modules/misc/lua/services_discovery.c

   1 /*****************************************************************************
   2  * services_discovery.c : Services discovery using lua scripts
   3  *****************************************************************************
   4  * Copyright (C) 2009 VideoLAN and AUTHORS
   5  *
   6  * Authors: Fabio Ritrovato <sephiroth87 at videolan dot 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 #ifdef HAVE_CONFIG_H
  24 # include "config.h"
  25 #endif
  26
  27 #include <vlc_common.h>
  28 #include <vlc_services_discovery.h>
  29
  30 #include "vlc.h"
  31 #include "libs.h"
  32
  33 /*****************************************************************************
  34  * Local prototypes
  35  *****************************************************************************/
  36 static void *Run( void * );
  37 static int   DoSearch( services_discovery_t *p_sd, const char *psz_query );
  38 static int   Search( services_discovery_t *p_sd, const char *psz_query );
  39
  40 static const char * const ppsz_sd_options[] = { "sd", "longname", NULL };
  41
  42 /*****************************************************************************
  43  * Local structures
  44  *****************************************************************************/
  45 struct services_discovery_sys_t
  46 {
  47     lua_State *L;
  48     char *psz_filename;
  49
  50     vlc_thread_t thread;
  51     vlc_mutex_t lock;
  52     vlc_cond_t cond;
  53     bool b_exiting;
  54
  55     char **ppsz_query;
  56     int i_query;
  57 };
  58 static const luaL_Reg p_reg[] = { { NULL, NULL } };
  59
  60 /*****************************************************************************
  61  * Open: initialize and create stuff
  62  *****************************************************************************/
  63 int Open_LuaSD( vlc_object_t *p_this )
  64 {
  65     services_discovery_t *p_sd = ( services_discovery_t * )p_this;
  66     services_discovery_sys_t *p_sys;
  67     lua_State *L = NULL;
  68     char *psz_name;
  69
  70     if( !strcmp(p_sd->psz_name, "lua"))
  71     {
  72         // We want to load the module name "lua"
  73         // This module can be used to load lua script not registered
  74         // as builtin lua SD modules.
  75         config_ChainParse( p_sd, "lua-", ppsz_sd_options, p_sd->p_cfg );
  76         psz_name = var_CreateGetString( p_sd, "lua-sd" );
  77     }
  78     else
  79     {
  80         // We are loading a builtin lua sd module.
  81         psz_name = strdup(p_sd->psz_name);
  82     }
  83
  84     if( !( p_sys = malloc( sizeof( services_discovery_sys_t ) ) ) )
  85     {
  86         free( psz_name );
  87         return VLC_ENOMEM;
  88     }
  89     p_sd->p_sys = p_sys;
  90     p_sd->pf_search = Search;
  91     p_sys->psz_filename = vlclua_find_file( p_this, "sd", psz_name );
  92     if( !p_sys->psz_filename )
  93     {
  94         msg_Err( p_sd, "Couldn't find lua services discovery script \"%s\".",
  95                  psz_name );
  96         free( psz_name );
  97         goto error;
  98     }
  99     free( psz_name );
 100     L = luaL_newstate();
 101     if( !L )
 102     {
 103         msg_Err( p_sd, "Could not create new Lua State" );
 104         goto error;
 105     }
 106     vlclua_set_this( L, p_sd );
 107     luaL_openlibs( L );
 108     luaL_register( L, "vlc", p_reg );
 109     luaopen_input( L );
 110     luaopen_msg( L );
 111     luaopen_misc( L );
 112     luaopen_net( L );
 113     luaopen_object( L );
 114     luaopen_sd( L );
 115     luaopen_strings( L );
 116     luaopen_variables( L );
 117     luaopen_stream( L );
 118     luaopen_gettext( L );
 119     luaopen_xml( L );
 120     luaopen_md5( L );
 121     lua_pop( L, 1 );
 122
 123     if( vlclua_add_modules_path( p_sd, L, p_sys->psz_filename ) )
 124     {
 125         msg_Warn( p_sd, "Error while setting the module search path for %s",
 126                   p_sys->psz_filename );
 127         goto error;
 128     }
 129     if( luaL_dofile( L, p_sys->psz_filename ) )
 130     {
 131         msg_Err( p_sd, "Error loading script %s: %s", p_sys->psz_filename,
 132                   lua_tostring( L, lua_gettop( L ) ) );
 133         lua_pop( L, 1 );
 134         goto error;
 135     }
 136     p_sys->L = L;
 137     vlc_mutex_init( &p_sys->lock );
 138     vlc_cond_init( &p_sys->cond );
 139     p_sys->b_exiting = false;
 140     TAB_INIT( p_sys->i_query, p_sys->ppsz_query );
 141
 142     if( vlc_clone (&p_sd->p_sys->thread, Run, p_sd, VLC_THREAD_PRIORITY_LOW) )
 143     {
 144         TAB_CLEAN( p_sys->i_query, p_sys->ppsz_query );
 145         vlc_cond_destroy( &p_sys->cond );
 146         vlc_mutex_destroy( &p_sys->lock );
 147         goto error;
 148     }
 149     return VLC_SUCCESS;
 150
 151 error:
 152     if( L )
