[vlc-devel] [PATCH 2/3] Create services_advertisement VLC object

Thomas Guillem thomas at gllm.fr
Mon Sep 2 14:00:33 CEST 2019



On Mon, Sep 2, 2019, at 07:25, Roland Bewick wrote:
> - Add services-advertisement object to libvlc
> - Parse --services-advertisement option and load modules on VLC startup
> - unload services advertisement modules on VLC shutdown
> ---
>  include/vlc_services_advertisement.h | 87 ++++++++++++++++++++++++++++
>  src/Makefile.am                      |  2 +
>  src/libvlc.c                         | 32 ++++++++++
>  src/libvlc.h                         |  2 +
>  src/misc/services_advertisement.c    | 84 +++++++++++++++++++++++++++
>  5 files changed, 207 insertions(+)
>  create mode 100644 include/vlc_services_advertisement.h
>  create mode 100644 src/misc/services_advertisement.c
> 
> diff --git a/include/vlc_services_advertisement.h 
> b/include/vlc_services_advertisement.h
> new file mode 100644
> index 0000000000..1f217cecf3
> --- /dev/null
> +++ b/include/vlc_services_advertisement.h
> @@ -0,0 +1,87 @@
> +/*****************************************************************************
> + * vlc_services_advertisement.h : Services Advertisement functions
> + 
> *****************************************************************************
> + * Copyright (C) 1999-2019 VLC authors and VideoLAN
> + *
> + * Authors:
> + *
> + * This program 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 program 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 program; if not, write to the Free Software 
> Foundation,
> + * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
> + 
> *****************************************************************************/
> +
> +#ifndef VLC_SERVICES_ADVERTISEMENT_H_
> +#define VLC_SERVICES_ADVERTISEMENT_H_
> +
> +#include <vlc_input.h>
> +
> +/**
> + * \file
> + * This file lists functions and structures for service advertisement 
> (SA) in vlc
> + */
> +
> +# ifdef __cplusplus
> +extern "C" {
> +# endif
> +
> +/**
> + * @{
> + */
> +
> +/**
> + * Main service advertisement structure to build a SA module
> + */
> +typedef struct services_advertisement_t

It should be named vlc_services_advertisement_t

> +{
> +    struct vlc_object_t obj;
> +
> +    struct services_advertisement_t *p_next;  /** Points to the next 
> SA element */
> +
> +    module_t *          p_module;             /**< Loaded module */
> +
> +    char *psz_name;                           /**< Main name of the SA 
> */
> +    config_chain_t *p_cfg;                    /**< Configuration for 
> the SA */
> +
> +    const char *description;                  /**< Human-readable name 
> */
> +
> +    void *p_sys;                              /**< Custom private data 
> */
> +} services_advertisement_t;

There are some members that should not be visible by a SA module, like p_next
You don't want to allow a SA module to mess with next SA modules for examples.
You should split this struct in two, the public one and the private one.

Example, In the internal part:
struct vlc_services_advertisement_priv_t
{
    struct vlc_services_advertisement_t sa;
    struct vlc_services_advertisement_t *next;
};

You allocate vlc_services_advertisement_priv_t directly, but pass &priv->sa to the modules.

If needed,  in your internal sa implemenation, you can add this helper to get the private struct from the public one.

static inline struct vlc_services_advertisement_priv_t *sa_get_priv( struct vlc_services_advertisement_t *sa)
{
    return container_of( sa, struct vlc_services_advertisement_priv_t, sa );
}

