summaryrefslogtreecommitdiff
path: root/src/mscorlib/src/System/Collections/Concurrent/ConcurrentDictionary.cs
diff options
context:
space:
mode:
Diffstat (limited to 'src/mscorlib/src/System/Collections/Concurrent/ConcurrentDictionary.cs')
-rw-r--r--src/mscorlib/src/System/Collections/Concurrent/ConcurrentDictionary.cs2095
1 files changed, 2095 insertions, 0 deletions
diff --git a/src/mscorlib/src/System/Collections/Concurrent/ConcurrentDictionary.cs b/src/mscorlib/src/System/Collections/Concurrent/ConcurrentDictionary.cs
new file mode 100644
index 0000000000..d805dc8be7
--- /dev/null
+++ b/src/mscorlib/src/System/Collections/Concurrent/ConcurrentDictionary.cs
@@ -0,0 +1,2095 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+//
+/*============================================================
+**
+**
+**
+** Purpose: A scalable dictionary for concurrent access
+**
+**
+===========================================================*/
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Runtime.InteropServices;
+using System.Runtime.Serialization;
+using System.Text;
+using System.Threading;
+using System.Security;
+using System.Security.Permissions;
+
+namespace System.Collections.Concurrent
+{
+
+ /// <summary>
+ /// Represents a thread-safe collection of keys and values.
+ /// </summary>
+ /// <typeparam name="TKey">The type of the keys in the dictionary.</typeparam>
+ /// <typeparam name="TValue">The type of the values in the dictionary.</typeparam>
+ /// <remarks>
+ /// All public and protected members of <see cref="ConcurrentDictionary{TKey,TValue}"/> are thread-safe and may be used
+ /// concurrently from multiple threads.
+ /// </remarks>
+#if !FEATURE_CORECLR
+ [Serializable]
+#endif
+ [ComVisible(false)]
+ [DebuggerTypeProxy(typeof(Mscorlib_DictionaryDebugView<,>))]
+ [DebuggerDisplay("Count = {Count}")]
+ [HostProtection(Synchronization = true, ExternalThreading = true)]
+ public class ConcurrentDictionary<TKey, TValue> : IDictionary<TKey, TValue>, IDictionary, IReadOnlyDictionary<TKey, TValue>
+ {
+ /// <summary>
+ /// Tables that hold the internal state of the ConcurrentDictionary
+ ///
+ /// Wrapping the three tables in a single object allows us to atomically
+ /// replace all tables at once.
+ /// </summary>
+ private class Tables
+ {
+ internal readonly Node[] m_buckets; // A singly-linked list for each bucket.
+ internal readonly object[] m_locks; // A set of locks, each guarding a section of the table.
+ internal volatile int[] m_countPerLock; // The number of elements guarded by each lock.
+ internal readonly IEqualityComparer<TKey> m_comparer; // Key equality comparer
+
+ internal Tables(Node[] buckets, object[] locks, int[] countPerLock, IEqualityComparer<TKey> comparer)
+ {
+ m_buckets = buckets;
+ m_locks = locks;
+ m_countPerLock = countPerLock;
+ m_comparer = comparer;
+ }
+ }
+#if !FEATURE_CORECLR
+ [NonSerialized]
+#endif
+ private volatile Tables m_tables; // Internal tables of the dictionary
+ // NOTE: this is only used for compat reasons to serialize the comparer.
+ // This should not be accessed from anywhere else outside of the serialization methods.
+ internal IEqualityComparer<TKey> m_comparer;
+#if !FEATURE_CORECLR
+ [NonSerialized]
+#endif
+ private readonly bool m_growLockArray; // Whether to dynamically increase the size of the striped lock
+
+ // How many times we resized becaused of collisions.
+ // This is used to make sure we don't resize the dictionary because of multi-threaded Add() calls
+ // that generate collisions. Whenever a GrowTable() should be the only place that changes this
+#if !FEATURE_CORECLR
+ // The field should be have been marked as NonSerialized but because we shipped it without that attribute in 4.5.1.
