Use lambda functions to handle events

src/EventManager.hpp

@@ -24,415 +24,546 @@
 #define LIBVLC_EVENTMANAGER_HPP
 
 #include <string>
+#include <iostream>
 
 #include "common.hpp"
 #include "Internal.hpp"
 
+#include <functional>
+#include <unordered_map>
+#include <memory>
+#include <atomic>
+
 namespace VLC
 {
 
 class Media;
 
-class IMediaEventCb
-{
-    public:
-        virtual ~IMediaEventCb() {}
-        virtual void metaChanged( libvlc_meta_t ) {}
-        virtual void subItemAdded( MediaPtr ) {}
-        virtual void durationChanged( int64_t ) {}
-        virtual void parsedChanged( bool ) {}
-        virtual void freed( MediaPtr ) {}
-        virtual void stateChanged( libvlc_state_t ) {}
-        virtual void subItemTreeAdded( MediaPtr ) {}
-};
+using EventToken = unsigned int;
 
-class IMediaPlayerEventCb
+/**
+ * @brief This class serves as a base for all event managers.
+ *
+ * All events can be handled by providing a std::function.
+ * libvlcpp will take ownership (ie. the function will be moved inside an internal list)
+ * If the provided std::function is a lambda, it may capture anything you desire
+ */
+class EventManager : public Internal<libvlc_event_manager_t>
 {
+private:
+    // Polymorphic base to hold a templated implementation
+    struct EventHandlerBase
+    {
+        using Wrapper = std::add_pointer<void(const libvlc_event_t*, void*)>::type;
+        virtual ~EventHandlerBase() {}
+    };
+
+    template <typename Ret, typename... Args>
+    class EventHandler : public EventHandlerBase
+    {
     public:
-        virtual ~IMediaPlayerEventCb(){}
-        virtual void mediaChanged( MediaPtr ) {}
-        virtual void nothingSpecial() {}
-        virtual void opening() {}
-        virtual void buffering( float ) {}
-        virtual void playing() {}
-        virtual void paused() {}
-        virtual void stopped() {}
-        virtual void forward() {}
-        virtual void backward() {}
-        virtual void endReached() {}
-        virtual void encounteredError() {}
-        virtual void timeChanged( libvlc_time_t ) {}
-        virtual void positionChanged( float ) {}
-        virtual void seekableChanged( bool ) {}
-        virtual void pausableChanged( bool ) {}
-        virtual void titleChanged( int ) {}
-        virtual void snapshotTaken( const std::string& ) {}
-        virtual void lengthChanged( libvlc_time_t ) {}
-        virtual void vout( int ) {}
-        virtual void scrambledChanged( int ) {}
-        virtual void eSAdded( libvlc_track_type_t, int ) {}
-        virtual void eSDeleted( libvlc_track_type_t, int ) {}
-        virtual void eSSelected( libvlc_track_type_t, int ) {}
+        using UserCallback = std::function<Ret(Args...)>;
+        EventHandler(EventManager& em, libvlc_event_e eventType, UserCallback&& userCallback, Wrapper wrapper)
+            : m_userCallback( userCallback )
+            , m_eventManager(&em)
+            , m_wrapper(wrapper)
+            , m_eventType( eventType )
+        {
+            if (libvlc_event_attach( *m_eventManager, m_eventType, m_wrapper, &m_userCallback ) != 0)
+                throw std::bad_alloc();
+        }
+
+        ~EventHandler()
+        {
+            libvlc_event_detach( *m_eventManager, m_eventType, m_wrapper, &m_userCallback );
+        }
+
+        EventHandler(const EventHandler&) = delete;
+
+    private:
+        UserCallback m_userCallback;
+        // EventManager always outlive EventHandler, no need for smart pointer
+        EventManager* m_eventManager;
+        Wrapper m_wrapper;
+        libvlc_event_e m_eventType;
+    };
+
+protected:
+    EventManager(InternalPtr ptr)
+        : Internal{ ptr, [](InternalPtr){ /* No-op; EventManager's are handled by their respective objects */ } }
+        , m_lastEvent(0)
+    {
+    }
+
+    template <typename Ret, typename... Args>
+    EventToken handle(libvlc_event_e eventType, std::function<Ret(Args...)>&& f, EventHandlerBase::Wrapper wrapper)
+    {
+        auto token = ++m_lastEvent;
+        m_lambdas[token] = std::unique_ptr<EventHandlerBase>( new EventHandler<Ret, Args...>(
+                                                                  *this, eventType, std::move( f ), wrapper ) );
+        return token;
+    }
+
+    EventToken handle(libvlc_event_e eventType, std::function<void()>&& f)
+    {
+        return handle(eventType, std::move( f ), [](const libvlc_event_t*, void* data)
+        {
+            auto callback = static_cast<std::function<void()>*>( data );
+            (*callback)();
+        });
+    }
+
+    void unregister(EventToken t)
+    {
+        if (t == 0)
+            return;
+        m_lambdas.erase(t);
+    }
+
+protected:
+    // We store the EventHandlerBase's as unique_ptr in order for the function stored within
+    // EventHandler<T> not to move to another memory location
+    std::unordered_map<EventToken, std::unique_ptr<EventHandlerBase>> m_lambdas;
+    std::atomic_uint m_lastEvent;
 };
 
