is interrupted, return nil."
              (progn
                (elmo-folder-update-number folder)
                (elmo-folder-process-crosspost folder)
-               (list nil nil nil) ; no updates.
+               0 ; no updates.
                )
-           (if delete-list (elmo-msgdb-delete-msgs
-                            (elmo-folder-msgdb folder) delete-list))
+           (when delete-list
+             (elmo-folder-detach-messages folder delete-list))
            (when new-list
-             (setq new-msgdb (elmo-folder-msgdb-create
-                              folder
-                              new-list
-                              new-mark unread-cached-mark
-                              read-uncached-mark important-mark
-                              seen-list))
              (elmo-msgdb-change-mark (elmo-folder-msgdb folder)
-                                     new-mark unread-uncached-mark)
-             ;; Clear seen-list.
+                                     elmo-msgdb-new-mark
+                                     elmo-msgdb-unread-uncached-mark)
+             (setq new-msgdb (elmo-folder-msgdb-create
+                              folder new-list flag-table))
+             ;; Clear flag-table
              (if (elmo-folder-persistent-p folder)
-                 (setq seen-list (elmo-msgdb-seen-save
-                                  (elmo-folder-msgdb-path folder) nil)))
+                 (elmo-flag-table-save (elmo-folder-msgdb-path folder)
+                                       nil))
              (setq before-append nil)
              (setq crossed (elmo-folder-append-msgdb folder new-msgdb))
              ;; process crosspost.
              ;; Return a cons cell of (NUMBER-CROSSPOSTS . NEW-MARK-ALIST).
              (elmo-folder-process-crosspost folder)
-             (elmo-folder-set-message-modified-internal folder t)
+             (elmo-folder-set-message-modified folder t)
              (elmo-folder-set-mark-modified-internal folder t))
            ;; return value.
-           (list new-msgdb delete-list crossed)))
+           (or crossed 0)))
       (quit
        ;; Resume to the original status.
-       (if before-append
-          (elmo-folder-set-msgdb-internal folder old-msgdb))
+       (if before-append (elmo-folder-set-msgdb-internal folder old-msgdb))
        (elmo-folder-set-killed-list-internal folder killed-list)
        nil))))
 
-(defun elmo-folder-messages (folder)
-  "Return number of messages in the FOLDER."
-  (length
-   (elmo-msgdb-get-number-alist
-    (elmo-folder-msgdb folder))))
-
-;;;
-(defun elmo-msgdb-load (folder)
-  (message "Loading msgdb for %s..." (elmo-folder-name-internal folder))
-  (let* ((path (elmo-folder-msgdb-path folder))
-        (overview (elmo-msgdb-overview-load path))
-        (msgdb (list overview
-                     (elmo-msgdb-number-load path)
-                     (elmo-msgdb-mark-load path)
-                     (elmo-msgdb-make-overview-hashtb overview))))
-    (message "Loading msgdb for %s...done" (elmo-folder-name-internal folder))
-    (elmo-folder-set-info-max-by-numdb folder
-                                      (elmo-msgdb-get-number-alist msgdb))
+(luna-define-generic elmo-folder-detach-messages (folder numbers)
+  "Remove messages with NUMBERS from MSGDB.")
+
+(luna-define-method elmo-folder-detach-messages ((folder elmo-folder)
+                                                numbers)
+  (elmo-msgdb-delete-msgs (elmo-folder-msgdb folder) numbers))
+
+(luna-define-generic elmo-folder-length (folder)
+  "Return number of messages in the FOLDER.")
+
+(luna-define-method elmo-folder-length ((folder elmo-folder))
+  (if (elmo-folder-msgdb-internal folder)
+      (elmo-msgdb-length (elmo-folder-msgdb folder))
+    0))
+
+(defun elmo-msgdb-load (folder &optional silent)
+  (unless silent
+    (message "Loading msgdb for %s..." (elmo-folder-name-internal folder)))
+  (let ((msgdb (elmo-load-msgdb (elmo-folder-msgdb-path folder))))
+    (elmo-folder-set-info-max-by-numdb
+     folder
+     (elmo-msgdb-list-messages msgdb))
+    (unless silent
+      (message "Loading msgdb for %s...done"
+              (elmo-folder-name-internal folder)))
     msgdb))
 
 (defun elmo-msgdb-delete-path (folder)
@@ -1503,6 +1651,11 @@ Return a hashtable for newsgroups."
            (funcall func nil)))
       (setq types (cdr types)))))
 
+(luna-define-method elmo-folder-rename-internal ((folder elmo-folder)
+                                                new-folder)
+  (error "Cannot rename %s folder"
+        (symbol-name (elmo-folder-type-internal folder))))
+
 
 ;;; Define folders.
 (elmo-define-folder ?% 'imap4)
@@ -1564,6 +1717,7 @@ Return a hashtable for newsgroups."
 
 ;; autoloads
 (autoload 'elmo-dop-queue-flush "elmo-dop")
+(autoload 'elmo-nntp-post "elmo-nntp")
 
 (require 'product)
 (product-provide (provide 'elmo) (require 'elmo-version))