+ // we can't add it back without breaking compat. To maximize compat we are going to keep the OptionalField attribute
+ // This will prevent cases where the field was not serialized.
+ [OptionalField]
+#endif
+ private int m_keyRehashCount;
+
+#if !FEATURE_CORECLR
+ [NonSerialized]
+#endif
+ private int m_budget; // The maximum number of elements per lock before a resize operation is triggered
+
+#if !FEATURE_CORECLR // These fields are not used in CoreCLR
+ private KeyValuePair<TKey, TValue>[] m_serializationArray; // Used for custom serialization
+
+ private int m_serializationConcurrencyLevel; // used to save the concurrency level in serialization
+
+ private int m_serializationCapacity; // used to save the capacity in serialization
+#endif
+ // The default concurrency level is DEFAULT_CONCURRENCY_MULTIPLIER * #CPUs. The higher the
+ // DEFAULT_CONCURRENCY_MULTIPLIER, the more concurrent writes can take place without interference
+ // and blocking, but also the more expensive operations that require all locks become (e.g. table
+ // resizing, ToArray, Count, etc). According to brief benchmarks that we ran, 4 seems like a good
+ // compromise.
+ private const int DEFAULT_CONCURRENCY_MULTIPLIER = 4;
+
+ // The default capacity, i.e. the initial # of buckets. When choosing this value, we are making
+ // a trade-off between the size of a very small dictionary, and the number of resizes when
+ // constructing a large dictionary. Also, the capacity should not be divisible by a small prime.
+ private const int DEFAULT_CAPACITY = 31;
+
+ // The maximum size of the striped lock that will not be exceeded when locks are automatically
+ // added as the dictionary grows. However, the user is allowed to exceed this limit by passing
+ // a concurrency level larger than MAX_LOCK_NUMBER into the constructor.
+ private const int MAX_LOCK_NUMBER = 1024;
+
+ // Whether TValue is a type that can be written atomically (i.e., with no danger of torn reads)
+ private static readonly bool s_isValueWriteAtomic = IsValueWriteAtomic();
+
+
+ /// <summary>
+ /// Determines whether type TValue can be written atomically
+ /// </summary>
+ private static bool IsValueWriteAtomic()
+ {
+ Type valueType = typeof(TValue);
+
+ //
+ // Section 12.6.6 of ECMA CLI explains which types can be read and written atomically without
+ // the risk of tearing.
+ //
+ // See http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-335.pdf
+ //
+ bool isAtomic =
+ (valueType.IsClass)
+ || valueType == typeof(Boolean)
+ || valueType == typeof(Char)
+ || valueType == typeof(Byte)
+ || valueType == typeof(SByte)
+ || valueType == typeof(Int16)
+ || valueType == typeof(UInt16)
+ || valueType == typeof(Int32)
+ || valueType == typeof(UInt32)
+ || valueType == typeof(Single);
+
+ if (!isAtomic && IntPtr.Size == 8)
+ {
+ isAtomic |= valueType == typeof(Double) || valueType == typeof(Int64);
+ }
+
+ return isAtomic;
+ }
+
+ /// <summary>
+ /// Initializes a new instance of the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// class that is empty, has the default concurrency level, has the default initial capacity, and
+ /// uses the default comparer for the key type.
+ /// </summary>
+ public ConcurrentDictionary() : this(DefaultConcurrencyLevel, DEFAULT_CAPACITY, true, EqualityComparer<TKey>.Default) { }
+
+ /// <summary>
+ /// Initializes a new instance of the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// class that is empty, has the specified concurrency level and capacity, and uses the default
+ /// comparer for the key type.
