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 #include <vlc/vlc.h>
  31
  32 #include <stdio.h>
  33 #include <stdlib.h>                                      /* malloc(), free() */
  34 #include <string.h>
  35
  36 #ifdef HAVE_UNISTD_H
  37 #    include <unistd.h>
  38 #endif
  39
  40 #include <vlc/decoder.h>
  41 #include <vlc/input.h>
  42 #include <vlc/intf.h>
  43 #include <vlc/vout.h>
  44
  45 #include <vlc_osd.h>
  46
  47 #include "vlc_keys.h"
  48
  49 #include "browser_open.h"
  50 #include "history.h"
  51 #include "xstrcat.h"
  52 #include "xurl.h"
  53
  54 #undef  CMML_INTF_USE_TIMED_URIS
  55
  56 #undef  CMML_INTF_DEBUG
  57 #undef  CMML_INTF_HISTORY_DEBUG
  58
  59 /*****************************************************************************
  60  * intf_sys_t: description and status of interface
  61  *****************************************************************************/
  62 struct intf_sys_t
  63 {
  64     decoder_t *         p_cmml_decoder;
  65     input_thread_t *    p_input;
  66
  67     vlc_bool_t          b_key_pressed;
  68 };
  69
  70 struct navigation_history_t
  71 {
  72     int i_history_size;
  73     int i_last_item;
  74 };
  75
  76 /*****************************************************************************
  77  * Local prototypes.
  78  *****************************************************************************/
  79 static int   InitThread                 ( intf_thread_t * );
  80 static int   MouseEvent                 ( vlc_object_t *, char const *,
  81                                           vlc_value_t, vlc_value_t, void * );
  82 static int   KeyEvent                   ( vlc_object_t *, char const *,
  83                                           vlc_value_t, vlc_value_t, void * );
  84
  85 static void  FollowAnchor               ( intf_thread_t * );
  86 static void  GoBack                     ( intf_thread_t * );
  87 static void  GoForward                  ( intf_thread_t * );
  88
  89 static int   FollowAnchorCallback       ( vlc_object_t *, char const *,
  90                                           vlc_value_t, vlc_value_t, void * );
  91 static int   GoBackCallback             ( vlc_object_t *, char const *,
  92                                           vlc_value_t, vlc_value_t, void * );
  93 static int   GoForwardCallback          ( vlc_object_t *, char const *,
  94                                           vlc_value_t, vlc_value_t, void * );
  95
  96 static char *GetTimedURLFromPlaylistItem( intf_thread_t *, playlist_item_t * );
  97 static char *GetTimedURIFragmentForTime ( int );
  98 static int   GetCurrentTimeInSeconds    ( input_thread_t * );
  99 static int   DisplayAnchor              ( intf_thread_t *, vout_thread_t *,
 100                                           char *, char * );
 101 static int   DisplayPendingAnchor       ( intf_thread_t *, vout_thread_t * );
 102 static history_t * GetHistory           ( playlist_t * );
 103 static void  ReplacePlaylistItem        ( playlist_t *, char * );
 104
 105 /* Exported functions */
 106 static void RunIntf        ( intf_thread_t *p_intf );
 107
 108 /*****************************************************************************
 109  * OpenIntf: initialize CMML interface
 110  *****************************************************************************/
 111 int E_(OpenIntf) ( vlc_object_t *p_this )
 112 {
 113     intf_thread_t *p_intf = (intf_thread_t *)p_this;
 114
 115     p_intf->p_sys = malloc( sizeof( intf_sys_t ) );
 116     if( p_intf->p_sys == NULL )
 117     {
 118         return( 1 );
 119     };
 120
 121     p_intf->pf_run = RunIntf;
 122
 123     var_AddCallback( p_intf->p_libvlc, "key-pressed", KeyEvent, p_intf );
 124     /* we also need to add the callback for "mouse-clicked", but do that later
 125      * when we've found a p_vout */
