Function evlBlobAppend

src/jrd/SysFunction.cpp:2402–2508

dsc* evlBlobAppend(thread_db* tdbb, const SysFunction* function, const NestValueArray& args,
	impure_value* impure)
{
	Request* request = tdbb->getRequest();
	jrd_tra* transaction = request ? request->req_transaction : tdbb->getTransaction();
	transaction = transaction->getOuter();

	blb* blob = NULL;
	bid blob_id;
	dsc blobDsc;

	blob_id.clear();
	blobDsc.clear();

	const dsc* argDsc = EVL_expr(tdbb, request, args[0]);
	const bool arg0_null = (request->req_flags & req_null) || (argDsc == NULL);

	if (!arg0_null && argDsc->isBlob())
	{
		blob_id = *reinterpret_cast<bid*>(argDsc->dsc_address);
		makeBlobAppendBlob(&blobDsc, argDsc, &blob_id);
	}

	// Try to get blob type from declared var\param
	if (!argDsc && (nodeIs<VariableNode>(args[0]) ||
					nodeIs<ParameterNode>(args[0]) ))
	{
		argDsc = EVL_assign_to(tdbb, args[0]);
		if (argDsc && argDsc->isBlob())
			makeBlobAppendBlob(&blobDsc, argDsc, &blob_id);
	}

	bool copyBlob = !blob_id.isEmpty();
	if (copyBlob)
	{
		if (!blob_id.bid_internal.bid_relation_id)
		{
			if (!transaction->tra_blobs->locate(blob_id.bid_temp_id()))
				status_exception::raise(Arg::Gds(isc_bad_segstr_id));

			BlobIndex blobIdx = transaction->tra_blobs->current();
			if (!blobIdx.bli_materialized && (blobIdx.bli_blob_object->blb_flags & BLB_close_on_read))
			{
				blob = blobIdx.bli_blob_object;
				copyBlob = false;
			}
		}
	}

	for (FB_SIZE_T i = 0; i < args.getCount(); i++)
	{
		if (i == 0)
		{
			if (arg0_null || argDsc->isBlob() && !copyBlob)
				continue;
		}
		else
		{