+ /// </summary>
+ /// <param name="concurrencyLevel">The estimated number of threads that will update the
+ /// <see cref="ConcurrentDictionary{TKey,TValue}"/> concurrently.</param>
+ /// <param name="capacity">The initial number of elements that the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// can contain.</param>
+ /// <exception cref="T:System.ArgumentOutOfRangeException"><paramref name="concurrencyLevel"/> is
+ /// less than 1.</exception>
+ /// <exception cref="T:System.ArgumentOutOfRangeException"> <paramref name="capacity"/> is less than
+ /// 0.</exception>
+ public ConcurrentDictionary(int concurrencyLevel, int capacity) : this(concurrencyLevel, capacity, false, EqualityComparer<TKey>.Default) { }
+
+ /// <summary>
+ /// Initializes a new instance of the <see cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// class that contains elements copied from the specified <see
+ /// cref="T:System.Collections.IEnumerable{KeyValuePair{TKey,TValue}}"/>, has the default concurrency
+ /// level, has the default initial capacity, and uses the default comparer for the key type.
+ /// </summary>
+ /// <param name="collection">The <see
+ /// cref="T:System.Collections.IEnumerable{KeyValuePair{TKey,TValue}}"/> whose elements are copied to
+ /// the new
+ /// <see cref="ConcurrentDictionary{TKey,TValue}"/>.</param>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="collection"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.ArgumentException"><paramref name="collection"/> contains one or more
+ /// duplicate keys.</exception>
+ public ConcurrentDictionary(IEnumerable<KeyValuePair<TKey, TValue>> collection) : this(collection, EqualityComparer<TKey>.Default) { }
+
+ /// <summary>
+ /// Initializes a new instance of the <see cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// class that is empty, has the specified concurrency level and capacity, and uses the specified
+ /// <see cref="T:System.Collections.Generic.IEqualityComparer{TKey}"/>.
+ /// </summary>
+ /// <param name="comparer">The <see cref="T:System.Collections.Generic.IEqualityComparer{TKey}"/>
+ /// implementation to use when comparing keys.</param>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="comparer"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ public ConcurrentDictionary(IEqualityComparer<TKey> comparer) : this(DefaultConcurrencyLevel, DEFAULT_CAPACITY, true, comparer) { }
+
+ /// <summary>
+ /// Initializes a new instance of the <see cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// class that contains elements copied from the specified <see
+ /// cref="T:System.Collections.IEnumerable"/>, has the default concurrency level, has the default
+ /// initial capacity, and uses the specified
+ /// <see cref="T:System.Collections.Generic.IEqualityComparer{TKey}"/>.
+ /// </summary>
+ /// <param name="collection">The <see
+ /// cref="T:System.Collections.IEnumerable{KeyValuePair{TKey,TValue}}"/> whose elements are copied to
+ /// the new
+ /// <see cref="ConcurrentDictionary{TKey,TValue}"/>.</param>
+ /// <param name="comparer">The <see cref="T:System.Collections.Generic.IEqualityComparer{TKey}"/>
+ /// implementation to use when comparing keys.</param>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="collection"/> is a null reference
+ /// (Nothing in Visual Basic). -or-
+ /// <paramref name="comparer"/> is a null reference (Nothing in Visual Basic).
+ /// </exception>
+ public ConcurrentDictionary(IEnumerable<KeyValuePair<TKey, TValue>> collection, IEqualityComparer<TKey> comparer)
+ : this(comparer)
+ {
+ if (collection == null) throw new ArgumentNullException("collection");
+
+ InitializeFromCollection(collection);
+ }
+
+ /// <summary>
+ /// Initializes a new instance of the <see cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// class that contains elements copied from the specified <see cref="T:System.Collections.IEnumerable"/>,
+ /// has the specified concurrency level, has the specified initial capacity, and uses the specified
+ /// <see cref="T:System.Collections.Generic.IEqualityComparer{TKey}"/>.
