git.sesse.net Git - vlc/blob - modules/codec/cmml/intf.c

   1 /*****************************************************************************
   2  * intf.c: interface for CMML annotations/hyperlinks
   3  *****************************************************************************
   4  * Copyright (C) 2003-2004 Commonwealth Scientific and Industrial Research
   5  *                         Organisation (CSIRO) Australia
   6  * Copyright (C) 2004 the VideoLAN team
   7  *
   8  * $Id$
   9  *
  10  * Authors: Andre Pang <Andre.Pang@csiro.au>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  25  *****************************************************************************/
  26
  27 /*****************************************************************************
  28  * Preamble
  29  *****************************************************************************/
  30 #ifdef HAVE_CONFIG_H
  31 # include "config.h"
  32 #endif
  33
  34 #include <vlc_common.h>
  35
  36 #include <stdio.h>
  37
  38 #ifdef HAVE_UNISTD_H
  39 #    include <unistd.h>
  40 #endif
  41
  42 #include <vlc_codec.h>
  43 #include <vlc_input.h>
  44 #include <vlc_interface.h>
  45 #include <vlc_vout.h>
  46 #include <vlc_playlist.h>
  47 #include <vlc_osd.h>
  48
  49 #include "vlc_keys.h"
  50
  51 #include "browser_open.h"
  52 #include "history.h"
  53 #include "xstrcat.h"
  54 #include "xurl.h"
  55
  56 #undef  CMML_INTF_USE_TIMED_URIS
  57
  58 #undef  CMML_INTF_DEBUG
  59 #undef  CMML_INTF_HISTORY_DEBUG
  60
  61 /*****************************************************************************
  62  * intf_sys_t: description and status of interface
  63  *****************************************************************************/
  64 struct intf_sys_t
  65 {
  66     decoder_t *         p_cmml_decoder;
  67     input_thread_t *    p_input;
  68
  69     int                 i_key_action;
  70 };
  71
  72 struct navigation_history_t
  73 {
  74     int i_history_size;
  75     int i_last_item;
  76 };
  77
  78 /*****************************************************************************
  79  * Local prototypes.
  80  *****************************************************************************/
  81
  82 int          OpenIntf               ( vlc_object_t * );
  83 void         CloseIntf              ( vlc_object_t * );
  84
  85 static int   InitThread                 ( intf_thread_t * );
  86 static int   MouseEvent                 ( vlc_object_t *, char const *,
  87                                           vlc_value_t, vlc_value_t, void * );
  88 static int   KeyEvent                   ( vlc_object_t *, char const *,
  89                                           vlc_value_t, vlc_value_t, void * );
  90
  91 static void  FollowAnchor               ( intf_thread_t * );
  92 static void  GoBack                     ( intf_thread_t * );
  93 static void  GoForward                  ( intf_thread_t * );
  94
  95 static int   FollowAnchorCallback       ( vlc_object_t *, char const *,
  96                                           vlc_value_t, vlc_value_t, void * );
  97 static int   GoBackCallback             ( vlc_object_t *, char const *,
  98                                           vlc_value_t, vlc_value_t, void * );
  99 static int   GoForwardCallback          ( vlc_object_t *, char const *,
 100                                           vlc_value_t, vlc_value_t, void * );
 101
 102 static char *GetTimedURLFromPlaylistItem( intf_thread_t *, playlist_item_t * );
 103 static char *GetTimedURIFragmentForTime ( int );
 104 static int   GetCurrentTimeInSeconds    ( input_thread_t * );
 105 static int   DisplayAnchor              ( intf_thread_t *, vout_thread_t *,
 106                                           char *, char * );
 107 static int   DisplayPendingAnchor       ( intf_thread_t *, vout_thread_t * );
