+(defun emacs-bzr-version-dirstate (dir)
+ "Try to return as a string the bzr revision ID of directory DIR.
+This uses the dirstate file's parent revision entry.
+Returns nil if unable to find this information."
+ (let ((file (expand-file-name ".bzr/checkout/dirstate" dir)))
+ (when (file-readable-p file)
+ (with-temp-buffer
+ (insert-file-contents file)
+ (and (looking-at "#bazaar dirstate flat format 3")
+ (forward-line 3)
+ (looking-at "[0-9]+\0\\([^\0\n]+\\)\0")
+ (match-string 1))))))
+
+(defun emacs-bzr-version-bzr (dir)
+ "Ask bzr itself for the version information for directory DIR."
+ ;; Comments on `bzr version-info':
+ ;; i) Unknown files also cause clean != 1.
+ ;; ii) It can be slow, contacting the upstream repo to get the
+ ;; branch nick if one is not set locally, even with a custom
+ ;; template that is not asking for the nick (as used here). You'd
+ ;; think the latter part would be trivial to fix:
+ ;; https://bugs.launchpad.net/bzr/+bug/882541/comments/3
+ ;; https://bugs.launchpad.net/bzr/+bug/629150
+ ;; You can set the nick locally with `bzr nick ...', which speeds
+ ;; things up enormously. `bzr revno' does not have this issue, but
+ ;; has no way to print the revision_id AFAICS.
+ (message "Waiting for bzr...")
+ (with-temp-buffer
+ (if (zerop
+ (call-process "bzr" nil '(t nil) nil "version-info"
+ "--custom"
+ "--template={revno} {revision_id} (clean = {clean})"
+ "dir"))
+ (buffer-string))))
+
+(defun emacs-bzr-get-version (&optional dir external)
+ "Try to return as a string the bzr revision of the Emacs sources.
+The format is: [revno] revision_id, where revno may be absent.