Add MPRIS support

Besides MPRIS support, this also adds support for hasPrevious() and
hasNext() in several parts to determine whether the
player/playlist/shuffler has a previous or next item.

core/include/JellyfinQt/viewmodel/platformmediacontrol.h

@@ -0,0 +1,127 @@
+/*
+ * Sailfin: a Jellyfin client written using Qt
+ * Copyright (C) 2021 Chris Josten and the Sailfin Contributors.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifndef JELLYFIN_VIEWMODEL_PLATFORMMEDIACONTROL_H
+#define JELLYFIN_VIEWMODEL_PLATFORMMEDIACONTROL_H
+
+#include <QObject>
+#include <QQmlParserStatus>
+#include <QScopedPointer>
+
+namespace Jellyfin {
+namespace ViewModel {
+
+class PlatformMediaControlPrivate;
+class PlaybackManager;
+
+/**
+ * @brief Exposes media control and information to the OS. Uses MPRIS on FreeDesktop-enabled systems.
+ */
+class PlatformMediaControl : public QObject, public QQmlParserStatus {
+    Q_OBJECT
+    Q_INTERFACES(QQmlParserStatus)
+public:
+    explicit PlatformMediaControl(QObject *parent = nullptr);
+
+    Q_PROPERTY(Jellyfin::ViewModel::PlaybackManager *playbackManager READ playbackManager WRITE setPlaybackManager NOTIFY playbackManagerChanged)
+    /**
+     * Whether the operating system can request the media player to quit. If set,
+     * the quitRequested signal may be emitted and the application should quit.
+     */
+    Q_PROPERTY(bool canQuit READ canQuit WRITE setCanQuit NOTIFY canQuitChanged)
+    Q_PROPERTY(bool canRaise READ canRaise WRITE setCanRaise NOTIFY canRaiseChanged)
+    Q_PROPERTY(QString playerName READ playerName WRITE setPlayerName NOTIFY playerNameChanged)
+    Q_PROPERTY(QString desktopFile READ playerName WRITE setPlayerName NOTIFY playerNameChanged)
+
+    PlaybackManager *playbackManager() const { return m_playbackManager; };
+
+    void setPlaybackManager(PlaybackManager *newPlaybackManager) {
+        m_playbackManager = newPlaybackManager;
+        emit playbackManagerChanged(newPlaybackManager);
+    };
+
+    bool canQuit() const { return m_canQuit; };
+    void setCanQuit(bool newCanQuit) {
+        m_canQuit = newCanQuit;
+        emit canQuitChanged(newCanQuit);
+    }
+
+    void requestQuit() {
+        emit quitRequested();
+    }
+
+    bool canRaise() const { return m_canRaise; };
+    void setCanRaise(bool newCanRaise) {
+        m_canRaise = newCanRaise;
+        emit canRaiseChanged(newCanRaise);
+    }
+
+    void requestRaise() {
+        emit raiseRequested();
+    };;
+
+    QString playerName() const { return m_playerName; }
+    void setPlayerName(QString newPlayerName) {
+        m_playerName = newPlayerName;
+        emit playerNameChanged(newPlayerName);
+    }
+
+    QString desktopFile() const { return m_desktopFile; }
+    void setDesktopFile(QString newDesktopFile) {
+        m_desktopFile = newDesktopFile;
+        emit desktopFileChanged(newDesktopFile);
+    }
+
+    void classBegin() override {
+        m_isParsing = true;
+    }
+    void componentComplete() override {
+        m_isParsing = false;
+        setup();
+    }
+
+
+
+signals:
+    void playbackManagerChanged(PlaybackManager *newPlaybackManager);
+    void canQuitChanged(bool newCanQuit);
+    void canRaiseChanged(bool newCanRaise);
+    void playerNameChanged(QString newPlayerName);
+    void desktopFileChanged(QString newDesktopFile);
+
+    void quitRequested();
+    void raiseRequested();
+
+private:
+    Q_DECLARE_PRIVATE(PlatformMediaControl)
+    PlatformMediaControlPrivate* d_ptr;
+    void setup();
+    bool m_isParsing = false;
+
+    PlaybackManager *m_playbackManager = nullptr;
+    bool m_canQuit = false;
+    bool m_canRaise = false;
+    QString m_playerName = QStringLiteral("JellyfinQt");
+    QString m_desktopFile = QStringLiteral("sailfin");
+};
+
+
+} // NS ViewModel
+} // NS Jellyfin
+
+#endif // PLATFORMMEDIACONTROL_H