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Diffstat (limited to 'emms-cache.el')
| -rw-r--r-- | emms-cache.el | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/emms-cache.el b/emms-cache.el new file mode 100644 index 0000000..792b1b8 --- /dev/null +++ b/emms-cache.el @@ -0,0 +1,195 @@ +;;; emms-cache.el --- persistence for emms-track + +;; Copyright (C) 2006, 2007, 2008, 2009 Free Software Foundation, Inc. + +;; Author: Damien Elmes <emacs@repose.cx> +;; Keywords: emms, mp3, mpeg, multimedia + +;; 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; see the file COPYING. If not, write to the +;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, +;; Boston, MA 02110-1301, USA. + +;;; Commentary: + +;; The cache is a mapping of a full path name to information, and so +;; it is invalidated when you rename or move files about. It also +;; does not differentiate between file or uri tracks. + +;; Because cache lookups are much faster than disk access, this works +;; much better with a later-do-interval of something like 0.001. Also +;; consider using synchronous mode, as it's quite fast now. + +;; This code is activated by (emms-standard) and above. + +;; To activate it by hand, use: + +;; (emms-cache 1) + +;;; Code: + +(require 'emms) +(require 'emms-info) + +(when (fboundp 'define-hash-table-test) + (define-hash-table-test 'string-hash 'string= 'sxhash)) + +(defvar emms-cache-db (make-hash-table + :test (if (fboundp 'define-hash-table-test) + 'string-hash + 'equal)) + "A mapping of paths to file info. +This is used to cache over emacs sessions.") + +(defvar emms-cache-dirty nil + "True if the cache has been updated since init.") + +(defcustom emms-cache-file (concat (file-name-as-directory emms-directory) "cache") + "A file used to store cached file information over sessions." + :group 'emms + :type 'file) + +(defcustom emms-cache-file-coding-system 'utf-8 + "Coding system used for saving `emms-cache-file'." + :group 'emms + :type 'coding-system) + +(defun emms-cache (arg) + "Turn on Emms caching if ARG is positive, off otherwise." + (interactive "p") + (if (and arg (> arg 0)) + (progn + (unless emms-cache-dirty + (emms-cache-restore)) + (unless noninteractive + (add-hook 'kill-emacs-hook 'emms-cache-save)) + (setq emms-cache-get-function 'emms-cache-get) + (setq emms-cache-set-function 'emms-cache-set) + (setq emms-cache-modified-function 'emms-cache-dirty)) + (remove-hook 'kill-emacs-hook 'emms-cache-save) + (setq emms-cache-get-function nil) + (setq emms-cache-set-function nil) + (setq emms-cache-modified-function nil))) + +;;;###autoload +(defun emms-cache-enable () + "Enable caching of Emms track data." + (interactive) + (emms-cache 1) + (message "Emms cache enabled")) + +;;;###autoload +(defun emms-cache-disable () + "Disable caching of Emms track data." + (interactive) + (emms-cache -1) + (message "Emms cache disabled")) + +;;;###autoload +(defun emms-cache-toggle () + "Toggle caching of Emms track data." + (interactive) + (if emms-cache-get-function + (emms-cache-disable) + (emms-cache-enable))) + +(defsubst emms-cache-dirty (&rest ignored) + "Mark the cache as dirty." + (setq emms-cache-dirty t)) + +(defun emms-cache-get (type path) + "Return a cache element for PATH, or nil." + (gethash path emms-cache-db)) + +;; Note we ignore TYPE, as it's stored in TRACK +(defun emms-cache-set (type path track) + "Set PATH to TRACK in the cache." + (puthash path track emms-cache-db) + (emms-cache-dirty)) + +(defun emms-cache-del (path) + "Remove a track from the cache, with key PATH." + (remhash path emms-cache-db) + (emms-cache-dirty)) + +(defun emms-cache-save () + "Save the track cache to a file." + (interactive) + (when emms-cache-dirty + (message "Saving emms track cache...") + (set-buffer (get-buffer-create " emms-cache ")) + (erase-buffer) + (insert + (concat ";;; .emms-cache -*- mode: emacs-lisp; coding: " + (symbol-name emms-cache-file-coding-system) + "; -*-\n")) + (maphash (lambda (k v) + (insert (format + "(puthash %S '%S emms-cache-db)\n" k v))) + emms-cache-db) + (when (fboundp 'set-buffer-file-coding-system) + (set-buffer-file-coding-system emms-cache-file-coding-system)) + (unless (file-directory-p (file-name-directory emms-cache-file)) + (make-directory (file-name-directory emms-cache-file))) + (write-region (point-min) (point-max) emms-cache-file) + (kill-buffer (current-buffer)) + (message "Saving emms track cache...done") + (setq emms-cache-dirty nil))) + +(defun emms-cache-restore () + "Restore the track cache from a file." + (interactive) + (load emms-cache-file t nil t) + (setq emms-cache-dirty nil)) + +(defun emms-cache-sync () + "Sync the cache with the data on disc. +Remove non-existent files, and update data for files which have +been modified." + (interactive) + (message "Syncing emms track cache...") + (let (removed) + (maphash (lambda (path track) + (when (eq (emms-track-get track 'type) 'file) + ;; if no longer here, remove + (if (not (file-exists-p path)) + (progn + (remhash path emms-cache-db) + (setq removed t)) + (let ((file-mtime (emms-info-track-file-mtime track)) + (info-mtime (emms-track-get track 'info-mtime))) + (when (or (not info-mtime) + (emms-time-less-p + info-mtime file-mtime)) + (run-hook-with-args 'emms-info-functions track)))))) + emms-cache-db) + (when removed + (setq emms-cache-dirty t))) + (message "Syncing emms track cache...done")) + +(defun emms-cache-reset () + "Reset the cache." + (interactive) + (when (yes-or-no-p "Really reset the cache?") + (setq emms-cache-db + (make-hash-table + :test (if (fboundp 'define-hash-table-test) + 'string-hash + 'equal))) + (setq emms-cache-dirty t) + (emms-cache-save))) + +(provide 'emms-cache) +;;; emms-cache.el ends here |