IMAP: use partial updates

Use partial updates for refreshing messages list. If old messages were
not changed on server side, we can just take new messages and join them
with old. It is much faster and saves a lot of traffic, especially on
large mailing lists.

diff --git a/elmo/elmo-imap4.el b/elmo/elmo-imap4.el
index 7b2c66d..cce89ad 100644 (file)
--- a/elmo/elmo-imap4.el
+++ b/elmo/elmo-imap4.el
@@ -1984,22 +1984,37 @@ Return nil if no complete line has arrived."
          (elmo-msgdb-killed-list-length killed))
        (elmo-imap4-response-value status 'messages)))))
 
+(defun elmo-imap4-folder-list-range (folder min max)
+  (elmo-imap4-list
+   folder
+   (concat
+    (let ((killed
+          (elmo-folder-killed-list-internal
+           folder)))
+      (if (and killed
+              (eq (length killed) 1)
+              (consp (car killed))
+              (eq (car (car killed)) 1))
+;; What about elmo-imap4-use-uid?
+         (format "uid %d:%s" (cdr (car killed)) max)
+       (format "uid %s:%s" min max)))
+    " undeleted")))
+
 (luna-define-method elmo-folder-list-messages-plugged ((folder
-                                                       elmo-imap4-folder)
-                                                      &optional
-                                                      enable-killed)
-  (elmo-imap4-list folder
-                  (concat
-                   (let ((killed
-                          (elmo-folder-killed-list-internal
-                           folder)))
-                     (if (and killed
-                              (eq (length killed) 1)
-                              (consp (car killed))
-                              (eq (car (car killed)) 1))
-                         (format "uid %d:*" (cdr (car killed)))
-                       "all"))
-                   " undeleted")))
+                                                        elmo-imap4-folder)
+                                                       &optional
+                                                       enable-killed)
+
+  (let* ((old (elmo-msgdb-list-messages (elmo-folder-msgdb folder)))
+         (new (elmo-imap4-folder-list-range folder
+               (1+ (or (elmo-folder-get-info-max folder) 0)) "*"))
+         (united-old-new (elmo-union old new)))
+    (if (= (length united-old-new) (or (elmo-folder-get-info-length folder) 0))
+        united-old-new
+      (elmo-union new
+                 (elmo-imap4-folder-list-range
+                  folder
+                  1 (1+ (or (elmo-folder-get-info-max folder) 0)))))))
 
 (luna-define-method elmo-folder-list-flagged-plugged
   ((folder elmo-imap4-folder) flag)
@@ -2559,6 +2574,9 @@ If optional argument REMOVE is non-nil, remove FLAG."
                                (setq response
                                      (elmo-imap4-read-response session tag))))
                  (progn
+                   (let ((exists (assq 'exists response))) ; update message count,
+                     (when exists                          ; so merge update can go
+                       (elmo-folder-set-info-hashtb folder nil (cadr exists))))
                    (elmo-imap4-session-set-current-mailbox-internal
                     session mailbox)
                    (elmo-imap4-session-set-read-only-internal