This is a first little piece of emacs-code, to achieve the task of writing log messages to _MTN/log instead of ChangeLog if appropriate. (Note that DVC already includes a similar feature, bound to C-x V a by default.)
Look at the source for a way to use it. From now on use mtn-add-change-log-entry instead of add-change-log-entry. mtn-add-change-log-entry will try do the right thing.
If a directory named _MTN exists in the buffers default-directory or in any parent directory, use _MTN/log, ../_MTN/log or whatsoever. ./ChangeLog (or better change-log-default-name as from customize) otherwise. All your customisations (M-x customize-group RET change-log RET) work as expected.
I have a symbolic link named current in my home directory, that always points the folder of the project I'm currently working on. If I mtn-add-change-log-entry on a file in there, these functions still search up the real directory tree.
So if /home/sebastian/current points to /home/sebastian/develop/gtkmm/application/src, and there are /home/sebastian/develop/gtkmm/_MTN AND /home/sebastian/_MTN, mtn-add-changelog-entry will choose /home/sebastian/develop/gtkmm/_MTN/log.
Since mtn-add-change-log-entry calls add-change-log-entry interactively, you still can choose to write to use an other file.
;; File: sr-monotone.el
;; $Revision: 1.2 $
;; Date: 2006-12-04
;; Author: Sebastian Rose <sebastian_rose@gmx.de>
;; License: GPL
;;
;; Copyright (c) 2006 Sebastian Rose <sebastian_rose@gmx.de>
;;
;;
;; Provides to funktions:
;; * mtn-get-parent-directory (child)
;; returns the parent directory or nil, if there is no parent.
;; I wrote it, since I could not find a function like this.
;; * mtn-add-change-log-entry ()
;; looks for _MTN directory and changes the behaviour of
;; add-change-log-entry to use /PATH/TO/_MTN as directory
;; and 'log' as the default filename for the logfile.
;;
;;
;;
;; Usage:
;;
;; THE ONE WAY
;; In your .emacs put this line:
;; (require 'sr-monotone)
;; ... and place this file somewhere in your load-path.
;;
;;
;; THE OTHER WAY
;; Copy the two functions here and paste them in your .emacs.
;;
;;
;;
;; Bind any key you like to mtn-add-change-log-entry.
;; (global-set-key [(f8)] 'mtn-add-change-log-entry)
;;
;; From now on only use mtn-add-change-log-entry. It detects automagically the
;; right way to call add-change-log-entry.
(provide 'sr-monotone)
(defun mtn-get-parent-directory (child)
"Retruns the parent directory or nil, if there is no parent.
Parent has always a trailing slash, or what ever is your systems
file separtor.
Improvements and suggestions to sebastian_rose@gmx.de."
(if (file-regular-p child)
(file-name-as-directory (file-name-directory child))
; this is else:
(let ((child (file-name-as-directory child)))
(let ((dir (file-name-as-directory (expand-file-name child)))
(parent (file-truename
(file-name-as-directory (expand-file-name (concat child ".."))))))
(if (string= dir parent)
nil
parent)))))
(defun mtn-add-change-log-entry()
"Searches in buffers default-directory and above for a directory
named '_MTN'. If it exists, monotone-add-change-log-entry calls
add-change-log-entry interactively with apropriate arguments.
Otherwise interactively calls add-change-log-entry the normal way.
So one can just bind this function to the keys, that call
add-change-log-entry now, and it will work just fine.
Improvements and suggestions to sebastian_rose@gmx.de."
(interactive)
(let ((filename buffer-file-name)
(is-mtn-dir nil)
(original-default-directory default-directory)
(original-change-log-filename nil))
(if (boundp 'change-log-default-name)
(setq original-change-log-filename change-log-default-name))
(unwind-protect
(progn
(if filename
(progn
(catch 'done
(while (setq filename (mtn-get-parent-directory filename))
(if (file-directory-p (concat filename "_MTN"))
(progn
(setq change-log-default-name "log")
(setq is-mtn-dir (concat filename "_MTN"))
(throw 'done 'is-mtn-dir)))))
(if is-mtn-dir
(let ((default-directory is-mtn-dir))
(call-interactively 'add-change-log-entry))
(call-interactively 'add-change-log-entry))
)))
(setq default-directory original-default-directory)
(setq change-log-default-name original-change-log-filename)
)))
;; 2006-16-12
;; This function is the one you need, to make add-change-log-entry
;; print the path of the file you're writing the change log entry for
;; relative to the root of your project directory.
;; If change-log-default-name is "log", this function assumes the
;; file is part of a monotone project and return the files path
;; relative to "/_MTN/..", just like monotone commands would do.
;; Otherwise returns the path of the file relative to the directory,
;; where the log file lives in.
;;
;; No leading slash prepended.
;;
;; To use this function type
;; M-x customize-variable RET add-log-file-name-function RET
;; and make it point to mtn-add-log-file-name.
;; Unfortunately this function relies on log-file, which is an undocumented
;; variable in add-log.el, actually a local variabel in function
;; add-log-file-name (buffer-file log-file).
;; But I couldn't find an other way, to get the logfile, the user has
;; choosen at this point.
;;
(defun mtn-add-log-file-name(original-name)
"Return the filename printed in _MTN/log (or ChangeLog) relative to
the projects root. That is the driectory the file ChangeLog lives in,
if not a monotone project, _MTN/../ otherwise.
Improvements and suggestions to sebastian_rose@gmx.de."
(let ((directory (mtn-get-parent-directory log-file))
(file (file-truename original-name)))
(if (string= change-log-default-name "log")
;; monotone
(let ((directory (mtn-get-parent-directory directory)))
(file-relative-name file directory))
;; else no monotone:
(file-relative-name file directory))))