 108 static history_t * GetHistory           ( playlist_t * );
 109 static void  ReplacePlaylistItem        ( playlist_t *, char * );
 110
 111 /* Exported functions */
 112 static void RunIntf        ( intf_thread_t *p_intf );
 113
 114 /*****************************************************************************
 115  * OpenIntf: initialize CMML interface
 116  *****************************************************************************/
 117 int OpenIntf ( vlc_object_t *p_this )
 118 {
 119     intf_thread_t *p_intf = (intf_thread_t *)p_this;
 120
 121     p_intf->p_sys = malloc( sizeof( intf_sys_t ) );
 122     if( p_intf->p_sys == NULL )
 123     {
 124         return( 1 );
 125     };
 126
 127     p_intf->pf_run = RunIntf;
 128
 129     var_AddCallback( p_intf->p_libvlc, "key-action", KeyEvent, p_intf );
 130     /* we also need to add the callback for "mouse-clicked", but do that later
 131      * when we've found a p_vout */
 132
 133     var_Create( p_intf->p_libvlc, "browse-go-back", VLC_VAR_VOID );
 134     var_AddCallback( p_intf->p_libvlc, "browse-go-back",
 135                      GoBackCallback, p_intf );
 136     var_Create( p_intf->p_libvlc, "browse-go-forward", VLC_VAR_VOID );
 137     var_AddCallback( p_intf->p_libvlc, "browse-go-forward",
 138                      GoForwardCallback, p_intf );
 139     var_Create( p_intf->p_libvlc, "browse-follow-anchor", VLC_VAR_VOID );
 140     var_AddCallback( p_intf->p_libvlc, "browse-follow-anchor",
 141                      FollowAnchorCallback, p_intf );
 142
 143     return( 0 );
 144 }
 145
 146 /*****************************************************************************
 147  * CloseIntf: destroy dummy interface
 148  *****************************************************************************/
 149 void CloseIntf ( vlc_object_t *p_this )
 150 {
 151     intf_thread_t * p_intf = (intf_thread_t *)p_this;
 152     vout_thread_t * p_vout;
 153
 154 #ifdef CMML_INTF_DEBUG
 155     msg_Dbg( p_intf, "freeing CMML interface" );
 156 #endif
 157
 158     /* erase the anchor text description from the video output if it exists */
 159     p_vout = vlc_object_find( p_intf, VLC_OBJECT_VOUT, FIND_ANYWHERE );
 160     if( p_vout )
 161     {
 162         /* enable CMML as a subtitle track */
 163         spu_Control( p_vout->p_spu, SPU_CHANNEL_CLEAR, DEFAULT_CHAN );
 164         vlc_object_release( p_vout );
 165     }
 166
 167     var_DelCallback( p_intf->p_libvlc, "key-action", KeyEvent, p_intf );
 168
 169     vlc_object_release( p_intf->p_sys->p_cmml_decoder );
 170
 171     free( p_intf->p_sys );
 172 }
 173
 174
 175 /*****************************************************************************
 176  * RunIntf: main loop
 177  *****************************************************************************/
 178 static void RunIntf( intf_thread_t *p_intf )
 179 {
 180     vout_thread_t * p_vout = NULL;
 181
 182     if( InitThread( p_intf ) < 0 )
 183     {
 184         msg_Err( p_intf, "can't initialize CMML interface" );
 185         return;
 186     }
 187 #ifdef CMML_INTF_DEBUG
 188     msg_Dbg( p_intf, "CMML intf initialized" );
 189 #endif
 190
 191     /* Main loop */
 192     while( vlc_object_alive (p_intf) )
 193     {
 194         /* if video output is dying, disassociate ourselves from it */
 195         if( p_vout && !vlc_object_alive (p_vout) )
 196         {
 197             var_DelCallback( p_vout, "mouse-clicked", MouseEvent, p_intf );
 198             vlc_object_release( p_vout );
 199             p_vout = NULL;
 200         }
 201
 202         /* find a video output if we currently don't have one */
 203         if( p_vout == NULL )
 204         {
 205             p_vout = vlc_object_find( p_intf->p_sys->p_input,
 206                                       VLC_OBJECT_VOUT, FIND_CHILD );
