Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/mscorlib/system/collections/Concurrent/CDSCollectionETWBCLProvider.cs

@@ -0,0 +1,128 @@
+// ==++==
+//
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+// =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
+//
+// CDSCollectionETWBCLProvider.cs
+//
+// <OWNER>[....]</OWNER>
+//
+// A helper class for firing ETW events related to the Coordination Data Structure 
+// collection types. This provider is used by CDS collections in both mscorlib.dll 
+// and System.dll. The purpose of sharing the provider class is to be able to enable 
+// ETW tracing on all CDS collection with a single ETW provider GUID, and to minimize
+// the number of providers in use.
+//
+// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace System.Collections.Concurrent
+{
+#if !FEATURE_PAL    // PAL doesn't support  eventing
+    using System.Diagnostics.Tracing;
+
+    /// <summary>Provides an event source for tracing CDS collection information.</summary>
+    [System.Runtime.CompilerServices.FriendAccessAllowed]
+    [EventSource(
+        Name = "System.Collections.Concurrent.ConcurrentCollectionsEventSource",
+        Guid = "35167F8E-49B2-4b96-AB86-435B59336B5E", 
+        LocalizationResources = "mscorlib")]
+    internal sealed class CDSCollectionETWBCLProvider : EventSource
+    {
+        /// <summary>
+        /// Defines the singleton instance for the collection ETW provider.
+        /// The collection provider GUID is {35167F8E-49B2-4b96-AB86-435B59336B5E}.
+        /// </summary>
+        public static CDSCollectionETWBCLProvider Log = new CDSCollectionETWBCLProvider();
+        /// <summary>Prevent external instantiation.  All logging should go through the Log instance.</summary>
+        private CDSCollectionETWBCLProvider() { }
+
+        /// <summary>Enabled for all keywords.</summary>
+        private const EventKeywords ALL_KEYWORDS = (EventKeywords)(-1);
+
+        //-----------------------------------------------------------------------------------
+        //        
+        // CDS Collection Event IDs (must be unique)
+        //
+
+        private const int CONCURRENTSTACK_FASTPUSHFAILED_ID = 1;
+        private const int CONCURRENTSTACK_FASTPOPFAILED_ID = 2;
+        private const int CONCURRENTDICTIONARY_ACQUIRINGALLLOCKS_ID = 3;
+        private const int CONCURRENTBAG_TRYTAKESTEALS_ID = 4;
+        private const int CONCURRENTBAG_TRYPEEKSTEALS_ID = 5;
+
+
+        /////////////////////////////////////////////////////////////////////////////////////
+        //
+        // ConcurrentStack Events
+        //
+
+        [Event(CONCURRENTSTACK_FASTPUSHFAILED_ID, Level = EventLevel.Warning)]
+        public void ConcurrentStack_FastPushFailed(int spinCount)
+        {
+            if (IsEnabled(EventLevel.Warning, ALL_KEYWORDS))
+            {
+                WriteEvent(CONCURRENTSTACK_FASTPUSHFAILED_ID, spinCount);
+            }
+        }
+
+        [Event(CONCURRENTSTACK_FASTPOPFAILED_ID, Level = EventLevel.Warning)]
+        public void ConcurrentStack_FastPopFailed(int spinCount)
+        {
+            if (IsEnabled(EventLevel.Warning, ALL_KEYWORDS))
+            {
+                WriteEvent(CONCURRENTSTACK_FASTPOPFAILED_ID, spinCount);
+            }
+        }
+
+
+        /////////////////////////////////////////////////////////////////////////////////////
+        //
+        // ConcurrentDictionary Events
+        //
+
+        [Event(CONCURRENTDICTIONARY_ACQUIRINGALLLOCKS_ID, Level = EventLevel.Warning)]
+        public void ConcurrentDictionary_AcquiringAllLocks(int numOfBuckets)
+        {
+            if (IsEnabled(EventLevel.Warning, ALL_KEYWORDS))
+            {
+                WriteEvent(CONCURRENTDICTIONARY_ACQUIRINGALLLOCKS_ID, numOfBuckets);
+            }
+        }
+
+
+
+        //
+        // Events below this point are used by the CDS types in System.DLL
+        //
+
+        /////////////////////////////////////////////////////////////////////////////////////
+        //
+        // ConcurrentBag Events
+        //
+
+        [Event(CONCURRENTBAG_TRYTAKESTEALS_ID, Level = EventLevel.Verbose)]
+        public void ConcurrentBag_TryTakeSteals()
+        {
+            if (IsEnabled(EventLevel.Verbose, ALL_KEYWORDS))
+            {
+                WriteEvent(CONCURRENTBAG_TRYTAKESTEALS_ID);
+            }
+        }
+
+        [Event(CONCURRENTBAG_TRYPEEKSTEALS_ID, Level = EventLevel.Verbose)]
+        public void ConcurrentBag_TryPeekSteals()
+        {
+            if (IsEnabled(EventLevel.Verbose, ALL_KEYWORDS))
+            {
+                WriteEvent(CONCURRENTBAG_TRYPEEKSTEALS_ID);
+            }
+        }
+    }
+
+#endif // !FEATURE_PAL
+}

mcs/class/referencesource/mscorlib/system/collections/Concurrent/IProducerConsumerCollection.cs

