emacs: resume messages

Provide functionality to resume editing a message previously saved with
notmuch-draft-save, including decoding the X-Notmuch-Emacs-Secure
header.

Resume gets the raw file from notmuch and using the emacs function
mime-to-mml reconstructs the message (including attachments).

'e' is bound to resume a draft from show or tree mode.

emacs/notmuch-draft.el

@@ -27,6 +27,7 @@
 (require 'notmuch-tag)
 
 (declare-function notmuch-show-get-message-id "notmuch-show" (&optional bare))
+(declare-function notmuch-message-mode "notmuch-mua")
 
 (defgroup notmuch-draft nil
   "Saving and editing drafts in Notmuch."
@@ -118,6 +119,27 @@ Used when a new version is saved, or the message is sent."
 	  (goto-char (+ (match-beginning 0) 2))
 	  (insert "!"))))))
 
+(defun notmuch-draft-unquote-some-mml ()
+  "Unquote the mml tags in `notmuch-draft-quoted-tags`."
+  (save-excursion
+    (when notmuch-draft-quoted-tags
+      (let ((re (concat "<#!+/?\\("
+			(mapconcat 'regexp-quote notmuch-draft-quoted-tags "\\|")
+			"\\)")))
+	(message-goto-body)
+	(while (re-search-forward re nil t)
+	  ;; Remove one ! from after the #.
+	  (goto-char (+ (match-beginning 0) 2))
+	  (delete-char 1))))
+    (let (secure-tag)
+      (save-restriction
+	(message-narrow-to-headers)
+	(setq secure-tag (message-fetch-field "X-Notmuch-Emacs-Secure" 't))
+	(message-remove-header "X-Notmuch-Emacs-Secure"))
+      (message-goto-body)
+      (when secure-tag
+	(insert secure-tag "\n")))))
+
 (defun notmuch-draft--has-encryption-tag ()
   "Returns t if there is an mml secure tag."
   (save-excursion
@@ -197,6 +219,46 @@ applied to newly inserted messages)."
   (notmuch-draft-save)
   (kill-buffer))
 
+(defun notmuch-draft-resume (id)
+  "Resume editing of message with id ID."
+  (let* ((tags (process-lines notmuch-command "search" "--output=tags"
+			      "--exclude=false" id))
+	 (draft (equal tags (notmuch-update-tags tags notmuch-draft-tags))))
+    (when (or draft
+	      (yes-or-no-p "Message does not appear to be a draft: really resume? "))
+      (switch-to-buffer (get-buffer-create (concat "*notmuch-draft-" id "*")))
+      (setq buffer-read-only nil)
+      (erase-buffer)
+      (let ((coding-system-for-read 'no-conversion))
+	(call-process notmuch-command nil t nil "show" "--format=raw" id))
+      (mime-to-mml)
+      (goto-char (point-min))
+      (when (re-search-forward "^$" nil t)
+	(replace-match mail-header-separator t t))
+      ;; Remove the Date and Message-ID headers (unless the user has
+      ;; explicitly customized emacs to tell us not to) as they will
+      ;; be replaced when the message is sent.
+      (save-restriction
+	(message-narrow-to-headers)
+	(when (member 'Message-ID message-deletable-headers)
+	  (message-remove-header "Message-ID"))
+	(when (member 'Date message-deletable-headers)
+	  (message-remove-header "Date"))
+	;; The X-Notmuch-Emacs-Draft header is a more reliable
+	;; indication of whether the message really is a draft.
+	(setq draft (> (message-remove-header "X-Notmuch-Emacs-Draft") 0)))
+      ;; If the message is not a draft we should not unquote any mml.
+      (when draft
+	(notmuch-draft-unquote-some-mml))
+      (notmuch-message-mode)
+      (message-goto-body)
+      (set-buffer-modified-p nil)
+      ;; If the resumed message was a draft then set the draft
+      ;; message-id so that we can delete the current saved draft if the
+      ;; message is resaved or sent.
+      (setq notmuch-draft-id (when draft id)))))
+
+
 (add-hook 'message-send-hook 'notmuch-draft--mark-deleted)
 