 207             if( p_vout )
 208             {
 209 #ifdef CMML_INTF_DEBUG
 210                 msg_Dbg( p_intf, "found vout thread" );
 211 #endif
 212                 var_AddCallback( p_vout, "mouse-clicked", MouseEvent, p_intf );
 213             }
 214         }
 215
 216         vlc_mutex_lock( &p_intf->change_lock );
 217
 218         /*
 219          * keyboard event
 220          */
 221         switch( p_intf->p_sys->i_key_action )
 222         {
 223             case ACTIONID_NAV_ACTIVATE:
 224                 FollowAnchor( p_intf );
 225                 break;
 226             case ACTIONID_HISTORY_BACK:
 227                 GoBack( p_intf );
 228                 break;
 229             case ACTIONID_HISTORY_FORWARD:
 230                 GoForward( p_intf );
 231                 break;
 232             default:
 233                 break;
 234         }
 235         p_intf->p_sys->i_key_action = 0;
 236         vlc_mutex_unlock( &p_intf->change_lock );
 237
 238         (void) DisplayPendingAnchor( p_intf, p_vout );
 239
 240         /* Wait a bit */
 241         msleep( INTF_IDLE_SLEEP );
 242     }
 243
 244     /* if we're here, the video output is dying: release the vout object */
 245
 246     if( p_vout )
 247     {
 248         var_DelCallback( p_vout, "mouse-clicked", MouseEvent, p_intf );
 249         vlc_object_release( p_vout );
 250     }
 251
 252     vlc_object_release( p_intf->p_sys->p_input );
 253 }
 254
 255 /*****************************************************************************
 256  * DisplayPendingAnchor: get a pending anchor description/URL from the CMML
 257  * decoder and display it on screen
 258  *****************************************************************************/
 259 static int DisplayPendingAnchor( intf_thread_t *p_intf, vout_thread_t *p_vout )
 260 {
 261     decoder_t *p_cmml_decoder;
 262     char *psz_description = NULL;
 263     char *psz_url = NULL;
 264
 265     intf_thread_t *p_primary_intf;
 266     vlc_value_t val;
 267
 268     p_cmml_decoder = p_intf->p_sys->p_cmml_decoder;
 269     if( var_Get( p_cmml_decoder, "psz-current-anchor-description", &val )
 270             != VLC_SUCCESS )
 271     {
 272         return true;
 273     }
 274
 275     if( !val.p_address )
 276         return true;
 277
 278     psz_description = val.p_address;
 279
 280     if( var_Get( p_cmml_decoder, "psz-current-anchor-url", &val )
 281             == VLC_SUCCESS )
 282     {
 283         psz_url = val.p_address;
 284     }
 285
 286     if( p_vout != NULL )
 287     {
 288         /* don't display anchor if main interface can display it */
 289         p_primary_intf = vlc_object_find( p_intf->p_libvlc, VLC_OBJECT_INTF,
 290                 FIND_CHILD );
 291
 292         if( p_primary_intf )
 293         {
 294             if( var_Get( p_primary_intf, "intf-displays-cmml-description", &val )
 295                     == VLC_SUCCESS )
 296             {
 297                 if( val.b_bool == true )
 298                 {
 299                     vlc_object_release( p_primary_intf );
 300                     return true;
 301                 }
 302             }
 303
 304             vlc_object_release( p_primary_intf );
 305         }
 306
 307         /* display anchor as subtitle on-screen */
 308         if( DisplayAnchor( p_intf, p_vout, psz_description, psz_url )
 309                 != VLC_SUCCESS )
 310         {
 311             /* text render unsuccessful: do nothing */
 312             return false;
 313         }
 314
 315         /* text render successful: clear description */
 316         val.p_address = NULL;
 317         if( var_Set( p_cmml_decoder, "psz-current-anchor-description", val )
 318                 != VLC_SUCCESS )
 319         {
 320             msg_Dbg( p_intf,
