git-email: Add ablitiy to re-write header.

* git-email.el (git-email--rewrite-header-in-buffer): New function.
(git-email-rewrite-header): Likewise.

Signed-off-by: Xinglu Chen <public@yoctocell.xyz>

1 files changed, 29 insertions, 0 deletions

diff --git a/git-email.el b/git-email.el
index fedd03d..21769fd 100644
--- a/git-email.el
+++ b/git-email.el
@@ -459,6 +459,35 @@ default behavior is to delete them after sending the message."
             (funcall git-email-send-email-function))
           buffers)))
 
+(defun git-email--rewrite-header-in-buffer (buffer header value)
+  (switch-to-buffer buffer)
+  (save-excursion
+    (goto-char (point-min))
+    (let* ((case-fold-search t))
+      (re-search-forward (concat "^" (capitalize header) ":") nil t )
+      (delete-region (point) (point-at-eol))
+      (insert " " value))))
+
+;;;###autoload
+(defun git-email-rewrite-header (header value)
+  "Re-write the value of HEADER to VALUE, if HEADER doesn't exist
+yet, just set it to VALUE.
+
+This is mainly useful if you forgot to Cc someone when using
+`git-email-format-patch', or if you are waiting for Debbugs to
+give you an address to send your patches to."
+  (interactive
+   (list (completing-read "Header to re-write: "
+                          git-email-headers)
+         (read-from-minibuffer "Set header to: ")))
+  (let ((buffers (message-buffers))
+        (start-buffer (current-buffer)))
+    (save-excursion
+       (mapc (lambda (buffer)
+               (git-email--rewrite-header-in-buffer buffer header value))
+             buffers))
+    (switch-to-buffer start-buffer)))
+
 ;;;###autoload
 (defun git-email-send-email (files)
   "Send FILES as patch(es) to someone using your MUA."