modules/lua/meta.c

   1 /*****************************************************************************
   2  * meta.c: Get meta/artwork using lua scripts
   3  *****************************************************************************
   4  * Copyright (C) 2007-2008 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Antoine Cellerier <dionoea at videolan tod org>
   8  *          Pierre d'Herbemont <pdherbemont # videolan.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /*****************************************************************************
  26  * Preamble
  27  *****************************************************************************/
  28 #ifndef  _GNU_SOURCE
  29 #   define  _GNU_SOURCE
  30 #endif
  31
  32 #ifdef HAVE_CONFIG_H
  33 # include "config.h"
  34 #endif
  35
  36 #include "vlc.h"
  37 #include "libs.h"
  38
  39 /*****************************************************************************
  40  * Init lua
  41  *****************************************************************************/
  42 static const luaL_Reg p_reg[] = { { NULL, NULL } };
  43
  44 static lua_State * init( vlc_object_t *p_this, input_item_t * p_item, const char *psz_filename )
  45 {
  46     lua_State * L = luaL_newstate();
  47     if( !L )
  48     {
  49         msg_Err( p_this, "Could not create new Lua State" );
  50         return NULL;
  51     }
  52
  53     vlclua_set_this( L, p_this );
  54
  55     /* Load Lua libraries */
  56     luaL_openlibs( L ); /* XXX: Don't open all the libs? */
  57
  58     luaL_register_namespace( L, "vlc", p_reg );
  59
  60     luaopen_msg( L );
  61     luaopen_stream( L );
  62     luaopen_strings( L );
  63     luaopen_variables( L );
  64     luaopen_object( L );
  65     luaopen_xml( L );
  66     luaopen_input_item( L, p_item );
  67
  68     if( vlclua_add_modules_path( L, psz_filename ) )
  69     {
  70         msg_Warn( p_this, "Error while setting the module search path for %s",
  71                   psz_filename );
  72         lua_close( L );
  73         return NULL;
  74     }
  75
  76     return L;
  77 }
  78
  79 /*****************************************************************************
  80  * Run a lua entry point function
  81  *****************************************************************************/
  82 static int run( vlc_object_t *p_this, const char * psz_filename,
  83                 lua_State * L, const char *luafunction,
  84                 const luabatch_context_t *p_context )
  85 {
  86     /* Ugly hack to delete previous versions of the fetchart()
  87      * functions. */
  88     lua_pushnil( L );
  89     lua_setglobal( L, luafunction );
  90
  91     /* Load and run the script(s) */
  92     if( vlclua_dofile( p_this, L, psz_filename ) )
  93     {
  94         msg_Warn( p_this, "Error loading script %s: %s", psz_filename,
  95                  lua_tostring( L, lua_gettop( L ) ) );
  96         goto error;
  97     }
  98
  99
 100     meta_fetcher_scope_t e_scope = FETCHER_SCOPE_NETWORK; /* default to restricted one */
 101     lua_getglobal( L, "descriptor" );
 102     if( lua_isfunction( L, lua_gettop( L ) ) && !lua_pcall( L, 0, 1, 0 ) )
 103     {
 104         lua_getfield( L, -1, "scope" );
 105         char *psz_scope = luaL_strdupornull( L, -1 );
 106         if ( psz_scope && !strcmp( psz_scope, "local" ) )
 107             e_scope = FETCHER_SCOPE_LOCAL;
 108         free( psz_scope );
 109         lua_pop( L, 1 );
 110     }
 111     lua_pop( L, 1 );
 112
 113     if ( p_context && p_context->pf_validator && !p_context->pf_validator( p_context, e_scope ) )
 114     {
 115         msg_Dbg( p_this, "skipping script (unmatched scope) %s", psz_filename );
 116         goto error;
 117     }
 118
 119     lua_getglobal( L, luafunction );
 120
 121     if( !lua_isfunction( L, lua_gettop( L ) ) )
 122     {
 123         msg_Warn( p_this, "Error while running script %s, "
 124                  "function %s() not found", psz_filename, luafunction );
 125         goto error;
 126     }
 127
 128     if( lua_pcall( L, 0, 1, 0 ) )
 129     {
 130         msg_Warn( p_this, "Error while running script %s, "
 131                  "function %s(): %s", psz_filename, luafunction,
 132                  lua_tostring( L, lua_gettop( L ) ) );
 133         goto error;
 134     }
 135     return VLC_SUCCESS;
 136
 137 error:
 138     lua_pop( L, 1 );
 139     return VLC_EGENERIC;
 140 }
 141
 142 /*****************************************************************************
 143  * Called through lua_scripts_batch_execute to call 'fetch_art' on the script
 144  * pointed by psz_filename.