 126
 127     var_Create( p_intf->p_libvlc, "browse-go-back", VLC_VAR_VOID );
 128     var_AddCallback( p_intf->p_libvlc, "browse-go-back",
 129                      GoBackCallback, p_intf );
 130     var_Create( p_intf->p_libvlc, "browse-go-forward", VLC_VAR_VOID );
 131     var_AddCallback( p_intf->p_libvlc, "browse-go-forward",
 132                      GoForwardCallback, p_intf );
 133     var_Create( p_intf->p_libvlc, "browse-follow-anchor", VLC_VAR_VOID );
 134     var_AddCallback( p_intf->p_libvlc, "browse-follow-anchor",
 135                      FollowAnchorCallback, p_intf );
 136
 137     return( 0 );
 138 }
 139
 140 /*****************************************************************************
 141  * CloseIntf: destroy dummy interface
 142  *****************************************************************************/
 143 void E_(CloseIntf) ( vlc_object_t *p_this )
 144 {
 145     intf_thread_t * p_intf = (intf_thread_t *)p_this;
 146     vout_thread_t * p_vout;
 147
 148 #ifdef CMML_INTF_DEBUG
 149     msg_Dbg( p_intf, "freeing CMML interface" );
 150 #endif
 151
 152     /* erase the anchor text description from the video output if it exists */
 153     p_vout = vlc_object_find( p_intf, VLC_OBJECT_VOUT, FIND_ANYWHERE );
 154     if( p_vout )
 155     {
 156         /* enable CMML as a subtitle track */
 157         spu_Control( p_vout->p_spu, SPU_CHANNEL_CLEAR, DEFAULT_CHAN );
 158         vlc_object_release( p_vout );
 159     }
 160
 161     var_DelCallback( p_intf->p_libvlc, "key-pressed", KeyEvent, p_intf );
 162
 163     vlc_object_release( p_intf->p_sys->p_cmml_decoder );
 164
 165     free( p_intf->p_sys );
 166 }
 167
 168
 169 /*****************************************************************************
 170  * RunIntf: main loop
 171  *****************************************************************************/
 172 static void RunIntf( intf_thread_t *p_intf )
 173 {
 174     vout_thread_t * p_vout = NULL;
 175
 176     if( InitThread( p_intf ) < 0 )
 177     {
 178         msg_Err( p_intf, "can't initialize CMML interface" );
 179         return;
 180     }
 181 #ifdef CMML_INTF_DEBUG
 182     msg_Dbg( p_intf, "CMML intf initialized" );
 183 #endif
 184
 185     /* if video output is dying, disassociate ourselves from it */
 186     if( p_vout && p_vout->b_die )
 187     {
 188         var_DelCallback( p_vout, "mouse-clicked", MouseEvent, p_intf );
 189         vlc_object_release( p_vout );
 190         p_vout = NULL;
 191     }
 192
 193     /* Main loop */
 194     while( !p_intf->b_die )
 195     {
 196
 197         /* find a video output if we currently don't have one */
 198         if( p_vout == NULL )
 199         {
 200             p_vout = vlc_object_find( p_intf->p_sys->p_input,
 201                                       VLC_OBJECT_VOUT, FIND_CHILD );
 202             if( p_vout )
 203             {
 204 #ifdef CMML_INTF_DEBUG
 205                 msg_Dbg( p_intf, "found vout thread" );
 206 #endif
 207                 var_AddCallback( p_vout, "mouse-clicked", MouseEvent, p_intf );
 208             }
 209         }
 210
 211         vlc_mutex_lock( &p_intf->change_lock );
 212
 213         /*
 214          * keyboard event
 215          */
 216         if( p_intf->p_sys->b_key_pressed )
 217         {
 218             vlc_value_t val;
 219             int i, i_action = -1;
 220             struct hotkey *p_hotkeys = p_intf->p_libvlc->p_hotkeys;
 221
 222             /* Find action triggered by hotkey (if any) */
 223             var_Get( p_intf->p_libvlc, "key-pressed", &val );
 224
 225             /* Acknowledge that we've handled the b_key_pressed event */
 226             p_intf->p_sys->b_key_pressed = VLC_FALSE;
 227
 228 #ifdef CMML_INTF_DEBUG
 229             msg_Dbg( p_intf, "Got a keypress: %d", val.i_int );
 230 #endif
