gmain.c

嵌入式下基于MiniGUI的Web Browser

static inline GSource *
next_valid_source (GMainContext *context,
		   GSource      *source)
{
  GSource *new_source = source ? source->next : context->source_list;

  while (new_source)
    {
      if (!SOURCE_DESTROYED (new_source))
	{
	  new_source->ref_count++;
	  break;
	}
      
      new_source = new_source->next;
    }

  if (source)
    SOURCE_UNREF (source, context);
	  
  return new_source;
}

/**
 * g_main_context_acquire:
 * @context: a #GMainContext
 * 
 * Tries to become the owner of the specified context.
 * If some other context is the owner of the context,
 * returns %FALSE immediately. Ownership is properly
 * recursive: the owner can require ownership again
 * and will release ownership when g_main_context_release()
 * is called as many times as g_main_context_acquire().
 *
 * You must be the owner of a context before you
 * can call g_main_context_prepare(), g_main_context_query(),
 * g_main_context_check(), g_main_context_dispatch().
 * 
 * Return value: %TRUE if the operation succeeded, and
 *   this thread is now the owner of @context.
 **/
gboolean 
g_main_context_acquire (GMainContext *context)
{
#ifdef G_THREADS_ENABLED
  gboolean result = FALSE;
  GThread *self = G_THREAD_SELF;

  if (context == NULL)
    context = g_main_context_default ();
  
  LOCK_CONTEXT (context);

  if (!context->owner)
    {
      context->owner = self;
      g_assert (context->owner_count == 0);
    }

  if (context->owner == self)
    {
      context->owner_count++;
      result = TRUE;
    }

  UNLOCK_CONTEXT (context); 
  
  return result;
#else /* !G_THREADS_ENABLED */
  return TRUE;
#endif /* G_THREADS_ENABLED */
}

/**
 * g_main_context_release:
 * @context: a #GMainContext
 * 
 * Releases ownership of a context previously acquired by this thread
 * with g_main_context_acquire(). If the context was acquired multiple
 * times, the only release ownership when g_main_context_release()
 * is called as many times as it was acquired.
 **/
void
g_main_context_release (GMainContext *context)
{
#ifdef G_THREADS_ENABLED
  if (context == NULL)
    context = g_main_context_default ();
  
  LOCK_CONTEXT (context);

  context->owner_count--;
  if (context->owner_count == 0)
    {
      context->owner = NULL;

      if (context->waiters)
	{
	  GMainWaiter *waiter = context->waiters->data;
	  gboolean loop_internal_waiter =
	    (waiter->mutex == g_static_mutex_get_mutex (&context->mutex));
	  context->waiters = g_slist_delete_link (context->waiters,
						  context->waiters);
	  if (!loop_internal_waiter)
	    g_mutex_lock (waiter->mutex);
	  
	  g_cond_signal (waiter->cond);
	  
	  if (!loop_internal_waiter)
	    g_mutex_unlock (waiter->mutex);
	}
    }

  UNLOCK_CONTEXT (context); 
#endif /* G_THREADS_ENABLED */
}

/**
 * g_main_context_wait:
 * @context: a #GMainContext
 * @cond: a condition variable
 * @mutex: a mutex, currently held
 * 
 * Tries to become the owner of the specified context,
 * as with g_main_context_acquire(). But if another thread
 * is the owner, atomically drop @mutex and wait on @cond until 
 * that owner releases ownership or until @cond is signaled, then
 * try again (once) to become the owner.
 * 
 * Return value: %TRUE if the operation succeeded, and
 *   this thread is now the owner of @context.
 **/
gboolean
g_main_context_wait (GMainContext *context,
		     GCond        *cond,
		     GMutex       *mutex)
{
#ifdef G_THREADS_ENABLED
  gboolean result = FALSE;
  GThread *self = G_THREAD_SELF;
  gboolean loop_internal_waiter;
  
  if (context == NULL)
    context = g_main_context_default ();

  loop_internal_waiter = (mutex == g_static_mutex_get_mutex (&context->mutex));
  
  if (!loop_internal_waiter)
    LOCK_CONTEXT (context);

  if (context->owner && context->owner != self)
    {
      GMainWaiter waiter;

      waiter.cond = cond;
      waiter.mutex = mutex;

      context->waiters = g_slist_append (context->waiters, &waiter);
      
      if (!loop_internal_waiter)
	UNLOCK_CONTEXT (context);
      g_cond_wait (cond, mutex);
      if (!loop_internal_waiter)      
	LOCK_CONTEXT (context);

      context->waiters = g_slist_remove (context->waiters, &waiter);
    }

  if (!context->owner)
    {
      context->owner = self;
      g_assert (context->owner_count == 0);
    }

  if (context->owner == self)
    {
      context->owner_count++;
      result = TRUE;
    }

  if (!loop_internal_waiter)
    UNLOCK_CONTEXT (context); 
  
  return result;
#else /* !G_THREADS_ENABLED */
  return TRUE;
#endif /* G_THREADS_ENABLED */
}