@@ -0,0 +1,119 @@
+// ==++==
+//
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+// =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
+//
+// IProducerConsumerCollection.cs
+//
+// <OWNER>[....]</OWNER>
+//
+// A common interface for all concurrent collections.
+//
+// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics;
+
+namespace System.Collections.Concurrent
+{
+
+    /// <summary>
+    /// Defines methods to manipulate thread-safe collections intended for producer/consumer usage.
+    /// </summary>
+    /// <typeparam name="T">Specifies the type of elements in the collection.</typeparam>
+    /// <remarks>
+    /// All implementations of this interface must enable all members of this interface
+    /// to be used concurrently from multiple threads.
+    /// </remarks>
+    public interface IProducerConsumerCollection<T> : IEnumerable<T>, ICollection
+    {
+
+        /// <summary>
+        /// Copies the elements of the <see cref="IProducerConsumerCollection{T}"/> to
+        /// an
+        /// <see cref="T:System.Array"/>, starting at a specified index.
+        /// </summary>
+        /// <param name="array">The one-dimensional <see cref="T:System.Array"/> that is the destination of
+        /// the elements copied from the <see cref="IProducerConsumerCollection{T}"/>.
+        /// The array must have zero-based indexing.</param>
+        /// <param name="index">The zero-based index in <paramref name="array"/> at which copying
+        /// begins.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="array"/> is a null reference (Nothing in
+        /// Visual Basic).</exception>
+        /// <exception cref="ArgumentOutOfRangeException"><paramref name="index"/> is less than
+        /// zero.</exception>
+        /// <exception cref="ArgumentException"><paramref name="index"/> is equal to or greater than the
+        /// length of the <paramref name="array"/>
+        /// -or- The number of elements in the source <see cref="ConcurrentQueue{T}"/> is greater than the
+        /// available space from <paramref name="index"/> to the end of the destination <paramref
+        /// name="array"/>.
+        /// </exception>
+        void CopyTo(T[] array, int index);
+
+        /// <summary>
+        /// Attempts to add an object to the <see
+        /// cref="IProducerConsumerCollection{T}"/>.
+        /// </summary>
+        /// <param name="item">The object to add to the <see
+        /// cref="IProducerConsumerCollection{T}"/>.</param>
+        /// <returns>true if the object was added successfully; otherwise, false.</returns>
+        /// <exception cref="T:System.ArgumentException">The <paramref name="item"/> was invalid for this collection.</exception>
+        bool TryAdd(T item);
+
+        /// <summary>
+        /// Attempts to remove and return an object from the <see cref="IProducerConsumerCollection{T}"/>.
+        /// </summary>
+        /// <param name="item">
+        /// When this method returns, if the object was removed and returned successfully, <paramref
+        /// name="item"/> contains the removed object. If no object was available to be removed, the value is
+        /// unspecified.
+        /// </param>
+        /// <returns>true if an object was removed and returned successfully; otherwise, false.</returns>
+        bool TryTake(out T item);
+
+        /// <summary>
+        /// Copies the elements contained in the <see cref="IProducerConsumerCollection{T}"/> to a new array.
+        /// </summary>
+        /// <returns>A new array containing the elements copied from the <see cref="IProducerConsumerCollection{T}"/>.</returns>
+        T[] ToArray();
+
+    }
+
+
+    /// <summary>
+    /// A debugger view of the IProducerConsumerCollection that makes it simple to browse the
+    /// collection's contents at a point in time.
+    /// </summary>
+    /// <typeparam name="T">The type of elements stored within.</typeparam>
+    internal sealed class SystemCollectionsConcurrent_ProducerConsumerCollectionDebugView<T>
+    {
+        private IProducerConsumerCollection<T> m_collection; // The collection being viewed.
+
+        /// <summary>
+        /// Constructs a new debugger view object for the provided collection object.
+        /// </summary>
+        /// <param name="collection">A collection to browse in the debugger.</param>
+        public SystemCollectionsConcurrent_ProducerConsumerCollectionDebugView(IProducerConsumerCollection<T> collection)
+        {
+            if (collection == null)
+            {
+                throw new ArgumentNullException("collection");
+            }
+
+            m_collection = collection;
+        }
+
+        /// <summary>
+        /// Returns a snapshot of the underlying collection's elements.
+        /// </summary>
+        [DebuggerBrowsable(DebuggerBrowsableState.RootHidden)]
+        public T[] Items
+        {
+            get { return m_collection.ToArray(); }
+        }
+
+    }
+}

mcs/class/referencesource/mscorlib/system/collections/Concurrent/OrderablePartitioner.cs

