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

Thomas Guillem thomas at gllm.fr
Mon Sep 2 18:36:34 CEST 2019



On Mon, Sep 2, 2019, at 14:00, Thomas Guillem wrote:
> 
> 
> 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;

And by the way, why do you need next here ? There should be only one SA module per VLC instance.

> };
> 
> 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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