/**
 * g_main_context_prepare:
 * @context: a #GMainContext
 * @priority: location to store priority of highest priority
 *            source already ready.
 * 
 * Prepares to poll sources within a main loop. The resulting information
 * for polling is determined by calling g_main_context_query ().
 * 
 * Return value: %TRUE if some source is ready to be dispatched
 *               prior to polling.
 **/
gboolean
g_main_context_prepare (GMainContext *context,
			gint         *priority)
{
  gint i;
  gint n_ready = 0;
  gint current_priority = G_MAXINT;
  GSource *source;

  if (context == NULL)
    context = g_main_context_default ();
  
  LOCK_CONTEXT (context);

  context->time_is_current = FALSE;

  if (context->in_check_or_prepare)
    {
      g_warning ("g_main_context_prepare() called recursively from within a source's check() or "
		 "prepare() member.");
      UNLOCK_CONTEXT (context);
      return FALSE;
    }

#ifdef G_THREADS_ENABLED
  if (context->poll_waiting)
    {
      g_warning("g_main_context_prepare(): main loop already active in another thread");
      UNLOCK_CONTEXT (context);
      return FALSE;
    }
  
  context->poll_waiting = TRUE;
#endif /* G_THREADS_ENABLED */

#if 0
  /* If recursing, finish up current dispatch, before starting over */
  if (context->pending_dispatches)
    {
      if (dispatch)
	g_main_dispatch (context, &current_time);
      
      UNLOCK_CONTEXT (context);
      return TRUE;
    }
#endif

  /* If recursing, clear list of pending dispatches */

  for (i = 0; i < context->pending_dispatches->len; i++)
    {
      if (context->pending_dispatches->pdata[i])
	SOURCE_UNREF ((GSource *)context->pending_dispatches->pdata[i], context);
    }
  g_ptr_array_set_size (context->pending_dispatches, 0);
  
  /* Prepare all sources */

  context->timeout = -1;
  
  source = next_valid_source (context, NULL);
  while (source)
    {
      gint source_timeout = -1;

      if ((n_ready > 0) && (source->priority > current_priority))
	{
	  SOURCE_UNREF (source, context);
	  break;
	}
      if ((source->flags & G_HOOK_FLAG_IN_CALL) && !(source->flags & G_SOURCE_CAN_RECURSE))
	goto next;

      if (!(source->flags & G_SOURCE_READY))
	{
	  gboolean result;
	  gboolean (*prepare)  (GSource  *source, 
				gint     *timeout);

	  prepare = source->source_funcs->prepare;
	  context->in_check_or_prepare++;
	  UNLOCK_CONTEXT (context);

	  result = (*prepare) (source, &source_timeout);

	  LOCK_CONTEXT (context);
	  context->in_check_or_prepare--;

	  if (result)
	    source->flags |= G_SOURCE_READY;
	}

      if (source->flags & G_SOURCE_READY)
	{
	  n_ready++;
	  current_priority = source->priority;
	  context->timeout = 0;
	}
      
      if (source_timeout >= 0)
	{
	  if (context->timeout < 0)
	    context->timeout = source_timeout;
	  else
	    context->timeout = MIN (context->timeout, source_timeout);
	}

    next:
      source = next_valid_source (context, source);
    }

  UNLOCK_CONTEXT (context);
  
  if (priority)
    *priority = current_priority;
  
  return (n_ready > 0);
}

/**
 * g_main_context_query:
 * @context: a #GMainContext
 * @max_priority: maximum priority source to check
 * @timeout: location to store timeout to be used in polling
 * @fds: location to store #GPollFD records that need to be polled.
 * @n_fds: length of @fds.
 * 
 * Determines information necessary to poll this main loop.
 * 
 * Return value: the number of records actually stored in @fds,
 *   or, if more than @n_fds records need to be stored, the number
 *   of records that need to be stored.
 **/
gint
g_main_context_query (GMainContext *context,
		      gint          max_priority,
		      gint         *timeout,
		      GPollFD      *fds,
		      gint          n_fds)
{
  gint n_poll;
  GPollRec *pollrec;
  
  LOCK_CONTEXT (context);

  pollrec = context->poll_records;
  n_poll = 0;
  while (pollrec && max_priority >= pollrec->priority)
    {
      if (pollrec->fd->events)
	{
	  if (n_poll < n_fds)
	    {
	      fds[n_poll].fd = pollrec->fd->fd;
	      /* In direct contradiction to the Unix98 spec, IRIX runs into
	       * difficulty if you pass in POLLERR, POLLHUP or POLLNVAL
	       * flags in the events field of the pollfd while it should
	       * just ignoring them. So we mask them out here.
	       */
	      fds[n_poll].events = pollrec->fd->events & ~(G_IO_ERR|G_IO_HUP|G_IO_NVAL);
	      fds[n_poll].revents = 0;
	    }
	  n_poll++;
	}
      
      pollrec = pollrec->next;
    }

#ifdef G_THREADS_ENABLED
  context->poll_changed = FALSE;
#endif
  
  if (timeout)
    {
      *timeout = context->timeout;
      if (timeout != 0)
	context->time_is_current = FALSE;
    }
  