 321                      "reset of psz-current-anchor-description failed" );
 322         }
 323         free( psz_description );
 324         psz_url = NULL;
 325     }
 326
 327     return true;
 328 }
 329
 330
 331 /*****************************************************************************
 332  * InitThread:
 333  *****************************************************************************/
 334 static int InitThread( intf_thread_t * p_intf )
 335 {
 336     /* We might need some locking here */
 337     if( vlc_object_alive (p_intf) )
 338     {
 339         input_thread_t * p_input;
 340         decoder_t *p_cmml_decoder;
 341
 342         p_cmml_decoder = vlc_object_find( p_intf, VLC_OBJECT_DECODER, FIND_PARENT );
 343         p_input = vlc_object_find( p_intf, VLC_OBJECT_INPUT, FIND_PARENT );
 344
 345 #ifdef CMML_INTF_DEBUG
 346         msg_Dbg( p_intf, "cmml decoder at %p, input thread at %p",
 347                  p_cmml_decoder, p_input );
 348 #endif
 349
 350         /* Maybe the input just died */
 351         if( p_input == NULL )
 352         {
 353             return VLC_EGENERIC;
 354         }
 355
 356         vlc_mutex_lock( &p_intf->change_lock );
 357
 358         p_intf->p_sys->p_input = p_input;
 359         p_intf->p_sys->p_cmml_decoder = p_cmml_decoder;
 360
 361         p_intf->p_sys->i_key_action = 0;
 362
 363         vlc_mutex_unlock( &p_intf->change_lock );
 364
 365         return VLC_SUCCESS;
 366     }
 367     else
 368     {
 369         return VLC_EGENERIC;
 370     }
 371 }
 372
 373 /*****************************************************************************
 374  * MouseEvent: callback for mouse events
 375  *****************************************************************************/
 376 static int MouseEvent( vlc_object_t *p_this, char const *psz_var,
 377                        vlc_value_t oldval, vlc_value_t newval, void *p_data )
 378 {
 379     VLC_UNUSED(p_this); VLC_UNUSED(psz_var);
 380     VLC_UNUSED(oldval); VLC_UNUSED(newval);
 381     VLC_UNUSED(p_data);
 382     /* TODO: handle mouse clicks on the anchor text */
 383
 384     return VLC_SUCCESS;
 385 }
 386
 387 /*****************************************************************************
 388  * KeyEvent: callback for keyboard events
 389  *****************************************************************************/
 390 static int KeyEvent( vlc_object_t *p_this, char const *psz_var,
 391                        vlc_value_t oldval, vlc_value_t newval, void *p_data )
 392 {
 393     VLC_UNUSED(p_this); VLC_UNUSED(psz_var);
 394     VLC_UNUSED(oldval); VLC_UNUSED(newval);
 395     intf_thread_t *p_intf = (intf_thread_t *)p_data;
 396     vlc_mutex_lock( &p_intf->change_lock );
 397
 398     p_intf->p_sys->i_key_action = newval.i_int;
 399
 400     vlc_mutex_unlock( &p_intf->change_lock );
 401
 402     return VLC_SUCCESS;
 403 }
 404
 405 /*****************************************************************************
 406  * FollowAnchor: follow the current anchor being displayed to the user
 407  *****************************************************************************/
 408 static void FollowAnchor ( intf_thread_t *p_intf )
 409 {
 410     intf_sys_t *p_sys;
 411     decoder_t *p_cmml_decoder;
 412     char *psz_url = NULL;
 413     vlc_value_t val;
 414
 415     msg_Dbg( p_intf, "User followed anchor" );
 416
 417     p_sys = p_intf->p_sys;
 418     p_cmml_decoder = p_sys->p_cmml_decoder;
 419
 420     if( var_Get( p_cmml_decoder, "psz-current-anchor-url", &val ) ==
 421             VLC_SUCCESS )
 422     {
 423         if( val.p_address ) psz_url = val.p_address;
 424     }
 425
 426 #ifdef CMML_INTF_DEBUG
 427     msg_Dbg( p_intf, "Current URL is \"%s\"", psz_url );
 428 #endif
 429
 430     if( psz_url )
 431     {
 432         playlist_t *p_playlist;
 433         playlist_item_t *p_current_item;