 231
 232             for( i = 0; p_hotkeys[i].psz_action != NULL; i++ )
 233             {
 234                 if( p_hotkeys[i].i_key == val.i_int )
 235                     i_action = p_hotkeys[i].i_action;
 236             }
 237
 238             /* What did the user do? */
 239             if( i_action != -1 )
 240             {
 241                 switch( i_action )
 242                 {
 243                     case ACTIONID_NAV_ACTIVATE:
 244                         FollowAnchor( p_intf );
 245                         break;
 246                     case ACTIONID_HISTORY_BACK:
 247                         GoBack( p_intf );
 248                         break;
 249                     case ACTIONID_HISTORY_FORWARD:
 250                         GoForward( p_intf );
 251                         break;
 252                     default:
 253                         break;
 254                 }
 255             }
 256         }
 257
 258         vlc_mutex_unlock( &p_intf->change_lock );
 259
 260         (void) DisplayPendingAnchor( p_intf, p_vout );
 261
 262         /* Wait a bit */
 263         msleep( INTF_IDLE_SLEEP );
 264     }
 265
 266     /* if we're here, the video output is dying: release the vout object */
 267
 268     if( p_vout )
 269     {
 270         var_DelCallback( p_vout, "mouse-clicked", MouseEvent, p_intf );
 271         vlc_object_release( p_vout );
 272     }
 273
 274     vlc_object_release( p_intf->p_sys->p_input );
 275 }
 276
 277 /*****************************************************************************
 278  * DisplayPendingAnchor: get a pending anchor description/URL from the CMML
 279  * decoder and display it on screen
 280  *****************************************************************************/
 281 static int DisplayPendingAnchor( intf_thread_t *p_intf, vout_thread_t *p_vout )
 282 {
 283     decoder_t *p_cmml_decoder;
 284     char *psz_description = NULL;
 285     char *psz_url = NULL;
 286
 287     intf_thread_t *p_primary_intf;
 288     vlc_value_t val;
 289
 290     p_cmml_decoder = p_intf->p_sys->p_cmml_decoder;
 291     if( var_Get( p_cmml_decoder, "psz-current-anchor-description", &val )
 292             != VLC_SUCCESS )
 293     {
 294         return VLC_TRUE;
 295     }
 296
 297     if( !val.p_address )
 298         return VLC_TRUE;
 299
 300     psz_description = val.p_address;
 301
 302     if( var_Get( p_cmml_decoder, "psz-current-anchor-url", &val )
 303             == VLC_SUCCESS )
 304     {
 305         psz_url = val.p_address;
 306     }
 307
 308     if( p_vout != NULL )
 309     {
 310         /* don't display anchor if main interface can display it */
 311         p_primary_intf = vlc_object_find( p_intf->p_libvlc, VLC_OBJECT_INTF,
 312                 FIND_CHILD );
 313
 314         if( p_primary_intf )
 315         {
 316             if( var_Get( p_primary_intf, "intf-displays-cmml-description", &val )
 317                     == VLC_SUCCESS )
 318             {
 319                 if( val.b_bool == VLC_TRUE )
 320                 {
 321                     vlc_object_release( p_primary_intf );
 322                     return VLC_TRUE;
 323                 }
 324             }
 325
 326             vlc_object_release( p_primary_intf );
 327         }
 328
 329         /* display anchor as subtitle on-screen */
 330         if( DisplayAnchor( p_intf, p_vout, psz_description, psz_url )
 331                 != VLC_SUCCESS )
 332         {
 333             /* text render unsuccessful: do nothing */
 334             return VLC_FALSE;
 335         }
 336
 337         /* text render successful: clear description */
 338         val.p_address = NULL;
 339         if( var_Set( p_cmml_decoder, "psz-current-anchor-description", val )
 340                 != VLC_SUCCESS )
 341         {
 342             msg_Dbg( p_intf,