-class IMediaListEventCb
+class MediaEventManager : public EventManager
 {
     public:
-        virtual ~IMediaListEventCb() {}
-        virtual void itemAdded( MediaPtr, int ) {}
-        virtual void willAddItem( MediaPtr, int ) {}
-        virtual void itemDeleted( MediaPtr, int ) {}
-        virtual void willDeleteItem( MediaPtr, int ) {}
-};
+        MediaEventManager(InternalPtr ptr) : EventManager( ptr ) {}
 
-// MediaListView events are not being sent by VLC, so we don't implement them here
+        EventToken onMetaChanged( std::function<void(libvlc_meta_t)>&& f)
+        {
+            return handle( libvlc_MediaMetaChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(libvlc_meta_t)>*>(data);
+                (*callback)( e->u.media_meta_changed.meta_type );
+            });
+        }
 
-class IMediaListPlayerEventCb
-{
-    public:
-        virtual ~IMediaListPlayerEventCb() {}
-        virtual void played() {}
-        virtual void nextItemSet( MediaPtr ) {}
-        virtual void stopped() {}
+        EventToken onSubItemAdded( std::function<void(MediaPtr)>&& f )
+        {
+            return handle(libvlc_MediaSubItemAdded, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(MediaPtr)>*>(data);
+                (*callback)( std::make_shared<Media>( e->u.media_subitem_added.new_child, true ) );
+            });
+        }
+
+        EventToken onDurationChanged( std::function<void(int64_t)>&& f )
+        {
+            return handle(libvlc_MediaDurationChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(int64_t)>*>(data);
+                (*callback)( e->u.media_duration_changed.new_duration );
+            });
+        }
+
+        EventToken onParsedChanged( std::function<void(bool)>&& f )
+        {
+            return handle( libvlc_MediaParsedChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(bool)>*>(data);
+                (*callback)( e->u.media_parsed_changed.new_status );
+            });
+        }
+
+        EventToken onFreed( std::function<void(MediaPtr)>&& f)
+        {
+            return handle(libvlc_MediaFreed, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(MediaPtr)>*>(data);
+                (*callback)( std::make_shared<Media>( e->u.media_freed.md, true ) );
+            });
+        }
+
+        EventToken onStateChanged( std::function<void(libvlc_state_t)>&& f)
+        {
+            return handle(libvlc_MediaStateChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(libvlc_state_t)>*>(data);
+                (*callback)( e->u.media_state_changed.new_state );
+            });
+        }
+
+        EventToken onSubItemTreeAdded( std::function<void(MediaPtr)>&& f)
+        {
+            return handle(libvlc_MediaSubItemAdded, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(MediaPtr)>*>(data);
+                (*callback)( std::make_shared<Media>( e->u.media_subitemtree_added.item, true ) );
+            });
+        }
 };
 