 153         lua_close( L );
 154     free( p_sys->psz_filename );
 155     free( p_sys );
 156     return VLC_EGENERIC;
 157 }
 158
 159 /*****************************************************************************
 160  * Close: cleanup
 161  *****************************************************************************/
 162 void Close_LuaSD( vlc_object_t *p_this )
 163 {
 164     services_discovery_t *p_sd = ( services_discovery_t * )p_this;
 165
 166     vlc_mutex_lock( &p_sd->p_sys->lock );
 167     p_sd->p_sys->b_exiting = true;
 168     vlc_mutex_unlock( &p_sd->p_sys->lock );
 169
 170     vlc_cancel( p_sd->p_sys->thread );
 171     vlc_join (p_sd->p_sys->thread, NULL);
 172
 173     for( int i = 0; i < p_sd->p_sys->i_query; i++ )
 174         free( p_sd->p_sys->ppsz_query[i] );
 175     TAB_CLEAN( p_sd->p_sys->i_query, p_sd->p_sys->ppsz_query );
 176
 177     vlc_cond_destroy( &p_sd->p_sys->cond );
 178     vlc_mutex_destroy( &p_sd->p_sys->lock );
 179     free( p_sd->p_sys->psz_filename );
 180     lua_close( p_sd->p_sys->L );
 181     free( p_sd->p_sys );
 182 }
 183
 184 /*****************************************************************************
 185  * Run: Thread entry-point
 186  ****************************************************************************/
 187 static void* Run( void *data )
 188 {
 189     services_discovery_t *p_sd = ( services_discovery_t * )data;
 190     services_discovery_sys_t *p_sys = p_sd->p_sys;
 191     lua_State *L = p_sys->L;
 192
 193     int cancel = vlc_savecancel();
 194
 195     lua_getglobal( L, "main" );
 196     if( !lua_isfunction( L, lua_gettop( L ) ) || lua_pcall( L, 0, 1, 0 ) )
 197     {
 198         msg_Err( p_sd, "Error while running script %s, "
 199                   "function main(): %s", p_sys->psz_filename,
 200                   lua_tostring( L, lua_gettop( L ) ) );
 201         lua_pop( L, 1 );
 202         vlc_restorecancel( cancel );
 203         return NULL;
 204     }
 205     msg_Dbg( p_sd, "LuaSD script loaded: %s", p_sys->psz_filename );
 206
 207     /* Force garbage collection, because the core will keep the SD
 208      * open, but lua will never gc until lua_close(). */
 209     lua_gc( L, LUA_GCCOLLECT, 0 );
 210
 211     vlc_restorecancel( cancel );
 212
 213     /* Main loop to handle search requests */
 214     vlc_mutex_lock( &p_sys->lock );
 215     mutex_cleanup_push( &p_sys->lock );
 216     while( !p_sys->b_exiting )
 217     {
 218         /* Wait for a request */
 219         while( !p_sys->i_query )
 220             vlc_cond_wait( &p_sys->cond, &p_sys->lock );
 221
 222         /* Execute every query each one protected against cancelation */
 223         cancel = vlc_savecancel();
 224         while( !p_sys->b_exiting && p_sys->i_query )
 225         {
 226             char *psz_query = p_sys->ppsz_query[p_sys->i_query - 1];
 227             REMOVE_ELEM( p_sys->ppsz_query, p_sys->i_query, p_sys->i_query - 1 );
 228
 229             vlc_mutex_unlock( &p_sys->lock );
 230             DoSearch( p_sd, psz_query );
 231             free( psz_query );
 232             vlc_mutex_lock( &p_sys->lock );
 233         }
 234         vlc_restorecancel( cancel );
 235     }
 236     vlc_cleanup_run();
 237
 238     return NULL;
 239 }
 240
 241 /*****************************************************************************
 242  * Search: search for items according to the given query
 243  ****************************************************************************/
 244 static int Search( services_discovery_t *p_sd, const char *psz_query )
 245 {
 246     services_discovery_sys_t *p_sys = p_sd->p_sys;
 247     vlc_mutex_lock( &p_sys->lock );
 248     TAB_APPEND( p_sys->i_query, p_sys->ppsz_query, strdup( psz_query ) );
 249     vlc_cond_signal( &p_sys->cond );
 250     vlc_mutex_unlock( &p_sys->lock );
 251
 252     return VLC_SUCCESS;
 253 }
 254
 255 static int DoSearch( services_discovery_t *p_sd, const char *psz_query )
 256 {
 257     services_discovery_sys_t *p_sys = p_sd->p_sys;
 258     lua_State *L = p_sys->L;
 259
 260     /* Lookup for the 'search' function */
 261     lua_getglobal( L, "search" );
 262     if( !lua_isfunction( L, lua_gettop( L ) ) )
 263     {
 264         msg_Err( p_sd, "The script '%s' does not define any 'search' function",
 265                  p_sys->psz_filename );
 266         lua_pop( L, 1 );
 267         return VLC_EGENERIC;
 268     }
 269
 270     /* Push the query */
 271     lua_pushstring( L, psz_query );
 272
 273     /* Call the 'search' function */
 274     if( lua_pcall( L, 1, 0, 0 ) )
 275     {
 276         msg_Err( p_sd, "Error while running the script '%s': %s",
 277                  p_sys->psz_filename, lua_tostring( L, lua_gettop( L ) ) );
 278         lua_pop( L, 1 );
 279         return VLC_EGENERIC;
 280     }
 281
 282     return VLC_SUCCESS;
 283 }