Add support for loading/saving m3u playlists

.gitignore

@@ -2,3 +2,5 @@
 .flatpak-builder
 .flatpak
 build
+.vscode/settings.json
+.gitignore

po/POTFILES

@@ -4,3 +4,4 @@ src/PlaybackManager.vala
 src/Views/NowPlayingView.vala
 src/Widgets/AlbumImage.vala
 src/Widgets/SeekBar.vala
+src/Services/M3U.vala

src/Application.vala

@@ -12,6 +12,7 @@ public class Music.Application : Gtk.Application {
     public const string ACTION_FIND = "action-find";
     public const string ACTION_CLEAR_QUEUE = "action-clear-queue";
     public const string ACTION_QUIT = "action-quit";
+    public const string ACTION_SAVE_M3U_PLAYLIST = "action-save-m3u-playlist";
 
     private const ActionEntry[] ACTION_ENTRIES = {
         { ACTION_PLAY_PAUSE, action_play_pause, null, "false" },
@@ -20,7 +21,8 @@ public class Music.Application : Gtk.Application {
         { ACTION_SHUFFLE, action_shuffle },
         { ACTION_FIND, action_find },
         { ACTION_CLEAR_QUEUE, action_clear_queue },
-        { ACTION_QUIT, quit }
+        { ACTION_QUIT, quit },
+        { ACTION_SAVE_M3U_PLAYLIST, action_save_m3u_playlist}
     };
 
     private PlaybackManager? playback_manager = null;
@@ -48,6 +50,7 @@ public class Music.Application : Gtk.Application {
 
         set_accels_for_action (ACTION_PREFIX + ACTION_FIND, {"<Ctrl>F"});
         set_accels_for_action (ACTION_PREFIX + ACTION_QUIT, {"<Ctrl>Q"});
+        set_accels_for_action (ACTION_PREFIX + ACTION_SAVE_M3U_PLAYLIST, {"<Ctrl>S"});
 
         ((SimpleAction) lookup_action (ACTION_PLAY_PAUSE)).set_enabled (false);
         ((SimpleAction) lookup_action (ACTION_PLAY_PAUSE)).set_state (false);
@@ -160,6 +163,15 @@ public class Music.Application : Gtk.Application {
                 continue;
             }
 
+            if ((file_path.ascii_down ().has_suffix (".m3u")) || (file_path.ascii_down ().has_suffix (".m3u8"))) {
+                foreach (var track in M3U.parse_playlist (file)) {
+                    elements += track;
+                }
+
+                // Avoid adding the m3u - Else its content gets re-added every startup
+                continue;
+            }
+
             elements += file;
         }
 
@@ -200,6 +212,10 @@ public class Music.Application : Gtk.Application {
         playback_manager.clear_queue ();
     }
 
+    private void action_save_m3u_playlist () {
+        M3U.save_playlist ((MainWindow)active_window, playback_manager.queue_liststore);
+    }
+
     private void on_bus_acquired (DBusConnection connection, string name) {
         try {
             connection.register_object ("/org/mpris/MediaPlayer2", new MprisRoot ());

src/Services/M3U.vala

@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: LGPL-3.0-or-later
+ * SPDX-FileCopyrightText: 2021 elementary, Inc. (https://elementary.io)
+ */
+
+namespace Music.M3U {
+
+    // Standard specification here: https://en.wikipedia.org/wiki/M3U
+    public File[] parse_playlist (File playlist) {
+        debug ("Parsing playlist: " + playlist.get_basename () + "\n");
+        File[] list = {};
+
+        try {
+            FileInputStream @is = playlist.read ();
+            DataInputStream dis = new DataInputStream (@is);
+            string line;
+
+            while ((line = dis.read_line ()) != null) {
+                print ("%s\n", line);
+
+                // Skip extended 
+                if (line.has_prefix ("#EXT")) {
+                    print ("Skipping EXTM3U: " + line + "\n");
+
+                } else {
+                    File target;
+
+                    if (line.ascii_down ().has_prefix ("file:///")) {
+                        target = File.new_for_uri (line);
+
+                    //FIXME: URL get skipped.
+                    //} else if (line.ascii_down ().has_prefix ("http")) {
+                    //    print ("URL are currently unsupported:" + line + "\n");
+
+                    } else {
+                        target = File.new_for_path (line);
+
+                    };
+
+                    // We do not need to test yet whether files exist
+                    list += target;
+                }
+            }
+
+        } catch (Error e) {
+            print ("Error: %s\n", e.message);
+        }
+
+        return list;
+
+    }
+
+    public void save_playlist (MainWindow parent, ListStore queue_liststore) {
+        debug ("Saving queue as playlist" + "\n");
+        string content = "";
+
+        for (var i = 0; i < queue_liststore.n_items; i++) {
+            var item = (Music.AudioObject)queue_liststore.get_item (i);
+            content = content + item.uri + "\n";
+        }
+
+        var save_dialog = new Gtk.FileDialog () {
+            initial_name = _("New playlist.m3u")
+        };
+
+        save_dialog.save.begin (parent, null, (obj, res) => {
+            try {
+                var file = save_dialog.save.end (res);
+                var dostream = new DataOutputStream (
+                                             file.replace (
+                                                           null,
+                                                           false,
+                                                           GLib.FileCreateFlags.REPLACE_DESTINATION
+                                             )
+                );
+
+            dostream.put_string (content);
+
+            } catch (Error err) {
+                    warning ("Failed to save file: %s", err.message);
+            }
+        });
+
+
+    }
+}

src/meson.build

@@ -9,6 +9,7 @@ sources = [
     'Widgets/AlbumImage.vala',
     'Widgets/SeekBar.vala',
     'Widgets/TrackRow.vala',
+    'Services/M3U.vala',
 ]
 
 executable(