Function SDW_check_conditional

src/jrd/sdw.cpp:331–395

bool SDW_check_conditional(thread_db* tdbb)
{
/**************************************
 *
 *	S D W _ c h e c k _ c o n d i t i o n a l
 *
 **************************************
 *
 * Functional description
 *	Check if a conditional shadow exists
 *	if so update meta data and return true
 *
 **************************************/
	SET_TDBB(tdbb);
	Database* dbb = tdbb->getDatabase();
	CHECK_DBB(dbb);

	SyncLockGuard guard(&dbb->dbb_shadow_sync, SYNC_EXCLUSIVE, "SDW_check_conditional");

	// first get rid of any shadows that need to be
	// deleted or shutdown; deleted shadows must also be shutdown

	// Check to see if there is a valid shadow in the shadow set,
	// if not then it is time to start an conditional shadow (if one has been defined).

	bool start_conditional = true;
	Shadow* next_shadow;
	for (Shadow* shadow = dbb->dbb_shadow; shadow; shadow = next_shadow)
	{
		next_shadow = shadow->sdw_next;

		if (!(shadow->sdw_flags & (SDW_delete | SDW_shutdown)))
			if (!(shadow->sdw_flags & SDW_INVALID))
			{
				start_conditional = false;
				break;
			}
	}

	// if there weren't any conventional shadows, now is
	// the time to start the first conditional shadow in the list
	// Note that allocate_shadow keeps the sdw_next list sorted

	if (start_conditional)
	{
		for (Shadow* shadow = dbb->dbb_shadow; shadow; shadow = shadow->sdw_next)
		{
			if ((shadow->sdw_flags & SDW_conditional) &&
				!(shadow->sdw_flags & (SDW_IGNORE | SDW_rollover)))
			{
				shadow->sdw_flags &= ~SDW_conditional;

				gds__log("conditional shadow %d %s activated for database %s",
						 shadow->sdw_number, shadow->sdw_file->fil_string, dbb->dbb_filename.c_str());
				USHORT file_flags = FILE_shadow;
				if (shadow->sdw_flags & SDW_manual)
					file_flags |= FILE_manual;
				MET_update_shadow(tdbb, shadow, file_flags);