modules/lua/demux.c

   1 /*****************************************************************************
   2  * demux.c :  Lua playlist demux module
   3  *****************************************************************************
   4  * Copyright (C) 2007-2008 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Antoine Cellerier <dionoea at videolan tod 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 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <assert.h>
  32
  33 #include "vlc.h"
  34 #include "libs.h"
  35
  36
  37 /*****************************************************************************
  38  * Local prototypes
  39  *****************************************************************************/
  40 static int Demux( demux_t *p_demux );
  41 static int Control( demux_t *p_demux, int i_query, va_list args );
  42
  43 /*****************************************************************************
  44  * Demux specific functions
  45  *****************************************************************************/
  46 struct demux_sys_t
  47 {
  48     lua_State *L;
  49     char *psz_filename;
  50 };
  51
  52 static int vlclua_demux_peek( lua_State *L )
  53 {
  54     demux_t *p_demux = (demux_t *)vlclua_get_this( L );
  55     int n = luaL_checkint( L, 1 );
  56     const uint8_t *p_peek;
  57
  58     int i_peek = stream_Peek( p_demux->s, &p_peek, n );
  59     if( i_peek > 0 )
  60         lua_pushlstring( L, (const char *)p_peek, i_peek );
  61     else
  62         lua_pushnil( L );
  63     return 1;
  64 }
  65
  66 static int vlclua_demux_read( lua_State *L )
  67 {
  68     demux_t *p_demux = (demux_t *)vlclua_get_this( L );
  69     const uint8_t *p_read;
  70     int n = luaL_checkint( L, 1 );
  71     int i_read = stream_Peek( p_demux->s, &p_read, n );
  72
  73     if( i_read > 0 )
  74     {
  75         lua_pushlstring( L, (const char *)p_read, i_read );
  76         int i_seek = stream_Read( p_demux->s, NULL, i_read );
  77         assert( i_read == i_seek );
  78     }
  79     else
  80         lua_pushnil( L );
  81
  82     return 1;
  83 }
  84
  85 static int vlclua_demux_readline( lua_State *L )
  86 {
  87     demux_t *p_demux = (demux_t *)vlclua_get_this( L );
  88     char *psz_line = stream_ReadLine( p_demux->s );
  89     if( psz_line )
  90     {
  91         lua_pushstring( L, psz_line );
  92         free( psz_line );
  93     }
  94     else
  95     {
  96         lua_pushnil( L );
  97     }
  98     return 1;
  99 }
 100
 101 /*****************************************************************************
 102  *
 103  *****************************************************************************/
 104 /* Functions to register */
 105 static const luaL_Reg p_reg[] =
 106 {
 107     { "peek", vlclua_demux_peek },
 108     { NULL, NULL }
 109 };
 110
 111 /* Functions to register for parse() function call only */
 112 static const luaL_Reg p_reg_parse[] =
 113 {
 114     { "read", vlclua_demux_read },
 115     { "readline", vlclua_demux_readline },
 116     { NULL, NULL }
 117 };
 118
 119 /*****************************************************************************
 120  * Called through lua_scripts_batch_execute to call 'probe' on
 121  * the script pointed by psz_filename.
 122  *****************************************************************************/
 123 static int probe_luascript( vlc_object_t *p_this, const char * psz_filename,
 124                             const luabatch_context_t *p_context )
 125 {
 126     VLC_UNUSED(p_context);
 127     demux_t * p_demux = (demux_t *)p_this;
 128
 129     p_demux->p_sys->psz_filename = strdup(psz_filename);
 130
 131     /* Initialise Lua state structure */
 132     lua_State *L = luaL_newstate();
 133     if( !L )
 134     {
 135         msg_Err( p_demux, "Could not create new Lua State" );
 136         goto error;
 137     }
 138     p_demux->p_sys->L = L;
 139
 140     /* Load Lua libraries */
 141     luaL_openlibs( L ); /* FIXME: Don't open all the libs? */
 142
 143     vlclua_set_this( L, p_demux );
 144     luaL_register( L, "vlc", p_reg );
 145     luaopen_msg( L );
 146     luaopen_strings( L );
 147     luaopen_stream( L );
 148     luaopen_variables( L );
 149     luaopen_xml( L );
 150     lua_pushstring( L, p_demux->psz_location );
 151     lua_setfield( L, -2, "path" );