-class IMediaDiscovererEventCb
+class MediaPlayerEventManager : public EventManager
 {
     public:
-        virtual ~IMediaDiscovererEventCb() {}
-        virtual void started() {}
-        virtual void stopped() {}
+        MediaPlayerEventManager(InternalPtr ptr) : EventManager( ptr ) {}
+
+        EventToken onMediaChanged( std::function<void(MediaPtr)>&& f )
+        {
+            return handle(libvlc_MediaPlayerMediaChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(MediaPtr)>*>( data );
+                (*callback)( std::make_shared<Media>( e->u.media_player_media_changed.new_media, true ) );
+            });
+        }
+        EventToken onNothingSpecial(std::function<void()>&& f)
+        {
+            return handle(libvlc_MediaPlayerNothingSpecial, std::move( f ));
+        }
+
+        EventToken onOpening(std::function<void()>&& f)
+        {
+            return handle(libvlc_MediaPlayerOpening, std::move( f ) );
+        }
+
+        EventToken onBuffering( std::function<void()>&& f)
+        {
+            return handle(libvlc_MediaPlayerBuffering, std::move( f ) );
+        }
+
+        EventToken onPlaying(std::function<void()>&& f)
+        {
+            return handle( libvlc_MediaPlayerPlaying, std::move( f ) );
+        }
+
+        EventToken onPaused(std::function<void()>&& f)
+        {
+            return handle( libvlc_MediaPlayerPaused, std::move( f ) );
+        }
+
+        EventToken onStopped(std::function<void()>&& f)
+        {
+            return handle( libvlc_MediaPlayerStopped, std::move( f ) );
+        }
+
+        EventToken onForward(std::function<void()>&& f)
+        {
+            return handle( libvlc_MediaPlayerForward, std::move( f ) );
+        }
+
+        EventToken onBackward(std::function<void()>&& f)
+        {
+            return handle( libvlc_MediaPlayerBackward, std::move( f ) );
+        }
+
+        EventToken onEndReached(std::function<void()>&& f)
+        {
+            return handle( libvlc_MediaPlayerEndReached, std::move( f ) );
+        }
+
+        EventToken onEncounteredError(std::function<void()>&& f)
+        {
+            return handle( libvlc_MediaPlayerEncounteredError, std::move( f ) );
+        }
+
+        EventToken onTimeChanged( std::function<void(libvlc_time_t)>&& f )
+        {
+            return handle( libvlc_MediaPlayerTimeChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(libvlc_time_t)>*>( data );
+                (*callback)( e->u.media_player_time_changed.new_time );
+            });
+        }
+
+        EventToken onPositionChanged( std::function<void(float)>&& f )
+        {
+            return handle( libvlc_MediaPlayerPositionChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(float)>*>( data );
+                (*callback)( e->u.media_player_position_changed.new_position );
+            });
+        }
+
+        EventToken onSeekableChanged( std::function<void(bool)>&& f )
+        {
+            return handle( libvlc_MediaPlayerSeekableChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(bool)>*>( data );
+                (*callback)( e->u.media_player_seekable_changed.new_seekable );
+            });
+        }
+
+        EventToken onPausableChanged( std::function<void(bool)>&& f )
+        {
+            return handle( libvlc_MediaPlayerSeekableChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(bool)>*>( data );
+                (*callback)( e->u.media_player_seekable_changed.new_seekable );
+            });
+        }
+
+        EventToken onTitleChanged( std::function<void(int)>&& f )
+        {
+            return handle( libvlc_MediaPlayerTitleChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(int)>*>( data );
+                (*callback)( e->u.media_player_title_changed.new_title );
+            });
+        }
+
+        EventToken onSnapshotTaken( std::function<void(std::string)>&& f )
+        {
+            return handle( libvlc_MediaPlayerSnapshotTaken, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(std::string)>*>( data );
+                (*callback)( e->u.media_player_snapshot_taken.psz_filename );
+            });
+        }
+
+        EventToken onLengthChanged( std::function<void(libvlc_time_t)>&& f )
+        {
+            return handle( libvlc_MediaPlayerLengthChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(libvlc_time_t)>*>( data );
+                (*callback)( e->u.media_player_length_changed.new_length );
+            });
+        }
+
+        EventToken onVout( std::function<void(int)>&& f )
+        {
+            return handle( libvlc_MediaPlayerVout, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(int)>*>( data );
+                (*callback)( e->u.media_player_vout.new_count );
+            });
+        }
+
+        EventToken onScrambledChanged( std::function<void(int)>&& f )
+        {
+            return handle( libvlc_MediaPlayerScrambledChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(int)>*>( data );
+                (*callback)( e->u.media_player_scrambled_changed.new_scrambled );
+            });
+        }
+
+        EventToken onESAdded( std::function<void(libvlc_track_type_t, int)>&& f )
+        {
+            return handle( libvlc_MediaPlayerESAdded, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(libvlc_track_type_t, int)>*>( data );
+                (*callback)( e->u.media_player_es_changed.i_type, e->u.media_player_es_changed.i_id );
+            });
+        }
+
+        EventToken onESDeleted( std::function<void(libvlc_track_type_t, int)>&& f )
+        {
+            return handle( libvlc_MediaPlayerESDeleted, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(libvlc_track_type_t, int)>*>( data );
+                (*callback)( e->u.media_player_es_changed.i_type, e->u.media_player_es_changed.i_id );
+            });
+        }
+
+        EventToken onESSelected( std::function<void(libvlc_track_type_t, int)>&& f )
+        {
+            return handle( libvlc_MediaPlayerESSelected, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(libvlc_track_type_t, int)>*>( data );
+                (*callback)( e->u.media_player_es_changed.i_type, e->u.media_player_es_changed.i_id );
+            });
+        }
 };
 
