C++ (Cpp) DataSource::NextValue示例

示例#1

void
ActivityView::_Refresh()
{
	bigtime_t lastTimeout = system_time() - RefreshInterval();
	BMessenger target(this);

	while (true) {
		status_t status = acquire_sem_etc(fRefreshSem, 1, B_ABSOLUTE_TIMEOUT,
			lastTimeout + RefreshInterval());
		if (status == B_OK || status == B_BAD_SEM_ID)
			break;
		if (status == B_INTERRUPTED)
			continue;

		SystemInfo info(fSystemInfoHandler);
		lastTimeout += RefreshInterval();

		fSourcesLock.Lock();

		for (uint32 i = fSources.CountItems(); i-- > 0;) {
			DataSource* source = fSources.ItemAt(i);
			DataHistory* values = fValues.ItemAt(i);

			int64 value = source->NextValue(info);
			values->AddValue(info.Time(), value);
		}

		fSourcesLock.Unlock();

		target.SendMessage(B_INVALIDATE);
	}
}