[vlc-devel] [PATCH 3/5] core: medialibrary: Add an event API

Romain Vimont rom1v at videolabs.io
Thu Aug 16 23:45:26 CEST 2018


On Thu, Aug 16, 2018 at 05:55:12PM +0200, Hugo Beauzée-Luyssen wrote:
> ---
>  include/vlc_media_library.h | 149 ++++++++++++++++++++++++++++++++++++
>  src/libvlccore.sym          |   2 +
>  src/misc/medialibrary.c     |  61 +++++++++++++++
>  3 files changed, 212 insertions(+)
> 
> diff --git a/include/vlc_media_library.h b/include/vlc_media_library.h
> index e1e08203f0..5928602144 100644
> --- a/include/vlc_media_library.h
> +++ b/include/vlc_media_library.h
> @@ -460,6 +460,139 @@ enum vlc_ml_playback_pref
>      VLC_ML_PLAYBACK_PREF_APP_SPECIFIC,
>  };
>  
> +enum vlc_ml_event_type
> +{
> +    /**
> +     * Entity modification callbacks. The affected entity ID will be passed in
> +     * vlc_ml_event_t::i_entity_id
> +     * When _DELETED callbacks get invoked, the entity will already have been
> +     * deleted from the database, and cannot be retrieved anymore
> +     */
> +    VLC_ML_EVENT_MEDIA_ADDED,
> +    VLC_ML_EVENT_MEDIA_UPDATED,
> +    VLC_ML_EVENT_MEDIA_DELETED,
> +    VLC_ML_EVENT_ARTIST_ADDED,
> +    VLC_ML_EVENT_ARTIST_UPDATED,
> +    VLC_ML_EVENT_ARTIST_DELETED,
> +    VLC_ML_EVENT_ALBUM_ADDED,
> +    VLC_ML_EVENT_ALBUM_UPDATED,
> +    VLC_ML_EVENT_ALBUM_DELETED,
> +    VLC_ML_EVENT_PLAYLIST_ADDED,
> +    VLC_ML_EVENT_PLAYLIST_UPDATED,
> +    VLC_ML_EVENT_PLAYLIST_DELETED,
> +    VLC_ML_EVENT_GENRE_ADDED,
> +    VLC_ML_EVENT_GENRE_UPDATED,
> +    VLC_ML_EVENT_GENRE_DELETED,
> +    /**
> +     * A discovery started.
> +     * For each VLC_ML_EVENT_DISCOVERY_STARTED event, there will be
> +     * 1 VLC_ML_EVENT_DISCOVERY_COMPLETED event, and N
> +     * VLC_ML_EVENT_DISCOVERY_COMPLETED events.
> +     * The entry point being discovered is stored in
> +     * vlc_ml_event_t::psz_entry_point.
> +     */
> +    VLC_ML_EVENT_DISCOVERY_STARTED,
> +    /**
> +     * Sent when a discovery or reload operation starts analyzing a new folder.
> +     * The discovered entry point is stored in vlc_ml_event_t::psz_entry_point.
> +     */
> +    VLC_ML_EVENT_DISCOVERY_PROGRESS,
> +    /**
> +     * Sent when an entry point discovery is completed.
> +     * The entry point that was being discovered is stored in
> +     * vlc_ml_event_t::psz_entry_point.
> +     */
> +    VLC_ML_EVENT_DISCOVERY_COMPLETED,
> +    /**
> +     * An entry point reload operation started.
> +     * For all the entry points being reloaded, N VLC_EVENT_DISCOVERY_PROGRESS
> +     * and 1 VLC_EVENT_RELOAD_COMPLETED event will be sent.
> +     * The entry point being reloaded is stored in
> +     * vlc_ml_event_t::psz_entry_point.
> +     */
> +    VLC_ML_EVENT_RELOAD_STARTED,
> +    /**
> +     * Sent when an entry point reload is completed.
> +     * The entry point that was being reloaded is stored in
> +     * vlc_ml_event_t::psz_entry_point.
> +     * The success state is stored in vlc_ml_event::b_success.
> +     */
> +    VLC_ML_EVENT_RELOAD_COMPLETED,
> +    /**
> +     * Sent when an entry point removal request has been processed.
> +     * The removed entry point is stored in vlc_ml_event_t::psz_entry_point and
> +     * the operation success is stored in vlc_ml_event_t::b_success
> +     */
> +    VLC_ML_EVENT_ENTRY_POINT_REMOVED,
> +    /**
> +     * Sent when an entry point ban request has been processed.
> +     * The banned entry point is stored in vlc_ml_event_t::psz_entry_point and
> +     * the operation success is stored in vlc_ml_event_t::b_success
> +     */
> +    VLC_ML_EVENT_ENTRY_POINT_BANNED,
> +    /**
> +     * Sent when an entry point unban request has been processed.
> +     * The unbanned entry point is stored in vlc_ml_event_t::psz_entry_point and
> +     * the operation success is stored in vlc_ml_event_t::b_success
> +     */
> +    VLC_ML_EVENT_ENTRY_POINT_UNBANNED,
> +    /**
> +     * Sent when a discoverer or parser threads changes its idle state.
> +     * The idle state is stored in vlc_ml_event_t::b_idle.
> +     * False means at least one background thread is in running, true means
> +     * both discoverer & parser threads are paused.
> +     */
> +    VLC_ML_EVENT_BACKGROUND_IDLE_CHANGED,
> +    /**
> +     * Sent when the parsing progress percentage gets updated.
> +     * The percentage is stored as a [0;100] integer, in
> +     * vlc_ml_event_t::i_progress
> +     * This value might decrease as more media get discovered, but it will only
> +     * increase once all discovery operations are completed.
> +     */
> +    VLC_ML_EVENT_PARSING_PROGRESS_UPDATED,
> +};
> +
> +typedef struct vlc_ml_event_t
> +{
> +    int i_type;
> +    union
> +    {
> +        struct
> +        {
