modules/lua/stream_filter.c

   1 /*****************************************************************************
   2  * stream_filter.c :  Lua playlist stream filter module
   3  *****************************************************************************
   4  * Copyright (C) 2007-2008 the VideoLAN team
   5  *
   6  * Authors: Antoine Cellerier <dionoea at videolan tod org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  21  *****************************************************************************/
  22
  23 /*****************************************************************************
  24  * Preamble
  25  *****************************************************************************/
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include <assert.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33
  34 #include <vlc_common.h>
  35 #include <vlc_access.h>
  36
  37 #include "vlc.h"
  38 #include "libs.h"
  39
  40 /*****************************************************************************
  41  * Demux specific functions
  42  *****************************************************************************/
  43 struct vlclua_playlist
  44 {
  45     lua_State *L;
  46     char *filename;
  47     char *access;
  48     const char *path;
  49 };
  50
  51 static int vlclua_demux_peek( lua_State *L )
  52 {
  53     stream_t *s = (stream_t *)vlclua_get_this(L);
  54     int n = luaL_checkinteger( L, 1 );
  55     const uint8_t *p_peek;
  56
  57     ssize_t val = vlc_stream_Peek(s->s, &p_peek, n);
  58     if (val > 0)
  59         lua_pushlstring(L, (const char *)p_peek, val);
  60     else
  61         lua_pushnil( L );
  62     return 1;
  63 }
  64
  65 static int vlclua_demux_read( lua_State *L )
  66 {
  67     stream_t *s = (stream_t *)vlclua_get_this(L);
  68     int n = luaL_checkinteger( L, 1 );
  69     char *buf = malloc(n);
  70
  71     if (buf != NULL)
  72     {
  73         ssize_t val = vlc_stream_Read(s->s, buf, n);
  74         if (val > 0)
  75             lua_pushlstring(L, buf, val);
  76         else
  77             lua_pushnil( L );
  78         free(buf);
  79     }
  80     else
  81         lua_pushnil( L );
  82
  83     return 1;
  84 }
  85
  86 static int vlclua_demux_readline( lua_State *L )
  87 {
  88     stream_t *s = (stream_t *)vlclua_get_this(L);
  89     char *line = vlc_stream_ReadLine(s->s);
  90
  91     if (line != NULL)
  92     {
  93         lua_pushstring(L, line);
  94         free(line);
  95     }
  96     else
  97         lua_pushnil( L );
  98
  99     return 1;
 100 }
 101
 102 /*****************************************************************************
 103  *
 104  *****************************************************************************/
 105 /* Functions to register */
 106 static const luaL_Reg p_reg[] =
 107 {
 108     { "peek", vlclua_demux_peek },
 109     { NULL, NULL }
 110 };
 111
 112 /* Functions to register for parse() function call only */
 113 static const luaL_Reg p_reg_parse[] =
 114 {
 115     { "read", vlclua_demux_read },
 116     { "readline", vlclua_demux_readline },
 117     { NULL, NULL }
 118 };
 119
 120 /*****************************************************************************
 121  * Called through lua_scripts_batch_execute to call 'probe' on
 122  * the script pointed by psz_filename.
 123  *****************************************************************************/
 124 static int probe_luascript(vlc_object_t *obj, const char *filename,
 125                            const luabatch_context_t *ctx)
 126 {
 127     stream_t *s = (stream_t *)obj;
 128     struct vlclua_playlist *sys = s->p_sys;
 129
 130     /* Initialise Lua state structure */
 131     lua_State *L = luaL_newstate();
 132     if( !L )
 133         return VLC_ENOMEM;
 134
 135     sys->L = L;
 136
 137     /* Load Lua libraries */
 138     luaL_openlibs( L ); /* FIXME: Don't open all the libs? */
 139
 140     vlclua_set_this(L, s);
 141     luaL_register_namespace( L, "vlc", p_reg );
 142     luaopen_msg( L );
 143     luaopen_strings( L );
 144     luaopen_stream( L );
 145     luaopen_variables( L );
 146     luaopen_xml( L );
 147
 148     if (sys->path != NULL)
 149         lua_pushstring(L, sys->path);
 150     else
 151         lua_pushnil(L);
 152     lua_setfield( L, -2, "path" );
 153
 154     if (sys->access != NULL)
 155         lua_pushstring(L, sys->access);
 156     else
 157         lua_pushnil(L);
 158     lua_setfield( L, -2, "access" );
 159
 160     lua_pop( L, 1 );
 161
 162     /* Setup the module search path */
 163     if (vlclua_add_modules_path(L, filename))
 164     {
 165         msg_Warn(s, "error setting the module search path for %s", filename);
 166         goto error;
 167     }
 168
 169     /* Load and run the script(s) */