+ /// </summary>
+ /// <param name="concurrencyLevel">The estimated number of threads that will update the
+ /// <see cref="ConcurrentDictionary{TKey,TValue}"/> concurrently.</param>
+ /// <param name="collection">The <see cref="T:System.Collections.IEnumerable{KeyValuePair{TKey,TValue}}"/> whose elements are copied to the new
+ /// <see cref="ConcurrentDictionary{TKey,TValue}"/>.</param>
+ /// <param name="comparer">The <see cref="T:System.Collections.Generic.IEqualityComparer{TKey}"/> implementation to use
+ /// when comparing keys.</param>
+ /// <exception cref="T:System.ArgumentNullException">
+ /// <paramref name="collection"/> is a null reference (Nothing in Visual Basic).
+ /// -or-
+ /// <paramref name="comparer"/> is a null reference (Nothing in Visual Basic).
+ /// </exception>
+ /// <exception cref="T:System.ArgumentOutOfRangeException">
+ /// <paramref name="concurrencyLevel"/> is less than 1.
+ /// </exception>
+ /// <exception cref="T:System.ArgumentException"><paramref name="collection"/> contains one or more duplicate keys.</exception>
+ public ConcurrentDictionary(
+ int concurrencyLevel, IEnumerable<KeyValuePair<TKey, TValue>> collection, IEqualityComparer<TKey> comparer)
+ : this(concurrencyLevel, DEFAULT_CAPACITY, false, comparer)
+ {
+ if (collection == null) throw new ArgumentNullException("collection");
+ if (comparer == null) throw new ArgumentNullException("comparer");
+
+ InitializeFromCollection(collection);
+ }
+
+ private void InitializeFromCollection(IEnumerable<KeyValuePair<TKey, TValue>> collection)
+ {
+ TValue dummy;
+ foreach (KeyValuePair<TKey, TValue> pair in collection)
+ {
+ if (pair.Key == null) throw new ArgumentNullException("key");
+
+ if (!TryAddInternal(pair.Key, pair.Value, false, false, out dummy))
+ {
+ throw new ArgumentException(GetResource("ConcurrentDictionary_SourceContainsDuplicateKeys"));
+ }
+ }
+
+ if (m_budget == 0)
+ {
+ m_budget = m_tables.m_buckets.Length / m_tables.m_locks.Length;
+ }
+
+ }
+
+ /// <summary>
+ /// Initializes a new instance of the <see cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// class that is empty, has the specified concurrency level, has the specified initial capacity, and
+ /// uses the specified <see cref="T:System.Collections.Generic.IEqualityComparer{TKey}"/>.
+ /// </summary>
+ /// <param name="concurrencyLevel">The estimated number of threads that will update the
+ /// <see cref="ConcurrentDictionary{TKey,TValue}"/> concurrently.</param>
+ /// <param name="capacity">The initial number of elements that the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// can contain.</param>
+ /// <param name="comparer">The <see cref="T:System.Collections.Generic.IEqualityComparer{TKey}"/>
+ /// implementation to use when comparing keys.</param>
+ /// <exception cref="T:System.ArgumentOutOfRangeException">
+ /// <paramref name="concurrencyLevel"/> is less than 1. -or-
+ /// <paramref name="capacity"/> is less than 0.
+ /// </exception>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="comparer"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ public ConcurrentDictionary(int concurrencyLevel, int capacity, IEqualityComparer<TKey> comparer)
+ : this(concurrencyLevel, capacity, false, comparer)
+ {
+ }
+
+ internal ConcurrentDictionary(int concurrencyLevel, int capacity, bool growLockArray, IEqualityComparer<TKey> comparer)
+ {
+ if (concurrencyLevel < 1)
+ {
+ throw new ArgumentOutOfRangeException("concurrencyLevel", GetResource("ConcurrentDictionary_ConcurrencyLevelMustBePositive"));
+ }
+ if (capacity < 0)
+ {
+ throw new ArgumentOutOfRangeException("capacity", GetResource("ConcurrentDictionary_CapacityMustNotBeNegative"));
+ }
+ if (comparer == null) throw new ArgumentNullException("comparer");
+
+ // The capacity should be at least as large as the concurrency level. Otherwise, we would have locks that don't guard
+ // any buckets.