> +            const char* psz_entry_point;
> +            bool b_success;
> +        } discovery;
> +        struct
> +        {
> +            uint8_t i_progress;
> +        } parser;
> +        union
> +        {
> +            const vlc_ml_media_t* p_media;
> +            const vlc_ml_artist_t* p_artist;
> +            const vlc_ml_album_t* p_album;
> +            const vlc_ml_playlist_t* p_playlist;
> +            const vlc_ml_genre_t* p_genre;
> +        } modification;
> +        struct
> +        {
> +            int64_t i_entity_id;
> +        } deletion;
> +        struct
> +        {
> +            bool b_idle;
> +        } background_tasks;
> +    };
> +} vlc_ml_event_t;
> +
> +typedef void (*vlc_ml_callback_t)( void* p_data, const vlc_ml_event_t* p_event );
> +
> +typedef struct vlc_medialibrary_callbacks_t
> +{
> +    void (*pf_send_event)( vlc_medialibrary_module_t* p_ml, const vlc_ml_event_t* p_event );
> +} vlc_medialibrary_callbacks_t;
> +
>  struct vlc_medialibrary_module_t
>  {
>      struct vlc_common_members obj;
> @@ -493,6 +626,8 @@ struct vlc_medialibrary_module_t
>       * Refer to the list of queries for the specific return type
>       */
>      void* (*pf_get)( struct vlc_medialibrary_module_t* p_ml, int i_query, int64_t i_id );
> +
> +    const vlc_medialibrary_callbacks_t* cbs;
>  };
>  
>  vlc_medialibrary_t* libvlc_MlCreate( libvlc_int_t* p_libvlc );
> @@ -505,6 +640,20 @@ VLC_API void* vlc_ml_get( vlc_medialibrary_t* p_ml, int i_query, int64_t i_id )
>  VLC_API int vlc_ml_control( vlc_medialibrary_t* p_ml, int i_query, ... ) VLC_USED;
>  VLC_API int vlc_ml_list( vlc_medialibrary_t* p_ml, int i_query,
>                               const vlc_ml_query_params_t* p_params, ... );
> +
> +/**
> + * \brief Registers a medialibrary callback.
> + * \returns A handle to the callback, to be passed to vlc_ml_unregister_callback
> + */
> +VLC_API void* vlc_ml_event_register_callback( vlc_medialibrary_t* p_ml, vlc_ml_callback_t cb, void* p_data );
> +
> +/**
> + * \brief Unregisters a medialibrary callback
> + * \param p_handle The handled returned by vlc_ml_register_callback
> + */
> +VLC_API void vlc_ml_event_unregister_callback( vlc_medialibrary_t* p_ml, void* p_handle );
> +
> +
>  VLC_API void vlc_ml_entrypoints_release( vlc_ml_entrypoint_t* p_list, size_t i_nb_items );
>  
>  VLC_API void vlc_ml_show_release( vlc_ml_show_t* p_show );
> diff --git a/src/libvlccore.sym b/src/libvlccore.sym
> index 63293849d6..19fb6d492e 100644
> --- a/src/libvlccore.sym
> +++ b/src/libvlccore.sym
> @@ -596,6 +596,8 @@ vlc_ml_instance_get
>  vlc_ml_get
>  vlc_ml_control
>  vlc_ml_list
> +vlc_ml_event_register_callback
> +vlc_ml_event_unregister_callback
>  vlc_ml_entrypoints_release
>  vlc_ml_show_release
>  vlc_ml_artist_release
> diff --git a/src/misc/medialibrary.c b/src/misc/medialibrary.c
> index 78ba661034..f9d842218c 100644
> --- a/src/misc/medialibrary.c
> +++ b/src/misc/medialibrary.c
> @@ -25,15 +25,32 @@
>  #include <vlc_common.h>
>  #include <vlc_media_library.h>
>  #include <vlc_modules.h>
> +#include <vlc_list.h>
> +#include <vlc_threads.h>
>  #include <libvlc.h>
>  
>  #include <assert.h>
>  
> +struct ml_callback_t
> +{
> +    vlc_ml_callback_t pf_cb;
> +    void* p_data;
> +    struct vlc_list node;
> +};
> +
>  struct vlc_medialibrary_t
>  {
>      vlc_medialibrary_module_t m;
> +
> +    vlc_mutex_t lock;
> +    struct vlc_list cbs;
>  };
>  
> +static vlc_medialibrary_t* ml_priv( vlc_medialibrary_module_t* p_ml )
> +{
> +    return container_of( p_ml, struct vlc_medialibrary_t, m );
> +}
> +
>  void vlc_ml_entrypoints_release( vlc_ml_entrypoint_t* p_list, size_t i_nb_items )
>  {
>      for ( size_t i = 0; i < i_nb_items; ++i )
> @@ -43,16 +60,58 @@ void vlc_ml_entrypoints_release( vlc_ml_entrypoint_t* p_list, size_t i_nb_items
>      free( p_list );
>  }
>  
> +static void vlc_ml_event_send( vlc_medialibrary_module_t* p_ml, const vlc_ml_event_t* p_event )
> +{
> +    vlc_medialibrary_t* p_priv = ml_priv( p_ml );
> +    vlc_mutex_lock( &p_priv->lock );
> +    struct ml_callback_t* p_cb;
> +    vlc_list_foreach( p_cb, &p_priv->cbs, node )
> +    {
> +        p_cb->pf_cb( p_cb->p_data, p_event );
> +    }
> +    vlc_mutex_unlock( &p_priv->lock );
> +}
> +
> +void* vlc_ml_event_register_callback( vlc_medialibrary_t* p_ml, vlc_ml_callback_t cb, void* p_data )
> +{
> +    struct ml_callback_t* p_cb = malloc( sizeof( *p_cb ) );
> +    if ( unlikely( p_cb == NULL ) )
> +        return NULL;
> +    p_cb->pf_cb = cb;
> +    p_cb->p_data = p_data;
> +    vlc_mutex_lock( &p_ml->lock );
> +    vlc_list_append( &p_cb->node, &p_ml->cbs );
> +    vlc_mutex_unlock( &p_ml->lock );
> +    return &p_cb->node;

