From: Tim Vaughan <timv@ughan.xyz>
Date: Sun, 8 Dec 2019 19:56:01 +0000 (+0100)
Subject: Decoupled browser from playback.
X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=commitdiff_plain;h=4c17fed4d674659349b4bf2e57750e99ee41e7e3;p=emus.git

Decoupled browser from playback.
---

diff --git a/emus.el b/emus.el
index e145fd4..ad7a5bd 100644
--- a/emus.el
+++ b/emus.el
@@ -1,17 +1,53 @@
-;;; emus.el --- Simple music player for Emacs.  -*- lexical-binding:t -*-
+;;; emus.el --- Simple mp3 player  -*- lexical-binding:t -*-
+
+;; Copyright (C) 2019 Tim Vaughan
 
 ;; Author: Tim Vaughan <timv@ughan.xyz>
+;; Created: 12 December 2019
 ;; Version: 1.0
 ;; Keywords: multimedia
-;; URL: https://thelambdalab.xyz/emus
+;; Homepage: http://thelambdalab.xy/emus
+;; Package-Requires: ((emacs "26"))
+
+;; This file is not part of GNU Emacs.
+
+;; This program 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 of the License, or
+;; (at your option) any later version.
+
+;; This program 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 this file.  If not, see <http://www.gnu.org/licenses/>.
 
 ;;; Commentary:
 
-;; This is a simple package for playing audio from a local library
-;; of audio files.
+;; This is a simple package for playing audio from a local directory
+;; tree of mp3 files.  It uses the program mpg123 as its back-end.
+;; Currently the library is loaded completely every time emus starts.
 
 ;;; Code:
 
+(provide 'emus)
+
+
+;;; Dependencies
+;;
+
+(require 'seq)
+
+
+;;; Global constants
+;;
+
+(defconst emus-version "1.0.0"
+  "Current version of emus.")
+
+
 ;;; Customizations
 ;;
 
@@ -57,19 +93,8 @@
 (defvar emus-records nil
   "Emus audio library.")
 
-(defun emus-make-record (filename tagstr)
-  (let ((artist "")
-        (album "")
-        (title ""))
-    (dolist (line (split-string tagstr "\n"))
-      (let ((found-artist (elt (split-string line "@I ID3v2.artist:") 1))
-            (found-album (elt (split-string line "@I ID3v2.album:") 1))
-            (found-title (elt (split-string line "@I ID3v2.title:") 1)))
-        (cond
-         (found-artist (setq artist found-artist))
-         (found-album (setq album found-album))
-         (found-title (setq title found-title)))))
-    (vector artist album title filename nil)))
+(defun emus-make-record (artist album title filename &optional pos)
+  (vector artist album title filename pos))
 
 (defun emus-record-artist (record)
   (elt record 0))
@@ -89,9 +114,8 @@
 (defun emus-set-record-browser-pos (record pos)
   (aset record 4 pos))
 
-(defun emus-update-records ()
-  (interactive)
-  (emus-suspend-cp)
+(defun emus--load-library (then)
+  (emus--suspend-cp)
   (setq emus-state 'stopped)
   (let ((proc (emus-get-process))
         (tagstr "")
@@ -101,20 +125,37 @@
                                (setq tagstr (concat tagstr string))
                                (when (string-suffix-p "@P 1\n" string)
                                  (add-to-list 'emus-records
-                                              (emus-make-record (car filenames)
-                                                                tagstr))
+                                              (emus--make-record-from-tagstr (car filenames)
+                                                                             tagstr))
                                  (setq tagstr "")
                                  (setq filenames (cdr filenames))
                                  (if filenames
                                      (emus-send-cmd "lp" (car filenames))
                                    (set-process-filter proc nil)
                                    (setq emus-records (reverse emus-records))
-                                   (emus-sort-records)
-                                   (emus-render-records)
-                                   (emus-resume-cp)))))
+                                   (emus--sort-records)
+                                   (unless emus-current-record
+                                     (setq emus-current-record (car emus-records)))
+                                   (funcall then)
+                                   ;; (emus-render-records)
+                                   (emus--resume-cp)))))
     (emus-send-cmd "lp" (car filenames))))
 