@@ -0,0 +1,284 @@
+// ==++==
+//
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+// =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
+//
+// OrderablePartitioner.cs
+//
+// <OWNER>[....]</OWNER>
+//
+// 
+//
+// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+using System;
+using System.Collections.Generic;
+using System.Security.Permissions;
+using System.Threading;
+
+namespace System.Collections.Concurrent
+{
+
+    /// <summary>
+    /// Represents a particular manner of splitting an orderable data source into multiple partitions.
+    /// </summary>
+    /// <typeparam name="TSource">Type of the elements in the collection.</typeparam>
+    /// <remarks>
+    /// <para>
+    /// Each element in each partition has an integer index associated with it, which determines the relative
+    /// order of that element against elements in other partitions.
+    /// </para>
+    /// <para>
+    /// Inheritors of <see cref="OrderablePartitioner{TSource}"/> must adhere to the following rules:
+    /// <ol>
+    /// <li>All indices must be unique, such that there may not be duplicate indices. If all indices are not
+    /// unique, the output ordering may be scrambled.</li>
+    /// <li>All indices must be non-negative. If any indices are negative, consumers of the implementation
+    /// may throw exceptions.</li>
+    /// <li><see cref="GetPartitions"/> and <see cref="GetOrderablePartitions"/> should throw a
+    /// <see cref="T:System.ArgumentOutOfRangeException"/> if the requested partition count is less than or
+    /// equal to zero.</li>
+    /// <li><see cref="GetPartitions"/> and <see cref="GetOrderablePartitions"/> should always return a number
+    /// of enumerables equal to the requested partition count. If the partitioner runs out of data and cannot
+    /// create as many partitions as requested, an empty enumerator should be returned for each of the
+    /// remaining partitions. If this rule is not followed, consumers of the implementation may throw a <see
+    /// cref="T:System.InvalidOperationException"/>.</li>
+    /// <li><see cref="GetPartitions"/>, <see cref="GetOrderablePartitions"/>,
+    /// <see cref="GetDynamicPartitions"/>, and <see cref="GetOrderableDynamicPartitions"/>
+    /// should never return null. If null is returned, a consumer of the implementation may throw a
+    /// <see cref="T:System.InvalidOperationException"/>.</li>
+    /// <li><see cref="GetPartitions"/>, <see cref="GetOrderablePartitions"/>,
+    /// <see cref="GetDynamicPartitions"/>, and <see cref="GetOrderableDynamicPartitions"/>
+    /// should always return partitions that can fully and uniquely enumerate the input data source. All of
+    /// the data and only the data contained in the input source should be enumerated, with no duplication
+    /// that was not already in the input, unless specifically required by the particular partitioner's
+    /// design. If this is not followed, the output ordering may be scrambled.</li>
+    /// <li>If <see cref="KeysOrderedInEachPartition"/> returns true, each partition must return elements
+    /// with increasing key indices.</li>
+    /// <li>If <see cref="KeysOrderedAcrossPartitions"/> returns true, all the keys in partition numbered N
+    /// must be larger than all the keys in partition numbered N-1.</li>
+    /// <li>If <see cref="KeysNormalized"/> returns true, all indices must be monotonically increasing from
+    /// 0, though not necessarily within a single partition.</li>
+    /// </ol>
+    /// </para>
+    /// </remarks>
+    [HostProtection(Synchronization = true, ExternalThreading = true)]
+    public abstract class OrderablePartitioner<TSource> : Partitioner<TSource>
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="OrderablePartitioner{TSource}"/> class with the
+        /// specified constraints on the index keys.
+        /// </summary>
+        /// <param name="keysOrderedInEachPartition">
+        /// Indicates whether the elements in each partition are yielded in the order of
+        /// increasing keys.
+        /// </param>
+        /// <param name="keysOrderedAcrossPartitions">
+        /// Indicates whether elements in an earlier partition always come before
+        /// elements in a later partition. If true, each element in partition 0 has a smaller order key than
+        /// any element in partition 1, each element in partition 1 has a smaller order key than any element
+        /// in partition 2, and so on.
+        /// </param>
+        /// <param name="keysNormalized">
+        /// Indicates whether keys are normalized. If true, all order keys are distinct
+        /// integers in the range [0 .. numberOfElements-1]. If false, order keys must still be dictinct, but
+        /// only their relative order is considered, not their absolute values.
+        /// </param>
+        protected OrderablePartitioner(bool keysOrderedInEachPartition, bool keysOrderedAcrossPartitions, bool keysNormalized)
+        {
+            KeysOrderedInEachPartition = keysOrderedInEachPartition;
+            KeysOrderedAcrossPartitions = keysOrderedAcrossPartitions;
+            KeysNormalized = keysNormalized;
+        }
+
+        /// <summary>
+        /// Partitions the underlying collection into the specified number of orderable partitions.
+        /// </summary>
+        /// <remarks>
+        /// Each partition is represented as an enumerator over key-value pairs.
+        /// The value of the pair is the element itself, and the key is an integer which determines
+        /// the relative ordering of this element against other elements in the data source.
+        /// </remarks>
+        /// <param name="partitionCount">The number of partitions to create.</param>
+        /// <returns>A list containing <paramref name="partitionCount"/> enumerators.</returns>
+        public abstract IList<IEnumerator<KeyValuePair<long, TSource>>> GetOrderablePartitions(int partitionCount);
+
+        /// <summary>
+        /// Creates an object that can partition the underlying collection into a variable number of
+        /// partitions.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// The returned object implements the <see
+        /// cref="T:System.Collections.Generic.IEnumerable{TSource}"/> interface. Calling <see
+        /// cref="System.Collections.Generic.IEnumerable{TSource}.GetEnumerator">GetEnumerator</see> on the
+        /// object creates another partition over the sequence.
+        /// </para>
+        /// <para>
+        /// Each partition is represented as an enumerator over key-value pairs. The value in the pair is the element
+        /// itself, and the key is an integer which determines the relative ordering of this element against
+        /// other elements.
+        /// </para>
+        /// <para>
+        /// The <see cref="GetOrderableDynamicPartitions"/> method is only supported if the <see
+        /// cref="System.Collections.Concurrent.Partitioner{TSource}.SupportsDynamicPartitions">SupportsDynamicPartitions</see>
+        /// property returns true.
+        /// </para>
+        /// </remarks>
+        /// <returns>An object that can create partitions over the underlying data source.</returns>
+        /// <exception cref="NotSupportedException">Dynamic partitioning is not supported by this
+        /// partitioner.</exception>
+        public virtual IEnumerable<KeyValuePair<long, TSource>> GetOrderableDynamicPartitions()
+        {
+            throw new NotSupportedException(Environment.GetResourceString("Partitioner_DynamicPartitionsNotSupported"));
+        }
+
+        /// <summary>
+        /// Gets whether elements in each partition are yielded in the order of increasing keys.
+        /// </summary>
+        public bool KeysOrderedInEachPartition { get; private set; }
+
+        /// <summary>
+        /// Gets whether elements in an earlier partition always come before elements in a later partition.
+        /// </summary>
+        /// <remarks>
+        /// If <see cref="KeysOrderedAcrossPartitions"/> returns true, each element in partition 0 has a
+        /// smaller order key than any element in partition 1, each element in partition 1 has a smaller
+        /// order key than any element in partition 2, and so on.
+        /// </remarks>
+        public bool KeysOrderedAcrossPartitions { get; private set; }
+
+        /// <summary>
+        /// Gets whether order keys are normalized.
+        /// </summary>
+        /// <remarks>
+        /// If <see cref="KeysNormalized"/> returns true, all order keys are distinct integers in the range
+        /// [0 .. numberOfElements-1]. If the property returns false, order keys must still be dictinct, but
+        /// only their relative order is considered, not their absolute values.
+        /// </remarks>
+        public bool KeysNormalized { get; private set; }
+
+        /// <summary>
+        /// Partitions the underlying collection into the given number of ordered partitions.
+        /// </summary>
+        /// <remarks>
+        /// The default implementation provides the same behavior as <see cref="GetOrderablePartitions"/> except
+        /// that the returned set of partitions does not provide the keys for the elements.
+        /// </remarks>
+        /// <param name="partitionCount">The number of partitions to create.</param>
+        /// <returns>A list containing <paramref name="partitionCount"/> enumerators.</returns>
+        public override IList<IEnumerator<TSource>> GetPartitions(int partitionCount)
+        {
+            IList<IEnumerator<KeyValuePair<long, TSource>>> orderablePartitions = GetOrderablePartitions(partitionCount);
+
+            if (orderablePartitions.Count != partitionCount)
+            {
+                throw new InvalidOperationException("OrderablePartitioner_GetPartitions_WrongNumberOfPartitions");
+            }
+
+            IEnumerator<TSource>[] partitions = new IEnumerator<TSource>[partitionCount];
+            for (int i = 0; i < partitionCount; i++)
+            {
+                partitions[i] = new EnumeratorDropIndices(orderablePartitions[i]);
+            }
+            return partitions;
+        }
+
+        /// <summary>
+        /// Creates an object that can partition the underlying collection into a variable number of
+        /// partitions.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// The returned object implements the <see
+        /// cref="T:System.Collections.Generic.IEnumerable{TSource}"/> interface. Calling <see
+        /// cref="System.Collections.Generic.IEnumerable{TSource}.GetEnumerator">GetEnumerator</see> on the
+        /// object creates another partition over the sequence.
+        /// </para>
+        /// <para>
+        /// The default implementation provides the same behavior as <see cref="GetOrderableDynamicPartitions"/> except
+        /// that the returned set of partitions does not provide the keys for the elements.
+        /// </para>
+        /// <para>
+        /// The <see cref="GetDynamicPartitions"/> method is only supported if the <see
+        /// cref="System.Collections.Concurrent.Partitioner{TSource}.SupportsDynamicPartitions"/>
+        /// property returns true.
+        /// </para>
+        /// </remarks>
+        /// <returns>An object that can create partitions over the underlying data source.</returns>
+        /// <exception cref="NotSupportedException">Dynamic partitioning is not supported by this
+        /// partitioner.</exception>
+        public override IEnumerable<TSource> GetDynamicPartitions()
+        {
+            IEnumerable<KeyValuePair<long, TSource>> orderablePartitions = GetOrderableDynamicPartitions();
+            return new EnumerableDropIndices(orderablePartitions);
+        }
+
+        /// <summary>
+        /// Converts an enumerable over key-value pairs to an enumerable over values.
+        /// </summary>
+        private class EnumerableDropIndices : IEnumerable<TSource>, IDisposable
+        {
+            private readonly IEnumerable<KeyValuePair<long, TSource>> m_source;
+            public EnumerableDropIndices(IEnumerable<KeyValuePair<long, TSource>> source)
+            {
+                m_source = source;
+            }
+            public IEnumerator<TSource> GetEnumerator()
+            {
+                return new EnumeratorDropIndices(m_source.GetEnumerator());
+            }
+            IEnumerator IEnumerable.GetEnumerator()
+            {
+                return ((EnumerableDropIndices)this).GetEnumerator();
+            }
+            public void Dispose()
+            {
+                IDisposable d = m_source as IDisposable;
+                if (d != null)
+                {
+                    d.Dispose();
+                }
+            }
+        }
+
+        private class EnumeratorDropIndices : IEnumerator<TSource>
+        {
+            private readonly IEnumerator<KeyValuePair<long, TSource>> m_source;
+            public EnumeratorDropIndices(IEnumerator<KeyValuePair<long, TSource>> source)
+            {
+                m_source = source;
+            }
+            public bool MoveNext()
+            {
+                return m_source.MoveNext();
+            }
+            public TSource Current
+            {
+                get
+                {
+                    return m_source.Current.Value;
+                }
+            }
+            Object IEnumerator.Current
+            {
+                get
+                {
+                    return ((EnumeratorDropIndices)this).Current;
+                }
+            }
+            public void Dispose()
+            {
+                m_source.Dispose();
+            }
+            public void Reset()
+            {
+                m_source.Reset();
+            }
+        }
+
+    }
+
+}

