libchimara/event.c

   1 #include "event.h"
   2 #include "magic.h"
   3 #include "glk.h"
   4 #include "window.h"
   5 #include "input.h"
   6 #include <string.h>
   7
   8 #include "chimara-glk.h"
   9 #include "chimara-glk-private.h"
  10
  11 extern GPrivate *glk_data_key;
  12
  13 #define EVENT_TIMEOUT_MICROSECONDS (3000000)
  14
  15 /* Internal function: push an event onto the event queue. If the event queue is
  16 full, wait for max three seconds and then drop the event. If the event queue is
  17 NULL, i.e. freed, then fail silently. */
  18 void
  19 event_throw(ChimaraGlk *glk, glui32 type, winid_t win, glui32 val1, glui32 val2)
  20 {
  21         ChimaraGlkPrivate *priv = CHIMARA_GLK_PRIVATE(glk);
  22
  23         if(!priv->event_queue)
  24                 return;
  25
  26         GTimeVal timeout;
  27         g_get_current_time(&timeout);
  28         g_time_val_add(&timeout, EVENT_TIMEOUT_MICROSECONDS);
  29
  30         g_mutex_lock(priv->event_lock);
  31
  32         /* Wait for room in the event queue */
  33         while( g_queue_get_length(priv->event_queue) >= EVENT_QUEUE_MAX_LENGTH )
  34                 if( !g_cond_timed_wait(priv->event_queue_not_full, priv->event_lock, &timeout) )
  35                 {
  36                         /* Drop the event after 3 seconds */
  37                         g_mutex_unlock(priv->event_lock);
  38                         return;
  39                 }
  40
  41         event_t *event = g_new0(event_t, 1);
  42         event->type = type;
  43         event->win = win;
  44         event->val1 = val1;
  45         event->val2 = val2;
  46         g_queue_push_head(priv->event_queue, event);
  47
  48         /* Signal that there is an event */
  49         g_cond_signal(priv->event_queue_not_empty);
  50
  51         g_mutex_unlock(priv->event_lock);
  52 }
  53
  54 /* Helper function: Wait for an event in the event queue. If it is a forced
  55  * input event, but no windows have an input request of that type, then wait
  56  * for the next event and put the forced input event back on top of the queue.
  57  */
  58 static void
  59 get_appropriate_event(event_t *event)
  60 {
  61         ChimaraGlkPrivate *glk_data = g_private_get(glk_data_key);
  62
  63         g_mutex_lock(glk_data->event_lock);
  64
  65         event_t *retrieved_event = NULL;
  66
  67         /* Wait for an event */
  68         if( g_queue_is_empty(glk_data->event_queue) )
  69                 g_cond_wait(glk_data->event_queue_not_empty, glk_data->event_lock);
  70
  71         retrieved_event = g_queue_pop_tail(glk_data->event_queue);
  72
  73         /* Signal that the event queue is no longer full */
  74         g_cond_signal(glk_data->event_queue_not_full);
  75
  76         g_mutex_unlock(glk_data->event_lock);
  77
  78         if(retrieved_event->type == evtype_ForcedCharInput)
  79         {
  80                 /* Check for forced character input in the queue */
  81                 winid_t win;
  82                 for(win = glk_window_iterate(NULL, NULL); win; win = glk_window_iterate(win, NULL))
  83                         if(win->input_request_type == INPUT_REQUEST_CHARACTER || win->input_request_type == INPUT_REQUEST_CHARACTER_UNICODE)
  84                                 break;
  85                 if(win)
  86                 {
  87                         force_char_input_from_queue(win, event);
  88                         g_free(retrieved_event);
  89                 }
  90                 else
  91                 {
  92                         get_appropriate_event(event);
  93                         g_mutex_lock(glk_data->event_lock);
  94                         g_queue_push_tail(glk_data->event_queue, retrieved_event);
  95                         g_cond_signal(glk_data->event_queue_not_empty);
  96                         g_mutex_unlock(glk_data->event_lock);
  97                 }
  98         }
  99         else if(retrieved_event->type == evtype_ForcedLineInput)
 100         {
 101                 /* Check for forced line input in the queue */
 102                 winid_t win;
 103                 for(win = glk_window_iterate(NULL, NULL); win; win = glk_window_iterate(win, NULL))
 104                         if(win->input_request_type == INPUT_REQUEST_LINE || win->input_request_type == INPUT_REQUEST_LINE_UNICODE)
 105                                 break;
 106                 if(win)
 107                 {
 108                         force_line_input_from_queue(win, event);
 109                         g_free(retrieved_event);
 110                 }
 111                 else
 112                 {
 113                         get_appropriate_event(event);
 114                         g_mutex_lock(glk_data->event_lock);
 115                         g_queue_push_tail(glk_data->event_queue, retrieved_event);
 116                         g_cond_signal(glk_data->event_queue_not_empty);
 117                         g_mutex_unlock(glk_data->event_lock);
 118                 }
 119         }
 120         else
 121         {
 122                 if(retrieved_event == NULL)
 123                 {
 124                         WARNING("Retrieved NULL event from non-empty event queue");
 125                         return;
 126                 }
 127                 memcpy(event, retrieved_event, sizeof(event_t));
 128                 g_free(retrieved_event);
 129         }
 130 }
 131
 132 /**
 133  * glk_select:
 134  * @event: Pointer to an #event_t.
 135  *
 136  * Causes the program to wait for an event, and then store it in the structure
 137  * pointed to by @event. Unlike most Glk functions that take pointers, the
 138  * argument of glk_select() may not be %NULL.