+ if (capacity < concurrencyLevel)
+ {
+ capacity = concurrencyLevel;
+ }
+
+ object[] locks = new object[concurrencyLevel];
+ for (int i = 0; i < locks.Length; i++)
+ {
+ locks[i] = new object();
+ }
+
+ int[] countPerLock = new int[locks.Length];
+ Node[] buckets = new Node[capacity];
+ m_tables = new Tables(buckets, locks, countPerLock, comparer);
+
+ m_growLockArray = growLockArray;
+ m_budget = buckets.Length / locks.Length;
+ }
+
+
+ /// <summary>
+ /// Attempts to add the specified key and value to the <see cref="ConcurrentDictionary{TKey,
+ /// TValue}"/>.
+ /// </summary>
+ /// <param name="key">The key of the element to add.</param>
+ /// <param name="value">The value of the element to add. The value can be a null reference (Nothing
+ /// in Visual Basic) for reference types.</param>
+ /// <returns>true if the key/value pair was added to the <see cref="ConcurrentDictionary{TKey,
+ /// TValue}"/>
+ /// successfully; otherwise, false.</returns>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.OverflowException">The <see cref="ConcurrentDictionary{TKey, TValue}"/>
+ /// contains too many elements.</exception>
+ public bool TryAdd(TKey key, TValue value)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+ TValue dummy;
+ return TryAddInternal(key, value, false, true, out dummy);
+ }
+
+ /// <summary>
+ /// Determines whether the <see cref="ConcurrentDictionary{TKey, TValue}"/> contains the specified
+ /// key.
+ /// </summary>
+ /// <param name="key">The key to locate in the <see cref="ConcurrentDictionary{TKey,
+ /// TValue}"/>.</param>
+ /// <returns>true if the <see cref="ConcurrentDictionary{TKey, TValue}"/> contains an element with
+ /// the specified key; otherwise, false.</returns>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ public bool ContainsKey(TKey key)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+
+ TValue throwAwayValue;
+ return TryGetValue(key, out throwAwayValue);
+ }
+
+ /// <summary>
+ /// Attempts to remove and return the the value with the specified key from the
+ /// <see cref="ConcurrentDictionary{TKey, TValue}"/>.
+ /// </summary>
+ /// <param name="key">The key of the element to remove and return.</param>
+ /// <param name="value">When this method returns, <paramref name="value"/> contains the object removed from the
+ /// <see cref="ConcurrentDictionary{TKey,TValue}"/> or the default value of <typeparamref
+ /// name="TValue"/>
+ /// if the operation failed.</param>
+ /// <returns>true if an object was removed successfully; otherwise, false.</returns>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ public bool TryRemove(TKey key, out TValue value)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+
+ return TryRemoveInternal(key, out value, false, default(TValue));
+ }
+
+ /// <summary>
+ /// Removes the specified key from the dictionary if it exists and returns its associated value.
+ /// If matchValue flag is set, the key will be removed only if is associated with a particular
+ /// value.
+ /// </summary>
+ /// <param name="key">The key to search for and remove if it exists.</param>
+ /// <param name="value">The variable into which the removed value, if found, is stored.</param>
+ /// <param name="matchValue">Whether removal of the key is conditional on its value.</param>
+ /// <param name="oldValue">The conditional value to compare against if <paramref name="matchValue"/> is true</param>
+ /// <returns></returns>
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "Reviewed for thread safety")]
+ private bool TryRemoveInternal(TKey key, out TValue value, bool matchValue, TValue oldValue)
+ {
+ while (true)
+ {
+ Tables tables = m_tables;
+
+ IEqualityComparer<TKey> comparer = tables.m_comparer;
+
+ int bucketNo, lockNo;
+ GetBucketAndLockNo(comparer.GetHashCode(key), out bucketNo, out lockNo, tables.m_buckets.Length, tables.m_locks.Length);
+
+ lock (tables.m_locks[lockNo])
+ {
+ // If the table just got resized, we may not be holding the right lock, and must retry.