mcs/class/referencesource/mscorlib/system/collections/Concurrent/Partitioner.cs

@@ -0,0 +1,105 @@
+// ==++==
+//
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+// =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
+//
+// Partitioner.cs
+//
+// <OWNER>[....]</OWNER>
+//
+// Represents a particular way of splitting a collection into multiple partitions.
+//
+// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+using System;
+using System.Collections.Generic;
+using System.Security.Permissions;
+using System.Threading;
+
+namespace System.Collections.Concurrent
+{
+    /// <summary>
+    /// Represents a particular manner of splitting a data source into multiple partitions.
+    /// </summary>
+    /// <typeparam name="TSource">Type of the elements in the collection.</typeparam>
+    /// <remarks>
+    /// <para>
+    /// Inheritors of <see cref="Partitioner{TSource}"/> must adhere to the following rules:
+    /// <ol>
+    /// <li><see cref="GetPartitions"/> should throw a
+    /// <see cref="T:System.ArgumentOutOfRangeException"/> if the requested partition count is less than or
+    /// equal to zero.</li>
+    /// <li><see cref="GetPartitions"/> should always return a number of enumerables equal to the requested
+    /// partition count. If the partitioner runs out of data and cannot create as many partitions as 
+    /// requested, an empty enumerator should be returned for each of the remaining partitions. If this rule
+    /// is not followed, consumers of the implementation may throw a <see
+    /// cref="T:System.InvalidOperationException"/>.</li>
+    /// <li><see cref="GetPartitions"/> and <see cref="GetDynamicPartitions"/>
+    /// should never return null. If null is returned, a consumer of the implementation may throw a
+    /// <see cref="T:System.InvalidOperationException"/>.</li>
+    /// <li><see cref="GetPartitions"/> and <see cref="GetDynamicPartitions"/> should always return
+    /// partitions that can fully and uniquely enumerate the input data source. All of the data and only the
+    /// data contained in the input source should be enumerated, with no duplication that was not already in
+    /// the input, unless specifically required by the particular partitioner's design. If this is not
+    /// followed, the output ordering may be scrambled.</li>
+    /// </ol>
+    /// </para>
+    /// </remarks>
+    [HostProtection(Synchronization = true, ExternalThreading = true)]
+    public abstract class Partitioner<TSource>
+    {
+        /// <summary>
+        /// Partitions the underlying collection into the given number of partitions.
+        /// </summary>
+        /// <param name="partitionCount">The number of partitions to create.</param>
+        /// <returns>A list containing <paramref name="partitionCount"/> enumerators.</returns>
+        public abstract IList<IEnumerator<TSource>> GetPartitions(int partitionCount);
+
+        /// <summary>
+        /// Gets whether additional partitions can be created dynamically.
+        /// </summary>
+        /// <returns>
+        /// true if the <see cref="Partitioner{TSource}"/> can create partitions dynamically as they are
+        /// requested; false if the <see cref="Partitioner{TSource}"/> can only allocate
+        /// partitions statically.
+        /// </returns>
+        /// <remarks>
+        /// <para>
+        /// If a derived class does not override and implement <see cref="GetDynamicPartitions"/>,
+        /// <see cref="SupportsDynamicPartitions"/> should return false. The value of <see
+        /// cref="SupportsDynamicPartitions"/> should not vary over the lifetime of this instance.
+        /// </para>
+        /// </remarks>
+        public virtual bool SupportsDynamicPartitions
+        {
+            get { return false; }
+        }
+
+        /// <summary>
+        /// Creates an object that can partition the underlying collection into a variable number of
+        /// partitions.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// The returned object implements the <see
+        /// cref="T:System.Collections.Generic.IEnumerable{TSource}"/> interface. Calling <see
+        /// cref="System.Collections.Generic.IEnumerable{TSource}.GetEnumerator">GetEnumerator</see> on the
+        /// object creates another partition over the sequence.
+        /// </para>
+        /// <para>
+        /// The <see cref="GetDynamicPartitions"/> method is only supported if the <see
+        /// cref="SupportsDynamicPartitions"/>
+        /// property returns true.
+        /// </para>
+        /// </remarks>
+        /// <returns>An object that can create partitions over the underlying data source.</returns>
+        /// <exception cref="NotSupportedException">Dynamic partitioning is not supported by this
+        /// partitioner.</exception>
+        public virtual IEnumerable<TSource> GetDynamicPartitions()
+        {
+            throw new NotSupportedException(Environment.GetResourceString("Partitioner_DynamicPartitionsNotSupported"));
+        }
+    }
+}

mcs/class/referencesource/mscorlib/system/collections/arraylist.cs.REMOVED.git-id

@@ -0,0 +1 @@
+0e7b25c8eec5ef2270f833d3acd6e2faa65156b0

mcs/class/referencesource/mscorlib/system/collections/caseinsensitivecomparer.cs

@@ -0,0 +1,80 @@
+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+/*============================================================
+**
+** Class: CaseInsensitiveComparer
+** 
+** <OWNER>[....]</OWNER>
+**
+**
+**
+============================================================*/
+namespace System.Collections {
+//This class does not contain members and does not need to be serializable
+    using System;
+    using System.Collections;
+    using System.Globalization;
+    using System.Diagnostics.Contracts;
+
+    [Serializable]
+[System.Runtime.InteropServices.ComVisible(true)]
+    public class CaseInsensitiveComparer : IComparer {
+        private CompareInfo m_compareInfo;
+        private static volatile CaseInsensitiveComparer m_InvariantCaseInsensitiveComparer;
+        
+        public CaseInsensitiveComparer() {
+            m_compareInfo = CultureInfo.CurrentCulture.CompareInfo;
+        }
+
+        public CaseInsensitiveComparer(CultureInfo culture) {
+            if (culture==null) {
+                throw new ArgumentNullException("culture");
+            }
+            Contract.EndContractBlock();
+            m_compareInfo = culture.CompareInfo;
+        }
+
+        public static CaseInsensitiveComparer Default
+        { 
+            get
+            {
+                Contract.Ensures(Contract.Result<CaseInsensitiveComparer>() != null);
+
+                return new CaseInsensitiveComparer(CultureInfo.CurrentCulture);
+            }
+        }
+        
+        public static CaseInsensitiveComparer DefaultInvariant
+        { 
+            get
+            {
+                Contract.Ensures(Contract.Result<CaseInsensitiveComparer>() != null);
+
+                if (m_InvariantCaseInsensitiveComparer == null) {
+                    m_InvariantCaseInsensitiveComparer = new CaseInsensitiveComparer(CultureInfo.InvariantCulture);
+                }
+                return m_InvariantCaseInsensitiveComparer;
+            }
+        }
+    
+        // Behaves exactly like Comparer.Default.Compare except that the comparison is case insensitive
+        // Compares two Objects by calling CompareTo.  If a == 
+        // b,0 is returned.  If a implements 
+        // IComparable, a.CompareTo(b) is returned.  If a 
+        // doesn't implement IComparable and b does, 
+        // -(b.CompareTo(a)) is returned, otherwise an 
+        // exception is thrown.
+        // 
+        public int Compare(Object a, Object b) {
+            String sa = a as String;
+            String sb = b as String;
+            if (sa != null && sb != null)
+                return m_compareInfo.Compare(sa, sb, CompareOptions.IgnoreCase);
+            else
+                return Comparer.Default.Compare(a,b);
+        }
+    }
+}

mcs/class/referencesource/mscorlib/system/collections/caseinsensitivehashcodeprovider.cs