 434         char *psz_uri_to_load;
 435         mtime_t i_seconds;
 436         vlc_value_t time;
 437
 438         p_playlist = pl_Yield( p_intf );
 439
 440         /* Get new URL */
 441         p_current_item = p_playlist->status.p_item;
 442         char *psz_uri = input_item_GetURI( p_current_item->p_input );
 443 #ifdef CMML_INTF_DEBUG
 444         msg_Dbg( p_intf, "Current playlist item URL is \"%s\"", psz_uri );
 445 #endif
 446
 447         psz_uri_to_load = XURL_Concat( psz_uri, psz_url );
 448         free( psz_uri );
 449
 450 #ifdef CMML_INTF_DEBUG
 451         msg_Dbg( p_intf, "URL to load is \"%s\"", psz_uri_to_load );
 452 #endif
 453
 454         if( var_Get( p_intf->p_sys->p_input, "time", &time ) )
 455         {
 456             msg_Dbg( p_intf, "couldn't get time from current clip" );
 457             time.i_time = 0;
 458         }
 459         i_seconds = time.i_time / 1000000;
 460 #ifdef CMML_INTF_DEBUG
 461         msg_Dbg( p_intf, "Current time is \"%lld\"", i_seconds );
 462 #endif
 463
 464         /* TODO: we need a (much) more robust way of detecting whether
 465          * the file's a media file ... */
 466         if( strstr( psz_uri_to_load, ".anx" ) != NULL )
 467         {
 468             history_t *p_history = NULL;
 469             history_item_t *p_history_item = NULL;
 470             char *psz_timed_url;
 471
 472             p_history = GetHistory( p_playlist );
 473
 474             /* create history item */
 475             psz_timed_url = GetTimedURLFromPlaylistItem( p_intf, p_current_item );
 476             p_history_item = historyItem_New( psz_timed_url, psz_timed_url );
 477             free( psz_timed_url );
 478
 479             if( !p_history_item )
 480             {
 481                 msg_Warn( p_intf, "could not initialise history item" );
 482             }
 483             else
 484             {
 485 #ifdef CMML_INTF_DEBUG
 486                 msg_Dbg( p_intf, "history pre-index %d", p_history->i_index );
 487 #endif
 488                 history_PruneAndInsert( p_history, p_history_item );
 489 #ifdef CMML_INTF_DEBUG
 490                 msg_Dbg( p_intf, "new history item at %p, uri is \"%s\"",
 491                          p_history_item, p_history_item->psz_uri );
 492                 msg_Dbg( p_intf, "history index now %d", p_history->i_index );
 493 #endif
 494             }
 495
 496             /* free current-anchor-url */
 497             free( psz_url );
 498             val.p_address = NULL;
 499             if( var_Set( p_cmml_decoder, "psz-current-anchor-url", val ) !=
 500                     VLC_SUCCESS )
 501             {
 502                 msg_Dbg( p_intf, "couldn't reset psz-current-anchor-url" );
 503             }
 504
 505             ReplacePlaylistItem( p_playlist, psz_uri_to_load );
 506         }
 507         else
 508         {
 509 #ifdef CMML_INTF_DEBUG
 510             msg_Dbg( p_intf, "calling browser_Open with \"%s\"", psz_url );
 511 #endif
 512             (void) browser_Open( psz_url );
 513             playlist_Control( p_playlist, PLAYLIST_PAUSE, false, 0 );
 514         }
 515
 516         free( psz_uri_to_load );
 517
 518         vlc_object_release( p_playlist );
 519     }
 520 }
 521
 522 static
 523 char *GetTimedURLFromPlaylistItem( intf_thread_t *p_intf,
 524         playlist_item_t *p_current_item )
 525 {
 526 #ifdef CMML_INTF_USE_TIMED_URIS
 527     char *psz_url = NULL;
 528     char *psz_return_value = NULL;
 529     char *psz_seconds = NULL;
 530     int i_seconds;
 531
 532     char *psz_uri = input_item_GetURI( p_current_item->p_input );
 533     psz_url = XURL_GetWithoutFragment( psz_uri );
 534     free( psz_uri );
 535
 536     /* Get current time as a string */
 537     if( XURL_IsFileURL( psz_url ) == true )
 538         psz_url = xstrcat( psz_url, "#" );