 343                      "reset of psz-current-anchor-description failed" );
 344         }
 345         free( psz_description );
 346         psz_url = NULL;
 347     }
 348
 349     return VLC_TRUE;
 350 }
 351
 352
 353 /*****************************************************************************
 354  * InitThread:
 355  *****************************************************************************/
 356 static int InitThread( intf_thread_t * p_intf )
 357 {
 358     /* We might need some locking here */
 359     if( !p_intf->b_die )
 360     {
 361         input_thread_t * p_input;
 362         decoder_t *p_cmml_decoder;
 363
 364         p_cmml_decoder = vlc_object_find( p_intf, VLC_OBJECT_DECODER, FIND_PARENT );
 365         p_input = vlc_object_find( p_intf, VLC_OBJECT_INPUT, FIND_PARENT );
 366
 367 #ifdef CMML_INTF_DEBUG
 368         msg_Dbg( p_intf, "cmml decoder at %p, input thread at %p",
 369                  p_cmml_decoder, p_input );
 370 #endif
 371
 372         /* Maybe the input just died */
 373         if( p_input == NULL )
 374         {
 375             return VLC_EGENERIC;
 376         }
 377
 378         vlc_mutex_lock( &p_intf->change_lock );
 379
 380         p_intf->p_sys->p_input = p_input;
 381         p_intf->p_sys->p_cmml_decoder = p_cmml_decoder;
 382
 383         p_intf->p_sys->b_key_pressed = VLC_FALSE;
 384
 385         vlc_mutex_unlock( &p_intf->change_lock );
 386
 387         return VLC_SUCCESS;
 388     }
 389     else
 390     {
 391         return VLC_EGENERIC;
 392     }
 393 }
 394
 395 /*****************************************************************************
 396  * MouseEvent: callback for mouse events
 397  *****************************************************************************/
 398 static int MouseEvent( vlc_object_t *p_this, char const *psz_var,
 399                        vlc_value_t oldval, vlc_value_t newval, void *p_data )
 400 {
 401     /* TODO: handle mouse clicks on the anchor text */
 402
 403     return VLC_SUCCESS;
 404 }
 405
 406 /*****************************************************************************
 407  * KeyEvent: callback for keyboard events
 408  *****************************************************************************/
 409 static int KeyEvent( vlc_object_t *p_this, char const *psz_var,
 410                        vlc_value_t oldval, vlc_value_t newval, void *p_data )
 411 {
 412     intf_thread_t *p_intf = (intf_thread_t *)p_data;
 413     vlc_mutex_lock( &p_intf->change_lock );
 414
 415     p_intf->p_sys->b_key_pressed = VLC_TRUE;
 416
 417     vlc_mutex_unlock( &p_intf->change_lock );
 418
 419     return VLC_SUCCESS;
 420 }
 421
 422 /*****************************************************************************
 423  * FollowAnchor: follow the current anchor being displayed to the user
 424  *****************************************************************************/
 425 static void FollowAnchor ( intf_thread_t *p_intf )
 426 {
 427     intf_sys_t *p_sys;
 428     decoder_t *p_cmml_decoder;
 429     char *psz_url = NULL;
 430     vlc_value_t val;
 431
 432     msg_Dbg( p_intf, "User followed anchor" );
 433
 434     p_sys = p_intf->p_sys;
 435     p_cmml_decoder = p_sys->p_cmml_decoder;
 436
 437     if( var_Get( p_cmml_decoder, "psz-current-anchor-url", &val ) ==
 438             VLC_SUCCESS )
 439     {
 440         if( val.p_address ) psz_url = val.p_address;
 441     }
 442
 443 #ifdef CMML_INTF_DEBUG
 444     msg_Dbg( p_intf, "Current URL is \"%s\"", psz_url );
 445 #endif
 446
 447     if( psz_url )
 448     {
 449         playlist_t *p_playlist;
 450         playlist_item_t *p_current_item;
 451         char *psz_uri_to_load;
 452         mtime_t i_seconds;
 453         vlc_value_t time;
 454
 455         p_playlist = (playlist_t *) vlc_object_find( p_intf,
