TableEventRegistry.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 System.Linq;

using Deveel.Data.Sql;
using Deveel.Data.Sql.Tables;
using Deveel.Data.Transactions;

namespace Deveel.Data {
    public sealed class TableEventRegistry : IEnumerable<ITableEvent> {
        private readonly List<ITableEvent> events;

        internal TableEventRegistry(TableSource tableSource) {
            if (tableSource == null)
                throw new ArgumentNullException("tableSource");

            TableSource = tableSource;
            CommitId = -1;

            events = new List<ITableEvent>();
        }

        internal TableSource TableSource { get; private set; }

        public int TableId {
            get { return TableSource.TableId; }
        }

        public long CommitId { get; internal set; }

        public IEnumerable<int> AddedRows {
            get {
                lock (this) {
                    var list = new List<int>();

                    foreach (var tableEvent in events.OfType<TableRowEvent>()) {
                        var eventType = tableEvent.EventType;
                        if (eventType == TableRowEventType.Add ||
                            eventType == TableRowEventType.UpdateAdd) {
                            list.Add(tableEvent.RowNumber);
                        } else if (eventType == TableRowEventType.Remove ||
                                   eventType == TableRowEventType.UpdateRemove) {
                            var index = list.IndexOf(tableEvent.RowNumber);
                            if (index != -1)
                                list.RemoveAt(index);
                        }
                    }

                    return list.ToArray();
                }
            }
        }

        public IEnumerable<int> RemovedRows {
            get {
                lock (this) {
                    var list = new List<int>();

                    foreach (var tableEvent in events.OfType<TableRowEvent>()) {
                        if (tableEvent.EventType == TableRowEventType.Remove ||
                            tableEvent.EventType == TableRowEventType.UpdateRemove)
                            list.Add(tableEvent.RowNumber);
                    }

                    return list.ToArray();
                }
            }
        }

        public int EventCount {
            get {
                lock (this) {
                    return events.Count;
                }
            }
        }

        internal void Rollback(int count) {
            lock (this) {
                if (count > events.Count)
                    throw new Exception("Trying to rollback more events than are in the registry.");

                List<int> toAdd = new List<int>();

                // Find all entries and added new rows to the table
                foreach (var tableEvent in events.OfType<TableRowEvent>()) {
                    if (tableEvent.EventType == TableRowEventType.Add ||
                        tableEvent.EventType == TableRowEventType.UpdateAdd)
                        toAdd.Add(tableEvent.RowNumber);
                }

                events.RemoveRange(0, count);

                // Mark all added entries to deleted.
                for (int i = 0; i < toAdd.Count; ++i) {
                    events.Add(new TableRowEvent(TableId, toAdd[i], TableRowEventType.Add));
                    events.Add(new TableRowEvent(TableId, toAdd[i], TableRowEventType.Remove));
                }

            }
        }

        internal void Register(ITableEvent tableEvent) {
            lock (this) {
                events.Add(tableEvent);
            }
        }

        internal void TestCommitClash(TableInfo tableInfo, TableEventRegistry journal) {
            lock (this) {
                // Very nasty search here...
                foreach (var rowEvent in events.OfType<TableRowEvent>()) {
                    if (rowEvent.EventType == TableRowEventType.Remove) {
                        var rowNum = rowEvent.RowNumber;
                        foreach (var otherRowEvent in journal.events.OfType<TableRowEvent>()) {
                            if (otherRowEvent.RowNumber == rowNum &&
                                otherRowEvent.EventType == TableRowEventType.Remove) {
                                throw new TransactionException(TransactionErrorCodes.RowRemoveClash,
                                    String.Format("Concurrent Serializable Transaction Conflict(1): " +
                                    "Current row remove clash ( row: {0}, table: {1})", rowNum, tableInfo.TableName));
                            }
                        }
                    }
                }               
            }
        }

        public IEnumerator<ITableEvent> GetEnumerator() {
            lock (this) {
                return events.GetEnumerator();
            }
        }

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

        public ITableEvent GetEvent(int index) {
            lock (this) {
                if (index < 0 || index >= events.Count)
                    throw new ArgumentOutOfRangeException("index");

                return events[index];
            }
        }
    }
}