> +
> +
> +/***********************************************************************
> + * Service Advertisement
> + 
> ***********************************************************************/
> +
> +/**
> + * Loads a service advertisement (SA) module for the given 
> configuration
> + * and adds it to the VLC's list of SA modules.
> + * 
> + * @param chain configuration chain string
> + * @return VLC_SUCCESS or an error code
> + */
> +int vlc_sa_Create( libvlc_int_t *libvlc, const char *chain );
> +
> +/**
> + * Stops and unloads all services advertisement modules.
> + * 
> + * @param libvlc the LibVLC instance
> + */
> +void vlc_sa_DestroyAll( libvlc_int_t *libvlc );
> +
> +
> +/** @} */
> +# ifdef __cplusplus
> +}
> +# endif
> +
> +#endif
> diff --git a/src/Makefile.am b/src/Makefile.am
> index 9f0b6df13a..09a69b99b4 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -85,6 +85,7 @@ pluginsinclude_HEADERS = \
>  	../include/vlc_probe.h \
>  	../include/vlc_rand.h \
>  	../include/vlc_services_discovery.h \
> +	../include/vlc_services_advertisement.h \
>  	../include/vlc_fingerprinter.h \
>  	../include/vlc_interrupt.h \
>  	../include/vlc_renderer_discovery.h \
> @@ -364,6 +365,7 @@ libvlccore_la_SOURCES = \
>  	misc/interrupt.c \
>  	misc/keystore.c \
>  	misc/renderer_discovery.c \
> +	misc/services_advertisement.c \
>  	misc/threads.c \
>  	misc/cpu.c \
>  	misc/epg.c \
> diff --git a/src/libvlc.c b/src/libvlc.c
> index ee88d363d4..8afdc64b14 100644
> --- a/src/libvlc.c
> +++ b/src/libvlc.c
> @@ -63,6 +63,7 @@
>  #include <vlc_modules.h>
>  #include <vlc_media_library.h>
>  #include <vlc_thumbnailer.h>
> +#include <vlc_services_advertisement.h>
>  
>  #include "libvlc.h"
>  
> @@ -92,6 +93,7 @@ libvlc_int_t * libvlc_InternalCreate( void )
>      priv = libvlc_priv (p_libvlc);
>      vlc_mutex_init(&priv->lock);
>      priv->interfaces = NULL;
> +    priv->services_advertisements = NULL;
>      priv->main_playlist = NULL;
>      priv->p_vlm = NULL;
>      priv->media_source_provider = NULL;
> @@ -116,6 +118,7 @@ int libvlc_InternalInit( libvlc_int_t *p_libvlc, int i_argc,
>      char *       psz_modules = NULL;
>      char *       psz_parser = NULL;
>      char *       psz_control = NULL;
> +    char *       psz_services_advertisement = NULL;
>      char        *psz_val;
>      int          i_ret = VLC_EGENERIC;
>  
> @@ -330,6 +333,32 @@ int libvlc_InternalInit( libvlc_int_t *p_libvlc, 
> int i_argc,
>      if( var_InheritBool( p_libvlc, "network-synchronisation") )
>          libvlc_InternalAddIntf( p_libvlc, "netsync,none" );
>  
> +    /*
> +     * Load service advertisement modules
> +     */
> +    psz_services_advertisement = var_InheritString( p_libvlc,
> +                                                    "services-advertisement" );
> +    psz_parser = psz_services_advertisement;
> +
> +    while( psz_parser && *psz_parser )
> +    {
> +        char *psz_module, *psz_temp;
> +        psz_module = psz_parser;
> +        psz_parser = strchr( psz_module, ':' );
> +        if( psz_parser )
> +        {
> +            *psz_parser = '\0';
> +            psz_parser++;
> +        }
> +        if( asprintf( &psz_temp, "%s,none", psz_module ) != -1)
> +        {
> +            vlc_sa_Create( p_libvlc, psz_temp );
> +            free( psz_temp );
> +        }
> +    }
> +
> +    free( psz_services_advertisement );
> +
>  #ifdef __APPLE__
>      var_Create( p_libvlc, "drawable-view-top", VLC_VAR_INTEGER );
>      var_Create( p_libvlc, "drawable-view-left", VLC_VAR_INTEGER );
> @@ -395,6 +424,9 @@ void libvlc_InternalCleanup( libvlc_int_t *p_libvlc )
>      msg_Dbg( p_libvlc, "removing all interfaces" );
>      intf_DestroyAll( p_libvlc );
>  
> +    /* Ask the service announcement modules to stop and destroy them */
> +    vlc_sa_DestroyAll( p_libvlc );
> +
