;;; mq.el --- Emacs support for Mercurial Queues

;; Copyright (C) 2006 Bryan O'Sullivan

;; Author: Bryan O'Sullivan <bos@serpentine.com>

;; mq.el is free software; you can redistribute it and/or modify it

;; under the terms of version 2 of the GNU General Public License as

;; published by the Free Software Foundation.

;; mq.el is distributed in the hope that it will be useful, but

;; WITHOUT ANY WARRANTY; without even the implied warranty of

;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

;; General Public License for more details.

;; You should have received a copy of the GNU General Public License

;; along with mq.el, GNU Emacs, or XEmacs; see the file COPYING (`C-h

;; C-l').  If not, write to the Free Software Foundation, Inc., 59

;; Temple Place - Suite 330, Boston, MA 02111-1307, USA.

(require 'mercurial)

(defcustom mq-mode-hook nil

  "Hook run when a buffer enters mq-mode."

  :type 'sexp

  :group 'mercurial)

(defcustom mq-global-prefix "\C-cq"

  "The global prefix for Mercurial Queues keymap bindings."

  :type 'sexp

  :group 'mercurial)

(defcustom mq-edit-mode-hook nil

  "Hook run after a buffer is populated to edit a patch description."

  :type 'sexp

  :group 'mercurial)

;;; Internal variables.

(defvar mq-mode nil

  "Is this file managed by MQ?")

(make-variable-buffer-local 'mq-mode)

(put 'mq-mode 'permanent-local t)

(defvar mq-patch-history nil)

(defvar mq-top-patch '(nil))

(defvar mq-prev-buffer nil)

(make-variable-buffer-local 'mq-prev-buffer)

(put 'mq-prev-buffer 'permanent-local t)

;;; Global keymap.

(defvar mq-global-map (make-sparse-keymap))

(fset 'mq-global-map mq-global-map)

(global-set-key mq-global-prefix 'mq-global-map)

(define-key mq-global-map "." 'mq-push)

(define-key mq-global-map ">" 'mq-push-all)

(define-key mq-global-map "," 'mq-pop)

(define-key mq-global-map "<" 'mq-pop-all)

(define-key mq-global-map "r" 'mq-refresh)

(define-key mq-global-map "e" 'mq-refresh-edit)

(define-key mq-global-map "n" 'mq-next)

(define-key mq-global-map "p" 'mq-previous)

(define-key mq-global-map "t" 'mq-top)

(add-minor-mode 'mq-mode 'mq-mode)

;;; Refresh edit mode keymap.

(defvar mq-edit-mode-map (make-sparse-keymap))

(define-key mq-edit-mode-map "\C-c\C-c" 'mq-edit-finish)

(define-key mq-edit-mode-map "\C-c\C-k" 'mq-edit-kill)

;;; Helper functions.

(defun mq-read-patch-name (&optional source prompt)

  "Read a patch name to use with a command.

May return nil, meaning \"use the default\"."

  (let ((patches (split-string

		  (hg-chomp (hg-run0 (or source "qseries"))) "\n")))

    (when current-prefix-arg

      (completing-read (format "Patch%s: " (or prompt ""))

		       (map 'list 'cons patches patches)

		       nil

		       nil

		       nil

		       'mq-patch-history))))

(defun mq-refresh-buffers (root)

  (save-excursion

    (dolist (buf (hg-buffers-visiting-repo root))

      (when (not (verify-visited-file-modtime buf))

	(set-buffer buf)

	(let ((ctx (hg-buffer-context)))

	  (message "Refreshing %s..." (buffer-name))

	  (revert-buffer t t t)

	  (hg-restore-context ctx)

	  (message "Refreshing %s...done" (buffer-name))))))

  (hg-update-mode-lines root)

  (mq-update-mode-lines root))

(defun mq-last-line ()

  (goto-char (point-max))

  (beginning-of-line)

  (when (looking-at "^$")

    (forward-line -1))

  (let ((bol (point)))

    (end-of-line)

    (let ((line (buffer-substring bol (point))))

      (when (> (length line) 0)

	line))))

(defun mq-push (&optional patch)

  "Push patches until PATCH is reached.

If PATCH is nil, push at most one patch."

  (interactive (list (mq-read-patch-name "qunapplied" " to push")))

  (let ((root (hg-root))

	(prev-buf (current-buffer))

	last-line ok)

    (unless root

      (error "Cannot push outside a repository!"))

    (hg-sync-buffers root)

    (let ((buf-name (format "MQ: Push %s" (or patch "next patch"))))

      (kill-buffer (get-buffer-create buf-name))

      (split-window-vertically)

      (other-window 1)

      (switch-to-buffer (get-buffer-create buf-name))

      (cd root)

      (message "Pushing...")

      (setq ok (= 0 (apply 'call-process (hg-binary) nil t t "qpush"

			   (if patch (list patch))))

	    last-line (mq-last-line))

      (let ((lines (count-lines (point-min) (point-max))))

	(if (and (equal lines 2) (string-match "Now at:" last-line))

	    (progn

	      (kill-buffer (current-buffer))

	      (delete-window))

	  (hg-view-mode prev-buf))))

    (mq-refresh-buffers root)

    (sit-for 0)

    (when last-line

      (if ok

	  (message "Pushing... %s" last-line)

	(error "Pushing... %s" last-line)))))

(defun mq-push-all ()

  "Push patches until all are applied."

  (interactive)

  (mq-push "-a"))

(defun mq-pop (&optional patch)

  "Pop patches until PATCH is reached.

If PATCH is nil, pop at most one patch."

  (interactive (list (mq-read-patch-name "qapplied" " to pop to")))

  (let ((root (hg-root))

	last-line ok)

    (unless root

      (error "Cannot pop outside a repository!"))