 170     if (vlclua_dofile(VLC_OBJECT(s), L, filename))
 171     {
 172         msg_Warn(s, "error loading script %s: %s", filename,
 173                  lua_tostring(L, lua_gettop(L)));
 174         goto error;
 175     }
 176
 177     lua_getglobal( L, "probe" );
 178     if( !lua_isfunction( L, -1 ) )
 179     {
 180         msg_Warn(s, "error running script %s: function %s(): %s",
 181                  filename, "probe", "not found");
 182         goto error;
 183     }
 184
 185     if( lua_pcall( L, 0, 1, 0 ) )
 186     {
 187         msg_Warn(s, "error running script %s: function %s(): %s",
 188                  filename, "probe", lua_tostring(L, lua_gettop(L)));
 189         goto error;
 190     }
 191
 192     if( lua_gettop( L ) )
 193     {
 194         if( lua_toboolean( L, 1 ) )
 195         {
 196             msg_Dbg(s, "Lua playlist script %s's "
 197                     "probe() function was successful", filename );
 198             lua_pop( L, 1 );
 199             sys->filename = strdup(filename);
 200             return VLC_SUCCESS;
 201         }
 202     }
 203
 204     (void) ctx;
 205 error:
 206     lua_pop( L, 1 );
 207     lua_close(sys->L);
 208     return VLC_EGENERIC;
 209 }
 210
 211 static int ReadDir(stream_t *s, input_item_node_t *node)
 212 {
 213     struct vlclua_playlist *sys = s->p_sys;
 214     lua_State *L = sys->L;
 215
 216     luaL_register_namespace( L, "vlc", p_reg_parse );
 217
 218     lua_getglobal( L, "parse" );
 219
 220     if( !lua_isfunction( L, -1 ) )
 221     {
 222         msg_Warn(s, "error running script %s: function %s(): %s",
 223                  sys->filename, "parse", "not found");
 224         return VLC_ENOITEM;
 225     }
 226
 227     if( lua_pcall( L, 0, 1, 0 ) )
 228     {
 229         msg_Warn(s, "error running script %s: function %s(): %s",
 230                  sys->filename, "parse", lua_tostring(L, lua_gettop(L)));
 231         return VLC_ENOITEM;
 232     }
 233
 234     if (!lua_gettop(L))
 235     {
 236         msg_Err(s, "script went completely foobar");
 237         return VLC_ENOITEM;
 238     }
 239
 240     if (!lua_istable(L, -1))
 241     {
 242         msg_Warn(s, "Playlist should be a table.");
 243         return VLC_ENOITEM;
 244     }
 245
 246     lua_pushnil(L);
 247
 248     /* playlist nil */
 249     while (lua_next(L, -2))
 250     {
 251         input_item_t *item = vlclua_read_input_item(VLC_OBJECT(s), L);
 252         if (item != NULL)
 253         {
 254             /* copy the original URL to the meta data,
 255              * if "URL" is still empty */
 256             char *url = input_item_GetURL(item);
 257             if (url == NULL && s->psz_url != NULL)
 258                 input_item_SetURL(item, s->psz_url);
 259             free(url);
 260
 261             input_item_node_AppendItem(node, item);
 262             input_item_Release(item);
 263         }
 264         /* pop the value, keep the key for the next lua_next() call */
 265         lua_pop(L, 1);
 266     }
 267     /* playlist */
 268
 269     return VLC_SUCCESS;
 270 }
 271
 272 /*****************************************************************************
 273  * Import_LuaPlaylist: main import function
 274  *****************************************************************************/
 275 int Import_LuaPlaylist(vlc_object_t *obj)
 276 {
 277     stream_t *s = (stream_t *)obj;
 278
 279     if( lua_Disabled( obj ) )
 280         return VLC_EGENERIC;
 281
 282     struct vlclua_playlist *sys = malloc(sizeof (*sys));
 283     if (unlikely(sys == NULL))
 284         return VLC_ENOMEM;
 285
 286     s->p_sys = sys;
 287     sys->access = NULL;
 288     sys->path = NULL;
 289
 290     if (s->psz_url != NULL)
 291     {   /* Backward compatibility hack: Lua scripts expect the URI scheme and
 292          * the rest of the URI separately. */
 293         const char *p = strstr(s->psz_url, "://");
 294         if (p != NULL)
 295         {
 296             sys->access = strndup(s->psz_url, p - s->psz_url);
 297             sys->path = p + 3;
 298         }
 299     }
 300
 301     int ret = vlclua_scripts_batch_execute(VLC_OBJECT(s), "playlist",
 302                                            probe_luascript, NULL);
 303     if (ret != VLC_SUCCESS)
 304     {
 305         free(sys->access);
 306         free(sys);
 307         return ret;
 308     }
 309
 310     s->pf_readdir = ReadDir;
 311     s->pf_control = access_vaDirectoryControlHelper;
 312     return VLC_SUCCESS;
 313 }
 314
 315 void Close_LuaPlaylist(vlc_object_t *obj)
 316 {
 317     stream_t *s = (stream_t *)obj;
 318     struct vlclua_playlist *sys = s->p_sys;
 319
 320     free(sys->filename);
 321     assert(sys->L != NULL);
 322     lua_close(sys->L);
 323     free(sys->access);
 324     free(sys);
 325 }