QueryReferencesVisitor.cs

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// 
//  Copyright 2010-2015 Deveel
// 
//    Licensed under the Apache License, Version 2.0 (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
// 
//        http://www.apache.org/licenses/LICENSE-2.0
// 
//    Unless required by applicable law or agreed to in writing, software
//    distributed under the License is distributed on an "AS IS" BASIS,
//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//    See the License for the specific language governing permissions and
//    limitations under the License.
//

using System;
using System.Collections.Generic;

using Deveel.Data.Sql.Expressions;
using Deveel.Data.Sql.Objects;

namespace Deveel.Data.Sql.Query {
    class QueryReferencesVisitor : SqlExpressionVisitor {
        public QueryReferencesVisitor(IList<QueryReference> list, int level) {
            References = list;
            Level = level;
        }

        public IList<QueryReference> References { get; private set; }

        public int Level { get; private set; }

        public override SqlExpression Visit(SqlExpression expression) {
            if (expression is QueryReferenceExpression)
                VisitQueryReference((QueryReferenceExpression) expression);

            return base.Visit(expression);
        }

        private void VisitQueryReference(QueryReferenceExpression expression) {
            References.Add(expression.QueryReference);
        }

        public override SqlExpression VisitConstant(SqlConstantExpression constant) {
            var value = constant.Value;
            if (!value.IsNull && value.Value is SqlQueryObject &&
                ((SqlQueryObject)value.Value).QueryPlan != null) {
                var queryObject = (SqlQueryObject)value.Value;
                var planNode = queryObject.QueryPlan;
                References = planNode.DiscoverQueryReferences(Level, References);
            }

            return base.VisitConstant(constant);
        }
    }
}