>      if ( priv->p_thumbnailer )
>          vlc_thumbnailer_Release( priv->p_thumbnailer );
>  
> diff --git a/src/libvlc.h b/src/libvlc.h
> index ff50bd9218..8f97b456f5 100644
> --- a/src/libvlc.h
> +++ b/src/libvlc.h
> @@ -193,6 +193,7 @@ typedef struct vlc_actions_t vlc_actions_t;
>  typedef struct vlc_playlist vlc_playlist_t;
>  typedef struct vlc_media_source_provider_t vlc_media_source_provider_t;
>  typedef struct intf_thread_t intf_thread_t;
> +typedef struct services_advertisement_t services_advertisement_t;
>  
>  typedef struct libvlc_priv_t
>  {
> @@ -210,6 +211,7 @@ typedef struct libvlc_priv_t
>      vlc_actions_t *actions; ///< Hotkeys handler
>      struct vlc_medialibrary_t *p_media_library; ///< Media library 
> instance
>      struct vlc_thumbnailer_t *p_thumbnailer; ///< Lazily instantiated 
> media thumbnailer
> +    services_advertisement_t * services_advertisements; // Linked-list 
> of SA modules
>  
>      /* Exit callback */
>      vlc_exit_t       exit;
> diff --git a/src/misc/services_advertisement.c 
> b/src/misc/services_advertisement.c
> new file mode 100644
> index 0000000000..c28db5e95c
> --- /dev/null
> +++ b/src/misc/services_advertisement.c
> @@ -0,0 +1,84 @@
> +/*****************************************************************************
> + * services_advertisement.c : Manage services advertisement modules
> + 
> *****************************************************************************
> + * Copyright (C) 1999-2019 VLC authors and VideoLAN
> + *
> + * Authors:
> + *
> + * This program 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 program 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 program; if not, write to the Free Software 
> Foundation,
> + * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
> + 
> *****************************************************************************/
> +#ifdef HAVE_CONFIG_H
> +# include "config.h"
> +#endif
> +#include <assert.h>
> +
> +#include <vlc_common.h>
> +#include <vlc_services_advertisement.h>
> +#include <vlc_modules.h>
> +#include "../libvlc.h"
> +
> +int vlc_sa_Create( libvlc_int_t *libvlc, const char *chain )
> +{
> +    assert( libvlc );
> +    libvlc_priv_t *priv = libvlc_priv( libvlc );
> +
> +    services_advertisement_t *sa = vlc_custom_create( libvlc, sizeof( 
> *sa ),
> +                                                 "services 
> advertisement" );
> +    if( unlikely( sa == NULL ) )
> +        return VLC_ENOMEM;
> +
> +    free( config_ChainCreate( &sa->psz_name, &sa->p_cfg, chain ) );
> +    
> +    sa->description = NULL;
> +
> +    sa->p_module = module_need( sa, "services_advertisement",
> +                                sa->psz_name, true );
> +    if ( sa->p_module == NULL )
> +    {
> +        msg_Err( sa, "no suitable services advertisement module" );
> +        return VLC_EGENERIC;
> +    }
> +
> +    vlc_mutex_lock( &priv->lock );
> +    sa->p_next = priv->services_advertisements;
> +    priv->services_advertisements = sa;
> +    vlc_mutex_unlock( &priv->lock );
> +
> +    return VLC_SUCCESS;
> +}
> +
> +void vlc_sa_DestroyAll( libvlc_int_t *libvlc )
> +{
> +    libvlc_priv_t *priv = libvlc_priv( libvlc );
> +
> +    vlc_mutex_lock( &priv->lock );
> +    services_advertisement_t *sa, **pp = 
> &priv->services_advertisements;
> +
> +    while( ( sa = *pp ) != NULL )
> +    {
> +        *pp = sa->p_next;
> +        vlc_mutex_unlock( &priv->lock );
> +
> +        if( sa->p_module )
> +            module_unneed( sa, sa->p_module );
> +
> +        config_ChainDestroy( sa->p_cfg );
> +        free( sa->psz_name );
> +        vlc_object_delete( sa );
> +
> +        vlc_mutex_lock( &priv->lock );
> +    }
> +    vlc_mutex_unlock( &priv->lock );
> +}
> \ No newline at end of file
> -- 
> 2.17.1
> 
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