  UNLOCK_CONTEXT (context);

  return n_poll;
}

/**
 * g_main_context_check:
 * @context: a #GMainContext
 * @max_priority: the maximum numerical priority of sources to check
 * @fds: array of #GPollFD's that was passed to the last call to
 *       g_main_context_query()
 * @n_fds: return value of g_main_context_query()
 * 
 * Passes the results of polling back to the main loop.
 * 
 * Return value: %TRUE if some sources are ready to be dispatched.
 **/
gboolean
g_main_context_check (GMainContext *context,
		      gint          max_priority,
		      GPollFD      *fds,
		      gint          n_fds)
{
  GSource *source;
  GPollRec *pollrec;
  gint n_ready = 0;
  gint i;
  
  LOCK_CONTEXT (context);

  if (context->in_check_or_prepare)
    {
      g_warning ("g_main_context_check() called recursively from within a source's check() or "
		 "prepare() member.");
      UNLOCK_CONTEXT (context);
      return FALSE;
    }
  
#ifdef G_THREADS_ENABLED
  if (!context->poll_waiting)
    {
#ifndef G_OS_WIN32
      gchar c;
      read (context->wake_up_pipe[0], &c, 1);
#endif
    }
  else
    context->poll_waiting = FALSE;

  /* If the set of poll file descriptors changed, bail out
   * and let the main loop rerun
   */
  if (context->poll_changed)
    {
      UNLOCK_CONTEXT (context);
      return 0;
    }
#endif /* G_THREADS_ENABLED */
  
  pollrec = context->poll_records;
  i = 0;
  while (i < n_fds)
    {
      if (pollrec->fd->events)
	{
	  pollrec->fd->revents = fds[i].revents;
	  i++;
	}
      pollrec = pollrec->next;
    }

  source = next_valid_source (context, NULL);
  while (source)
    {
      if ((n_ready > 0) && (source->priority > max_priority))
	{
	  SOURCE_UNREF (source, context);
	  break;
	}
      if ((source->flags & G_HOOK_FLAG_IN_CALL) && !(source->flags & G_SOURCE_CAN_RECURSE))
	goto next;

      if (!(source->flags & G_SOURCE_READY))
	{
	  gboolean result;
	  gboolean (*check) (GSource  *source);

	  check = source->source_funcs->check;
	  
	  context->in_check_or_prepare++;
	  UNLOCK_CONTEXT (context);
	  
	  result = (*check) (source);
	  
	  LOCK_CONTEXT (context);
	  context->in_check_or_prepare--;
	  
	  if (result)
	    source->flags |= G_SOURCE_READY;
	}

      if (source->flags & G_SOURCE_READY)
	{
	  source->ref_count++;
	  g_ptr_array_add (context->pending_dispatches, source);

	  n_ready++;

          /* never dispatch sources with less priority than the first
           * one we choose to dispatch
           */
          max_priority = source->priority;
	}

    next:
      source = next_valid_source (context, source);
    }

  UNLOCK_CONTEXT (context);

  return n_ready > 0;
}

/**
 * g_main_context_dispatch:
 * @context: a #GMainContext
 * 
 * Dispatches all pending sources.
 **/
void
g_main_context_dispatch (GMainContext *context)
{
  LOCK_CONTEXT (context);

  if (context->pending_dispatches->len > 0)
    {
      g_main_dispatch (context);
    }

  UNLOCK_CONTEXT (context);
}

/* HOLDS context lock */
static gboolean
g_main_context_iterate (GMainContext *context,
			gboolean      block,
			gboolean      dispatch,
			GThread      *self)
{
  gint max_priority;
  gint timeout;
  gboolean some_ready;
  gint nfds, allocated_nfds;
  GPollFD *fds = NULL;
  
  UNLOCK_CONTEXT (context);

#ifdef G_THREADS_ENABLED
  if (!g_main_context_acquire (context))
    {
      gboolean got_ownership;
      
      g_return_val_if_fail (g_thread_supported (), FALSE);

      if (!block)
	return FALSE;

      LOCK_CONTEXT (context);
      
      if (!context->cond)
	context->cond = g_cond_new ();
          
      got_ownership = g_main_context_wait (context,
					   context->cond,
					   g_static_mutex_get_mutex (&context->mutex));

      if (!got_ownership)
	{