@@ -0,0 +1,83 @@
+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+/*============================================================
+**
+** Class: CaseInsensitiveHashCodeProvider
+** 
+** <OWNER>[....]</OWNER>
+**
+**
+** Purpose: Designed to support hashtables which require 
+** case-insensitive behavior while still maintaining case,
+** this provides an efficient mechanism for getting the 
+** hashcode of the string ignoring case.
+**
+**
+============================================================*/
+namespace System.Collections {
+//This class does not contain members and does not need to be serializable
+    using System;
+    using System.Collections;
+    using System.Globalization;
+    using System.Diagnostics.Contracts;
+
+    [Serializable]  
+    [Obsolete("Please use StringComparer instead.")]    
+    [System.Runtime.InteropServices.ComVisible(true)]
+    public class CaseInsensitiveHashCodeProvider : IHashCodeProvider {
+        private TextInfo m_text;
+        private static volatile CaseInsensitiveHashCodeProvider m_InvariantCaseInsensitiveHashCodeProvider = null;
+
+        public CaseInsensitiveHashCodeProvider() {
+            m_text = CultureInfo.CurrentCulture.TextInfo;
+        }
+
+        public CaseInsensitiveHashCodeProvider(CultureInfo culture) {
+            if (culture==null) {
+                throw new ArgumentNullException("culture");
+            }
+            Contract.EndContractBlock();
+            m_text = culture.TextInfo;
+        }
+
+        public static CaseInsensitiveHashCodeProvider Default
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<CaseInsensitiveHashCodeProvider>() != null);
+
+                return new CaseInsensitiveHashCodeProvider(CultureInfo.CurrentCulture);
+            }
+        }
+        
+        public static CaseInsensitiveHashCodeProvider DefaultInvariant
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<CaseInsensitiveHashCodeProvider>() != null);
+
+                if (m_InvariantCaseInsensitiveHashCodeProvider == null) {
+                    m_InvariantCaseInsensitiveHashCodeProvider = new CaseInsensitiveHashCodeProvider(CultureInfo.InvariantCulture);
+                }
+                return m_InvariantCaseInsensitiveHashCodeProvider;
+            }
+        }
+
+        public int GetHashCode(Object obj) {
+            if (obj==null) {
+                throw new ArgumentNullException("obj");
+            }
+            Contract.EndContractBlock();
+
+            String s = obj as String;
+            if (s==null) {
+                return obj.GetHashCode();
+            }
+
+            return m_text.GetCaseInsensitiveHashCode(s);
+        }
+    }
+}

mcs/class/referencesource/mscorlib/system/collections/collectionbase.cs

@@ -0,0 +1,217 @@
+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+//------------------------------------------------------------------------------
+//------------------------------------------------------------------------------
+// <OWNER>[....]</OWNER>
+// 
+
+namespace System.Collections {
+    using System;
+    using System.Diagnostics.Contracts;
+
+    // Useful base class for typed read/write collections where items derive from object
+    [Serializable]
+[System.Runtime.InteropServices.ComVisible(true)]
+    public abstract class CollectionBase : IList {
+        ArrayList list;
+
+        protected CollectionBase() {
+            list = new ArrayList();
+        }
+        
+        protected CollectionBase(int capacity) {
+            list = new ArrayList(capacity);
+        }
+
+
+        protected ArrayList InnerList { 
+            get { 
+                if (list == null)
+                    list = new ArrayList();
+                return list;
+            }
+        }
+
+        protected IList List {
+            get { return (IList)this; }
+        }
+
+        [System.Runtime.InteropServices.ComVisible(false)]        
+        public int Capacity {
+            get {
+                return InnerList.Capacity;
+            }
+            set {
+                InnerList.Capacity = value;
+            }
+        }
+
+
+        public int Count {
+            get {
+                return list == null ? 0 : list.Count;
+            }
+        }
+
+        public void Clear() {
+            OnClear();
+            InnerList.Clear();
+            OnClearComplete();
+        }
+
+        public void RemoveAt(int index) {
+            if (index < 0 || index >= Count)
+                throw new ArgumentOutOfRangeException("index", Environment.GetResourceString("ArgumentOutOfRange_Index"));
+            Contract.EndContractBlock();
+            Object temp = InnerList[index];
+            OnValidate(temp);
+            OnRemove(index, temp);
+            InnerList.RemoveAt(index);
+            try {
+                OnRemoveComplete(index, temp);
+            }
+            catch {
+                InnerList.Insert(index, temp);
+                throw;
+            }
+
+        }
+
+        bool IList.IsReadOnly {
+            get { return InnerList.IsReadOnly; }
+        }
+
+        bool IList.IsFixedSize {
+            get { return InnerList.IsFixedSize; }
+        }
+
+        bool ICollection.IsSynchronized {
+            get { return InnerList.IsSynchronized; }
+        }
+
+        Object ICollection.SyncRoot {
+            get { return InnerList.SyncRoot; }
+        }
+
+        void ICollection.CopyTo(Array array, int index) {
+            InnerList.CopyTo(array, index);
+        }
+
+        Object IList.this[int index] {
+            get { 
+                if (index < 0 || index >= Count)
+                    throw new ArgumentOutOfRangeException("index", Environment.GetResourceString("ArgumentOutOfRange_Index"));
+                Contract.EndContractBlock();
+                return InnerList[index]; 
+            }
+            set { 
+                if (index < 0 || index >= Count)
+                    throw new ArgumentOutOfRangeException("index", Environment.GetResourceString("ArgumentOutOfRange_Index"));
+                Contract.EndContractBlock();
+                OnValidate(value);
+                Object temp = InnerList[index];
+                OnSet(index, temp, value); 
+                InnerList[index] = value; 
+                try {
+                    OnSetComplete(index, temp, value);
+                }
+                catch {
+                    InnerList[index] = temp; 
+                    throw;
+                }
+            }
+        }
+
+        bool IList.Contains(Object value) {
+            return InnerList.Contains(value);
+        }
+
+        int IList.Add(Object value) {
+            OnValidate(value);
+            OnInsert(InnerList.Count, value);
+            int index = InnerList.Add(value);
+            try {
+                OnInsertComplete(index, value);
+            }
+            catch {
+                InnerList.RemoveAt(index);
+                throw;
+            }
+            return index;
+        }
+
+       
+        void IList.Remove(Object value) {
+            OnValidate(value);
+            int index = InnerList.IndexOf(value);
+            if (index < 0) throw new ArgumentException(Environment.GetResourceString("Arg_RemoveArgNotFound"));
+            OnRemove(index, value);
+            InnerList.RemoveAt(index);
+            try{
+                OnRemoveComplete(index, value);
+            }
+            catch {
+                InnerList.Insert(index, value);
+                throw;
+            }
+        }
+
+        int IList.IndexOf(Object value) {
+            return InnerList.IndexOf(value);
+        }
+
+        void IList.Insert(int index, Object value) {
+            if (index < 0 || index > Count)
+                throw new ArgumentOutOfRangeException("index", Environment.GetResourceString("ArgumentOutOfRange_Index"));
+            Contract.EndContractBlock();
+            OnValidate(value);
+            OnInsert(index, value);
+            InnerList.Insert(index, value);
+            try {
+                OnInsertComplete(index, value);
+            }
+            catch {
+                InnerList.RemoveAt(index);
+                throw;
+            }
+        }
+
+        public IEnumerator GetEnumerator() {
+            return InnerList.GetEnumerator();
+        }
+
+        protected virtual void OnSet(int index, Object oldValue, Object newValue) { 
+        }
+
+        protected virtual void OnInsert(int index, Object value) { 
+        }
+
+        protected virtual void OnClear() { 
+        }
+
+        protected virtual void OnRemove(int index, Object value) { 
+        }
+
+        protected virtual void OnValidate(Object value) { 
+            if (value == null) throw new ArgumentNullException("value");
+            Contract.EndContractBlock();
+        }
+
+        protected virtual void OnSetComplete(int index, Object oldValue, Object newValue) { 
+        }
+
+        protected virtual void OnInsertComplete(int index, Object value) { 
+        }
+
+        protected virtual void OnClearComplete() { 
+        }
+
+        protected virtual void OnRemoveComplete(int index, Object value) { 
+        }
+    
+    }
+
+}