 456                 VLC_OBJECT_PLAYLIST, FIND_ANYWHERE );
 457         if ( !p_playlist )
 458         {
 459             msg_Warn( p_intf, "can't find playlist" );
 460             return;
 461         }
 462
 463         /* Get new URL */
 464         p_current_item = p_playlist->status.p_item;
 465 #ifdef CMML_INTF_DEBUG
 466         msg_Dbg( p_intf, "Current playlist item URL is \"%s\"",
 467                 p_current_item->input.psz_uri );
 468 #endif
 469
 470         psz_uri_to_load = XURL_Concat( p_current_item->p_input->psz_uri,
 471                                        psz_url );
 472
 473 #ifdef CMML_INTF_DEBUG
 474         msg_Dbg( p_intf, "URL to load is \"%s\"", psz_uri_to_load );
 475 #endif
 476
 477         if( var_Get( p_intf->p_sys->p_input, "time", &time ) )
 478         {
 479             msg_Dbg( p_intf, "couldn't get time from current clip" );
 480             time.i_time = 0;
 481         }
 482         i_seconds = time.i_time / 1000000;
 483 #ifdef CMML_INTF_DEBUG
 484         msg_Dbg( p_intf, "Current time is \"%lld\"", i_seconds );
 485 #endif
 486
 487         /* TODO: we need a (much) more robust way of detecting whether
 488          * the file's a media file ... */
 489         if( strstr( psz_uri_to_load, ".anx" ) != NULL )
 490         {
 491             history_t *p_history = NULL;
 492             history_item_t *p_history_item = NULL;
 493             char *psz_timed_url;
 494
 495             p_history = GetHistory( p_playlist );
 496
 497             /* create history item */
 498             psz_timed_url = GetTimedURLFromPlaylistItem( p_intf, p_current_item );
 499             p_history_item = historyItem_New( psz_timed_url, psz_timed_url );
 500             free( psz_timed_url );
 501
 502             if( !p_history_item )
 503             {
 504                 msg_Warn( p_intf, "could not initialise history item" );
 505             }
 506             else
 507             {
 508 #ifdef CMML_INTF_DEBUG
 509                 msg_Dbg( p_intf, "history pre-index %d", p_history->i_index );
 510 #endif
 511                 history_PruneAndInsert( p_history, p_history_item );
 512 #ifdef CMML_INTF_DEBUG
 513                 msg_Dbg( p_intf, "new history item at %p, uri is \"%s\"",
 514                          p_history_item, p_history_item->psz_uri );
 515                 msg_Dbg( p_intf, "history index now %d", p_history->i_index );
 516 #endif
 517             }
 518
 519             /* free current-anchor-url */
 520             free( psz_url );
 521             val.p_address = NULL;
 522             if( var_Set( p_cmml_decoder, "psz-current-anchor-url", val ) !=
 523                     VLC_SUCCESS )
 524             {
 525                 msg_Dbg( p_intf, "couldn't reset psz-current-anchor-url" );
 526             }
 527
 528             ReplacePlaylistItem( p_playlist, psz_uri_to_load );
 529         }
 530         else
 531         {
 532 #ifdef CMML_INTF_DEBUG
 533             msg_Dbg( p_intf, "calling browser_Open with \"%s\"", psz_url );
 534 #endif
 535             (void) browser_Open( psz_url );
 536             playlist_Control( p_playlist, PLAYLIST_PAUSE, 0 );
 537         }
 538
 539         free( psz_uri_to_load );
 540
 541         vlc_object_release( p_playlist );
 542     }
 543 }
 544
 545 static
 546 char *GetTimedURLFromPlaylistItem( intf_thread_t *p_intf,
 547         playlist_item_t *p_current_item )
 548 {
 549 #ifdef CMML_INTF_USE_TIMED_URIS
 550     char *psz_url = NULL;
 551     char *psz_return_value = NULL;
 552     char *psz_seconds = NULL;
 553     int i_seconds;
 554
 555     psz_url = XURL_GetWithoutFragment( p_current_item->input->psz_uri );
 556
 557     /* Get current time as a string */
 558     if( XURL_IsFileURL( psz_url ) == VLC_TRUE )
 559         psz_url = xstrcat( psz_url, "#" );
 560     else
