Table.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;
using System.Collections.Generic;

using Deveel.Data.Index;
using Deveel.Data.Transactions;
using Deveel.Data.Types;

namespace Deveel.Data.Sql.Tables {
    public abstract class Table : IQueryTable, ILockable {
        // Stores col name -> col index lookups
        private Dictionary<ObjectName, int> colNameLookup;
        private readonly object colLookupLock = new object();

        ~Table() {
            Dispose(false);
        }

        public abstract IEnumerator<Row> GetEnumerator();

        IEnumerator IEnumerable.GetEnumerator() {
            return GetEnumerator();
        }

        public void Dispose() {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing) {
        }

        public abstract IContext Context { get; }

        public abstract TableInfo TableInfo { get; }

        public bool IsLocked { get; private set; }

        object ILockable.RefId {
            get { return TableInfo.TableName; }
        }

        int IQueryTable.ColumnCount {
            get { return ColumnCount; }
        }

        protected virtual int ColumnCount {
            get { return TableInfo.ColumnCount; }
        }

        public abstract int RowCount { get; }

        public abstract void Lock();

        public abstract void Release();

        protected virtual void OnLockAcquired(Lock @lock) {
            Lock();
        }

        protected virtual void OnLockReleased(Lock @lock) {
            Release();
        }

        void ILockable.Acquired(Lock @lock) {
            try {
                OnLockAcquired(@lock);
            } finally {
                IsLocked = true;
            }
        }

        void ILockable.Released(Lock @lock) {
            try {
                OnLockReleased(@lock);
            } finally {
                IsLocked = true;
            }
        }

        protected virtual int IndexOfColumn(ObjectName columnName) {
            return TableInfo.IndexOfColumn(columnName.Name);
        }

        protected virtual ObjectName GetResolvedColumnName(int column) {
            return TableInfo[column].FullColumnName;
        }

        ObjectName IQueryTable.GetResolvedColumnName(int column) {
            return GetResolvedColumnName(column);
        }

        ColumnIndex IQueryTable.GetIndex(int column, int originalColumn, ITable table) {
            return GetIndex(column, originalColumn, table);
        }

        protected virtual ColumnIndex GetIndex(int column, int originalColumn, ITable table) {
            return GetIndex(column);
        }

        protected abstract IEnumerable<int> ResolveRows(int column, IEnumerable<int> rowSet, ITable ancestor);

        IEnumerable<int> IQueryTable.ResolveRows(int columnOffset, IEnumerable<int> rows, ITable ancestor) {
            return ResolveRows(columnOffset, rows, ancestor);
        }

        protected abstract RawTableInfo GetRawTableInfo(RawTableInfo rootInfo);

        RawTableInfo IQueryTable.GetRawTableInfo(RawTableInfo rootInfo) {
            return GetRawTableInfo(rootInfo);
        }

        public abstract DataObject GetValue(long rowNumber, int columnOffset);

        public ColumnIndex GetIndex(int columnOffset) {
            return GetIndex(columnOffset, columnOffset, this);
        }

        public ObjectName FullName {
            get { return TableInfo.TableName; }
        }

        DbObjectType IDbObject.ObjectType {
            get { return DbObjectType.Table; }
        }

        protected int FindColumn(ObjectName columnName) {
            lock (colLookupLock) {
                if (colNameLookup == null)
                    colNameLookup = new Dictionary<ObjectName, int>(30);

                int index;
                if (!colNameLookup.TryGetValue(columnName, out index)) {
                    index = IndexOfColumn(columnName);
                    colNameLookup[columnName] = index;
                }

                return index;
            }
        }

        int IQueryTable.FindColumn(ObjectName columnName) {
            return FindColumn(columnName);
        }

        private SqlType GetColumnType(int columnOffset) {
            return TableInfo[columnOffset].ColumnType;
        }

        private SqlType GetColumnType(ObjectName columnName) {
            return GetColumnType(FindColumn(columnName));
        }

        ITableVariableResolver IQueryTable.GetVariableResolver() {
            return new TableVariableResolver(this);
        }

        #region TableVariableResolver

        class TableVariableResolver : ITableVariableResolver {
            public TableVariableResolver(Table table) 
                : this(table, -1) {
            }

            public TableVariableResolver(Table table, int rowIndex) {
                this.table = table;
                this.rowIndex = rowIndex;
            }

            private readonly Table table;
            private readonly int rowIndex;

            private int FindColumnName(ObjectName columnName) {
                int colIndex = table.FindColumn(columnName);
                if (colIndex == -1) {
                    throw new InvalidOperationException("Can't find column: " + columnName);
                }
                return colIndex;
            }

            public DataObject Resolve(ObjectName columnName) {
                return table.GetValue(rowIndex, FindColumnName(columnName));
            }

            public SqlType ReturnType(ObjectName columnName) {
                return table.GetColumnType(columnName);
            }

            public ITableVariableResolver ForRow(int row) {
                return new TableVariableResolver(table, row);
            }
        }

        #endregion
    }
}