 539     else
 540         psz_url = xstrcat( psz_url, "?" );
 541
 542     /* jump back to 2 seconds before where we are now */
 543     i_seconds = GetCurrentTimeInSeconds( p_intf->p_sys->p_input ) - 2;
 544     psz_seconds = GetTimedURIFragmentForTime( i_seconds < 0 ? 0 : i_seconds );
 545     if( psz_seconds )
 546     {
 547         psz_url = xstrcat( psz_url, psz_seconds );
 548         free( psz_seconds );
 549         psz_return_value = psz_url;
 550     }
 551
 552     return psz_return_value;
 553 #else
 554     VLC_UNUSED(p_intf);
 555     void *p;
 556
 557     /* Suppress warning messages about unused functions */
 558     p = GetTimedURIFragmentForTime; /* unused */
 559     p = GetCurrentTimeInSeconds;    /* unused */
 560
 561     return input_item_GetURI( p_current_item->p_input );
 562 #endif
 563 }
 564
 565
 566 /*
 567  * Get the current time, rounded down to the nearest second
 568  *
 569  * http://www.ietf.org/internet-drafts/draft-pfeiffer-temporal-fragments-02.txt
 570  */
 571 static
 572 int GetCurrentTimeInSeconds( input_thread_t *p_input )
 573 {
 574     vlc_value_t time;
 575     mtime_t i_seconds;
 576
 577     var_Get( p_input, "time", &time );
 578     i_seconds = time.i_time / 1000000;
 579     return i_seconds;
 580 }
 581
 582 static
 583 char *GetTimedURIFragmentForTime( int seconds )
 584 {
 585     char *psz_time;
 586
 587     asprintf( &psz_time, "%d", seconds );
 588     return psz_time;
 589 }
 590
 591 static
 592 int GoBackCallback( vlc_object_t *p_this, char const *psz_var,
 593                     vlc_value_t oldval, vlc_value_t newval, void *p_data )
 594 {
 595     VLC_UNUSED(p_this); VLC_UNUSED(psz_var);
 596     VLC_UNUSED(oldval); VLC_UNUSED(newval);
 597     intf_thread_t *p_intf = (intf_thread_t *) p_data;
 598     GoBack( p_intf );
 599     return VLC_SUCCESS;
 600 }
 601
 602 static
 603 int GoForwardCallback( vlc_object_t *p_this, char const *psz_var,
 604                        vlc_value_t oldval, vlc_value_t newval, void *p_data )
 605 {
 606     VLC_UNUSED(p_this); VLC_UNUSED(psz_var);
 607     VLC_UNUSED(oldval); VLC_UNUSED(newval);
 608     intf_thread_t *p_intf = (intf_thread_t *) p_data;
 609     GoForward( p_intf );
 610     return VLC_SUCCESS;
 611 }
 612
 613 static
 614 int FollowAnchorCallback( vlc_object_t *p_this, char const *psz_var,
 615                           vlc_value_t oldval, vlc_value_t newval,
 616                           void *p_data )
 617 {
 618     VLC_UNUSED(p_this); VLC_UNUSED(psz_var);
 619     VLC_UNUSED(oldval); VLC_UNUSED(newval);
 620     intf_thread_t *p_intf = (intf_thread_t *) p_data;
 621     FollowAnchor( p_intf );
 622     return VLC_SUCCESS;
 623 }
 624
 625 static
 626 void GoBack( intf_thread_t *p_intf )
 627 {
 628     vlc_value_t history;
 629     history_t *p_history = NULL;
 630     history_item_t *p_history_item = NULL;
 631     history_item_t *p_new_history_item = NULL;
 632     playlist_t *p_playlist = NULL;
 633     char *psz_timed_url = NULL;
 634     playlist_item_t *p_current_item;
 635
 636 #ifdef CMML_INTF_DEBUG
 637     msg_Dbg( p_intf, "Going back in navigation history" );
 638 #endif
 639
 640     /* Find the playlist */
 641     p_playlist = pl_Yield( p_intf );
 642
 643     /* Retrieve navigation history from playlist */
 644     if( var_Get( p_playlist, "navigation-history", &history ) != VLC_SUCCESS ||
 645         !history.p_address )
 646     {
 647         /* History doesn't exist yet: ignore user's request */
 648         msg_Warn( p_intf, "can't go back: no history exists yet" );
 649         vlc_object_release( p_playlist );
 650         return;
 651     }
 652
 653     p_history = history.p_address;
 654 #ifdef CMML_INTF_DEBUG
 655     msg_Dbg( p_intf, "back: nav history retrieved from %p", p_history );