 561         psz_url = xstrcat( psz_url, "?" );
 562
 563     /* jump back to 2 seconds before where we are now */
 564     i_seconds = GetCurrentTimeInSeconds( p_intf->p_sys->p_input ) - 2;
 565     psz_seconds = GetTimedURIFragmentForTime( i_seconds < 0 ? 0 : i_seconds );
 566     if( psz_seconds )
 567     {
 568         psz_url = xstrcat( psz_url, psz_seconds );
 569         free( psz_seconds );
 570         psz_return_value = psz_url;
 571     }
 572
 573     return psz_return_value;
 574 #else
 575     void *p;
 576
 577     /* Suppress warning messages about unused functions */
 578     p = GetTimedURIFragmentForTime; /* unused */
 579     p = GetCurrentTimeInSeconds;    /* unused */
 580
 581     return strdup( p_current_item->p_input->psz_uri );
 582 #endif
 583 }
 584
 585
 586 /*
 587  * Get the current time, rounded down to the nearest second
 588  *
 589  * http://www.ietf.org/internet-drafts/draft-pfeiffer-temporal-fragments-02.txt
 590  */
 591 static
 592 int GetCurrentTimeInSeconds( input_thread_t *p_input )
 593 {
 594     vlc_value_t time;
 595     mtime_t i_seconds;
 596
 597     var_Get( p_input, "time", &time );
 598     i_seconds = time.i_time / 1000000;
 599     return i_seconds;
 600 }
 601
 602 static
 603 char *GetTimedURIFragmentForTime( int seconds )
 604 {
 605     char *psz_time;
 606
 607     asprintf( &psz_time, "%d", seconds );
 608     return psz_time;
 609 }
 610
 611 static
 612 int GoBackCallback( vlc_object_t *p_this, char const *psz_var,
 613                     vlc_value_t oldval, vlc_value_t newval, void *p_data )
 614 {
 615     intf_thread_t *p_intf = (intf_thread_t *) p_data;
 616     GoBack( p_intf );
 617     return VLC_SUCCESS;
 618 }
 619
 620 static
 621 int GoForwardCallback( vlc_object_t *p_this, char const *psz_var,
 622                        vlc_value_t oldval, vlc_value_t newval, void *p_data )
 623 {
 624     intf_thread_t *p_intf = (intf_thread_t *) p_data;
 625     GoForward( p_intf );
 626     return VLC_SUCCESS;
 627 }
 628
 629 static
 630 int FollowAnchorCallback( vlc_object_t *p_this, char const *psz_var,
 631                           vlc_value_t oldval, vlc_value_t newval,
 632                           void *p_data )
 633 {
 634     intf_thread_t *p_intf = (intf_thread_t *) p_data;
 635     FollowAnchor( p_intf );
 636     return VLC_SUCCESS;
 637 }
 638
 639 static
 640 void GoBack( intf_thread_t *p_intf )
 641 {
 642     vlc_value_t history;
 643     history_t *p_history = NULL;
 644     history_item_t *p_history_item = NULL;
 645     history_item_t *p_new_history_item = NULL;
 646     playlist_t *p_playlist = NULL;
 647     char *psz_timed_url = NULL;
 648     playlist_item_t *p_current_item;
 649
 650 #ifdef CMML_INTF_DEBUG
 651     msg_Dbg( p_intf, "Going back in navigation history" );
 652 #endif
 653
 654     /* Find the playlist */
 655     p_playlist = (playlist_t *) vlc_object_find( p_intf,
 656             VLC_OBJECT_PLAYLIST, FIND_ANYWHERE );
 657     if ( !p_playlist )
 658     {
 659         msg_Warn( p_intf, "can't find playlist" );
 660         return;
 661     }
 662
 663     /* Retrieve navigation history from playlist */
 664     if( var_Get( p_playlist, "navigation-history", &history ) != VLC_SUCCESS ||
 665         !history.p_address )
 666     {
 667         /* History doesn't exist yet: ignore user's request */
 668         msg_Warn( p_intf, "can't go back: no history exists yet" );
 669         vlc_object_release( p_playlist );
 670         return;
 671     }
 672
 673     p_history = history.p_address;
 674 #ifdef CMML_INTF_DEBUG
 675     msg_Dbg( p_intf, "back: nav history retrieved from %p", p_history );
 676     msg_Dbg( p_intf, "nav history index:%d, p_xarray:%p", p_history->i_index,
 677              p_history->p_xarray );
 678 #endif
 679
 680     /* Check whether we can go back in the history */
