[gnome-music/wip/jfelder/open-audio-files: 16/18] grilowrappers: Add support for filesystem source

[Jean Felder <jfelder src gnome org>]

commit 009bc9f751896ef110db3d35d71a8e200192dd7b
Author: Jean Felder <jfelder src gnome org>
Date:   Fri Dec 3 16:36:25 2021 +0100

    grilowrappers: Add support for filesystem source
    
    This source will be used at launch to load audio files received from
    command line.

 gnomemusic/coregrilo.py                          |  19 +++-
 gnomemusic/grilowrappers/grlfilesystemwrapper.py | 106 +++++++++++++++++++++++
 2 files changed, 123 insertions(+), 2 deletions(-)
---
diff --git a/gnomemusic/coregrilo.py b/gnomemusic/coregrilo.py
index e5c17acab..def0fa796 100644
--- a/gnomemusic/coregrilo.py
+++ b/gnomemusic/coregrilo.py
@@ -22,12 +22,14 @@
 # code, but you are not obligated to do so.  If you do not wish to do so,
 # delete this exception statement from your version.
 
+from typing import List
 import weakref
 
 import gi
 gi.require_version("Grl", "0.3")
-from gi.repository import Grl, GLib, GObject, Gtk
+from gi.repository import Grl, Gio, GLib, GObject, Gtk
 
+from gnomemusic.grilowrappers.grlfilesystemwrapper import GrlFileSystemWrapper
 from gnomemusic.grilowrappers.grlsearchwrapper import GrlSearchWrapper
 from gnomemusic.grilowrappers.grltrackerwrapper import GrlTrackerWrapper
 from gnomemusic.trackerwrapper import TrackerState, TrackerWrapper
@@ -37,7 +39,6 @@ class CoreGrilo(GObject.GObject):
 
     _blocklist = [
         'grl-bookmarks',
-        'grl-filesystem',
         'grl-itunes-podcast',
         'grl-metadata-store',
         'grl-podcasts'
@@ -157,6 +158,11 @@ class CoreGrilo(GObject.GObject):
             music_dir = GLib.get_user_special_dir(
                 GLib.UserDirectory.DIRECTORY_MUSIC)
             self._log.debug("XDG Music dir is: {}".format(music_dir))
+        elif source.props.source_id == "grl-filesystem":
+            new_wrapper = GrlFileSystemWrapper(
+                source, self._application)
+            self._wrappers[source.props.source_id] = new_wrapper
+            self._log.debug(f"Adding file system source {source}")
         elif (source.props.source_id not in self._search_wrappers.keys()
                 and source.props.source_id not in self._wrappers.keys()
                 and source.props.source_id != "grl-tracker3-source"
@@ -300,3 +306,12 @@ class CoreGrilo(GObject.GObject):
         if "grl-tracker3-source" in self._wrappers:
             self._wrappers["grl-tracker3-source"].create_playlist(
                 playlist_title, callback)
+
+    def load_files(self, files: List[Gio.File]) -> None:
+        """Use the filesystem plugin to load audio files
+
+        :param list files: list of files
+        """
+        if "grl-filesystem" in self._wrappers:
+            for file in files:
+                self._wrappers["grl-filesystem"].load_file(file)
diff --git a/gnomemusic/grilowrappers/grlfilesystemwrapper.py 
b/gnomemusic/grilowrappers/grlfilesystemwrapper.py
new file mode 100644
index 000000000..a9d91ffce
--- /dev/null
+++ b/gnomemusic/grilowrappers/grlfilesystemwrapper.py
@@ -0,0 +1,106 @@
+# Copyright 2022 The GNOME Music developers
+#
+# GNOME Music 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 2 of the License, or
+# (at your option) any later version.
+#
+# GNOME Music 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 GNOME Music; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+# The GNOME Music authors hereby grant permission for non-GPL compatible
+# GStreamer plugins to be used and distributed together with GStreamer
+# and GNOME Music.  This permission is above and beyond the permissions
+# granted by the GPL license by which GNOME Music is covered.  If you
+# modify this code, you may extend this exception to your version of the
+# code, but you are not obligated to do so.  If you do not wish to do so,
+# delete this exception statement from your version.
+
+from __future__ import annotations
+from typing import Optional
+import typing
+
+from gi.repository import Gio, GLib, GObject, Grl
+
+from gnomemusic.coresong import CoreSong
+if typing.TYPE_CHECKING:
+    from gnomemusic.application import Application
+
+
+class GrlFileSystemWrapper(GObject.GObject):
+    """Wrapper for the Grilo FileSystem source.
+    """
+
+    METADATA_KEYS = [
+        Grl.METADATA_KEY_ID,
+        Grl.METADATA_KEY_TITLE,
+        Grl.METADATA_KEY_URL
+    ]
+
+    def __init__(self, source: Grl.Source, application: Application) -> None:
+        """Initialize the FileSystem wrapper
+
+        :param Grl.Source source: The Grilo source to wrap
+        :param Application application: Application instance
+        """
+        super().__init__()
+
+        self._application = application
+        self._coreselection = application.props.coreselection
+        self._log = application.props.log
+        self._source = source
+
+        self._fast_options = Grl.OperationOptions()
+        self._fast_options.set_resolution_flags(
+            Grl.ResolutionFlags.FAST_ONLY | Grl.ResolutionFlags.IDLE_RELAY)
+
+        coremodel = application.props.coremodel
+        self._files_model = coremodel.props.files
+
+    def load_file(self, file: Gio.File) -> None:
+        """Load an audio file
+
+        :param Grl.Media media: The directory to browse
+        """
+        def resolve_cb(
+                source: Grl.Source, op_id: int,
+                resolved_media: Optional[Grl.Media],
+                error: Optional[GLib.Error]) -> None:
+            if error:
+                self._log.warning(f"Error: {error.domain}, {error.message}")
+                return
+
+            if (not resolved_media
+                    or not resolved_media.is_audio()):
+                return
+
+            coresong = CoreSong(self._application, resolved_media)
+            self._files_model.append(coresong)
+
+        # filesystem resolve operation does not check the mime type and
+        # accepts any valid uri.
+        # This step ensures that "file" is a valid audio file.
+        try:
+            info = file.query_info(
+                Gio.FILE_ATTRIBUTE_STANDARD_CONTENT_TYPE,
+                Gio.FileQueryInfoFlags.NONE)
+        except GLib.GError as error:
+            self._log.warning(f"Error: {error.message}")
+            return
+
+        content_type = info.get_content_type()
+        if (not content_type
+                or not content_type.startswith("audio")):
+            self._log.warning(f"{file.get_uri()} is not a valid audio file.")
+            return
+
+        media = Grl.Media.audio_new()
+        media.set_id(file.get_uri())
+        self._source.resolve(
+            media, self.METADATA_KEYS, self._fast_options, resolve_cb)