Add wrapper for 'git-format-patch'

This lets the user generate patches and automatically compses an email
for each patch.

* git-email.el (git-email-format-patch-default-args):
(git-email-format-patch-extra-args):
(git-email-format-patch):

1 files changed, 51 insertions, 3 deletions

diff --git a/git-email.el b/git-email.el
index c5ee138..441a097 100644
--- a/git-email.el
+++ b/git-email.el
@@ -37,9 +37,6 @@
 ;;; TODO:
 
 ;; * Add proper syntax highlighting to diffs in the message buffer.
-;;
-;; * Add wrapper for 'git format-patch' that automatically marks the
-;;   the newly generated patch files.
 
 ;;; Code:
 
@@ -73,6 +70,17 @@ in you git config.  If the variable is not set, the 'to' address will be empty."
   :group 'git-email
   :type '(symbol))
 
+(defcustom git-email-format-patch-default-args ""
+  "Default arguments to give to 'git format-patch'."
+  :type 'string
+  :group 'git-email)
+
+(defcustom git-email-format-patch-extra-args
+  '("--cover-letter" "--thread" "--output-directory" "--signoff" "--to")
+  "List of arguments to display in `git-email-format-patch'."
+  :type '(string)
+  :group 'git-email)
+
 (defun git-email--extract-header (header)
   "Extract HEADER from current buffer."
   (goto-char (point-min))
@@ -146,6 +154,46 @@ If no marks are found, return the filename at point."
 	  (git-email--compose-email file)
 	  (run-hooks 'git-email-post-compose-email-hook))))
 
+;;;###autoload
+(defun git-email-format-patch (&optional args)
+  "Format and send patch(es) using 'git format-patch'.
+With optional ARGS (\\[universal-argument]) you can specify extra
+arguments to give to 'git format-patch'.  By default, the
+arguments in `git-email-format-patch-default-args' will be used."
+  (interactive "P")
+  (let* ((default-directory (cdr (project-current)))
+	 (revs (split-string (shell-command-to-string
+			      "git log --format='%h %d %s'")
+			     "\n"))
+	 ;; Sort the candidates correctly.
+	 ;; See https://emacs.stackexchange.com/a/41808.
+	 (sorted-revs
+	  (lambda (string pred action)
+	    (if (eq action 'metadata)
+		'(metadata (display-sort-function . identity)
+			   (cycle-sort-function . identity))
+	      (complete-with-action
+	       action revs string pred))))
+	 (rev (substring (completing-read "Revision: " sorted-revs) 0 7))
+	 ;; Extra arguments.
+	 (args (if args
+		   (apply
+		    #'concat (mapcar
+			      (lambda (a) (concat a " "))
+			      (list (completing-read-multiple
+				     "Args: "
+			     git-email-format-patch-extra-args))))
+		 git-email-format-patch-default-args))
+	 ;; List of patches generated, the last element is an empty string
+	 ;; so remove it.  Reverse the list so we edit the cover letter first.
+	 (files (nreverse (butlast (split-string (shell-command-to-string
+			       (concat "git format-patch " args " " rev))
+			      "\n")))))
+    (dolist (file files)
+      (run-hooks 'git-email-pre-compose-email-hook)
+      (git-email--compose-email file)
+      (run-hooks 'git-email-post-compose-email-hook))))
+
 (defun git-email--remove-subject (header)
   "Remove HEADER if it is the subject."
   (not (string-equal (symbol-name (car header)) "subject")))