Couldn't you return p_cb directly and avoid the container_of() in
unregister_callback()?

> +}
> +
> +void vlc_ml_event_unregister_callback( vlc_medialibrary_t* p_ml, void* p_handle )
> +{
> +    struct ml_callback_t* p_cb = container_of( p_handle, struct ml_callback_t, node );
> +    vlc_mutex_lock( &p_ml->lock );
> +    vlc_list_remove( (struct vlc_list*)p_handle );
> +    vlc_mutex_unlock( &p_ml->lock );
> +    free( p_cb );
> +}
> +
> +static vlc_medialibrary_callbacks_t callbacks = {

Could be "static const".

Otherwise, LGTM.

> +    .pf_send_event = &vlc_ml_event_send
> +};
> +
>  vlc_medialibrary_t* libvlc_MlCreate( libvlc_int_t* p_libvlc  )
>  {
>      vlc_medialibrary_t *p_ml = vlc_custom_create( VLC_OBJECT( p_libvlc ),
>                                                    sizeof( *p_ml ), "medialibrary" );
>      if ( unlikely( p_ml == NULL ) )
>          return NULL;
> +    vlc_mutex_init( &p_ml->lock );
> +    vlc_list_init( &p_ml->cbs );
> +    p_ml->m.cbs = &callbacks;
>      p_ml->m.p_module = module_need( &p_ml->m, "medialibrary", NULL, false );
>      if ( p_ml->m.p_module == NULL )
>      {
>          vlc_object_release( &p_ml->m );
> +        vlc_mutex_destroy( &p_ml->lock );
>          return NULL;
>      }
>      return p_ml;
> @@ -62,6 +121,8 @@ void libvlc_MlRelease( vlc_medialibrary_t* p_ml )
>  {
>      assert( p_ml != NULL );
>      module_unneed( &p_ml->m, p_ml->m.p_module );
> +    assert( vlc_list_is_empty( &p_ml->cbs ) );
> +    vlc_mutex_destroy( &p_ml->lock );
>      vlc_object_release( &p_ml->m );
>  }
>  
> -- 
> 2.18.0
> 
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