 152     lua_pushstring( L, p_demux->psz_access );
 153     lua_setfield( L, -2, "access" );
 154
 155     lua_pop( L, 1 );
 156
 157     /* Setup the module search path */
 158     if( vlclua_add_modules_path( L, psz_filename ) )
 159     {
 160         msg_Warn( p_demux, "Error while setting the module search path for %s",
 161                   psz_filename );
 162         goto error;
 163     }
 164
 165     /* Load and run the script(s) */
 166     if( vlclua_dofile( VLC_OBJECT(p_demux), L, psz_filename ) )
 167     {
 168         msg_Warn( p_demux, "Error loading script %s: %s", psz_filename,
 169                   lua_tostring( L, lua_gettop( L ) ) );
 170         goto error;
 171     }
 172
 173     lua_getglobal( L, "probe" );
 174
 175     if( !lua_isfunction( L, -1 ) )
 176     {
 177         msg_Warn( p_demux, "Error while running script %s, "
 178                   "function probe() not found", psz_filename );
 179         goto error;
 180     }
 181
 182     if( lua_pcall( L, 0, 1, 0 ) )
 183     {
 184         msg_Warn( p_demux, "Error while running script %s, "
 185                   "function probe(): %s", psz_filename,
 186                   lua_tostring( L, lua_gettop( L ) ) );
 187         goto error;
 188     }
 189
 190     if( lua_gettop( L ) )
 191     {
 192         if( lua_toboolean( L, 1 ) )
 193         {
 194             msg_Dbg( p_demux, "Lua playlist script %s's "
 195                      "probe() function was successful", psz_filename );
 196             lua_pop( L, 1 );
 197             return VLC_SUCCESS;
 198         }
 199     }
 200
 201 error:
 202     lua_pop( L, 1 );
 203     lua_close( p_demux->p_sys->L );
 204     p_demux->p_sys->L = NULL;
 205     FREENULL( p_demux->p_sys->psz_filename );
 206     return VLC_EGENERIC;
 207 }
 208
 209 /*****************************************************************************
 210  * Import_LuaPlaylist: main import function
 211  *****************************************************************************/
 212 int Import_LuaPlaylist( vlc_object_t *p_this )
 213 {
 214     demux_t *p_demux = (demux_t *)p_this;
 215     int ret;
 216
 217     p_demux->p_sys = calloc( 1, sizeof( demux_sys_t ) );
 218     if( !p_demux->p_sys )
 219         return VLC_ENOMEM;
 220
 221     p_demux->pf_control = Control;
 222     p_demux->pf_demux = Demux;
 223
 224     ret = vlclua_scripts_batch_execute( p_this, "playlist",
 225                                         &probe_luascript, NULL );
 226     if( ret )
 227         Close_LuaPlaylist( p_this );
 228     return ret;
 229 }
 230
 231
 232 /*****************************************************************************
 233  * Deactivate: frees unused data
 234  *****************************************************************************/
 235 void Close_LuaPlaylist( vlc_object_t *p_this )
 236 {
 237     demux_t *p_demux = (demux_t *)p_this;
 238     if( p_demux->p_sys->L )
 239         lua_close( p_demux->p_sys->L );
 240     free( p_demux->p_sys->psz_filename );
 241     free( p_demux->p_sys );
 242 }
 243
 244 static int Demux( demux_t *p_demux )
 245 {
 246     lua_State *L = p_demux->p_sys->L;
 247     char *psz_filename = p_demux->p_sys->psz_filename;
 248
 249     input_item_t *p_current_input = input_GetItem( p_demux->p_input );
 250
 251     luaL_register( L, "vlc", p_reg_parse );
 252
 253     lua_getglobal( L, "parse" );
 254
 255     if( !lua_isfunction( L, -1 ) )
 256     {
 257         msg_Warn( p_demux, "Error while running script %s, "
 258                   "function parse() not found", psz_filename );
 259         return VLC_EGENERIC;
 260     }
 261
 262     if( lua_pcall( L, 0, 1, 0 ) )
 263     {
 264         msg_Warn( p_demux, "Error while running script %s, "
 265                   "function parse(): %s", psz_filename,
 266                   lua_tostring( L, lua_gettop( L ) ) );
 267         return VLC_EGENERIC;
 268     }
 269
 270     if( lua_gettop( L ) )
 271         vlclua_playlist_add_internal( p_demux, L, NULL, p_current_input, 0 );
 272     else
 273         msg_Err( p_demux, "Script went completely foobar" );
 274
 275     return -1; /* Needed for correct operation of go back */
 276 }
 277
 278 static int Control( demux_t *p_demux, int i_query, va_list args )
 279 {
 280     VLC_UNUSED(p_demux); VLC_UNUSED(i_query); VLC_UNUSED(args);
 281     return VLC_EGENERIC;
 282 }