research.m1stereo.tv/gitweb/ - melted/blob - src/framework/mlt_events.c

   1 /**
   2  * \file mlt_events.c
   3  * \brief event handling
   4  * \see mlt_events_struct
   5  *
   6  * Copyright (C) 2004-2009 Ushodaya Enterprises Limited
   7  * \author Charles Yates <charles.yates@pandora.be>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22  */
  23
  24 #include <stdlib.h>
  25 #include <stdarg.h>
  26 #include <string.h>
  27 #include <pthread.h>
  28
  29 #include "mlt_properties.h"
  30 #include "mlt_events.h"
  31
  32 /* Memory leak checks. */
  33
  34 #undef _MLT_EVENT_CHECKS_
  35
  36 #ifdef _MLT_EVENT_CHECKS_
  37 static int events_created = 0;
  38 static int events_destroyed = 0;
  39 #endif
  40
  41 /** \brief Events class
  42  *
  43  * Events provide messages and notifications between services and the application.
  44  * A service can register an event and fire/send it upon certain conditions or times.
  45  * Likewise, a service or an application can listen/receive specific events on specific
  46  * services.
  47  */
  48
  49 struct mlt_events_struct
  50 {
  51         mlt_properties owner;
  52         mlt_properties list;
  53 };
  54
  55 typedef struct mlt_events_struct *mlt_events;
  56
  57 /** \brief Event class
  58  *
  59  */
  60
  61 struct mlt_event_struct
  62 {
  63         mlt_events owner;
  64         int ref_count;
  65         int block_count;
  66         mlt_listener listener;
  67         void *service;
  68 };
  69
  70 /** Increment the reference count on this event.
  71  *
  72  * \public \memberof mlt_event_struct
  73  * \param this an event
  74  */
  75
  76 void mlt_event_inc_ref( mlt_event this )
  77 {
  78         if ( this != NULL )
  79                 this->ref_count ++;
  80 }
  81
  82 /** Increment the block count on this event.
  83  *
  84  * \public \memberof mlt_event_struct
  85  * \param this an event
  86  */
  87
  88 void mlt_event_block( mlt_event this )
  89 {
  90         if ( this != NULL && this->owner != NULL )
  91                 this->block_count ++;
  92 }
  93
  94 /** Decrement the block count on this event.
  95  *
  96  * \public \memberof mlt_event_struct
  97  * \param this an event
  98  */
  99
 100 void mlt_event_unblock( mlt_event this )
 101 {
 102         if ( this != NULL && this->owner != NULL )
 103                 this->block_count --;
 104 }
 105
 106 /** Close this event.
 107  *
 108  * \public \memberof mlt_event_struct
 109  * \param this an event
 110  */
 111
 112 void mlt_event_close( mlt_event this )
 113 {
 114         if ( this != NULL )
 115         {
 116                 if ( -- this->ref_count == 1 )
 117                         this->owner = NULL;
 118                 if ( this->ref_count <= 0 )
 119                 {
 120 #ifdef _MLT_EVENT_CHECKS_
 121                         mlt_log( NULL, MLT_LOG_DEBUG, "Events created %d, destroyed %d\n", events_created, ++events_destroyed );
 122 #endif
 123                         free( this );
 124                 }
 125         }
 126 }
 127
 128 /* Forward declaration to private functions.
 129 */
 130
 131 static mlt_events mlt_events_fetch( mlt_properties );
 132 static void mlt_events_store( mlt_properties, mlt_events );
 133 static void mlt_events_close( mlt_events );
 134
 135 /** Initialise the events structure.
 136  *
 137  * \public \memberof mlt_events_struct
 138  * \param this a properties list
 139  */
 140
 141 void mlt_events_init( mlt_properties this )
 142 {
 143         mlt_events events = mlt_events_fetch( this );
 144         if ( events == NULL )
 145         {
 146                 events = malloc( sizeof( struct mlt_events_struct ) );
 147                 events->list = mlt_properties_new( );
 148                 mlt_events_store( this, events );
 149         }
 150 }
 151
 152 /** Register an event and transmitter.