+ // This should be a rare occurence.
+ if (tables != m_tables)
+ {
+ continue;
+ }
+
+ Node prev = null;
+ for (Node curr = tables.m_buckets[bucketNo]; curr != null; curr = curr.m_next)
+ {
+ Assert((prev == null && curr == tables.m_buckets[bucketNo]) || prev.m_next == curr);
+
+ if (comparer.Equals(curr.m_key, key))
+ {
+ if (matchValue)
+ {
+ bool valuesMatch = EqualityComparer<TValue>.Default.Equals(oldValue, curr.m_value);
+ if (!valuesMatch)
+ {
+ value = default(TValue);
+ return false;
+ }
+ }
+
+ if (prev == null)
+ {
+ Volatile.Write<Node>(ref tables.m_buckets[bucketNo], curr.m_next);
+ }
+ else
+ {
+ prev.m_next = curr.m_next;
+ }
+
+ value = curr.m_value;
+ tables.m_countPerLock[lockNo]--;
+ return true;
+ }
+ prev = curr;
+ }
+ }
+
+ value = default(TValue);
+ return false;
+ }
+ }
+
+ /// <summary>
+ /// Attempts to get the value associated with the specified key from the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>.
+ /// </summary>
+ /// <param name="key">The key of the value to get.</param>
+ /// <param name="value">When this method returns, <paramref name="value"/> contains the object from
+ /// the
+ /// <see cref="ConcurrentDictionary{TKey,TValue}"/> with the specified key or the default value of
+ /// <typeparamref name="TValue"/>, if the operation failed.</param>
+ /// <returns>true if the key was found in the <see cref="ConcurrentDictionary{TKey,TValue}"/>;
+ /// otherwise, false.</returns>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "Reviewed for thread safety")]
+ public bool TryGetValue(TKey key, out TValue value)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+
+ int bucketNo, lockNoUnused;
+
+ // We must capture the m_buckets field in a local variable. It is set to a new table on each table resize.
+ Tables tables = m_tables;
+ IEqualityComparer<TKey> comparer = tables.m_comparer;
+ GetBucketAndLockNo(comparer.GetHashCode(key), out bucketNo, out lockNoUnused, tables.m_buckets.Length, tables.m_locks.Length);
+
+ // We can get away w/out a lock here.
+ // The Volatile.Read ensures that the load of the fields of 'n' doesn't move before the load from buckets[i].
+ Node n = Volatile.Read<Node>(ref tables.m_buckets[bucketNo]);
+
+ while (n != null)
+ {
+ if (comparer.Equals(n.m_key, key))
+ {
+ value = n.m_value;
+ return true;
+ }
+ n = n.m_next;
+ }
+
+ value = default(TValue);
+ return false;
+ }
+
+ /// <summary>
+ /// Compares the existing value for the specified key with a specified value, and if they're equal,
+ /// updates the key with a third value.
+ /// </summary>
+ /// <param name="key">The key whose value is compared with <paramref name="comparisonValue"/> and
+ /// possibly replaced.</param>
+ /// <param name="newValue">The value that replaces the value of the element with <paramref
+ /// name="key"/> if the comparison results in equality.</param>
+ /// <param name="comparisonValue">The value that is compared to the value of the element with
+ /// <paramref name="key"/>.</param>
+ /// <returns>true if the value with <paramref name="key"/> was equal to <paramref
+ /// name="comparisonValue"/> and replaced with <paramref name="newValue"/>; otherwise,
+ /// false.</returns>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null
+ /// reference.</exception>
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "Reviewed for thread safety")]
+ public bool TryUpdate(TKey key, TValue newValue, TValue comparisonValue)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+
+ IEqualityComparer<TValue> valueComparer = EqualityComparer<TValue>.Default;
+
+ while (true)
+ {
+ int bucketNo;
+ int lockNo;
+ int hashcode;
+
+ Tables tables = m_tables;
+ IEqualityComparer<TKey> comparer = tables.m_comparer;
+
+ hashcode = comparer.GetHashCode(key);
+ GetBucketAndLockNo(hashcode, out bucketNo, out lockNo, tables.m_buckets.Length, tables.m_locks.Length);
+
+ lock (tables.m_locks[lockNo])
+ {
+ // If the table just got resized, we may not be holding the right lock, and must retry.
