UserContextTable.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.Index;
using Deveel.Data.Sql.Triggers;

namespace Deveel.Data.Sql.Tables {
    class UserContextTable : BaseDataTable, IMutableTable {
        public UserContextTable(IQuery context, ITable table) {
            Context = context;
            Table = table;
        }

        public ITable Table { get; private set; }

        public IQuery Context { get; private set; }

        private IMutableTable MutableTable {
            get { return Table as IMutableTable; }
        }

        private bool IsMutable {
            get { return Table is IMutableTable; }
        }

        public override IEnumerator<Row> GetEnumerator() {
            return Table.GetEnumerator();
        }

        public override TableInfo TableInfo {
            get { return Table.TableInfo; }
        }

        public override int RowCount {
            get { return Table.RowCount; }
        }

        protected override int ColumnCount {
            get { return Table.ColumnCount(); }
        }

        private void OnTableEvent(TriggerEventType eventType, RowId rowId, Row row) {
            Context.FireTriggers(new TableEvent(this, eventType, rowId, row));
        }

        protected override IEnumerable<int> ResolveRows(int column, IEnumerable<int> rowSet, ITable ancestor) {
            if (!TableName.Equals(ancestor.TableInfo.TableName) && 
                !ancestor.TableInfo.TableName.Equals(Table.TableInfo.TableName))
                throw new Exception("Method routed to incorrect table ancestor.");

            return rowSet;
        }

        protected override ColumnIndex GetColumnIndex(int columnOffset) {
            return Table.GetIndex(columnOffset);
        }

        protected override void SetupIndexes(Type indexType) {
        }

        public override DataObject GetValue(long rowNumber, int columnOffset) {
            return Table.GetValue(rowNumber, columnOffset);
        }

        public override void Lock() {
            if (IsMutable)
                MutableTable.AddLock();
        }

        public override void Release() {
            if (IsMutable)
                MutableTable.RemoveLock();
        }

        TableEventRegistry IMutableTable.EventRegistry {
            get { return MutableTable.EventRegistry; }
        }

        void IMutableTable.AddLock() {
            MutableTable.AddLock();
        }

        void IMutableTable.RemoveLock() {
            MutableTable.RemoveLock();
        }

        public RowId AddRow(Row row) {
            OnTableEvent(TriggerEventType.BeforeInsert, RowId.Null, row);
            
            var newRowId = MutableTable.AddRow(row);

            OnTableEvent(TriggerEventType.AfterInsert, newRowId, row);

            return newRowId;
        }

        public void UpdateRow(Row row) {
            if (row == null)
                throw new ArgumentNullException("row");

            var rowId = row.RowId;
            if (rowId.IsNull)
                throw new ArgumentException("Cannot update a row with NULL ROWID");

            OnTableEvent(TriggerEventType.BeforeUpdate, rowId, row);

            MutableTable.UpdateRow(row);
        }

        public bool RemoveRow(RowId rowId) {
            OnTableEvent(TriggerEventType.BeforeDelete, rowId, null);

            // TODO: Maybe we should return the row removed here
            var result = MutableTable.RemoveRow(rowId);

            OnTableEvent(TriggerEventType.AfterDelete, rowId, null);

            return result;
        }

        void IMutableTable.FlushIndexes() {
            MutableTable.FlushIndexes();
        }

        void IMutableTable.AssertConstraints() {
            MutableTable.AssertConstraints();
        }

        protected override void Dispose(bool disposing) {
            Context = null;
            Table = null;

            base.Dispose(disposing);
        }
    }
}