 656     msg_Dbg( p_intf, "nav history index:%d, p_xarray:%p", p_history->i_index,
 657              p_history->p_xarray );
 658 #endif
 659
 660     /* Check whether we can go back in the history */
 661     if( history_CanGoBack( p_history ) == false )
 662     {
 663         msg_Warn( p_intf, "can't go back: already at beginning of history" );
 664         vlc_object_release( p_playlist );
 665         return;
 666     }
 667
 668     p_current_item = p_playlist->status.p_item;
 669
 670     /* Save the currently-playing media in a new history item */
 671     psz_timed_url = GetTimedURLFromPlaylistItem( p_intf, p_current_item );
 672     p_new_history_item = historyItem_New( psz_timed_url, psz_timed_url );
 673     free( psz_timed_url );
 674
 675     if( !p_new_history_item )
 676     {
 677 #ifdef CMML_INTF_DEBUG
 678         msg_Dbg( p_intf, "back: could not initialise new history item" );
 679 #endif
 680         vlc_object_release( p_playlist );
 681         return;
 682     }
 683
 684     /* Go back in the history, saving the currently-playing item */
 685     (void) history_GoBackSavingCurrentItem( p_history, p_new_history_item );
 686     p_history_item = history_Item( p_history );
 687
 688 #ifdef CMML_INTF_DEBUG
 689     msg_Dbg( p_intf, "retrieving item from h index %d", p_history->i_index );
 690     msg_Dbg( p_intf, "got previous history item: %p", p_history_item );
 691     msg_Dbg( p_intf, "prev history item URL: \"%s\"", p_history_item->psz_uri );
 692 #endif
 693
 694     ReplacePlaylistItem( p_playlist, p_history_item->psz_uri );
 695     vlc_object_release( p_playlist );
 696 }
 697
 698 static
 699 void GoForward( intf_thread_t *p_intf )
 700 {
 701     vlc_value_t history;
 702     history_t *p_history = NULL;
 703     history_item_t *p_history_item = NULL;
 704     history_item_t *p_new_history_item = NULL;
 705     playlist_t *p_playlist = NULL;
 706     playlist_item_t *p_current_item;
 707
 708 #ifdef CMML_INTF_DEBUG
 709     msg_Dbg( p_intf, "Going forward in navigation history" );
 710 #endif
 711
 712     /* Find the playlist */
 713     p_playlist = pl_Yield( p_intf );
 714
 715     /* Retrieve navigation history from playlist */
 716     if( var_Get( p_playlist, "navigation-history", &history ) != VLC_SUCCESS ||
 717         !history.p_address )
 718     {
 719         /* History doesn't exist yet: ignore user's request */
 720         msg_Warn( p_intf, "can't go back: no history exists yet" );
 721         vlc_object_release( p_playlist );
 722         return;
 723     }
 724
 725     p_history = history.p_address;
 726 #ifdef CMML_INTF_DEBUG
 727     msg_Dbg( p_intf, "forward: nav history retrieved from %p", p_history );
 728     msg_Dbg( p_intf, "nav history index:%d, p_xarray:%p", p_history->i_index,
 729              p_history->p_xarray );
 730 #endif
 731
 732     /* Check whether we can go forward in the history */
 733     if( history_CanGoForward( p_history ) == false )
 734     {
 735         msg_Warn( p_intf, "can't go forward: already at end of history" );
 736         vlc_object_release( p_playlist );
 737         return;
 738     }
 739
 740     /* Save the currently-playing media in a new history item */
 741     p_new_history_item = malloc( sizeof(history_item_t) );
 742     if( !p_new_history_item )
 743     {
 744 #ifdef CMML_INTF_DEBUG
 745         msg_Dbg( p_intf, "forward: could not initialise new history item" );
 746 #endif
 747         vlc_object_release( p_playlist );
 748         return;
 749     }
 750     p_current_item = p_playlist->status.p_item;
 751     p_new_history_item->psz_uri = GetTimedURLFromPlaylistItem( p_intf,
 752             p_current_item );
 753     p_new_history_item->psz_name = p_new_history_item->psz_uri;
 754
 755     /* Go forward in the history, saving the currently-playing item */
 756     (void) history_GoForwardSavingCurrentItem( p_history, p_new_history_item );
