ConcurrentLookup.cs :  » 2.6.4-mono-.net-core » System.Linq » System » Linq » C# / CSharp Open Source

#if NET_4_0
//
// ConcurrentLookup.cs
//
// Author:
//       Jrmie "Garuma" Laval <jeremie.laval@gmail.com>
//
// Copyright (c) 2010 Jrmie "Garuma" Laval
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

using System;
using System.Threading;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Concurrent;

namespace System.Linq{
  internal class ConcurrentLookup<TKey, TElement> : ILookup<TKey, TElement>
  {
    ConcurrentDictionary<TKey, IEnumerable<TElement>> dictionary;

    private class AddSlot
    {
      TElement element;

      internal AddSlot (TElement element)
      {
        this.element = element;
      }

      internal IEnumerable<TElement> AddMethod (TKey key)
      {
        List<TElement> list = new List<TElement> ();
        list.Add (element);

        return list;
      }

      internal IEnumerable<TElement> UpdateMethod (TKey key, IEnumerable<TElement> old)
      {
        ICollection<TElement> coll = (ICollection<TElement>)old;
        coll.Add (element);

        return coll;
      }
    }

    internal ConcurrentLookup (IEqualityComparer<TKey> comparer)
    {
      this.dictionary = new ConcurrentDictionary<TKey, IEnumerable<TElement>> (comparer);
    }

    internal void Add (TKey key, TElement element)
    {
      AddSlot slot = new AddSlot (element);
      dictionary.AddOrUpdate (key, slot.AddMethod, slot.UpdateMethod);
    }

    public bool Contains (TKey key)
    {
      return dictionary.ContainsKey (key);
    }

    public IEnumerable<TElement> this[TKey key] {
      get {
        return dictionary[key];
      }
    }

    public int Count {
      get {
        return dictionary.Count;
      }
    }
    
    public IList<TKey> Keys {
      get {
        return (IList<TKey>)dictionary.Keys;
      }
    }

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

    IEnumerator<IGrouping<TKey, TElement>> IEnumerable<IGrouping<TKey, TElement>>.GetEnumerator ()
    {
      return GetEnumeratorInternal ();
    }

    IEnumerator<IGrouping<TKey, TElement>> GetEnumeratorInternal ()
    {
      return dictionary.Select ((pair) => new ConcurrentGrouping<TKey, TElement> (pair.Key, pair.Value)).GetEnumerator ();
    }
  }
}

#endif