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;;; emms-bookmarks.el --- Bookmarks for Emms. -*- lexical-binding: t; -*-
;; Copyright (C) 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
;; Author: Yoni Rabkin <yrk@gnu.org>
;; Keywords: emms, bookmark
;; This file is part of EMMS.
;; EMMS is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 3, or (at your option)
;; any later version.
;;
;; EMMS 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 EMMS; if not, write to the Free Software Foundation,
;; Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
;;; Commentary:
;;
;; You can use this to add ``temporal bookmarks'' (term by Lucas
;; Bonnet) to your media files. The interesting functions here are
;; `emms-bookmarks-next', `emms-bookmarks-prev', `emms-bookmarks-add'
;; (which pauses the player while you describe the bookmark) and
;; `emms-bookmarks-clear'. All of which do exactly what you think
;; they do.
;;; Code:
;; dependencies
(require 'emms)
(require 'emms-playing-time)
(defvar emms-bookmarks-prev-overshoot 5
"Time in seconds for skipping a previous bookmark.")
(defun emms-bookmarks-reset (track)
"Remove all the bookmarks from TRACK."
(emms-track-set track 'bookmarks nil))
(defun emms-bookmarks-straight-insertion-sort (item l acc)
"Insert ITEM into the already sorted L, ACC should be nil."
(if (null l)
(append acc (list item))
(cond ((< (cdr item) (cdr (car l))) (append acc (list item (car l)) (cdr l)))
(t (emms-bookmarks-straight-insertion-sort item (cdr l) (append acc (list (car l))))))))
(defun emms-bookmarks-get (track)
"Return the bookmark property from TRACK."
(emms-track-get track 'bookmarks))
(defun emms-bookmarks-set (track desc time)
"Set bookmark property for TRACK, text DESC at TIME seconds."
(let ((old-bookmarks (emms-track-get track 'bookmarks))
(new-bookmarks nil))
(setq new-bookmarks (emms-bookmarks-straight-insertion-sort (cons desc time) old-bookmarks nil))
(emms-track-set track 'bookmarks new-bookmarks)))
(defun emms-bookmarks-set-current (desc)
"Set bookmark property for the current track with text DESC."
(emms-bookmarks-set (emms-playlist-current-selected-track) desc emms-playing-time))
(defun emms-bookmarks-search (time track test)
"Return a bookmark based on heuristics.
TIME should be a reference point in seconds.
TRACK should be an Emms track.
TEST should be a numerical comparator predicate."
(let ((s (append (list (cons "time" time)) (copy-sequence (emms-bookmarks-get track)))))
(sort s #'(lambda (a b) (funcall test (cdr a) (cdr b))))
(while (not (= time (cdar s)))
(setq s (cdr s)))
(when (cdr s)
(car (cdr s)))))
(defun emms-bookmarks-next-1 (time track)
"Return the bookmark after TIME for TRACK, otherwise return nil."
(emms-bookmarks-search time track #'<))
(defun emms-bookmarks-prev-1 (time track)
"Return the bookmark before TIME for TRACK, otherwise return nil."
(emms-bookmarks-search (- time emms-bookmarks-prev-overshoot) track #'>))
(defun emms-bookmarks-goto (search-f track failure-message)
"Seek the player to a bookmark.
SEARCH-F should be a function which returns a bookmark.
TRACK should be an Emms track.
FAILURE-MESSAGE should be a string."
;; note that when emms is paused then `emms-player-playing-p' => t
(when (not emms-player-playing-p)
(emms-start))
(let ((m (funcall search-f emms-playing-time track)))
(if m
(progn
(emms-player-seek-to (cdr m))
(message "%s" (car m)))
(message "%s" failure-message))))
;; entry points
(defun emms-bookmarks-next ()
"Seek to the next bookmark in the current track."
(interactive)
(emms-bookmarks-goto #'emms-bookmarks-next-1
(emms-playlist-current-selected-track)
"No next bookmark"))
(defun emms-bookmarks-prev ()
"Seek to the previous bookmark in the current track."
(interactive)
(emms-bookmarks-goto #'emms-bookmarks-prev-1
(emms-playlist-current-selected-track)
"No previous bookmark"))
(defmacro emms-bookmarks-with-paused-player (&rest body)
"Eval BODY with player paused."
`(progn
(when (not emms-player-paused-p) (emms-pause))
,@body
(when emms-player-paused-p (emms-pause))))
;; can't use `interactive' to promt the user here because we want to
;; pause the player before the prompt appears.
(defun emms-bookmarks-add ()
"Add a new bookmark to the current track.
This function pauses the player while prompting the user for a
description of the bookmark. The function resumes the player
after the prompt."
(interactive)
(emms-bookmarks-with-paused-player
(let ((desc (read-string "Description: ")))
(if (emms-playlist-current-selected-track)
(emms-bookmarks-set-current desc)
(error "No current track to bookmark")))))
(defun emms-bookmarks-clear ()
"Remove all the bookmarks from the current track."
(interactive)
(let ((this (emms-playlist-current-selected-track)))
(when this (emms-bookmarks-reset this))))
(provide 'emms-bookmarks)
;;; emms-bookmarks.el ends here
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