 153  *
 154  * \public \memberof mlt_events_struct
 155  * \param this a properties list
 156  * \param id the name of an event
 157  * \param transmitter the callback function to send an event message
 158  * \return true if there was an error
 159  */
 160
 161 int mlt_events_register( mlt_properties this, const char *id, mlt_transmitter transmitter )
 162 {
 163         int error = 1;
 164         mlt_events events = mlt_events_fetch( this );
 165         if ( events != NULL )
 166         {
 167                 mlt_properties list = events->list;
 168                 char temp[ 128 ];
 169                 error = mlt_properties_set_data( list, id, transmitter, 0, NULL, NULL );
 170                 sprintf( temp, "list:%s", id );
 171                 if ( mlt_properties_get_data( list, temp, NULL ) == NULL )
 172                         mlt_properties_set_data( list, temp, mlt_properties_new( ), 0, ( mlt_destructor )mlt_properties_close, NULL );
 173         }
 174         return error;
 175 }
 176
 177 /** Fire an event.
 178  *
 179  * This takes a variable number of arguments to supply to the listener.
 180
 181  * \public \memberof mlt_events_struct
 182  * \param this a properties list
 183  * \param id the name of an event
 184  */
 185
 186 void mlt_events_fire( mlt_properties this, const char *id, ... )
 187 {
 188         mlt_events events = mlt_events_fetch( this );
 189         if ( events != NULL )
 190         {
 191                 int i = 0;
 192                 va_list alist;
 193                 void *args[ 10 ];
 194                 mlt_properties list = events->list;
 195                 mlt_properties listeners = NULL;
 196                 char temp[ 128 ];
 197                 mlt_transmitter transmitter = mlt_properties_get_data( list, id, NULL );
 198                 sprintf( temp, "list:%s", id );
 199                 listeners = mlt_properties_get_data( list, temp, NULL );
 200
 201                 va_start( alist, id );
 202                 do
 203                         args[ i ] = va_arg( alist, void * );
 204                 while( args[ i ++ ] != NULL );
 205                 va_end( alist );
 206
 207                 if ( listeners != NULL )
 208                 {
 209                         for ( i = 0; i < mlt_properties_count( listeners ); i ++ )
 210                         {
 211                                 mlt_event event = mlt_properties_get_data_at( listeners, i, NULL );
 212                                 if ( event != NULL && event->owner != NULL && event->block_count == 0 )
 213                                 {
 214                                         if ( transmitter != NULL )
 215                                                 transmitter( event->listener, event->owner, event->service, args );
 216                                         else
 217                                                 event->listener( event->owner, event->service );
 218                                 }
 219                         }
 220                 }
 221         }
 222 }
 223
 224 /** Register a listener.
 225  *
 226  * \public \memberof mlt_events_struct
 227  * \param this a properties list
 228  * \param service an opaque pointer
 229  * \param id the name of the event to listen for
 230  * \param listener the callback to receive an event message
 231  * \return
 232  */
 233
 234 mlt_event mlt_events_listen( mlt_properties this, void *service, const char *id, mlt_listener listener )
 235 {
 236         mlt_event event = NULL;
 237         mlt_events events = mlt_events_fetch( this );
 238         if ( events != NULL )
 239         {
 240                 mlt_properties list = events->list;
 241                 mlt_properties listeners = NULL;
 242                 char temp[ 128 ];
 243                 sprintf( temp, "list:%s", id );
 244                 listeners = mlt_properties_get_data( list, temp, NULL );
 245                 if ( listeners != NULL )
 246                 {
 247                         int first_null = -1;
 248                         int i = 0;
 249                         for ( i = 0; event == NULL && i < mlt_properties_count( listeners ); i ++ )
 250                         {
 251                                 mlt_event entry = mlt_properties_get_data_at( listeners, i, NULL );
 252                                 if ( entry != NULL && entry->owner != NULL )
 253                                 {
 254                                         if ( entry->service == service && entry->listener == listener )
 255                                                 event = entry;
 256                                 }
 257                                 else if ( ( entry == NULL || entry->owner == NULL ) && first_null == -1 )
 258                                 {
 259                                         first_null = i;
 260                                 }
 261                         }
 262
 263                         if ( event == NULL )
 264                         {
 265                                 event = malloc( sizeof( struct mlt_event_struct ) );
 266                                 if ( event != NULL )
 267                                 {
 268 #ifdef _MLT_EVENT_CHECKS_
 269                                         events_created ++;
 270 #endif
 271                                         sprintf( temp, "%d", first_null == -1 ? mlt_properties_count( listeners ) : first_null );
 272                                         event->owner = events;
 273                                         event->ref_count = 0;
 274                                         event->block_count = 0;
 275                                         event->listener = listener;
 276                                         event->service = service;
 277                                         mlt_properties_set_data( listeners, temp, event, 0, ( mlt_destructor )mlt_event_close, NULL );
 278                                         mlt_event_inc_ref( event );
 279                                 }
 280                         }
 281
 282                 }
 283         }
 284         return event;
 285 }
 286
 287 /** Block all events for a given service.