mcs/class/referencesource/mscorlib/system/collections/comparer.cs

@@ -0,0 +1,100 @@
+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+/*============================================================
+**
+** Class:  Comparer
+** 
+** <OWNER>[....]</OWNER>
+**
+**
+** Purpose: Default IComparer implementation.
+**
+** 
+===========================================================*/
+namespace System.Collections {
+    
+    using System;
+    using System.Globalization;
+    using System.Runtime.Serialization;
+    using System.Security.Permissions;
+    using System.Diagnostics.Contracts;
+    
+    [Serializable]
+[System.Runtime.InteropServices.ComVisible(true)]
+    public sealed class Comparer : IComparer , ISerializable
+    {
+        private CompareInfo m_compareInfo;   
+        public static readonly Comparer Default = new Comparer(CultureInfo.CurrentCulture);
+        public static readonly Comparer DefaultInvariant = new Comparer(CultureInfo.InvariantCulture);
+        
+        private const String CompareInfoName = "CompareInfo";
+
+        private Comparer() {
+            m_compareInfo = null;
+        }
+
+        public Comparer(CultureInfo culture) {
+            if (culture==null) {
+                throw new ArgumentNullException("culture");
+            }
+            Contract.EndContractBlock();
+            m_compareInfo = culture.CompareInfo;
+        }
+        
+        private Comparer(SerializationInfo info, StreamingContext context) {            
+            m_compareInfo = null;
+            SerializationInfoEnumerator enumerator = info.GetEnumerator();                        
+            while( enumerator.MoveNext()) {
+                switch( enumerator.Name) {
+                    case CompareInfoName:
+                        m_compareInfo = (CompareInfo) info.GetValue(CompareInfoName, typeof(CompareInfo));
+                        break;
+                }
+            }
+        }
+    
+        // Compares two Objects by calling CompareTo.  If a == 
+        // b,0 is returned.  If a implements 
+        // IComparable, a.CompareTo(b) is returned.  If a 
+        // doesn't implement IComparable and b does, 
+        // -(b.CompareTo(a)) is returned, otherwise an 
+        // exception is thrown.
+        // 
+        public int Compare(Object a, Object b) {
+            if (a == b) return 0;
+            if (a == null) return -1;
+            if (b == null) return 1;
+            if (m_compareInfo != null) {
+                String sa = a as String;
+                String sb = b as String;
+                if (sa != null && sb != null)
+                    return m_compareInfo.Compare(sa, sb);
+            }
+
+            IComparable ia = a as IComparable;
+            if (ia != null)
+                return ia.CompareTo(b);
+
+            IComparable ib = b as IComparable;
+            if (ib != null)
+                return -ib.CompareTo(a);
+
+            throw new ArgumentException(Environment.GetResourceString("Argument_ImplementIComparable"));
+        }
+
+        [System.Security.SecurityCritical]  // auto-generated_required
+        public void GetObjectData(SerializationInfo info, StreamingContext context) {
+            if (info==null) {
+                throw new ArgumentNullException("info");
+            }
+            Contract.EndContractBlock();
+
+            if( m_compareInfo != null) {
+                info.AddValue(CompareInfoName, m_compareInfo);
+            }
+        }        
+    }
+}

mcs/class/referencesource/mscorlib/system/collections/compatiblecomparer.cs

@@ -0,0 +1,69 @@
+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+// <OWNER>[....]</OWNER>
+// 
+
+using System.Diagnostics.Contracts;
+
+namespace System.Collections {
+
+    [Serializable]
+    internal class CompatibleComparer: IEqualityComparer {
+        IComparer _comparer;
+#pragma warning disable 618
+        IHashCodeProvider _hcp;
+
+        internal CompatibleComparer(IComparer comparer, IHashCodeProvider hashCodeProvider) {
+            _comparer = comparer;
+            _hcp = hashCodeProvider;
+        }
+#pragma warning restore 618
+
+        public int Compare(Object a, Object b) {
+            if (a == b) return 0;
+            if (a == null) return -1;
+            if (b == null) return 1;
+            if (_comparer != null)
+                return _comparer.Compare(a,b);
+            IComparable ia = a as IComparable;
+            if (ia != null)
+                return ia.CompareTo(b);
+
+            throw new ArgumentException(Environment.GetResourceString("Argument_ImplementIComparable"));
+        }
+
+        public new bool Equals(Object a, Object b) {
+            return Compare(a, b) == 0;                
+        }
+
+        public int GetHashCode(Object obj) {
+            if( obj == null) {
+                throw new ArgumentNullException("obj");
+            }
+            Contract.EndContractBlock();
+
+            if (_hcp != null)
+                return _hcp.GetHashCode(obj);
+            return obj.GetHashCode();
+        }
+
+        // These are helpers for the Hashtable to query the IKeyComparer infrastructure.
+        internal IComparer Comparer {
+            get {
+                return _comparer;
+            }
+        }
+
+        // These are helpers for the Hashtable to query the IKeyComparer infrastructure.
+#pragma warning disable 618
+        internal IHashCodeProvider HashCodeProvider {
+            get {
+                return _hcp;
+            }
+        }
+#pragma warning restore 618
+    }
+}

