IMAP: added support for RFC4731

This extension (called ESEARCH) allows to reduce traffic from IMAP server,
if server supports it.

Severs known to support ESEARCH: Zimbra, Dovecot 1.2.

http://tools.ietf.org/html/rfc4731

diff --git a/elmo/elmo-imap4.el b/elmo/elmo-imap4.el
index 0cc8e37..29a2d6a 100644 (file)
--- a/elmo/elmo-imap4.el
+++ b/elmo/elmo-imap4.el
@@ -745,17 +745,52 @@ Returns response value if selecting folder succeed. "
   ;; Not used.
   )
 
+(defun elmo-imap4-elist (folder query tags)
+  (let ((session (elmo-imap4-get-session folder)))
+    (elmo-imap4-session-select-mailbox
+     session
+     (elmo-imap4-folder-mailbox-internal folder))
+    (let ((answer (elmo-imap4-response-value
+                  (elmo-imap4-send-command-wait
+                   session query) 'esearch))
+         tag result)
+      (while answer
+       (setq tag (intern (downcase (car answer))))
+       (cond ((eq tag 'uid)
+              nil)
+             ((memq tag tags)
+              (setq result
+                    (append result
+                            (if (eq tag 'all)
+                                (sort
+                                 (elmo-number-set-to-number-list
+                                  (mapcar #'(lambda (x)
+                                              (let ((y (split-string x ":")))
+                                                (if (null (cdr y))
+                                                    (string-to-number (car y))
+                                                  (cons (string-to-number (car y))
+                                                        (string-to-number (cadr y))))))
+                                          (split-string (cadr answer) "\,"))) '<)
+                              (string-to-number (cadr answer))))))
+             (t nil))
+       (setq answer (cdr answer)))
+      result)))
+
 (defun elmo-imap4-list (folder flag)
   (let ((session (elmo-imap4-get-session folder)))
     (elmo-imap4-session-select-mailbox
      session
      (elmo-imap4-folder-mailbox-internal folder))
-    (elmo-imap4-response-value
-     (elmo-imap4-send-command-wait
-      session
-      (format (if elmo-imap4-use-uid "uid search %s"
-               "search %s") flag))
-     'search)))
+    (if (elmo-imap4-session-capable-p session 'esearch)
+       (elmo-imap4-elist folder
+                         (concat (if elmo-imap4-use-uid "uid " "")
+                                 "search return (all) " flag) '(all))
+      (elmo-imap4-response-value
+       (elmo-imap4-send-command-wait
+       session
+       (format (if elmo-imap4-use-uid "uid search %s"
+                 "search %s") flag))
+       'search))))
 
 (defun elmo-imap4-session-flag-available-p (session flag)
   (case flag
@@ -1408,6 +1443,9 @@ Return nil if no complete line has arrived."
                        (read (concat "("
                                      (buffer-substring (point) (point-max))
                                      ")"))))
+          (ESEARCH     (list
+                        'esearch
+                        (cddr (split-string (buffer-substring (point) (point-max)) " " "\,"))))
           (STATUS     (elmo-imap4-parse-status))
           ;; Added
           (NAMESPACE  (elmo-imap4-parse-namespace))