SnapshotIndexSet.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.IO;

namespace Deveel.Data.Index {
    internal class SnapshotIndexSet : IIndexSet {
        private readonly IndexSetStore indexSetStore;
        private List<StoreIndex> indexes;

        private bool disposed;

        private static readonly StoreIndex[] EmptyIndex = new StoreIndex[0];

        public SnapshotIndexSet(IndexSetStore indexSetStore, IndexBlock[] blocks) {
            this.indexSetStore = indexSetStore;
            IndexBlocks = blocks;

            // Not disposed.
            disposed = false;

        }

        ~SnapshotIndexSet() {
            Dispose(false);
        }

        public IEnumerable<StoreIndex> AllIndices {
            get {
                if (indexes == null)
                    return EmptyIndex;

                return indexes.ToArray();
            }
        }

        public IndexBlock[] IndexBlocks { get; private set; }

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

        private void Dispose(bool disposing) {
            if (!disposed) {
                if (disposing) {
                    try {
                        if (indexes != null) {
                            foreach (var index in indexes) {
                                index.Dispose();
                            }
                        }

                        // Release reference to the index_blocks;
                        foreach (var block in IndexBlocks) {
                            block.RemoveReference();
                        }
                    } catch (Exception) {
                    }
                }

                indexes = null;
                IndexBlocks = null;
                disposed = true;
            }
        }


        public IIndex GetIndex(int offset) {
            // Create if not exist.
            if (indexes == null) {
                indexes = new List<StoreIndex>();
            } else {
                // If this list has already been created, return it
                foreach (var index in indexes) {
                    if (index.IndexNumber == offset)
                        return index;
                }
            }

            try {
                var index = (StoreIndex) IndexBlocks[offset].CreateIndex();
                indexes.Add(index);
                return index;
            } catch (IOException e) {
                throw new Exception("IO Error: " + e.Message, e);
            }
        }
    }
}