[PATCH v2] emacs: Add more processing of displayed headers.

[David Edmondson <dme@dme.org>]

Wrap headers to the width of the window and indent continuations.
---
 emacs/notmuch-show.el |   43 ++++++++++++++++++++++++++++++++++++-------
 1 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index 7469e2e..a589d37 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -68,9 +68,16 @@ any given message."
   :type 'boolean
   :group 'notmuch-show)
 
-(defvar notmuch-show-markup-headers-hook '(notmuch-show-colour-headers)
+(defcustom notmuch-show-markup-headers-hook '(notmuch-show-colour-headers
+					      notmuch-show-fill-headers
+					      notmuch-show-indent-continuations)
   "A list of functions called to decorate the headers listed in
-`notmuch-message-headers'.")
+`notmuch-message-headers'."
+  :type 'hook
+  :options '(notmuch-show-colour-headers
+	     notmuch-show-fill-headers
+	     notmuch-show-indent-continuations)
+  :group 'notmuch-show)
 
 (defcustom notmuch-show-hook '(notmuch-show-turn-on-visual-line-mode)
   "Functions called after populating a `notmuch-show' buffer."
@@ -269,13 +276,35 @@ operation on the contents of the current buffer."
     (overlay-put (make-overlay (point) (re-search-forward ".*$"))
 		 'face face)))
 
-(defun notmuch-show-colour-headers ()
+(defun notmuch-show-colour-headers (depth)
   "Apply some colouring to the current headers."
   (goto-char (point-min))
   (while (looking-at "^[A-Za-z][-A-Za-z0-9]*:")
     (notmuch-show-fontify-header)
     (forward-line)))
 
+(defun notmuch-show-fill-headers (depth)
+  "Wrap the text of the current headers."
+
+  ;; '-5' to allow for the indentation code.
+  (let ((fill-column (- (window-width) depth 5)))
+    (goto-char (point-min))
+    (while (not (eobp))
+      (let ((start (point)))
+	(end-of-line)
+	;; We're left at the start of the next line, so there's no need
+	;; to move forward after filling.
+	(fill-region-as-paragraph start (point))))))
+
+(defun notmuch-show-indent-continuations (depth)
+  "Indent any continuation lines."
+  (goto-char (point-min))
+  (while (not (eobp))
+    (if (not (looking-at "^[A-Za-z][-A-Za-z0-9]*:"))
+	;; Four spaces tends to work well with 'To' and 'Cc' headers.
+	(insert "    "))
+    (forward-line)))
+
 (defun notmuch-show-spaces-n (n)
   "Return a string comprised of `n' spaces."
   (make-string n ? ))
@@ -366,7 +395,7 @@ message at DEPTH in the current thread."
   "Insert a single header."
   (insert header ": " header-value "\n"))
 
-(defun notmuch-show-insert-headers (headers)
+(defun notmuch-show-insert-headers (headers depth)
   "Insert the headers of the current message."
   (let ((start (point)))
     (mapc (lambda (header)
@@ -379,7 +408,7 @@ message at DEPTH in the current thread."
     (save-excursion
       (save-restriction
 	(narrow-to-region start (point-max))
-	(run-hooks 'notmuch-show-markup-headers-hook)))))
+	(run-hook-with-args 'notmuch-show-markup-headers-hook depth)))))
 
 (define-button-type 'notmuch-show-part-button-type
   'action 'notmuch-show-part-button-default
@@ -671,7 +700,7 @@ current buffer, if possible."
     ;; Override `notmuch-message-headers' to force `From' to be
     ;; displayed.
     (let ((notmuch-message-headers '("From" "Subject" "To" "Cc" "Date")))
-      (notmuch-show-insert-headers (plist-get message :headers)))
+      (notmuch-show-insert-headers (plist-get message :headers) 0))
 
     ;; Blank line after headers to be compatible with the normal
     ;; message display.
@@ -864,7 +893,7 @@ current buffer, if possible."
     ;; Set `headers-start' to point after the 'Subject:' header to be
     ;; compatible with the existing implementation. This just sets it
     ;; to after the first header.
-    (notmuch-show-insert-headers headers)
+    (notmuch-show-insert-headers headers depth)
     (save-excursion
       (goto-char content-start)
       ;; If the subject of this message is the same as that of the
-- 
1.7.8.3