>From a3298310fe5f399dacd5ab13b725a95d9c626a21 Mon Sep 17 00:00:00 2001
From: Rasmus <address@hidden>
Date: Thu, 28 Apr 2016 17:15:29 +0200
Subject: [PATCH 1/3] org-macro: Maybe get modification-time from vc.el

* org-macro.el (org-macro-initialize-templates): Check modification-time
  in version control via vc.
* doc/org.texi (Macro replacement): Document new behavior.
* etc/ORG-NEWS: Mention new behavior.
---
 doc/org.texi      |  6 +++---
 etc/ORG-NEWS      |  4 +++-
 lisp/org-macro.el | 27 ++++++++++++++++++++++++++-
 3 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/doc/org.texi b/doc/org.texi
index 17b01c2..bc08277 100644
--- a/doc/org.texi
+++ b/doc/org.texi
@@ -10251,9 +10251,9 @@ understood by @code{format-time-string}.
 @cindex time, macro
 @cindex modification time, macro
 These macros refer to the date and time when the document is exported and to
-the modification date and time of the file being exported, respectively.
address@hidden should be a format string understood by
address@hidden
+the modification date, potentially found via version control, and time of the
+file being exported, respectively.  @var{FORMAT} should be a format string
+understood by @code{format-time-string}.
 
 @item @address@hidden@address@hidden@address@hidden
 @cindex input file, macro
diff --git a/etc/ORG-NEWS b/etc/ORG-NEWS
index 99241e2..c8b1627 100644
--- a/etc/ORG-NEWS
+++ b/etc/ORG-NEWS
@@ -104,7 +104,9 @@ is straightforward.  For example
 becomes
 
 : ("pdf" . (lambda (file link) (foo)))
-
+*** ~{{{modification-time}}}~ tries to obtain time via =vc=
+As a fallback, the modification time will be found via the file
+system.
 ** New features
 *** New org-protocol key=value syntax
 
diff --git a/lisp/org-macro.el b/lisp/org-macro.el
index 5e9be98..debe6b0 100644
--- a/lisp/org-macro.el
+++ b/lisp/org-macro.el
@@ -59,6 +59,9 @@
 (declare-function org-mode "org" ())
 (declare-function org-remove-double-quotes "org" (s))
 (declare-function org-with-wide-buffer "org-macs" (&rest body))
+(declare-function vc-backend "vc-hooks" (f))
+(declare-function vc-call "vc-hooks" (&rest args))
+(declare-function vc-exec-after "vc-dispatcher" (code))
 
 ;;; Variables
 
@@ -148,7 +151,29 @@ function installs the following ones: \"property\",
 		    (cons "modification-time"
 			  (format "(eval (format-time-string \"$1\" '%s))"
 				  (prin1-to-string
-				   (nth 5 (file-attributes visited-file)))))))))
+				   (or
+				    ;; First, check if file has a VC modification time.
+				    (save-window-excursion
+				      (when (vc-backend visited-file)
+					(let ((buf (get-buffer-create " *org-vc*"))
+					      date)
+					  (vc-call print-log visited-file buf nil nil 1)
+					  (with-current-buffer buf
+					    (vc-exec-after
+					     (lambda ()
+					       (goto-char (point-min))
+					       (when (search-forward-regexp "Date:?[ \t]*" nil t)
+						 (let ((time (parse-time-string
+							      (buffer-substring
+							       (point) (point-at-eol)))))
+						   (when (org-some 'identity time)
+						     (setq date (apply 'encode-time time))))))))
+					  (let ((proc (get-buffer-process buf)))
+					    (while (and proc (accept-process-output proc .5 nil t))))
+					  (kill-buffer " *org-vc*")
+					  date)))
+				    ;; Otherwise use the time registered by the file system.
+				    (nth 5 (file-attributes visited-file))))))))))
     (setq org-macro-templates templates)))
 
 (defun org-macro-expand (macro templates)
-- 
2.8.0