-(defun emus-sort-records ()
+(defun emus--make-record-from-tagstr (filename tagstr)
+  (let ((artist "")
+        (album "")
+        (title ""))
+    (dolist (line (split-string tagstr "\n"))
+      (let ((found-artist (elt (split-string line "@I ID3v2.artist:") 1))
+            (found-album (elt (split-string line "@I ID3v2.album:") 1))
+            (found-title (elt (split-string line "@I ID3v2.title:") 1)))
+        (cond
+         (found-artist (setq artist found-artist))
+         (found-album (setq album found-album))
+         (found-title (setq title found-title)))))
+    (emus-make-record artist album title filename nil)))
+
+(defun emus--sort-records ()
   (sort emus-records
         (lambda (r1 r2)
           (let ((artist1 (emus-record-artist r1))
@@ -123,7 +164,13 @@
                 (let ((album1 (emus-record-album r1))
                       (album2 (emus-record-album r2)))
                   (string< album1 album2))
-              (string< artist1 artist2))))))        
+              (string< artist1 artist2))))))
+
+(defmacro emus--with-library (&rest args)
+  `(if emus-records
+       (progn ,@args)
+     (emus--load-library
+      (lambda () ,@args))))
 
 ;;; mpg123 process
 ;;
@@ -172,10 +219,10 @@
 (defvar emus-state 'stopped)
 (defvar emus-continuous-playback t)
 
-(defun emus-suspend-cp ()
+(defun emus--suspend-cp ()
   (setq emus-continuous-playback nil))
 
-(defun emus-resume-cp ()
+(defun emus--resume-cp ()
   (setq emus-continuous-playback t)
   (set-process-filter (emus-get-process)
                       (lambda (proc string)
@@ -186,59 +233,64 @@
 
 (defun emus-play-record (record)
   "Set RECORD as current and start playing."
-  (let ((old-record emus-current-record))
-    (emus-send-cmd "l" (emus-record-file record))
-    (setq emus-state 'playing)
-    (setq emus-current-record record)
-    (emus-update-record old-record)
-    (emus-update-record record)
-    (emus-resume-cp)))
+  (emus--with-library
+   (let ((old-record emus-current-record))
+     (emus-send-cmd "l" (emus-record-file record))
+     (setq emus-state 'playing)
+     (setq emus-current-record record)
+     (emus--update-record old-record)
+     (emus--update-record record)
+     (emus--resume-cp))))
 
 (defun emus-select-record (record)
   "Set RECORD as current, but do not start playing."
-  (let ((old-record emus-current-record))
-    (setq emus-state 'stopped)
-    (setq emus-current-record record)
-    (emus-update-record old-record)
-    (emus-update-record record)
-    (emus-send-cmd "o")
-    (emus-resume-cp)))
+  (emus--with-library
+   (let ((old-record emus-current-record))
+     (setq emus-state 'stopped)
+     (setq emus-current-record record)
+     (emus--update-record old-record)
+     (emus--update-record record)
+     (emus-send-cmd "o")
+     (emus--resume-cp))))
 
 (defun emus-stop ()
   "Stop playback of the current record."
   (interactive)
-  (setq emus-state 'stopped)
-  (emus-update-record emus-current-record)
-  (emus-send-cmd "s"))
+  (emus--with-library
+   (setq emus-state 'stopped)
+   (emus--update-record emus-current-record)
+   (emus-send-cmd "s")))
 
