* lisp/emms-metaplaylist-mode.el: re-write.

This is all but a re-write of metaplaylist mode to make it a more
usable.

1 files changed, 110 insertions, 50 deletions

diff --git a/lisp/emms-metaplaylist-mode.el b/lisp/emms-metaplaylist-mode.el
index 572b7b9..e1ccda7 100644
--- a/lisp/emms-metaplaylist-mode.el
+++ b/lisp/emms-metaplaylist-mode.el
@@ -1,6 +1,6 @@
 ;;; emms-metaplaylist-mode.el --- A major mode for lists of Emms playlists
 
-;; Copyright (C) 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+;; Copyright (C) 2006, 2007, 2008, 2009, 2017 Free Software Foundation, Inc.
 
 ;; Author: Yoni Rabkin <yrk@gnu.org>
 
@@ -42,7 +42,7 @@
   :prefix "emms-metaplaylist-mode-"
   :group 'multimedia)
 
-(defcustom emms-metaplaylist-mode-buffer-name "*Emms Playlists*"
+(defcustom emms-metaplaylist-mode-buffer-name "*Emms Playlist Buffers*"
   "*Name of the buffer in which Emms playlists will be listed."
   :type 'string
   :group 'emms-metaplaylist-mode)
@@ -81,13 +81,16 @@
 (defconst emms-metaplaylist-mode-map
   (let ((map (make-sparse-keymap)))
     (set-keymap-parent map text-mode-map)
-    (define-key map (kbd "n") 'next-line)
-    (define-key map (kbd "p") 'previous-line)
+    (define-key map (kbd "n")   'next-line)
+    (define-key map (kbd "p")   'previous-line)
     (define-key map (kbd "RET") 'emms-metaplaylist-mode-goto-current)
-    (define-key map (kbd "q") 'kill-this-buffer)
-    (define-key map (kbd "?") 'describe-mode)
-    (define-key map (kbd "SPC") 'emms-metaplaylist-set-active)
-    (define-key map (kbd "c") 'emms-metaplaylist-new-buffer)
+    (define-key map (kbd "SPC") 'emms-metaplaylist-mode-set-active)
+    (define-key map (kbd "g")   'emms-metaplaylist-mode-update)
+    (define-key map (kbd "C")   'emms-metaplaylist-mode-new-buffer)
+    (define-key map (kbd "C-k") 'emms-metaplaylist-mode-kill-buffer)
+    (define-key map (kbd "c")   'emms-metaplaylist-mode-center-current)
+    (define-key map (kbd "q")   'kill-this-buffer)
+    (define-key map (kbd "?")   'describe-mode)
     map)
   "Keymap for `emms-metaplaylist-mode'.")
 
@@ -98,62 +101,115 @@
 (defun emms-metaplaylist-mode-goto-current ()
   "Switch to the buffer at point."
   (interactive)
-  (switch-to-buffer
-   (buffer-substring (point-at-bol)
-		     (point-at-eol))))
+  (let ((buffer (get-buffer
+		 (buffer-substring (point-at-bol)
+				   (point-at-eol)))))
+  (emms-playlist-set-playlist-buffer buffer)
+  (switch-to-buffer buffer)))
+
+(defun emms-metaplaylist-mode-write (playlists)
+  "Print the sorted list of PLAYLISTS."
+  (delete-region (point-min) (point-max))
+  (mapc (lambda (buf)
+	  (let ((inhibit-read-only t))
+	    (insert (buffer-name buf))
+	    (add-text-properties
+	     (point-at-bol) (point-at-eol)
+	     (list 'face
+		   (if (eq buf emms-playlist-buffer)
+		       'emms-metaplaylist-mode-current-face
+		     'emms-metaplaylist-mode-face)))
+	    (newline)))
+	playlists))
+
+;; Emms' list changes order, and that's OK, but we want something
+;; stable for display purposes.
+(defun emms-metaplaylist-mode-sorted-buffer-list ()
+  "Return a sorted list of playlist buffers."
+  (sort
+   (copy-tree		    
+    (emms-playlist-buffer-list))
+   #'(lambda (a b)
+       (string< (buffer-name a)
+		(buffer-name b)))))
+
+(defun emms-metaplaylist-mode-center-current ()
+  "Center on the current playlist buffer"
+  (interactive)
+  (when (not emms-playlist-buffer)
+    (error "no current playlist buffer"))
+  (goto-char (point-min))
+  (when (not (search-forward-regexp
+	      (or (buffer-name emms-playlist-buffer)
+		  "")
+	      (point-max) t))
+    (goto-char (point-min)))
+  (goto-char (point-at-bol)))
 
