FunctionInfo.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 Deveel.Data;
using Deveel.Data.Sql;
using Deveel.Data.Sql.Expressions;
using Deveel.Data.Types;

namespace Deveel.Data.Routines {
    public sealed class FunctionInfo : RoutineInfo {
        public FunctionInfo(ObjectName routineName, FunctionType functionType) 
            : this(routineName, (SqlType)null, functionType) {
        }

        public FunctionInfo(ObjectName routineName, SqlType returnType) 
            : this(routineName, returnType, FunctionType.Static) {
        }

        public FunctionInfo(ObjectName routineName, SqlType returnType, FunctionType functionType) 
            : base(routineName) {
            ReturnType = returnType;
            FunctionType = functionType;
            AssertUnboundAtEnd();
        }

        public FunctionInfo(ObjectName routineName, RoutineParameter[] parameters) 
            : this(routineName, parameters, FunctionType.Static) {
        }

        public FunctionInfo(ObjectName routineName, RoutineParameter[] parameters, FunctionType functionType) 
            : this(routineName, parameters, null, functionType) {
        }

        public FunctionInfo(ObjectName routineName, RoutineParameter[] parameters, SqlType returnType) 
            : this(routineName, parameters, returnType, FunctionType.Static) {
        }

        public FunctionInfo(ObjectName routineName, RoutineParameter[] parameters, SqlType returnType, FunctionType functionType) 
            : base(routineName, parameters) {
            ReturnType = returnType;
            FunctionType = functionType;
            AssertUnboundAtEnd();
        }

        public override RoutineType RoutineType {
            get { return RoutineType.Function; }
        }

        public SqlType ReturnType { get; private set; }

        private void AssertUnboundAtEnd() {
            for (int i = 0; i < Parameters.Length; i++) {
                var param = Parameters[i];
                if (param.IsUnbounded) {
                    if (HasUnboundParameter)
                        throw new ArgumentException("Cannot specify more than one 'unbounded' argument for a function.");

                    if (i != Parameters.Length - 1)
                        throw new ArgumentException("An unbounded parameter must be present only at the end.");

                    HasUnboundParameter = true;
                }
            }
        }

        private bool HasUnboundParameter { get; set; }

        public FunctionType FunctionType { get; private set; }

        internal override bool MatchesInvoke(Invoke request, IQuery query) {
            if (request == null)
                return false;

            bool ignoreCase = true;
            if (query != null)
                ignoreCase = query.IgnoreIdentifiersCase();

            if (!RoutineName.Equals(request.RoutineName, ignoreCase))
                return false;

            // TODO: add a better resolution to obtain the final type of the argument
            //       and compare it to the parameter type definition
            bool unboundedSeen = false;
            for (int i = 0; i < request.Arguments.Length; i++) {
                var argType = request.Arguments[i].ReturnType(query, null);

                if (i + 1 > Parameters.Length) {
                    if (!unboundedSeen)
                        return false;

                    // TODO: verify the type of the argument (how to evaluate?)

                } else {
                    var param = Parameters[i];
                    unboundedSeen = param.IsUnbounded;

                    var paramType = param.Type;

                    if (!paramType.IsComparable(argType))
                        return false;
                }
            }

            if (!unboundedSeen &&
                request.Arguments.Length != Parameters.Length)
                return false;

            return true;
        }
    }
}