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 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include <vlc_common.h>
  36 #include <vlc_access.h>
  37
  38 #include "vlc.h"
  39 #include "libs.h"
  40
  41 /*****************************************************************************
  42  * Demux specific functions
  43  *****************************************************************************/
  44 struct vlclua_playlist
  45 {
  46     lua_State *L;
  47     char *filename;
  48     char *access;
  49     const char *path;
  50 };
  51
  52 static int vlclua_demux_peek( lua_State *L )
  53 {
  54     stream_t *s = (stream_t *)vlclua_get_this(L);
  55     int n = luaL_checkint( L, 1 );
  56     const uint8_t *p_peek;
  57
  58     ssize_t val = vlc_stream_Peek(s->p_source, &p_peek, n);
  59     if (val > 0)
  60         lua_pushlstring(L, (const char *)p_peek, val);
  61     else
  62         lua_pushnil( L );
  63     return 1;
  64 }
  65
  66 static int vlclua_demux_read( lua_State *L )
  67 {
  68     stream_t *s = (stream_t *)vlclua_get_this(L);
  69     int n = luaL_checkint( L, 1 );
  70     char *buf = malloc(n);
  71
  72     if (buf != NULL)
  73     {
  74         ssize_t val = vlc_stream_Read(s->p_source, buf, n);
  75         if (val > 0)
  76             lua_pushlstring(L, buf, val);
  77         else
  78             lua_pushnil( L );
  79         free(buf);
  80     }
  81     else
  82         lua_pushnil( L );
  83
  84     return 1;
  85 }
  86
  87 static int vlclua_demux_readline( lua_State *L )
  88 {
  89     stream_t *s = (stream_t *)vlclua_get_this(L);
  90     char *line = vlc_stream_ReadLine(s->p_source);
  91
  92     if (line != NULL)
  93     {
  94         lua_pushstring(L, line);
  95         free(line);
  96     }
  97     else
  98         lua_pushnil( L );
  99
 100     return 1;
 101 }
 102
 103 /*****************************************************************************
 104  *
 105  *****************************************************************************/
 106 /* Functions to register */
 107 static const luaL_Reg p_reg[] =
 108 {
 109     { "peek", vlclua_demux_peek },
 110     { NULL, NULL }
 111 };
 112
 113 /* Functions to register for parse() function call only */
 114 static const luaL_Reg p_reg_parse[] =
 115 {
 116     { "read", vlclua_demux_read },
 117     { "readline", vlclua_demux_readline },
 118     { NULL, NULL }
 119 };
 120
 121 /*****************************************************************************
 122  * Called through lua_scripts_batch_execute to call 'probe' on
 123  * the script pointed by psz_filename.
 124  *****************************************************************************/
 125 static int probe_luascript(vlc_object_t *obj, const char *filename,
 126                            const luabatch_context_t *ctx)
 127 {
 128     stream_t *s = (stream_t *)obj;
 129     struct vlclua_playlist *sys = s->p_sys;
 130
 131     /* Initialise Lua state structure */
 132     lua_State *L = luaL_newstate();
 133     if( !L )
 134         return VLC_ENOMEM;
 135
 136     sys->L = L;
 137
 138     /* Load Lua libraries */
 139     luaL_openlibs( L ); /* FIXME: Don't open all the libs? */
 140
 141     vlclua_set_this(L, s);
 142     luaL_register_namespace( L, "vlc", p_reg );
 143     luaopen_msg( L );
 144     luaopen_strings( L );
 145     luaopen_stream( L );
 146     luaopen_variables( L );
 147     luaopen_xml( L );
 148
 149     if (sys->path != NULL)
 150         lua_pushstring(L, sys->path);
 151     else
 152         lua_pushnil(L);
 153     lua_setfield( L, -2, "path" );
 154
 155     if (sys->access != NULL)
 156         lua_pushstring(L, sys->access);
 157     else
 158         lua_pushnil(L);
 159     lua_setfield( L, -2, "access" );
 160
 161     lua_pop( L, 1 );
 162
 163     /* Setup the module search path */
 164     if (vlclua_add_modules_path(L, filename))
 165     {
 166         msg_Warn(s, "error setting the module search path for %s", filename);
 167         goto error;
 168     }
 169
 170     /* Load and run the script(s) */
 171     if (vlclua_dofile(VLC_OBJECT(s), L, filename))
 172     {
 173         msg_Warn(s, "error loading script %s: %s", filename,
 174                  lua_tostring(L, lua_gettop(L)));
 175         goto error;
 176     }
 177
 178     lua_getglobal( L, "probe" );
 179     if( !lua_isfunction( L, -1 ) )
 180     {
 181         msg_Warn(s, "error running script %s: function %s(): %s",