    (hg-sync-buffers root)

    (set-buffer (generate-new-buffer "qpop"))

    (cd root)

    (message "Popping...")

    (setq ok (= 0 (apply 'call-process (hg-binary) nil t t "qpop"

			 (if patch (list patch))))

	  last-line (mq-last-line))

    (kill-buffer (current-buffer))

    (mq-refresh-buffers root)

    (sit-for 0)

    (when last-line

      (if ok

	  (message "Popping... %s" last-line)

	(error "Popping... %s" last-line)))))

(defun mq-pop-all ()

  "Push patches until none are applied."

  (interactive)

  (mq-pop "-a"))

(defun mq-refresh-internal (root &rest args)

  (hg-sync-buffers root)

  (let ((patch (mq-patch-info "qtop")))

    (message "Refreshing %s..." patch)

    (let ((ret (apply 'hg-run "qrefresh" args)))

      (if (equal (car ret) 0)

	  (message "Refreshing %s... done." patch)

	(error "Refreshing %s... %s" patch (hg-chomp (cdr ret)))))))

(defun mq-refresh ()

  "Refresh the topmost applied patch."

  (interactive)

  (let ((root (hg-root)))

    (unless root

      (error "Cannot refresh outside of a repository!"))

  (mq-refresh-internal root)))

(defun mq-patch-info (cmd &optional msg)

  (let* ((ret (hg-run cmd))

	 (info (hg-chomp (cdr ret))))

    (if (equal (car ret) 0)

	(if msg

	    (message "%s patch: %s" msg info)

	  info)

      (error "%s" info))))

(defun mq-top ()

  "Print the name of the topmost applied patch."

  (interactive)

  (mq-patch-info "qtop" "Top"))

(defun mq-next ()

  "Print the name of the next patch to be pushed."

  (interactive)

  (mq-patch-info "qnext" "Next"))

(defun mq-previous ()

  "Print the name of the first patch below the topmost applied patch.

This would become the active patch if popped to."

  (interactive)

  (mq-patch-info "qprev" "Previous"))

(defun mq-edit-finish ()

  "Finish editing the description of this patch, and refresh the patch."

  (interactive)

  (unless (equal (mq-patch-info "qtop") mq-top)

    (error "Topmost patch has changed!"))

  (hg-sync-buffers hg-root)

  (mq-refresh-internal hg-root "-m" (buffer-substring (point-min) (point-max)))

  (let ((buf mq-prev-buffer))

    (kill-buffer nil)

    (switch-to-buffer buf)))

(defun mq-edit-kill ()

  "Kill the edit currently being prepared."

  (interactive)

  (when (or (not (buffer-modified-p)) (y-or-n-p "Really kill this edit? "))

    (let ((buf mq-prev-buffer))

      (kill-buffer nil)

      (switch-to-buffer buf))))

(defun mq-get-top (root)

  (let ((entry (assoc root mq-top-patch)))

    (if entry

        (cdr entry))))

(defun mq-set-top (root patch)

  (let ((entry (assoc root mq-top-patch)))

    (if entry

        (if patch

            (setcdr entry patch)

          (setq mq-top-patch (delq entry mq-top-patch)))

      (setq mq-top-patch (cons (cons root patch) mq-top-patch)))))

(defun mq-update-mode-lines (root)

  (let ((cwd default-directory))

    (cd root)

    (condition-case nil

        (mq-set-top root (mq-patch-info "qtop"))

      (error (mq-set-top root nil)))

    (cd cwd))

  (let ((patch (mq-get-top root)))

    (save-excursion

      (dolist (buf (hg-buffers-visiting-repo root))

        (set-buffer buf)

        (if mq-mode

            (setq mq-mode (or (and patch (concat " MQ:" patch)) " MQ")))))))

(defun mq-mode (&optional arg)

  "Minor mode for Mercurial repositories with an MQ patch queue"

  (interactive "i")

  (cond ((hg-root)

         (setq mq-mode (if (null arg) (not mq-mode)

                         arg))

         (mq-update-mode-lines (hg-root))))

  (run-hooks 'mq-mode-hook))

(defun mq-edit-mode ()

  "Mode for editing the description of a patch.

Key bindings

------------

\\[mq-edit-finish]	use this description

\\[mq-edit-kill]	abandon this description"

  (interactive)

  (use-local-map mq-edit-mode-map)

  (set-syntax-table text-mode-syntax-table)

  (setq local-abbrev-table text-mode-abbrev-table

	major-mode 'mq-edit-mode

	mode-name "MQ-Edit")

  (set-buffer-modified-p nil)

  (setq buffer-undo-list nil)

  (run-hooks 'text-mode-hook 'mq-edit-mode-hook))

(defun mq-refresh-edit ()

  "Refresh the topmost applied patch, editing the patch description."

  (interactive)

  (while mq-prev-buffer

    (set-buffer mq-prev-buffer))

  (let ((root (hg-root))

	(prev-buffer (current-buffer))

	(patch (mq-patch-info "qtop")))

    (hg-sync-buffers root)

    (let ((buf-name (format "*MQ: Edit description of %s*" patch)))

      (switch-to-buffer (get-buffer-create buf-name))

      (when (= (point-min) (point-max))

	(set (make-local-variable 'hg-root) root)

	(set (make-local-variable 'mq-top) patch)

	(setq mq-prev-buffer prev-buffer)

	(insert (hg-run0 "qheader"))

	(goto-char (point-min)))

      (mq-edit-mode)

      (cd root)))

  (message "Type `C-c C-c' to finish editing and refresh the patch."))

(provide 'mq)

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