 

emacs/notmuch-show.el

@@ -38,6 +38,7 @@
 (require 'notmuch-mua)
 (require 'notmuch-crypto)
 (require 'notmuch-print)
+(require 'notmuch-draft)
 
 (declare-function notmuch-call-notmuch-process "notmuch" (&rest args))
 (declare-function notmuch-search-next-thread "notmuch" nil)
@@ -50,6 +51,7 @@
 		  (&optional query query-context target buffer-name open-target))
 (declare-function notmuch-tree-get-message-properties "notmuch-tree" nil)
 (declare-function notmuch-read-query "notmuch" (prompt))
+(declare-function notmuch-draft-resume "notmuch-draft" (id))
 
 (defcustom notmuch-message-headers '("Subject" "To" "Cc" "Date")
   "Headers that should be shown in a message, in this order.
@@ -1445,6 +1447,7 @@ reset based on the original query."
     (define-key map "|" 'notmuch-show-pipe-message)
     (define-key map "w" 'notmuch-show-save-attachments)
     (define-key map "V" 'notmuch-show-view-raw-message)
+    (define-key map "e" 'notmuch-show-resume-message)
     (define-key map "c" 'notmuch-show-stash-map)
     (define-key map "h" 'notmuch-show-toggle-visibility-headers)
     (define-key map "k" 'notmuch-tag-jump)
@@ -1982,6 +1985,11 @@ to show, nil otherwise."
     (setq buffer-read-only t)
     (view-buffer buf 'kill-buffer-if-not-modified)))
 
+(defun notmuch-show-resume-message ()
+  "Resume EDITING the current draft message."
+  (interactive)
+  (notmuch-draft-resume (notmuch-show-get-message-id)))
+
 (put 'notmuch-show-pipe-message 'notmuch-doc
      "Pipe the contents of the current message to a command.")
 (put 'notmuch-show-pipe-message 'notmuch-prefix-doc

emacs/notmuch-tree.el

@@ -293,6 +293,7 @@ FUNC."
     (define-key map "*" 'notmuch-tree-tag-thread)
     (define-key map " " 'notmuch-tree-scroll-or-next)
     (define-key map (kbd "DEL") 'notmuch-tree-scroll-message-window-back)
+    (define-key map "e" 'notmuch-tree-resume-message)
     map))
 (fset 'notmuch-tree-mode-map notmuch-tree-mode-map)
 
@@ -405,6 +406,15 @@ NOT change the database."
    (list (notmuch-read-tag-changes (notmuch-tree-get-tags) "Tag message" "-")))
   (notmuch-tree-tag tag-changes))
 
+(defun notmuch-tree-resume-message ()
+  "Resume EDITING the current draft message."
+  (interactive)
+  (notmuch-tree-close-message-window)
+  (let ((id (notmuch-tree-get-message-id)))
+    (if id
+	(notmuch-draft-resume id)
+      (message "No message to resume!"))))
+
 ;; The next two functions close the message window before calling
 ;; notmuch-search or notmuch-tree but they do so after the user has
 ;; entered the query (in case the user was basing the query on

test/T630-emacs-draft.sh

@@ -52,4 +52,19 @@ count2=$(notmuch count subject:draft-test-0004)
 
 test_expect_equal "$count1,$count2" "3,0"
 
+test_begin_subtest "Resuming a signed draft"
+
+test_emacs '(notmuch-show "subject:draft-test-0003")
+	    (notmuch-show-resume-message)
+	    (test-output)'
+notmuch_dir_sanitize OUTPUT > OUTPUT.clean
+cat <<EOF | notmuch_dir_sanitize >EXPECTED
+From: Notmuch Test Suite <test_suite@notmuchmail.org>
+To: 
+Subject: draft-test-0003
+Fcc: MAIL_DIR/sent
+--text follows this line--
+<#secure method=pgpmime mode=sign>
+EOF
+test_expect_equal_file EXPECTED OUTPUT.clean
 test_done