mcs/class/referencesource/mscorlib/system/collections/dictionarybase.cs

@@ -0,0 +1,183 @@
+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+//------------------------------------------------------------------------------
+//------------------------------------------------------------------------------
+// <OWNER>[....]</OWNER>
+// 
+
+namespace System.Collections {
+
+    using System;
+    using System.Security.Permissions;
+
+    // Useful base class for typed read/write collections where items derive from object
+    [Serializable]
+[System.Runtime.InteropServices.ComVisible(true)]
+    public abstract class DictionaryBase : IDictionary {
+        Hashtable hashtable;
+
+        protected Hashtable InnerHashtable { 
+            get { 
+                if (hashtable == null)
+                    hashtable = new Hashtable();
+                return hashtable;
+            }
+        }
+
+        protected IDictionary Dictionary {
+            get { return (IDictionary) this; }
+        }
+
+        public int Count {
+            // to avoid newing inner list if no items are ever added
+            get { return hashtable == null ? 0 : hashtable.Count; }
+        }
+
+        bool IDictionary.IsReadOnly {
+            get { return InnerHashtable.IsReadOnly; }
+        }
+
+        bool IDictionary.IsFixedSize {
+            get { return InnerHashtable.IsFixedSize; }
+        }
+
+        bool ICollection.IsSynchronized {
+            get { return InnerHashtable.IsSynchronized; }
+        }
+
+        ICollection IDictionary.Keys {
+            get {
+                return InnerHashtable.Keys;
+            }
+        }
+
+        Object ICollection.SyncRoot {
+            get { return InnerHashtable.SyncRoot; }
+        }
+
+        ICollection IDictionary.Values {
+            get {
+                return InnerHashtable.Values;
+            }
+        }
+
+        public void CopyTo(Array array, int index) {
+            InnerHashtable.CopyTo(array, index);
+        }
+
+        object IDictionary.this[object key] {
+            get {
+                object currentValue = InnerHashtable[key];
+                OnGet(key, currentValue);
+                return currentValue; 
+            }
+            set { 
+                OnValidate(key, value);
+                bool keyExists = true;
+                Object temp = InnerHashtable[key];
+                if( temp == null) {
+                    keyExists = InnerHashtable.Contains(key);
+                }
+
+                OnSet(key, temp, value); 
+                InnerHashtable[key] = value; 
+                try {
+                    OnSetComplete(key, temp, value); 
+                }
+                catch {
+                   if( keyExists) {
+                       InnerHashtable[key] = temp; 
+                   }
+                   else {
+                       InnerHashtable.Remove(key);
+                   }
+                   throw;
+                }
+            }
+        }
+
+        bool IDictionary.Contains(object key) {
+            return InnerHashtable.Contains(key);
+        }
+
+        void IDictionary.Add(object key, object value) {
+            OnValidate(key, value);
+            OnInsert(key, value); 
+            InnerHashtable.Add(key, value);
+            try {
+                OnInsertComplete(key, value);
+            }
+            catch {
+                InnerHashtable.Remove(key);
+                throw;
+            }
+        }
+
+        public void Clear() {
+            OnClear();
+            InnerHashtable.Clear();
+            OnClearComplete();
+        }
+
+        void IDictionary.Remove(object key) {
+            if(InnerHashtable.Contains(key)) {
+                Object temp = InnerHashtable[key];
+                OnValidate(key, temp);
+                OnRemove(key, temp);
+
+                InnerHashtable.Remove(key);
+                try {
+                    OnRemoveComplete(key, temp);
+                }
+                catch {
+                    InnerHashtable.Add(key, temp);
+                    throw;
+                }
+            }
+        }
+
+        public IDictionaryEnumerator GetEnumerator() {
+            return InnerHashtable.GetEnumerator();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator() {
+            return InnerHashtable.GetEnumerator();
+        }
+
+        protected virtual object OnGet(object key, object currentValue) {
+            return currentValue;
+        }
+
+        protected virtual void OnSet(object key, object oldValue, object newValue) { 
+        }
+
+        protected virtual void OnInsert(object key, object value) { 
+        }
+
+        protected virtual void OnClear() { 
+        }
+
+        protected virtual void OnRemove(object key, object value) { 
+        }
+
+        protected virtual void OnValidate(object key, object value) {
+        }
+        
+        protected virtual void OnSetComplete(object key, object oldValue, object newValue) { 
+        }
+
+        protected virtual void OnInsertComplete(object key, object value) { 
+        }
+
+        protected virtual void OnClearComplete() { 
+        }
+
+        protected virtual void OnRemoveComplete(object key, object value) { 
+        }
+        
+    }
+
+}

mcs/class/referencesource/mscorlib/system/collections/dictionaryentry.cs

@@ -0,0 +1,56 @@
+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+/*============================================================
+**
+** Interface:  DictionaryEntry
+** 
+** <OWNER>[....]</OWNER>
+**
+**
+** Purpose: Return Value for IDictionaryEnumerator::GetEntry
+**
+** 
+===========================================================*/
+namespace System.Collections {
+    
+    using System;
+    // A DictionaryEntry holds a key and a value from a dictionary.
+    // It is returned by IDictionaryEnumerator::GetEntry().
+[System.Runtime.InteropServices.ComVisible(true)]
+    [Serializable]
+    public struct DictionaryEntry
+    {
+        private Object _key;
+        private Object _value;
+    
+        // Constructs a new DictionaryEnumerator by setting the Key
+        // and Value fields appropriately.
+        public DictionaryEntry(Object key, Object value) {
+            _key = key;
+            _value = value;
+        }
+
+        public Object Key {
+            get {
+                return _key;
+            }
+            
+            set {
+                _key = value;
+            }
+        }
+
+        public Object Value {
+            get {
+                return _value;
+            }
+
+            set {
+                _value = value;
+            }
+        }
+    }
+}

mcs/class/referencesource/mscorlib/system/collections/emptyreadonlydictionaryinternal.cs

@@ -0,0 +1,196 @@
+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+/*============================================================
+**
+** Class:  EmptyReadOnlyDictionaryInternal
+**
+** <OWNER>[....]</OWNER>
+**
+**
+** Purpose: List for exceptions.
+**
+** 
+===========================================================*/
+
+using System.Diagnostics.Contracts;
+
+namespace System.Collections {
+    ///    This is a simple implementation of IDictionary that is empty and readonly.
+    [Serializable]
+    internal sealed class EmptyReadOnlyDictionaryInternal: IDictionary {
+
+        // Note that this class must be agile with respect to AppDomains.  See its usage in
+        // System.Exception to understand why this is the case.
+
+        public EmptyReadOnlyDictionaryInternal() {
+        }
+
+        // IEnumerable members
+
+        IEnumerator IEnumerable.GetEnumerator() {
+            return new NodeEnumerator();
+        }
+
+        // ICollection members
+
+        public void CopyTo(Array array, int index)  {
+            if (array==null)
+                throw new ArgumentNullException("array");
+
+            if (array.Rank != 1)
+                throw new ArgumentException(Environment.GetResourceString("Arg_RankMultiDimNotSupported"));
+
+            if (index < 0)
+                throw new ArgumentOutOfRangeException("index", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
+
+            if ( array.Length - index < this.Count ) 
+                throw new ArgumentException( Environment.GetResourceString("ArgumentOutOfRange_Index"), "index");
+            Contract.EndContractBlock();
+
+            // the actual copy is a NOP
+        }
+
+        public int Count {
+            get {
+                return 0;
+            }
+        }   
+
+        public Object SyncRoot {
+            get {
+                return this;
+            }
+        }
+
+        public bool IsSynchronized {
+            get {
+                return false;
+            }
+        }
+
+        // IDictionary members
+
+        public Object this[Object key] {
+            get {
+                if (key == null) {
+                    throw new ArgumentNullException("key", Environment.GetResourceString("ArgumentNull_Key"));
+                }
+                Contract.EndContractBlock();
+                return null;
+            }
+            set {
+                if (key == null) {
+                    throw new ArgumentNullException("key", Environment.GetResourceString("ArgumentNull_Key"));
+                }
+
+                if (!key.GetType().IsSerializable)                 
+                    throw new ArgumentException(Environment.GetResourceString("Argument_NotSerializable"), "key");                    
+
+                if( (value != null) && (!value.GetType().IsSerializable ) )
+                    throw new ArgumentException(Environment.GetResourceString("Argument_NotSerializable"), "value");                    
+                Contract.EndContractBlock();
+
+                throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_ReadOnly"));
+            }
+        }
+
+        public ICollection Keys {
+            get {
+                return EmptyArray<Object>.Value;
+            }
+        }
+
+        public ICollection Values {
+            get {
+                return EmptyArray<Object>.Value;
+            }
+        }
+
+        public bool Contains(Object key) {
+            return false;
+        }
+
+        public void Add(Object key, Object value) {
+            if (key == null) {
+                throw new ArgumentNullException("key", Environment.GetResourceString("ArgumentNull_Key"));
+            }
+
+            if (!key.GetType().IsSerializable)                 
+                throw new ArgumentException(Environment.GetResourceString("Argument_NotSerializable"), "key" );                    
+
+            if( (value != null) && (!value.GetType().IsSerializable) )
+                throw new ArgumentException(Environment.GetResourceString("Argument_NotSerializable"), "value");                    
+            Contract.EndContractBlock();
+
+            throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_ReadOnly"));
+        }
+
+        public void Clear() {
+            throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_ReadOnly"));
+        }
+
+        public bool IsReadOnly {
+            get {
+                return true;
+            }
+        }
+
+        public bool IsFixedSize {
+            get {
+                return true;
+            }
+        }
+
+        public IDictionaryEnumerator GetEnumerator() {
+            return new NodeEnumerator();
+        }
+
+        public void Remove(Object key) {
+            throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_ReadOnly"));
+        }
+
+        private sealed class NodeEnumerator : IDictionaryEnumerator {
+
+            public NodeEnumerator() {
+            }
+
+            // IEnumerator members
+
+            public bool MoveNext() {
+                return false;
+            }
+
+            public Object Current {
+                get {
+                    throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_EnumOpCantHappen"));
+                }
+            }
+
+            public void Reset() {
+            }
+
+            // IDictionaryEnumerator members
+
+            public Object Key {
+                get {
+                    throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_EnumOpCantHappen"));
+                }
+            }
+
+            public Object Value {
+                get {
+                    throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_EnumOpCantHappen"));
+                }
+            }
+
+            public DictionaryEntry Entry {
+                get {
+                    throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_EnumOpCantHappen"));
+                }
+            }
+        }
+    }
+}