 (defun emus-playpause ()
   (interactive)
-  (when emus-current-record
-    (if (eq emus-state 'stopped)
-        (emus-play-record emus-current-record)
-      (emus-send-cmd "p")
-      (pcase emus-state
-        ((or 'paused 'stopped) (setq emus-state 'playing))
-        ('playing (setq emus-state 'paused)))
-      (unless (eq emus-state 'paused)))
-    (emus-update-record emus-current-record)))
-
-(defun emus-set-volume (pct)
-  (emus-send-cmd "v" (number-to-string pct)))
+  (emus--with-library
+   (when emus-current-record
+     (if (eq emus-state 'stopped)
+         (emus-play-record emus-current-record)
+       (emus-send-cmd "p")
+       (pcase emus-state
+         ((or 'paused 'stopped) (setq emus-state 'playing))
+         ('playing (setq emus-state 'paused)))
+       (unless (eq emus-state 'paused)))
+     (emus--update-record emus-current-record))))
 
 (defvar emus-current-volume 100)
 
-(defun emus-volume-delta (delta)
-  (setq emus-current-volume (max 0 (min 100 (+ emus-current-volume delta))))
-  (emus-set-volume emus-current-volume))
+(defun emus-set-volume (pct)
+  (emus--with-library
+   (setq emus-current-volume pct)
+   (emus-send-cmd "v" (number-to-string pct))))
+
+(defun emus-volume-increase-by (delta)
+  (emus-set-volume (max 0 (min 100 (+ emus-current-volume delta)))))
 
 (defun emus-volume-up ()
   (interactive)
-  (emus-volume-delta 10))
+  (emus-volume-increase-by 10))
 
 (defun emus-volume-down ()
   (interactive)
-  (emus-volume-delta -10))
+  (emus-volume-increase-by -10))
 
 (defun emus-play-nearby (offset)
   (let ((idx (seq-position emus-records emus-current-record)))
@@ -249,7 +301,7 @@
                   (emus-play-record next-record)
                 (emus-select-record next-record))
             (error "Track does not exist")))
-      (error "No track is currently selected."))))
+      (error "No track is currently selected"))))
 
 (defun emus-play-next ()
   (interactive)
@@ -261,25 +313,26 @@
 
 (defun emus-display-status ()
   (interactive)
-  (message
-   (concat "Emus: Volume %d%%"
-           (pcase emus-state
-             ('stopped " [Stopped]")
-             ('paused " [Paused]")
-             ('playing " [Playing]")
-             (_ ""))
-           (if emus-current-record
-               (format " - %.30s (%.20s)"
-                       (emus-record-title emus-current-record)
-                       (emus-record-artist emus-current-record))
-             ""))
-   emus-current-volume))
+  (emus--with-library
+   (message
+    (concat "Emus: Volume %d%%"
+            (pcase emus-state
+              ('stopped " [Stopped]")
+              ('paused " [Paused]")
+              ('playing " [Playing]")
+              (_ ""))
+            (if emus-current-record
+                (format " - %.30s (%.20s)"
+                        (emus-record-title emus-current-record)
+                        (emus-record-artist emus-current-record))
+              ""))
+    emus-current-volume)))
 
 
 ;;; Browser
 ;;
 
-(defun emus-insert-record (record &optional prev-record first)
+(defun emus--insert-record (record &optional prev-record first)
   (let* ((artist (emus-record-artist record))
          (album (emus-record-album record))
          (title (emus-record-title record))
@@ -288,7 +341,7 @@
       (unless (equal (emus-record-artist prev-record) artist)
         (insert-text-button
          (propertize artist 'face 'emus-artist)
-         'action #'emus-click-record
+         'action #'emus--click-record
          'follow-link t
          'help-echo help-str
          'emus-record record)
@@ -296,7 +349,7 @@
       (unless (equal (emus-record-album prev-record) album)
         (insert-text-button
          (propertize (concat "  " album) 'face 'emus-album)
-         'action #'emus-click-record
+         'action #'emus--click-record
          'follow-link t
          'help-echo help-str
          'emus-record record)
@@ -317,7 +370,7 @@
                     'face (if is-current
                               'emus-track-current
                             'emus-track)))
-       'action #'emus-click-record
+       'action #'emus--click-record
        'follow-link t
        'help-echo help-str
        'emus-record record)
@@ -326,7 +379,7 @@
                                     'emus-track-current
                                   'emus-track))))))
 