-class IVLMEventCb
+class MediaListEventManager : public EventManager
 {
     public:
-        virtual ~IVLMEventCb() {}
-        virtual void mediaAdded( const std::string& ) {}
-        virtual void mediaRemoved( const std::string& ) {}
-        virtual void mediaChanged( const std::string& ) {}
-        virtual void mediaInstanceStarted( const std::string&, const std::string& ) {}
-        virtual void mediaInstanceStopped( const std::string&, const std::string& ) {}
-        virtual void mediaInstanceStatusInit( const std::string&, const std::string& ) {}
-        virtual void mediaInstanceStatusOpening( const std::string&, const std::string& ) {}
-        virtual void mediaInstanceStatusPlaying( const std::string&, const std::string& ) {}
-        virtual void mediaInstanceStatusPause( const std::string&, const std::string& ) {}
-        virtual void mediaInstanceStatusEnd( const std::string&, const std::string& ) {}
-        virtual void mediaInstanceStatusError( const std::string&, const std::string& ) {}
+        MediaListEventManager(InternalPtr ptr) : EventManager( ptr ) {}
+
+        EventToken onItemAdded( std::function<void(MediaPtr, int)>&& f )
+        {
+            return handle(libvlc_MediaListItemAdded, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(MediaPtr, int)>*>( data );
+                (*callback)( std::make_shared<Media>( e->u.media_list_item_added.item, true ), e->u.media_list_item_added.index );
+            });
+        }
+
+        EventToken onWillAddItem( std::function<void(MediaPtr, int)>&& f )
+        {
+            return handle( libvlc_MediaListWillAddItem, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(MediaPtr, int)>*>( data );
+                (*callback)(std::make_shared<Media>( e->u.media_list_will_add_item.item, true ), e->u.media_list_will_add_item.index );
+            });
+        }
+
+        EventToken onItemDeleted( std::function<void(MediaPtr, int)>&& f )
+        {
+            return handle(libvlc_MediaListItemDeleted, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(MediaPtr, int)>*>( data );
+                (*callback)( std::make_shared<Media>( e->u.media_list_item_deleted.item, true ), e->u.media_list_item_deleted.index );
+            });
+        }
+
+        EventToken onWillDeleteItem( std::function<void(MediaPtr, int)>&& f )
+        {
+            return handle(libvlc_MediaListWillDeleteItem, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(MediaPtr, int)>*>( data );
+                (*callback)( std::make_shared<Media>( e->u.media_list_will_delete_item.item, true ), e->u.media_list_will_delete_item.index );
+            });
+        }
 };
 
-class EventManager : public Internal<libvlc_event_manager_t>
+// MediaListView events are not being sent by VLC, so we don't implement them here
+
+class MediaListPlayerEventManager : public EventManager
 {
     public:
-        EventManager(InternalPtr ptr)
-            : Internal{ ptr, [](InternalPtr){ /* No-op; EventManager's are handled by their respective objects */ } }
+        MediaListPlayerEventManager(InternalPtr ptr) : EventManager( ptr ) {}
+
+        EventToken onPlayed(std::function<void()>&& f)
         {
+            return handle(libvlc_MediaListPlayerPlayed, std::move( f ) );
         }
 
-        bool attach( libvlc_event_type_t type, IMediaEventCb* cb )
+        EventToken onNextItemSet( std::function<void(MediaPtr)>&& f )
         {
-            if ( cb == NULL )
-                return false;
-            if ( type < libvlc_MediaMetaChanged || type > libvlc_MediaSubItemTreeAdded )
-                return false;
-            libvlc_event_attach( *this,type, &handleMediaEvent, cb );
-            return true;
+            return handle(libvlc_MediaListPlayerNextItemSet, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(MediaPtr)>*>( data );
+                (*callback)( std::make_shared<Media>( e->u.media_list_player_next_item_set.item, true ) );
+            });
         }
 
