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