MutableTableExtensions.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 System.Linq;

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

namespace Deveel.Data.Sql.Tables {
    public static class MutableTableExtensions {
        public static bool RemoveRow(this IMutableTable table, int rowIndex) {
            return table.RemoveRow(new RowId(table.TableInfo.Id, rowIndex));
        }

        public static void DeleteRows(this IMutableTable table, IEnumerable<int> rows) {
            foreach (var row in rows) {
                table.RemoveRow(row);
            }
        }

        public static Row NewRow(this IMutableTable table) {
            return new Row(table);
        }

        public static int Delete(this IMutableTable table, ITable t) {
            return Delete(table, t, -1);
        }

        public static int Delete(this IMutableTable table, ITable other, int limit) {
            List<int> rowSet = new List<int>(other.RowCount);
            var e = other.GetEnumerator();
            while (e.MoveNext()) {
                rowSet.Add(e.Current.RowId.RowNumber);
            }

            // HACKY: Find the first column of this table in the search table.  This
            //   will allow us to generate a row set of only the rows in the search
            //   table.
            int firstColumn = other.IndexOfColumn(table.GetResolvedColumnName(0));

            if (firstColumn == -1)
                throw new DatabaseSystemException("Search table does not contain any reference to table being deleted from");

            // Generate a row set that is in this tables domain.
            var rowsToDelete = other.ResolveRows(firstColumn, rowSet, table).ToList();

            // row_set may contain duplicate row indices, therefore we must sort so
            // any duplicates are grouped and therefore easier to find.
            rowSet.Sort();

            // If limit less than zero then limit is whole set.
            if (limit < 0)
                limit = Int32.MaxValue;

            // Remove each row in row set in turn.  Make sure we don't remove the
            // same row index twice.
            int len = System.Math.Min(rowsToDelete.Count, limit);
            int lastRemoved = -1;
            int removeCount = 0;
            for (int i = 0; i < len; ++i) {
                int toRemove = rowsToDelete[i];
                if (toRemove < lastRemoved)
                    throw new DatabaseSystemException("Internal error: row sorting error or row set not in the range > 0");

                if (toRemove != lastRemoved) {
                    table.RemoveRow(toRemove);
                    lastRemoved = toRemove;
                    ++removeCount;
                }
            }

            if (removeCount > 0)
                // Perform a referential integrity check on any changes to the table.
                table.AssertConstraints();

            return removeCount;
        }

        public static bool Delete(this IMutableTable table, int columnOffset, DataObject value) {
            var list = table.SelectRowsEqual(columnOffset, value).ToArray();
            if (list.Length == 0)
                return false;

            return table.RemoveRow(list[0]);
        }

        public static int Update(this IMutableTable mutableTable, IQuery context, ITable table,
            IEnumerable<SqlAssignExpression> assignList, int limit) {

            // Get the rows from the input table.
            var rowSet = new List<int>();
            var e = table.GetEnumerator();
            while (e.MoveNext()) {
                rowSet.Add(e.Current.RowId.RowNumber);
            }

            // HACKY: Find the first column of this table in the search table.  This
            //   will allow us to generate a row set of only the rows in the search
            //   table.
            int firstColumn = table.FindColumn(mutableTable.GetResolvedColumnName(0));
            if (firstColumn == -1)
                throw new InvalidOperationException("Search table does not contain any " +
                                            "reference to table being updated from");

            // Convert the row_set to this table's domain.
            rowSet = table.ResolveRows(firstColumn, rowSet, mutableTable).ToList();

            // NOTE: Assume there's no duplicate rows.

            // If limit less than zero then limit is whole set.
            if (limit < 0)
                limit = Int32.MaxValue;

            // Update each row in row set in turn up to the limit.
            int len = System.Math.Min(rowSet.Count, limit);

            int updateCount = 0;
            for (int i = 0; i < len; ++i) {
                int toUpdate = rowSet[i];

                // Make a row object from this row (plus keep the original intact
                // in case we need to roll back to it).
                var row = mutableTable.GetRow(toUpdate);
                row.SetFromTable();

                // Run each assignment on the row.
                foreach (var assignment in assignList) {
                    row.EvaluateAssignment(assignment, context);
                }

                // Update the row
                mutableTable.UpdateRow(row);

                ++updateCount;
            }

            if (updateCount > 0)
                // Perform a referential integrity check on any changes to the table.
                mutableTable.AssertConstraints();

            return updateCount;
        }
    }
}