 681     if( history_CanGoBack( p_history ) == VLC_FALSE )
 682     {
 683         msg_Warn( p_intf, "can't go back: already at beginning of history" );
 684         vlc_object_release( p_playlist );
 685         return;
 686     }
 687
 688     p_current_item = p_playlist->status.p_item;
 689
 690     /* Save the currently-playing media in a new history item */
 691     psz_timed_url = GetTimedURLFromPlaylistItem( p_intf, p_current_item );
 692     p_new_history_item = historyItem_New( psz_timed_url, psz_timed_url );
 693     free( psz_timed_url );
 694
 695     if( !p_new_history_item )
 696     {
 697 #ifdef CMML_INTF_DEBUG
 698         msg_Dbg( p_intf, "back: could not initialise new history item" );
 699 #endif
 700         vlc_object_release( p_playlist );
 701         return;
 702     }
 703
 704     /* Go back in the history, saving the currently-playing item */
 705     (void) history_GoBackSavingCurrentItem( p_history, p_new_history_item );
 706     p_history_item = history_Item( p_history );
 707
 708 #ifdef CMML_INTF_DEBUG
 709     msg_Dbg( p_intf, "retrieving item from h index %d", p_history->i_index );
 710     msg_Dbg( p_intf, "got previous history item: %p", p_history_item );
 711     msg_Dbg( p_intf, "prev history item URL: \"%s\"", p_history_item->psz_uri );
 712 #endif
 713
 714     ReplacePlaylistItem( p_playlist, p_history_item->psz_uri );
 715     vlc_object_release( p_playlist );
 716 }
 717
 718 static
 719 void GoForward( intf_thread_t *p_intf )
 720 {
 721     vlc_value_t history;
 722     history_t *p_history = NULL;
 723     history_item_t *p_history_item = NULL;
 724     history_item_t *p_new_history_item = NULL;
 725     playlist_t *p_playlist = NULL;
 726     playlist_item_t *p_current_item;
 727
 728 #ifdef CMML_INTF_DEBUG
 729     msg_Dbg( p_intf, "Going forward in navigation history" );
 730 #endif
 731
 732     /* Find the playlist */
 733     p_playlist = (playlist_t *) vlc_object_find( p_intf,
 734             VLC_OBJECT_PLAYLIST, FIND_ANYWHERE );
 735     if ( !p_playlist )
 736     {
 737         msg_Warn( p_intf, "can't find playlist" );
 738         return;
 739     }
 740
 741     /* Retrieve navigation history from playlist */
 742     if( var_Get( p_playlist, "navigation-history", &history ) != VLC_SUCCESS ||
 743         !history.p_address )
 744     {
 745         /* History doesn't exist yet: ignore user's request */
 746         msg_Warn( p_intf, "can't go back: no history exists yet" );
 747         vlc_object_release( p_playlist );
 748         return;
 749     }
 750
 751     p_history = history.p_address;
 752 #ifdef CMML_INTF_DEBUG
 753     msg_Dbg( p_intf, "forward: nav history retrieved from %p", p_history );
 754     msg_Dbg( p_intf, "nav history index:%d, p_xarray:%p", p_history->i_index,
 755              p_history->p_xarray );
 756 #endif
 757
 758     /* Check whether we can go forward in the history */
 759     if( history_CanGoForward( p_history ) == VLC_FALSE )
 760     {
 761         msg_Warn( p_intf, "can't go forward: already at end of history" );
 762         vlc_object_release( p_playlist );
 763         return;
 764     }
 765
 766     /* Save the currently-playing media in a new history item */
 767     p_new_history_item = malloc( sizeof(history_item_t) );
 768     if( !p_new_history_item )
 769     {
 770 #ifdef CMML_INTF_DEBUG
 771         msg_Dbg( p_intf, "forward: could not initialise new history item" );
 772 #endif
 773         vlc_object_release( p_playlist );
 774         return;
 775     }
 776     p_current_item = p_playlist->status.p_item;
 777     p_new_history_item->psz_uri = GetTimedURLFromPlaylistItem( p_intf,
 778             p_current_item );
 779     p_new_history_item->psz_name = p_new_history_item->psz_uri;
 780
 781     /* Go forward in the history, saving the currently-playing item */
