modules/lua/meta.c

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