 288  *
 289  * \public \memberof mlt_events_struct
 290  * \param this a properties list
 291  * \param service an opaque pointer
 292  */
 293
 294 void mlt_events_block( mlt_properties this, void *service )
 295 {
 296         mlt_events events = mlt_events_fetch( this );
 297         if ( events != NULL )
 298         {
 299                 int i = 0, j = 0;
 300                 mlt_properties list = events->list;
 301                 for ( j = 0; j < mlt_properties_count( list ); j ++ )
 302                 {
 303                         char *temp = mlt_properties_get_name( list, j );
 304                         if ( !strncmp( temp, "list:", 5 ) )
 305                         {
 306                                 mlt_properties listeners = mlt_properties_get_data( list, temp, NULL );
 307                                 for ( i = 0; i < mlt_properties_count( listeners ); i ++ )
 308                                 {
 309                                         mlt_event entry = mlt_properties_get_data_at( listeners, i, NULL );
 310                                         if ( entry != NULL && entry->service == service )
 311                                                 mlt_event_block( entry );
 312                                 }
 313                         }
 314                 }
 315         }
 316 }
 317
 318 /** Unblock all events for a given service.
 319  *
 320  * \public \memberof mlt_events_struct
 321  * \param this a properties list
 322  * \param service an opaque pointer
 323  */
 324
 325 void mlt_events_unblock( mlt_properties this, void *service )
 326 {
 327         mlt_events events = mlt_events_fetch( this );
 328         if ( events != NULL )
 329         {
 330                 int i = 0, j = 0;
 331                 mlt_properties list = events->list;
 332                 for ( j = 0; j < mlt_properties_count( list ); j ++ )
 333                 {
 334                         char *temp = mlt_properties_get_name( list, j );
 335                         if ( !strncmp( temp, "list:", 5 ) )
 336                         {
 337                                 mlt_properties listeners = mlt_properties_get_data( list, temp, NULL );
 338                                 for ( i = 0; i < mlt_properties_count( listeners ); i ++ )
 339                                 {
 340                                         mlt_event entry = mlt_properties_get_data_at( listeners, i, NULL );
 341                                         if ( entry != NULL && entry->service == service )
 342                                                 mlt_event_unblock( entry );
 343                                 }
 344                         }
 345                 }
 346         }
 347 }
 348
 349 /** Disconnect all events for a given service.
 350  *
 351  * \public \memberof mlt_events_struct
 352  * \param this a properties list
 353  * \param service an opaque pointer
 354  */
 355
 356 void mlt_events_disconnect( mlt_properties this, void *service )
 357 {
 358         mlt_events events = mlt_events_fetch( this );
 359         if ( events != NULL )
 360         {
 361                 int i = 0, j = 0;
 362                 mlt_properties list = events->list;
 363                 for ( j = 0; j < mlt_properties_count( list ); j ++ )
 364                 {
 365                         char *temp = mlt_properties_get_name( list, j );
 366                         if ( !strncmp( temp, "list:", 5 ) )
 367                         {
 368                                 mlt_properties listeners = mlt_properties_get_data( list, temp, NULL );
 369                                 for ( i = 0; i < mlt_properties_count( listeners ); i ++ )
 370                                 {
 371                                         mlt_event entry = mlt_properties_get_data_at( listeners, i, NULL );
 372                                         char *name = mlt_properties_get_name( listeners, i );
 373                                         if ( entry != NULL && entry->service == service )
 374                                                 mlt_properties_set_data( listeners, name, NULL, 0, NULL, NULL );
 375                                 }
 376                         }
 377                 }
 378         }
 379 }
 380
 381 /** \brief private to mlt_events_struct, used by mlt_events_wait_for() */
 382
 383 typedef struct
 384 {
 385         int done;
 386         pthread_cond_t cond;
 387         pthread_mutex_t mutex;
 388 }
 389 condition_pair;
 390
 391 /** The event listener callback for the wait functions.
