Function ProcessElemMatchOperator

pg_documentdb/src/opclass/index_support.c:5794–5863

static Expr *
ProcessElemMatchOperator(bytea *options, Datum queryValue, const
						 MongoIndexOperatorInfo *operator, List *args)
{
	pgbson *queryBson = DatumGetPgBson(queryValue);
	pgbsonelement argElement = { 0 };
	PgbsonToSinglePgbsonElement(queryBson, &argElement);


	BsonQueryOperatorContext context = { 0 };
	BsonQueryOperatorContextCommonBuilder(&context);
	context.documentExpr = linitial(args);

	/* Convert the pgbson query into a query AST that processes bson */
	Expr *expr = CreateQualForBsonExpression(&argElement.bsonValue,
											 argElement.path, &context);

	/* Get the underlying list of expressions that are AND-ed */
	List *clauses = make_ands_implicit(expr);

	IndexElemmatchState elemMatchState = { 0 };

	WalkExprAndAddSupportedElemMatchExprs(clauses, options, &elemMatchState,
										  argElement.path);

	if (elemMatchState.pathStates == NIL)
	{
		return NULL;
	}

	ListCell *cell;

	List *overallQuals = NIL;
	foreach(cell, elemMatchState.pathStates)
	{
		IndexElemMatchPathState *pathState = lfirst(cell);
		ListCell *innerCell;

		pgbson_writer writer;
		PgbsonWriterInit(&writer);
		pgbson_array_writer arrayWriter;
		PgbsonWriterStartArray(&writer, "", 0, &arrayWriter);

		foreach(innerCell, pathState->singleOps)
		{
			IndexElemMatchSingleOp *singleOp = lfirst(innerCell);

			pgbson_writer qualWriter;
			PgbsonArrayWriterStartDocument(&arrayWriter, &qualWriter);
			PgbsonWriterAppendInt32(&qualWriter, "op", 2, singleOp->op);
			PgbsonWriterAppendValue(&qualWriter, "value", 5, &singleOp->value);
			PgbsonWriterAppendBool(&qualWriter, "isTopLevel", 10, pathState->isTopLevel);
			PgbsonArrayWriterEndDocument(&arrayWriter, &qualWriter);
		}

		pgbsonelement queryElement;
		queryElement.path = pathState->indexPath;
		queryElement.pathLength = pathState->indexPathLength;