-        bool attach( libvlc_event_type_t type, IMediaPlayerEventCb* cb )
+        EventToken onStopped(std::function<void()>&& f)
         {
-            if ( cb == NULL )
-                return false;
-            if ( type < libvlc_MediaPlayerMediaChanged || type > libvlc_MediaPlayerESSelected )
-                return false;
-            libvlc_event_attach( *this,type, &handleMediaPlayerEvent, cb );
-            return true;
+            return handle(libvlc_MediaListPlayerStopped, std::move( f ) );
         }
+};
 
-        bool attach( libvlc_event_type_t type, IMediaListEventCb* cb )
+class MediaDiscovererEventManager : public EventManager
+{
+    public:
+        MediaDiscovererEventManager(InternalPtr ptr) : EventManager( ptr ) {}
+
+        EventToken onStarted(std::function<void()>&& f)
         {
-            if ( cb == NULL )
-                return false;
-            if ( type < libvlc_MediaListItemAdded || type > libvlc_MediaListWillDeleteItem )
-                return false;
-            libvlc_event_attach( *this,type, &handleMediaListEvent, cb );
-            return true;
+            return handle(libvlc_MediaDiscovererStarted, std::move( f ) );
         }
 
-        bool attach( libvlc_event_type_t type, IMediaListPlayerEventCb* cb )
+        EventToken onStopped(std::function<void()>&& f)
         {
-            if ( cb == NULL )
-                return false;
-            if ( type < libvlc_MediaListPlayerPlayed || type > libvlc_MediaListPlayerStopped )
-                return false;
-            libvlc_event_attach( *this,type, &handleMediaListPlayerEvent, cb );
-            return true;
+            return handle(libvlc_MediaDiscovererEnded, std::move( f ) );
         }
+};
 
-        bool attach( libvlc_event_type_t type, IMediaDiscovererEventCb* cb )
+class VLMEventManager : public EventManager
+{
+    public:
+        using EventManager::EventManager;
+
+        EventToken onMediaAdded( std::function<void(const std::string&)>&& f )
         {
-            if ( cb == NULL )
-                return false;
-            if ( type < libvlc_MediaDiscovererStarted || type > libvlc_MediaDiscovererEnded )
-                return false;
-            libvlc_event_attach( *this,type, &handleMediaDiscovererEvent, cb );
-            return true;
+            return handle(libvlc_VlmMediaAdded, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(const std::string&)>*>( data );
+                (*callback)( e->u.vlm_media_event.psz_media_name ? e->u.vlm_media_event.psz_media_name : "" );
+            });
         }
 
-        bool attach( libvlc_event_type_t type, IVLMEventCb* cb )
+        EventToken onMediaRemoved( std::function<void(const std::string&)>&& f )
         {
-            if ( cb == NULL )
-                return false;
-            if ( type < libvlc_VlmMediaAdded || type > libvlc_VlmMediaInstanceStatusError )
-                return false;
-            libvlc_event_attach( *this,type, &handleVLMEvent, cb );
-            return true;
+            return handle(libvlc_VlmMediaRemoved, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(const std::string&)>*>( data );
+                (*callback)( e->u.vlm_media_event.psz_media_name ? e->u.vlm_media_event.psz_media_name : "" );
+            });
         }
 
-        void detach( libvlc_event_type_t type, IMediaEventCb* cb )
+        EventToken onMediaChanged( std::function<void(const std::string&)>&& f )
         {
-            libvlc_event_detach( *this,type, &handleMediaEvent, cb );
+            return handle(libvlc_VlmMediaChanged, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(const std::string&)>*>( data );
+                (*callback)( e->u.vlm_media_event.psz_media_name ? e->u.vlm_media_event.psz_media_name : "" );
+            });
+        }
+        EventToken onMediaInstanceStarted( std::function<void(const std::string&, const std::string&)>&& f )
+        {
+            return handle(libvlc_VlmMediaInstanceStarted, std::move( f ), [](const libvlc_event_t* e, void* data)
+            {
+                auto callback = static_cast<std::function<void(const std::string&, const std::string&)>*>( data );
+                (*callback)( e->u.vlm_media_event.psz_media_name ? e->u.vlm_media_event.psz_media_name : "",
+                             e->u.vlm_media_event.psz_instance_name ? e->u.vlm_media_event.psz_instance_name : "" );
+            });
         }
 
-        void detach( libvlc_event_type_t type, IMediaPlayerEventCb* cb )
+        EventToken onMediaInstanceStopped( std::function<void(const std::string&, const std::string&)>&& f )