+ // This should be a rare occurence.
+ if (tables != m_tables)
+ {
+ continue;
+ }
+
+ // Try to find this key in the bucket
+ Node prev = null;
+ for (Node node = tables.m_buckets[bucketNo]; node != null; node = node.m_next)
+ {
+ Assert((prev == null && node == tables.m_buckets[bucketNo]) || prev.m_next == node);
+ if (comparer.Equals(node.m_key, key))
+ {
+ if (valueComparer.Equals(node.m_value, comparisonValue))
+ {
+ if (s_isValueWriteAtomic)
+ {
+ node.m_value = newValue;
+ }
+ else
+ {
+ Node newNode = new Node(node.m_key, newValue, hashcode, node.m_next);
+
+ if (prev == null)
+ {
+ tables.m_buckets[bucketNo] = newNode;
+ }
+ else
+ {
+ prev.m_next = newNode;
+ }
+ }
+
+ return true;
+ }
+
+ return false;
+ }
+
+ prev = node;
+ }
+
+ //didn't find the key
+ return false;
+ }
+ }
+ }
+
+ /// <summary>
+ /// Removes all keys and values from the <see cref="ConcurrentDictionary{TKey,TValue}"/>.
+ /// </summary>
+ public void Clear()
+ {
+ int locksAcquired = 0;
+ try
+ {
+ AcquireAllLocks(ref locksAcquired);
+
+ Tables newTables = new Tables(new Node[DEFAULT_CAPACITY], m_tables.m_locks, new int[m_tables.m_countPerLock.Length], m_tables.m_comparer);
+ m_tables = newTables;
+ m_budget = Math.Max(1, newTables.m_buckets.Length / newTables.m_locks.Length);
+ }
+ finally
+ {
+ ReleaseLocks(0, locksAcquired);
+ }
+ }
+
+ /// <summary>
+ /// Copies the elements of the <see cref="T:System.Collections.Generic.ICollection"/> to an array of
+ /// type <see cref="T:System.Collections.Generic.KeyValuePair{TKey,TValue}"/>, starting at the
+ /// specified array index.
+ /// </summary>
+ /// <param name="array">The one-dimensional array of type <see
+ /// cref="T:System.Collections.Generic.KeyValuePair{TKey,TValue}"/>
+ /// that is the destination of the <see
+ /// cref="T:System.Collections.Generic.KeyValuePair{TKey,TValue}"/> elements copied from the <see
+ /// cref="T:System.Collections.ICollection"/>. 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="T:System.ArgumentNullException"><paramref name="array"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.ArgumentOutOfRangeException"><paramref name="index"/> is less than
+ /// 0.</exception>
+ /// <exception cref="T:System.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="T:System.Collections.ICollection"/>
+ /// is greater than the available space from <paramref name="index"/> to the end of the destination
+ /// <paramref name="array"/>.</exception>
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "ConcurrencyCop just doesn't know about these locks")]
+ void ICollection<KeyValuePair<TKey, TValue>>.CopyTo(KeyValuePair<TKey, TValue>[] array, int index)
+ {
+ if (array == null) throw new ArgumentNullException("array");
+ if (index < 0) throw new ArgumentOutOfRangeException("index", GetResource("ConcurrentDictionary_IndexIsNegative"));
+
+ int locksAcquired = 0;
+ try
+ {
+ AcquireAllLocks(ref locksAcquired);
+
+ int count = 0;
+
+ for (int i = 0; i < m_tables.m_locks.Length && count >= 0; i++)
+ {
+ count += m_tables.m_countPerLock[i];
+ }
+
+ if (array.Length - count < index || count < 0) //"count" itself or "count + index" can overflow
+ {
+ throw new ArgumentException(GetResource("ConcurrentDictionary_ArrayNotLargeEnough"));
+ }
+
+ CopyToPairs(array, index);
+ }
+ finally
+ {
+ ReleaseLocks(0, locksAcquired);
+ }
+ }
+
+ /// <summary>
+ /// Copies the key and value pairs stored in the <see cref="ConcurrentDictionary{TKey,TValue}"/> to a
+ /// new array.