 139  *
 140  * Most of the time, you only get the events that you request. However, there
 141  * are some events which can arrive at any time. This is why you must always
 142  * call glk_select() in a loop, and continue the loop until you get the event
 143  * you really want.
 144  */
 145 void
 146 glk_select(event_t *event)
 147 {
 148         g_return_if_fail(event != NULL);
 149
 150         ChimaraGlkPrivate *glk_data = g_private_get(glk_data_key);
 151
 152         get_appropriate_event(event);
 153
 154         /* Check for interrupt */
 155         glk_tick();
 156
 157         /* If the event was a line input event, the library must release the buffer */
 158         if(event->type == evtype_LineInput && glk_data->unregister_arr)
 159         {
 160         if(event->win->input_request_type == INPUT_REQUEST_LINE_UNICODE)
 161                         (*glk_data->unregister_arr)(event->win->line_input_buffer_unicode, event->win->line_input_buffer_max_len, "&+#!Iu", event->win->buffer_rock);
 162                 else
 163             (*glk_data->unregister_arr)(event->win->line_input_buffer, event->win->line_input_buffer_max_len, "&+#!Cn", event->win->buffer_rock);
 164     }
 165
 166         /* If an abort event was generated, the thread should have exited by now */
 167         g_assert(event->type != evtype_Abort);
 168 }
 169
 170 /**
 171  * glk_select_poll:
 172  * @event: Return location for an event.
 173  *
 174  * You can also inquire if an event is available, without stopping to wait for
 175  * one to occur.
 176  *
 177  * This checks if an internally-spawned event is available. If so, it stores it
 178  * in the structure pointed to by @event. If not, it sets
 179  * <code>@event->type</code> to %evtype_None. Either way, it returns almost
 180  * immediately.
 181  *
 182  * The first question you now ask is, what is an internally-spawned event?
 183  * glk_select_poll() does not check for or return %evtype_CharInput,
 184  * %evtype_LineInput, %evtype_MouseInput, or %evtype_Hyperlink events. It is
 185  * intended for you to test conditions which may have occurred while you are
 186  * computing, and not interfacing with the player. For example, time may pass
 187  * during slow computations; you can use glk_select_poll() to see if a
 188  * %evtype_Timer event has occurred. (See <link
 189  * linkend="chimara-Timer-Events">Timer Events</link>.)
 190  *
 191  * At the moment, glk_select_poll() checks for %evtype_Timer, %evtype_Arrange,
 192  * %evtype_Redraw and %evtype_SoundNotify events. But see <link
 193  * linkend="chimara-Other-Events">Other Events</link>.
 194  *
 195  * The second question is, what does it mean that glk_select_poll() returns
 196  * <quote>almost immediately</quote>? In some Glk libraries, text that you send
 197  * to a window is buffered; it does not actually appear until you request player
 198  * input with glk_select(). glk_select_poll() attends to this buffer-flushing
 199  * task in the same way. (Although it does not do the <quote><computeroutput>Hit
 200  * any key to scroll down</computeroutput></quote> waiting which may be done in
 201  * glk_select(); that's a player-input task.)
 202  *
 203  * Similarly, on multitasking platforms, glk_select() may yield time to other
 204  * processes; and glk_select_poll() does this as well.
 205  *
 206  * The upshot of this is that you should not call glk_select_poll() very often.
 207  * If you are not doing much work between player inputs, you should not need to
 208  * call it at all.
 209  *
 210  * <note><para>
 211  *  For example, in a virtual machine interpreter, you should not call
 212  *  glk_select_poll() after every opcode.
 213  * </para></note>
 214  *
 215  * However, if you are doing intense computation, you may wish to call
 216  * glk_select_poll() every so often to yield time to other processes. And if you
 217  * are printing intermediate results during this computation, you should
 218  * glk_select_poll() every so often, so that you can be certain your output will
 219  * be displayed before the next glk_select().
 220  *
 221  * <note><para>
 222  *  However, you should call glk_tick() often &mdash; once per opcode in a VM
 223  *  interpreter. See <link linkend="chimara-The-Tick-Thing">The Tick
 224  *  Thing</link>.
 225  * </para></note>
 226  */
 227 void
 228 glk_select_poll(event_t *event)
 229 {
 230         g_return_if_fail(event != NULL);
 231
 232         ChimaraGlkPrivate *glk_data = g_private_get(glk_data_key);
 233
 234         event->type = evtype_None;
 235
 236         g_mutex_lock(glk_data->event_lock);
 237
 238         if( !g_queue_is_empty(glk_data->event_queue) )
 239         {
 240                 GList *link;
 241                 int count;
 242                 for(count = 0; (link = g_queue_peek_nth_link(glk_data->event_queue, count)) != NULL; count++)
 243                 {
 244                         glui32 type = ((event_t *)link->data)->type;
 245                         if(type != evtype_CharInput && type != evtype_LineInput && type != evtype_MouseInput && type != evtype_Hyperlink)
 246                         {
 247                                 memcpy(event, link->data, sizeof(event_t));
 248                                 g_free(link->data);
 249                                 g_queue_delete_link(glk_data->event_queue, link);
 250                                 g_cond_signal(glk_data->event_queue_not_full);
 251                                 break;
 252                         }
 253                 }
 254         }
 255
 256         g_mutex_unlock(glk_data->event_lock);
 257
 258         /* Check for interrupt */
 259         glk_tick();
 260
 261         /* If an abort event was generated, the thread should have exited by now */
 262         g_assert(event->type != evtype_Abort);
 263 }