 392  *
 393  * \private \memberof mlt_events_struct
 394  * \param this a properties list
 395  * \param pair a condition pair
 396  */
 397
 398 static void mlt_events_listen_for( mlt_properties this, condition_pair *pair )
 399 {
 400         pthread_mutex_lock( &pair->mutex );
 401         if ( pair->done == 0 )
 402         {
 403                 pthread_cond_signal( &pair->cond );
 404                 pthread_mutex_unlock( &pair->mutex );
 405         }
 406 }
 407
 408 /** Prepare to wait for an event.
 409  *
 410  * \public \memberof mlt_events_struct
 411  * \param this a properties list
 412  * \param id the name of the event to wait for
 413  * \return an event
 414  */
 415
 416 mlt_event mlt_events_setup_wait_for( mlt_properties this, const char *id )
 417 {
 418         condition_pair *pair = malloc( sizeof( condition_pair ) );
 419         pair->done = 0;
 420         pthread_cond_init( &pair->cond, NULL );
 421         pthread_mutex_init( &pair->mutex, NULL );
 422         pthread_mutex_lock( &pair->mutex );
 423         return mlt_events_listen( this, pair, id, ( mlt_listener )mlt_events_listen_for );
 424 }
 425
 426 /** Wait for an event.
 427  *
 428  * \public \memberof mlt_events_struct
 429  * \param this a properties list
 430  * \param event an event
 431  */
 432
 433 void mlt_events_wait_for( mlt_properties this, mlt_event event )
 434 {
 435         if ( event != NULL )
 436         {
 437                 condition_pair *pair = event->service;
 438                 pthread_cond_wait( &pair->cond, &pair->mutex );
 439         }
 440 }
 441
 442 /** Cleanup after waiting for an event.
 443  *
 444  * \public \memberof mlt_events_struct
 445  * \param this a properties list
 446  * \param event an event
 447  */
 448
 449 void mlt_events_close_wait_for( mlt_properties this, mlt_event event )
 450 {
 451         if ( event != NULL )
 452         {
 453                 condition_pair *pair = event->service;
 454                 event->owner = NULL;
 455                 pair->done = 0;
 456                 pthread_mutex_unlock( &pair->mutex );
 457                 pthread_mutex_destroy( &pair->mutex );
 458                 pthread_cond_destroy( &pair->cond );
 459         }
 460 }
 461
 462 /** Fetch the events object.
 463  *
 464  * \private \memberof mlt_events_struct
 465  * \param this a properties list
 466  * \return an events object
 467  */
 468
 469 static mlt_events mlt_events_fetch( mlt_properties this )
 470 {
 471         mlt_events events = NULL;
 472         if ( this != NULL )
 473                 events = mlt_properties_get_data( this, "_events", NULL );
 474         return events;
 475 }
 476
 477 /** Store the events object.
 478  *
 479  * \private \memberof mlt_events_struct
 480  * \param this a properties list
 481  * \param events an events object
 482  */
 483
 484 static void mlt_events_store( mlt_properties this, mlt_events events )
 485 {
 486         if ( this != NULL && events != NULL )
 487                 mlt_properties_set_data( this, "_events", events, 0, ( mlt_destructor )mlt_events_close, NULL );
 488 }
 489
 490 /** Close the events object.
 491  *
 492  * \private \memberof mlt_events_struct
 493  * \param events an events object
 494  */
 495
 496 static void mlt_events_close( mlt_events events )
 497 {
 498         if ( events != NULL )
 499         {
 500                 mlt_properties_close( events->list );
 501                 free( events );
 502         }
 503 }