 757     p_history_item = history_Item( p_history );
 758
 759 #ifdef CMML_INTF_DEBUG
 760     msg_Dbg( p_intf, "retrieving item from h index %d", p_history->i_index );
 761     msg_Dbg( p_intf, "got next history item: %p", p_history_item );
 762     msg_Dbg( p_intf, "next history item URL: \"%s\"", p_history_item->psz_uri );
 763 #endif
 764
 765     ReplacePlaylistItem( p_playlist, p_history_item->psz_uri );
 766     vlc_object_release( p_playlist );
 767 }
 768
 769 static void ReplacePlaylistItem( playlist_t *p_playlist, char *psz_uri )
 770 {
 771     playlist_Stop( p_playlist );
 772     (void) playlist_Add( p_playlist, psz_uri, psz_uri,
 773                          PLAYLIST_INSERT /* FIXME: used to be PLAYLIST_REPLACE */, PLAYLIST_END|PLAYLIST_GO, true /* FIXME: p_playlist->status.i_index */,
 774                          false);
 775 }
 776
 777 /****************************************************************************
 778  * DisplayAnchor: displays an anchor on the given video output
 779  ****************************************************************************/
 780 static int DisplayAnchor( intf_thread_t *p_intf,
 781         vout_thread_t *p_vout,
 782         char *psz_anchor_description,
 783         char *psz_anchor_url )
 784 {
 785     int i_margin_h, i_margin_v;
 786     mtime_t i_now;
 787
 788     i_margin_h = 0;
 789     i_margin_v = 10;
 790
 791     i_now = mdate();
 792
 793     if( p_vout )
 794     {
 795         if( psz_anchor_url )
 796         {
 797             /* Should display subtitle underlined and in blue, but it looks
 798              * like VLC doesn't implement any text styles yet.  D'oh! */
 799             // p_style = &blue_with_underline;
 800
 801         }
 802
 803         /* TODO: p_subpicture doesn't have the proper i_x and i_y
 804          * coordinates.  Need to look at the subpicture display system to
 805          * work out why. */
 806         if ( vout_ShowTextAbsolute( p_vout, DEFAULT_CHAN,
 807                 psz_anchor_description, NULL, OSD_ALIGN_BOTTOM,
 808                 i_margin_h, i_margin_v, i_now, 0 ) == VLC_SUCCESS )
 809         {
 810             /* Displayed successfully */
 811         }
 812         else
 813         {
 814             return VLC_EGENERIC;
 815         }
 816     }
 817     else
 818     {
 819         msg_Dbg( p_intf, "DisplayAnchor couldn't find a video output" );
 820         return VLC_EGENERIC;
 821     }
 822
 823     return VLC_SUCCESS;
 824 }
 825
 826 static history_t * GetHistory( playlist_t *p_playlist )
 827 {
 828     vlc_value_t val;
 829     history_t *p_history = NULL;
 830
 831     if( var_Get( p_playlist, "navigation-history", &val ) != VLC_SUCCESS )
 832     {
 833         /* history doesn't exist yet: need to create it */
 834         history_t *new_history = history_New();
 835         val.p_address = new_history;
 836         var_Create( p_playlist, "navigation-history",
 837                 VLC_VAR_ADDRESS|VLC_VAR_DOINHERIT );
 838         if( var_Set( p_playlist, "navigation-history", val ) != VLC_SUCCESS )
 839         {
 840             msg_Warn( p_playlist, "could not initialise history" );
 841         }
 842         else
 843         {
 844             p_history = new_history;
 845 #ifdef CMML_INTF_HISTORY_DEBUG
 846             msg_Dbg( p_playlist, "nav history created at %p", new_history );
 847             msg_Dbg( p_playlist, "nav history index:%d, p_xarray:%p",
 848                      p_history->i_index, p_history->p_xarray );
 849 #endif
 850         }
 851     }
 852     else
 853     {
 854         p_history = val.p_address;
 855 #ifdef CMML_INTF_HISTORY_DEBUG
 856         msg_Dbg( p_playlist, "nav history retrieved from %p", p_history );
 857 #endif
 858     }
 859
 860     return p_history;
 861 }
 862