 782     (void) history_GoForwardSavingCurrentItem( p_history, p_new_history_item );
 783     p_history_item = history_Item( p_history );
 784
 785 #ifdef CMML_INTF_DEBUG
 786     msg_Dbg( p_intf, "retrieving item from h index %d", p_history->i_index );
 787     msg_Dbg( p_intf, "got next history item: %p", p_history_item );
 788     msg_Dbg( p_intf, "next history item URL: \"%s\"", p_history_item->psz_uri );
 789 #endif
 790
 791     ReplacePlaylistItem( p_playlist, p_history_item->psz_uri );
 792     vlc_object_release( p_playlist );
 793 }
 794
 795 static void ReplacePlaylistItem( playlist_t *p_playlist, char *psz_uri )
 796 {
 797     playlist_Stop( p_playlist );
 798     (void) playlist_Add( p_playlist, psz_uri, psz_uri,
 799                          PLAYLIST_INSERT /* FIXME: used to be PLAYLIST_REPLACE */, PLAYLIST_END|PLAYLIST_GO, VLC_TRUE /* FIXME: p_playlist->status.i_index */ );
 800 }
 801
 802 /****************************************************************************
 803  * DisplayAnchor: displays an anchor on the given video output
 804  ****************************************************************************/
 805 static int DisplayAnchor( intf_thread_t *p_intf,
 806         vout_thread_t *p_vout,
 807         char *psz_anchor_description,
 808         char *psz_anchor_url )
 809 {
 810     int i_margin_h, i_margin_v;
 811     mtime_t i_now;
 812
 813     i_margin_h = 0;
 814     i_margin_v = 10;
 815
 816     i_now = mdate();
 817
 818     if( p_vout )
 819     {
 820         if( psz_anchor_url )
 821         {
 822             /* Should display subtitle underlined and in blue, but it looks
 823              * like VLC doesn't implement any text styles yet.  D'oh! */
 824             // p_style = &blue_with_underline;
 825
 826         }
 827
 828         /* TODO: p_subpicture doesn't have the proper i_x and i_y
 829          * coordinates.  Need to look at the subpicture display system to
 830          * work out why. */
 831         if ( vout_ShowTextAbsolute( p_vout, DEFAULT_CHAN,
 832                 psz_anchor_description, NULL, OSD_ALIGN_BOTTOM,
 833                 i_margin_h, i_margin_v, i_now, 0 ) == VLC_SUCCESS )
 834         {
 835             /* Displayed successfully */
 836         }
 837         else
 838         {
 839             return VLC_EGENERIC;
 840         }
 841     }
 842     else
 843     {
 844         msg_Dbg( p_intf, "DisplayAnchor couldn't find a video output" );
 845         return VLC_EGENERIC;
 846     }
 847
 848     return VLC_SUCCESS;
 849 }
 850
 851 static history_t * GetHistory( playlist_t *p_playlist )
 852 {
 853     vlc_value_t val;
 854     history_t *p_history = NULL;
 855
 856     if( var_Get( p_playlist, "navigation-history", &val ) != VLC_SUCCESS )
 857     {
 858         /* history doesn't exist yet: need to create it */
 859         history_t *new_history = history_New();
 860         val.p_address = new_history;
 861         var_Create( p_playlist, "navigation-history",
 862                 VLC_VAR_ADDRESS|VLC_VAR_DOINHERIT );
 863         if( var_Set( p_playlist, "navigation-history", val ) != VLC_SUCCESS )
 864         {
 865             msg_Warn( p_playlist, "could not initialise history" );
 866         }
 867         else
 868         {
 869             p_history = new_history;
 870 #ifdef CMML_INTF_HISTORY_DEBUG
 871             msg_Dbg( p_playlist, "nav history created at %p", new_history );
 872             msg_Dbg( p_playlist, "nav history index:%d, p_xarray:%p",
 873                      p_history->i_index, p_history->p_xarray );
 874 #endif
 875         }
 876     }
 877     else
 878     {
 879         p_history = val.p_address;
 880 #ifdef CMML_INTF_HISTORY_DEBUG
 881         msg_Dbg( p_playlist, "nav history retrieved from %p", p_history );
 882 #endif
 883     }
 884
 885     return p_history;
 886 }
 887