From 7c3cec13b87404a985dc8f821f8ef6af3d072073 Mon Sep 17 00:00:00 2001
From: Nikolaus Rath <Nikolaus@rath.org>
Date: Tue, 14 Jul 2015 19:03:09 -0700
Subject: [PATCH 2/2] nnimap.el: Add support for IMAP namespaces.

* lisp/gnus/nnimap.el (nnimap-use-namespaces): introduced new server variable.
(nnimap-group-to-imap, nnimap-get-groups): transform IMAP group names
to Gnus group name by stripping / prefixing personal namespace prefix.
(nnimap-open-connection-1): ask server for namespaces and store them.
---
 lisp/gnus/nnimap.el | 66 ++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 53 insertions(+), 13 deletions(-)

diff --git a/lisp/gnus/nnimap.el b/lisp/gnus/nnimap.el
index a942d8..3ede4d 100644
--- a/lisp/gnus/nnimap.el
+++ b/lisp/gnus/nnimap.el
@@ -55,6 +55,13 @@
 If nnimap-stream is `ssl', this will default to `imaps'.  If not,
 it will default to `imap'.")
 
+(defvoo nnimap-use-namespaces nil
+  "Whether to use IMAP namespaces.
+If in Gnus your folder names in all start with (e.g.) `INBOX',
+you probably want to set this to t. The effects of this are
+purely cosmetical, but changing this variable will affect the
+names of your nnimap groups. ")
+
 (defvoo nnimap-stream 'undecided
   "How nnimap talks to the IMAP server.
 The value should be either `undecided', `ssl' or `tls',
@@ -116,6 +123,8 @@ some servers.")
 (defun nnimap-encode-gnus-group (group)
   (encode-coding-string group 'utf-8))
 
+(setq nnimap-namespaces nil)
+
 (defvoo nnimap-fetch-partial-articles nil
   "If non-nil, Gnus will fetch partial articles.
 If t, Gnus will fetch only the first part.  If a string, it
@@ -168,7 +177,17 @@ textual parts.")
 
 (defun nnimap-group-to-imap (group)
   "Convert Gnus group name to IMAP mailbox name."
-  (utf7-encode group t))
+  (let* ((prefix (cadr (assoc (nnoo-current-server 'nnimap)
+                              nnimap-namespaces)))
+         (inbox (substring prefix 0 -1)))
+    (utf7-encode
+     (cond ((or (not prefix)
+                (string-equal group inbox))
+            group)
+           ((string-prefix-p "#" group)
+            (substring group 1))
+           (t
+            (concat prefix group))) t)))
 
 (defun nnimap-buffer ()
   (nnimap-find-process-buffer nntp-server-buffer))
@@ -445,7 +464,8 @@ textual parts.")
 	     (props (cdr stream-list))
 	     (greeting (plist-get props :greeting))
 	     (capabilities (plist-get props :capabilities))
-	     (stream-type (plist-get props :type)))
+	     (stream-type (plist-get props :type))
+             (server (nnoo-current-server 'nnimap)))
 	(when (and stream (not (memq (process-status stream) '(open run))))
 	  (setq stream nil))
 
@@ -478,9 +498,7 @@ textual parts.")
                                ;; the virtual server name and the address
                                (nnimap-credentials
 				(gnus-delete-duplicates
-				 (list
-                                  (nnoo-current-server 'nnimap)
-				  nnimap-address))
+				 (list server nnimap-address))
                                 ports
                                 nnimap-user))))
 		  (setq nnimap-object nil)
@@ -499,7 +517,21 @@ textual parts.")
 		      (dolist (response (cddr (nnimap-command "CAPABILITY")))
 			(when (string= "CAPABILITY" (upcase (car response)))
 			  (setf (nnimap-capabilities nnimap-object)
-				(mapcar #'upcase (cdr response))))))
+				(mapcar #'upcase (cdr response)))))
+                      (when (and nnimap-use-namespaces
+                                 (nnimap-capability "NAMESPACE"))
+                        (erase-buffer)
+                        (nnimap-wait-for-response (nnimap-send-command "NAMESPACE"))
+                        (let ((response (nnimap-last-response-string)))
+                          (when (string-match
+                                 "^\\*\\W+NAMESPACE\\W+((\"\\([^\"\n]+\\)\"\\W+\"\\(.\\)\"))\\W+"
+                                 response)
+                            (let ((namespace (cons (match-string 1 response)
+                                                   (match-string 2 response)))
+                                  (entry (assoc server nnimap-namespaces)))
+                              (if entry
+                                  (setcdr entry namespace)
+                                (push (cons server namespace) nnimap-namespaces)))))))
 		  ;; If the login failed, then forget the credentials
 		  ;; that are now possibly cached.
 		  (dolist (host (list (nnoo-current-server 'nnimap)
@@ -1272,8 +1304,12 @@ If LIMIT, first try to limit the search to the N last articles."
 
 (defun nnimap-get-groups ()
   (erase-buffer)
-  (let ((sequence (nnimap-send-command "LIST \"\" \"*\""))
-	groups)
+  (let* ((sequence (nnimap-send-command "LIST \"\" \"*\""))
+         (prefix (cadr (assoc (nnoo-current-server 'nnimap)
+                              nnimap-namespaces)))
+         (prefix-len (length prefix))
+         (inbox (substring prefix 0 -1))
+         groups)
     (nnimap-wait-for-response sequence)
     (subst-char-in-region (point-min) (point-max)
 			  ?\\ ?% t)
@@ -1290,11 +1326,15 @@ If LIMIT, first try to limit the search to the N last articles."
 			   (skip-chars-backward " \r\"")
 			   (point)))))
 	(unless (member '%NoSelect flags)
-	  (push (utf7-decode (if (stringp group)
-				 group
-			       (format "%s" group))
-                             t)
-		groups))))
+          (let* ((group (utf7-decode (if (stringp group) group
+                                       (format "%s" group)) t))
+                 (group (cond ((equal inbox group)
+                               group)
+                              ((string-prefix-p prefix group)
+                               (substring group prefix-len))
+                              (t
+                               (concat "#" group)))))
+            (push group groups)))))
     (nreverse groups)))
 
 (defun nnimap-get-responses (sequences)
-- 
2.11.0