 182                  filename, "probe", "not found");
 183         goto error;
 184     }
 185
 186     if( lua_pcall( L, 0, 1, 0 ) )
 187     {
 188         msg_Warn(s, "error running script %s: function %s(): %s",
 189                  filename, "probe", lua_tostring(L, lua_gettop(L)));
 190         goto error;
 191     }
 192
 193     if( lua_gettop( L ) )
 194     {
 195         if( lua_toboolean( L, 1 ) )
 196         {
 197             msg_Dbg(s, "Lua playlist script %s's "
 198                     "probe() function was successful", filename );
 199             lua_pop( L, 1 );
 200             sys->filename = strdup(filename);
 201             return VLC_SUCCESS;
 202         }
 203     }
 204
 205     (void) ctx;
 206 error:
 207     lua_pop( L, 1 );
 208     lua_close(sys->L);
 209     return VLC_EGENERIC;
 210 }
 211
 212 static int ReadDir(stream_t *s, input_item_node_t *node)
 213 {
 214     struct vlclua_playlist *sys = s->p_sys;
 215     lua_State *L = sys->L;
 216
 217     luaL_register_namespace( L, "vlc", p_reg_parse );
 218
 219     lua_getglobal( L, "parse" );
 220
 221     if( !lua_isfunction( L, -1 ) )
 222     {
 223         msg_Warn(s, "error running script %s: function %s(): %s",
 224                  sys->filename, "parse", "not found");
 225         return VLC_ENOITEM;
 226     }
 227
 228     if( lua_pcall( L, 0, 1, 0 ) )
 229     {
 230         msg_Warn(s, "error running script %s: function %s(): %s",
 231                  sys->filename, "parse", lua_tostring(L, lua_gettop(L)));
 232         return VLC_ENOITEM;
 233     }
 234
 235     if (!lua_gettop(L))
 236     {
 237         msg_Err(s, "script went completely foobar");
 238         return VLC_ENOITEM;
 239     }
 240
 241     if (!lua_istable(L, -1))
 242     {
 243         msg_Warn(s, "Playlist should be a table.");
 244         return VLC_ENOITEM;
 245     }
 246
 247     lua_pushnil(L);
 248
 249     /* playlist nil */
 250     while (lua_next(L, -2))
 251     {
 252         input_item_t *item = vlclua_read_input_item(VLC_OBJECT(s), L);
 253         if (item != NULL)
 254         {
 255             /* copy the original URL to the meta data,
 256              * if "URL" is still empty */
 257             char *url = input_item_GetURL(item);
 258             if (url == NULL && s->psz_url != NULL)
 259                 input_item_SetURL(item, s->psz_url);
 260             free(url);
 261
 262             input_item_node_AppendItem(node, item);
 263             input_item_Release(item);
 264         }
 265         /* pop the value, keep the key for the next lua_next() call */
 266         lua_pop(L, 1);
 267     }
 268     /* playlist */
 269
 270     return VLC_SUCCESS;
 271 }
 272
 273 /*****************************************************************************
 274  * Import_LuaPlaylist: main import function
 275  *****************************************************************************/
 276 int Import_LuaPlaylist(vlc_object_t *obj)
 277 {
 278     stream_t *s = (stream_t *)obj;
 279
 280     if( !vlc_stream_Control( s->p_source, STREAM_IS_DIRECTORY ) )
 281         return VLC_EGENERIC;
 282
 283     struct vlclua_playlist *sys = malloc(sizeof (*sys));
 284     if (unlikely(sys == NULL))
 285         return VLC_ENOMEM;
 286
 287     s->p_sys = sys;
 288     sys->access = NULL;
 289     sys->path = NULL;
 290
 291     if (s->psz_url != NULL)
 292     {   /* Backward compatibility hack: Lua scripts expect the URI scheme and
 293          * the rest of the URI separately. */
 294         const char *p = strstr(s->psz_url, "://");
 295         if (p != NULL)
 296         {
 297             sys->access = strndup(s->psz_url, p - s->psz_url);
 298             sys->path = p + 3;
 299         }
 300     }
 301
 302     int ret = vlclua_scripts_batch_execute(VLC_OBJECT(s), "playlist",
 303                                            probe_luascript, NULL);
 304     if (ret != VLC_SUCCESS)
 305     {
 306         free(sys->access);
 307         free(sys);
 308         return ret;
 309     }
 310
 311     s->pf_readdir = ReadDir;
 312     s->pf_control = access_vaDirectoryControlHelper;
 313     return VLC_SUCCESS;
 314 }
 315
 316 void Close_LuaPlaylist(vlc_object_t *obj)
 317 {
 318     stream_t *s = (stream_t *)obj;
 319     struct vlclua_playlist *sys = s->p_sys;
 320
 321     free(sys->filename);
 322     assert(sys->L != NULL);
 323     lua_close(sys->L);
 324     free(sys->access);
 325     free(sys);
 326 }