-;; Since there will never be a significantly large amount of playlist
-;; buffers co-existing at once, we allow ourselves not to keep
-;; state. We regenerate the playlists buffer anew on demand.
 (defun emms-metaplaylist-mode-create ()
-  "Create or recreate the meta-playlist buffer."
+  "Create the meta-playlist buffer."
   (let ((name emms-metaplaylist-mode-buffer-name)
-	(playlists (emms-playlist-buffer-list)))
+	(playlists (emms-metaplaylist-mode-sorted-buffer-list)))
     (if playlists
-	(progn
-	  (condition-case nil
-	      (kill-buffer name)
-	    (error nil))
-	  (get-buffer-create name)
-	  (with-current-buffer name
-	    (emms-metaplaylist-mode)
-	    (save-excursion
-	      (mapc (lambda (buf)
-		      (let ((inhibit-read-only t))
-			(insert (buffer-name buf))
-			(add-text-properties
-			 (point-at-bol) (point-at-eol)
-			 (list 'face
-			       (if (eq buf emms-playlist-buffer)
-				   'emms-metaplaylist-mode-current-face
-				 'emms-metaplaylist-mode-face)))
-			(newline)))
-		    playlists))
-	    (current-buffer)))	       ; return the buffer as lisp obj
+	(with-current-buffer (get-buffer-create name)
+	  (emms-metaplaylist-mode)
+	  (emms-metaplaylist-mode-write playlists)
+	  (emms-metaplaylist-mode-center-current)
+	  (current-buffer))
       (error "No Emms playlist buffers"))))
 
+(defun emms-metaplaylist-mode-assert-buffer ()
+  "Assert that we are in the metaplaylist mode buffer."
+  (when (not (eq (current-buffer)
+		 (get-buffer emms-metaplaylist-mode-buffer-name)))
+    (error "not the metalplaylist buffer")))
+
+(defun emms-metaplaylist-mode-update ()
+  "Update the metalplaylist display."
+  (interactive)
+  (emms-metaplaylist-mode-assert-buffer)
+  (let ((inhibit-read-only t))
+    (emms-metaplaylist-mode-write
+     (emms-metaplaylist-mode-sorted-buffer-list)))
+  (emms-metaplaylist-mode-center-current))
+
+(defun emms-metaplaylist-mode-kill-buffer ()
+  "Kill the buffer at point"
+  (interactive)
+  (let ((buffer (get-buffer
+		 (buffer-substring (point-at-bol)
+				   (point-at-eol)))))
+    (when (not buffer)
+      (error "can't find buffer at point"))
+    (if (y-or-n-p (format "kill playlist buffer \"%s\"?"
+			  (buffer-name buffer)))
+	(kill-buffer buffer)
+      (message "Buffer kill aborted."))
+    (emms-metaplaylist-mode-update)))
+
+
 ;;; --------------------------------------------------------
-;;; Playlist Management : creation, deletion (?)
+;;; Playlist Management
 ;;; --------------------------------------------------------
 
-(defun emms-metaplaylist-new-buffer (buffer-name)
-  "Creates a new buffer called buffer-name, which will be ready
-to host EMMS tracks."
+(defun emms-metaplaylist-mode-new-buffer (buffer-name)
+  "Creates a new buffer playlist buffer BUFFER-NAME."
   (interactive "sBuffer Name: ")
-  (if(get-buffer buffer-name)
+  (if (get-buffer buffer-name)
       (error "Buffer must not exist.")
     (let ((buf (get-buffer-create buffer-name)))
       (with-current-buffer buf
-        (setq emms-playlist-buffer-p t)))
-    (message "Buffer created")))
+	(emms-playlist-mode)
+	(setq emms-playlist-buffer-p t)))
+    (emms-metaplaylist-mode-update)))
 
-(defun emms-metaplaylist-set-active ()
+(defun emms-metaplaylist-mode-set-active ()
+  "Set the buffer at point to be the active playlist."
   (interactive)
   (emms-playlist-set-playlist-buffer 
    (get-buffer (buffer-substring (point-at-bol) (point-at-eol))))
-  (let ((ici (point)))
-    (emms-metaplaylist-mode-go)
-    (goto-char ici)))
+  (emms-metaplaylist-mode-update))
+
 
 ;;; --------------------------------------------------------
 ;;; Mode entry
@@ -162,12 +218,16 @@ to host EMMS tracks."
 (defun emms-metaplaylist-mode-go ()
   "Single entry point to the metaplaylist interface."
   (interactive)
-  (emms-metaplaylist-mode-create)
-  (switch-to-buffer emms-metaplaylist-mode-buffer-name))
+  (let ((mpm-buffer (get-buffer emms-metaplaylist-mode-buffer-name)))
+    (if mpm-buffer
+	(with-current-buffer mpm-buffer
+	  (emms-metaplaylist-mode-update))
+      (setq mpm-buffer (emms-metaplaylist-mode-create)))
+    (switch-to-buffer mpm-buffer)))
 
 (defun emms-metaplaylist-mode ()
   "A major mode for Emms playlists."
-;;  (interactive)
+  ;;  (interactive)
   (kill-all-local-variables)
 
   (use-local-map emms-metaplaylist-mode-map)