mcs/class/referencesource/mscorlib/system/collections/generic/comparer.cs

@@ -0,0 +1,177 @@
+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+// <OWNER>[....]</OWNER>
+// 
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics.Contracts;
+//using System.Globalization;
+using System.Runtime.CompilerServices;
+
+namespace System.Collections.Generic
+{    
+    [Serializable]
+    [TypeDependencyAttribute("System.Collections.Generic.ObjectComparer`1")] 
+    public abstract class Comparer<T> : IComparer, IComparer<T>
+    {
+        static volatile Comparer<T> defaultComparer;    
+
+        public static Comparer<T> Default {
+            get {
+                Contract.Ensures(Contract.Result<Comparer<T>>() != null);
+
+                Comparer<T> comparer = defaultComparer;
+                if (comparer == null) {
+                    comparer = CreateComparer();
+                    defaultComparer = comparer;
+                }
+                return comparer;
+            }
+        }
+
+        public static Comparer<T> Create(Comparison<T> comparison)
+        {
+            Contract.Ensures(Contract.Result<Comparer<T>>() != null);
+
+            if (comparison == null)
+                throw new ArgumentNullException("comparison");
+
+            return new ComparisonComparer<T>(comparison);
+        }
+
+        //
+        // Note that logic in this method is replicated in vm\compile.cpp to ensure that NGen
+        // saves the right instantiations
+        //
+        [System.Security.SecuritySafeCritical]  // auto-generated
+        private static Comparer<T> CreateComparer() {
+            RuntimeType t = (RuntimeType)typeof(T);
+
+            // If T implements IComparable<T> return a GenericComparer<T>
+#if FEATURE_LEGACYNETCF
+            // Pre-Apollo Windows Phone call the overload that sorts the keys, not values this achieves the same result
+            if (CompatibilitySwitches.IsAppEarlierThanWindowsPhone8) {
+                if (t.ImplementInterface(typeof(IComparable<T>))) {
+                    return (Comparer<T>)RuntimeTypeHandle.CreateInstanceForAnotherGenericParameter((RuntimeType)typeof(GenericComparer<int>), t);
+                }
+            }
+            else
+#endif
+                if (typeof(IComparable<T>).IsAssignableFrom(t)) {
+#if MONO
+                    return (Comparer<T>)RuntimeType.CreateInstanceForAnotherGenericParameter (typeof(GenericComparer<>), t);
+#else
+                    return (Comparer<T>)RuntimeTypeHandle.CreateInstanceForAnotherGenericParameter((RuntimeType)typeof(GenericComparer<int>), t);
+#endif
+                }
+
+            // If T is a Nullable<U> where U implements IComparable<U> return a NullableComparer<U>
+            if (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>)) {
+                RuntimeType u = (RuntimeType)t.GetGenericArguments()[0];
+                if (typeof(IComparable<>).MakeGenericType(u).IsAssignableFrom(u)) {
+#if MONO
+                    return (Comparer<T>)RuntimeType.CreateInstanceForAnotherGenericParameter (typeof(NullableComparer<>), u);
+#else
+                    return (Comparer<T>)RuntimeTypeHandle.CreateInstanceForAnotherGenericParameter((RuntimeType)typeof(NullableComparer<int>), u);
+#endif
+                }
+            }
+            // Otherwise return an ObjectComparer<T>
+          return new ObjectComparer<T>();
+        }
+
+        public abstract int Compare(T x, T y);
+
+        int IComparer.Compare(object x, object y) {
+            if (x == null) return y == null ? 0 : -1;
+            if (y == null) return 1;
+            if (x is T && y is T) return Compare((T)x, (T)y);
+            ThrowHelper.ThrowArgumentException(ExceptionResource.Argument_InvalidArgumentForComparison);
+            return 0;
+        }
+    }
+
+    [Serializable]
+    internal class GenericComparer<T> : Comparer<T> where T: IComparable<T>
+    {    
+        public override int Compare(T x, T y) {
+            if (x != null) {
+                if (y != null) return x.CompareTo(y);
+                return 1;
+            }
+            if (y != null) return -1;
+            return 0;
+        }
+
+        // Equals method for the comparer itself. 
+        public override bool Equals(Object obj){
+            GenericComparer<T> comparer = obj as GenericComparer<T>;
+            return comparer != null;
+        }        
+
+        public override int GetHashCode() {
+            return this.GetType().Name.GetHashCode();
+        }
+    }
+
+    [Serializable]
+    internal class NullableComparer<T> : Comparer<Nullable<T>> where T : struct, IComparable<T>
+    {
+        public override int Compare(Nullable<T> x, Nullable<T> y) {
+            if (x.HasValue) {
+                if (y.HasValue) return x.value.CompareTo(y.value);
+                return 1;
+            }
+            if (y.HasValue) return -1;
+            return 0;
+        }
+
+        // Equals method for the comparer itself. 
+        public override bool Equals(Object obj){
+            NullableComparer<T> comparer = obj as NullableComparer<T>;
+            return comparer != null;
+        }        
+
+
+        public override int GetHashCode() {
+            return this.GetType().Name.GetHashCode();
+        }
+    }
+
+    [Serializable]
+    internal class ObjectComparer<T> : Comparer<T>
+    {
+        public override int Compare(T x, T y) {
+            return System.Collections.Comparer.Default.Compare(x, y);
+        }
+
+        // Equals method for the comparer itself. 
+        public override bool Equals(Object obj){
+            ObjectComparer<T> comparer = obj as ObjectComparer<T>;
+            return comparer != null;
+        }        
+
+        public override int GetHashCode() {
+            return this.GetType().Name.GetHashCode();
+        }
+    }
+
+    [Serializable]
+    internal class ComparisonComparer<T> : Comparer<T>
+    {
+        private readonly Comparison<T> _comparison;
+
+        public ComparisonComparer(Comparison<T> comparison) {
+            _comparison = comparison;
+        }
+
+        public override int Compare(T x, T y) {
+            return _comparison(x, y);
+        }
+    }
+}