 145  *****************************************************************************/
 146 static bool validate_scope( const luabatch_context_t *p_context, meta_fetcher_scope_t e_scope )
 147 {
 148     if ( p_context->e_scope == FETCHER_SCOPE_ANY )
 149         return true;
 150     else
 151         return ( p_context->e_scope == e_scope );
 152 }
 153
 154 static int fetch_art( vlc_object_t *p_this, const char * psz_filename,
 155                       const luabatch_context_t *p_context )
 156 {
 157     lua_State *L = init( p_this, p_context->p_item, psz_filename );
 158     if( !L )
 159         return VLC_EGENERIC;
 160
 161     int i_ret = run(p_this, psz_filename, L, "fetch_art", p_context);
 162     if(i_ret != VLC_SUCCESS)
 163     {
 164         lua_close( L );
 165         return i_ret;
 166     }
 167
 168     if(lua_gettop( L ))
 169     {
 170         const char * psz_value;
 171
 172         if( lua_isstring( L, -1 ) )
 173         {
 174             psz_value = lua_tostring( L, -1 );
 175             if( psz_value && *psz_value != 0 )
 176             {
 177                 lua_Dbg( p_this, "setting arturl: %s", psz_value );
 178                 input_item_SetArtURL ( p_context->p_item, psz_value );
 179                 lua_close( L );
 180                 return VLC_SUCCESS;
 181             }
 182         }
 183         else if( !lua_isnoneornil( L, -1 ) )
 184         {
 185             msg_Err( p_this, "Lua art fetcher script %s: "
 186                  "didn't return a string", psz_filename );
 187         }
 188     }
 189     else
 190     {
 191         msg_Err( p_this, "Script went completely foobar" );
 192     }
 193
 194     lua_close( L );
 195     return VLC_EGENERIC;
 196 }
 197
 198 /*****************************************************************************
 199  * Called through lua_scripts_batch_execute to call 'read_meta' on the script
 200  * pointed by psz_filename.
 201  *****************************************************************************/
 202 static int read_meta( vlc_object_t *p_this, const char * psz_filename,
 203                       const luabatch_context_t *p_context )
 204 {
 205     /* FIXME: merge with finder */
 206     demux_meta_t *p_demux_meta = (demux_meta_t *)p_this;
 207     VLC_UNUSED( p_context );
 208
 209     lua_State *L = init( p_this, p_demux_meta->p_item, psz_filename );
 210     if( !L )
 211         return VLC_EGENERIC;
 212
 213     int i_ret = run(p_this, psz_filename, L, "read_meta", NULL);
 214     lua_close( L );
 215
 216     // Continue even if an error occurred: all "meta reader" are always run.
 217     return i_ret == VLC_SUCCESS ? VLC_EGENERIC : i_ret;
 218 }
 219
 220
 221 /*****************************************************************************
 222  * Called through lua_scripts_batch_execute to call 'fetch_meta' on the script
 223  * pointed by psz_filename.
 224  *****************************************************************************/
 225 static int fetch_meta( vlc_object_t *p_this, const char * psz_filename,
 226                        const luabatch_context_t *p_context )
 227 {
 228     lua_State *L = init( p_this, p_context->p_item, psz_filename );
 229     if( !L )
 230         return VLC_EGENERIC;
 231
 232     int ret = run(p_this, psz_filename, L, "fetch_meta", p_context);
 233     lua_close( L );
 234
 235     return ret;
 236 }
 237
 238 /*****************************************************************************
 239  * Read meta.
 240  *****************************************************************************/
 241
 242 int ReadMeta( demux_meta_t *p_this )
 243 {
 244     if( lua_Disabled( p_this ) )
 245         return VLC_EGENERIC;
 246
 247     return vlclua_scripts_batch_execute( VLC_OBJECT(p_this), "meta"DIR_SEP"reader",
 248                                          (void*) &read_meta, NULL );
 249 }
 250
 251
 252 /*****************************************************************************
 253  * Read meta.
 254  *****************************************************************************/
 255
 256 int FetchMeta( meta_fetcher_t *p_finder )
 257 {
 258     if( lua_Disabled( p_finder ) )
 259         return VLC_EGENERIC;
 260
 261     luabatch_context_t context = { p_finder->p_item, p_finder->e_scope, validate_scope };
 262
 263     return vlclua_scripts_batch_execute( VLC_OBJECT(p_finder), "meta"DIR_SEP"fetcher",
 264                                          &fetch_meta, (void*)&context );
 265 }
 266
 267
 268 /*****************************************************************************
 269  * Module entry point for art.
 270  *****************************************************************************/
 271 int FindArt( meta_fetcher_t *p_finder )
 272 {
 273     if( lua_Disabled( p_finder ) )
 274         return VLC_EGENERIC;
 275
 276     luabatch_context_t context = { p_finder->p_item, p_finder->e_scope, validate_scope };
 277
 278     return vlclua_scripts_batch_execute( VLC_OBJECT(p_finder), "meta"DIR_SEP"art",
 279                                          &fetch_art, (void*)&context );
 280 }
 281