-(defun emus-update-record (record)
+(defun emus--update-record (record)
   (let ((record-pos (emus-record-browser-pos record)))
     (when (and (get-buffer "*emus*")
                (emus-record-browser-pos record))
@@ -337,10 +390,10 @@
             (search-forward "\n")
             (delete-region record-pos (point))
             (goto-char record-pos)
-            (emus-insert-record record)
+            (emus--insert-record record)
             (goto-char old-point))))))
 
-(defun emus-render-records ()
+(defun emus--render-records ()
   (with-current-buffer "*emus*"
     (let ((inhibit-read-only t)
           (old-pos (point)))
@@ -348,11 +401,11 @@
       (goto-char (point-min))
       (let ((prev-record nil))
         (dolist (record emus-records)
-          (emus-insert-record record prev-record (not prev-record))
+          (emus--insert-record record prev-record (not prev-record))
           (setq prev-record record)))
       (goto-char old-pos))))
 
-(defun emus-click-record (button)
+(defun emus--click-record (button)
   (emus-play-record (button-get button 'emus-record))
   (emus-display-status))
 
@@ -367,18 +420,23 @@
 (defun emus-browse ()
   "Switch to *emus* audio library browser."
   (interactive)
-  (switch-to-buffer "*emus*")
-  (emus-browser-mode)
-  (emus-volume emus-current-volume)
-  (if emus-records
-      (emus-render-records)
-    (emus-update-records)))
+  (emus--with-library
+   (switch-to-buffer "*emus*")
+   (emus-browser-mode)
+   (emus--render-records)
+   (emus-centre-current)))
+
+(defun emus-refresh ()
+  (interactive)
+  (emus-stop)
+  (setq emus-records nil)
+  (emus-browse))
 
 (defun emus-playpause-status () (interactive) (emus-playpause) (emus-display-status))
 (defun emus-stop-status () (interactive) (emus-stop) (emus-display-status))
 (defun emus-volume-up-status () (interactive) (emus-volume-up) (emus-display-status))
 (defun emus-volume-down-status () (interactive) (emus-volume-down) (emus-display-status))
-(defun emus-update-records-status () (interactive) (emus-update-records) (emus-display-status))
+(defun emus-refresh-status () (interactive) (emus-refresh) (emus-display-status))
 (defun emus-play-next-status () (interactive) (emus-play-next) (emus-display-status))
 (defun emus-play-prev-status () (interactive) (emus-play-prev) (emus-display-status))
 (defun emus-centre-current-status () (interactive) (emus-centre-current) (emus-display-status))
@@ -390,7 +448,7 @@
     (define-key map (kbd "+") 'emus-volume-up-status)
     (define-key map (kbd "=") 'emus-volume-up-status)
     (define-key map (kbd "-") 'emus-volume-down-status)
-    (define-key map (kbd "R") 'emus-update-records-status)
+    (define-key map (kbd "R") 'emus-refresh-status)
     (define-key map (kbd "n") 'emus-play-next-status)
     (define-key map (kbd "p") 'emus-play-prev-status)
     (define-key map (kbd "c") 'emus-centre-current-status)
@@ -401,7 +459,7 @@
         (kbd "+") 'emus-volume-up-status
         (kbd "=") 'emus-volume-up-status
         (kbd "-") 'emus-volume-down-status
-        (kbd "R") 'emus-update-records-status
+        (kbd "R") 'emus-refresh-status
         (kbd "n") 'emus-play-next-status
         (kbd "p") 'emus-play-prev-status
         (kbd "c") 'emus-centre-current-status))
@@ -414,6 +472,4 @@
 (when (fboundp 'evil-set-initial-state)
   (evil-set-initial-state 'emus-browser-mode 'motion))
 
-;;; Debugging
-
 ;;; emus.el ends here