+ /// </summary>
+ /// <returns>A new array containing a snapshot of key and value pairs copied from the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>.</returns>
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "ConcurrencyCop just doesn't know about these locks")]
+ public KeyValuePair<TKey, TValue>[] ToArray()
+ {
+ int locksAcquired = 0;
+ try
+ {
+ AcquireAllLocks(ref locksAcquired);
+ int count = 0;
+ checked
+ {
+ for (int i = 0; i < m_tables.m_locks.Length; i++)
+ {
+ count += m_tables.m_countPerLock[i];
+ }
+ }
+
+ KeyValuePair<TKey, TValue>[] array = new KeyValuePair<TKey, TValue>[count];
+
+ CopyToPairs(array, 0);
+ return array;
+ }
+ finally
+ {
+ ReleaseLocks(0, locksAcquired);
+ }
+ }
+
+ /// <summary>
+ /// Copy dictionary contents to an array - shared implementation between ToArray and CopyTo.
+ ///
+ /// Important: the caller must hold all locks in m_locks before calling CopyToPairs.
+ /// </summary>
+ private void CopyToPairs(KeyValuePair<TKey, TValue>[] array, int index)
+ {
+ Node[] buckets = m_tables.m_buckets;
+ for (int i = 0; i < buckets.Length; i++)
+ {
+ for (Node current = buckets[i]; current != null; current = current.m_next)
+ {
+ array[index] = new KeyValuePair<TKey, TValue>(current.m_key, current.m_value);
+ index++; //this should never flow, CopyToPairs is only called when there's no overflow risk
+ }
+ }
+ }
+
+ /// <summary>
+ /// Copy dictionary contents to an array - shared implementation between ToArray and CopyTo.
+ ///
+ /// Important: the caller must hold all locks in m_locks before calling CopyToEntries.
+ /// </summary>
+ private void CopyToEntries(DictionaryEntry[] array, int index)
+ {
+ Node[] buckets = m_tables.m_buckets;
+ for (int i = 0; i < buckets.Length; i++)
+ {
+ for (Node current = buckets[i]; current != null; current = current.m_next)
+ {
+ array[index] = new DictionaryEntry(current.m_key, current.m_value);
+ index++; //this should never flow, CopyToEntries is only called when there's no overflow risk
+ }
+ }
+ }
+
+ /// <summary>
+ /// Copy dictionary contents to an array - shared implementation between ToArray and CopyTo.
+ ///
+ /// Important: the caller must hold all locks in m_locks before calling CopyToObjects.
+ /// </summary>
+ private void CopyToObjects(object[] array, int index)
+ {
+ Node[] buckets = m_tables.m_buckets;
+ for (int i = 0; i < buckets.Length; i++)
+ {
+ for (Node current = buckets[i]; current != null; current = current.m_next)
+ {
+ array[index] = new KeyValuePair<TKey, TValue>(current.m_key, current.m_value);
+ index++; //this should never flow, CopyToObjects is only called when there's no overflow risk
+ }
+ }
+ }
+
+ /// <summary>Returns an enumerator that iterates through the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>.</summary>
+ /// <returns>An enumerator for the <see cref="ConcurrentDictionary{TKey,TValue}"/>.</returns>
+ /// <remarks>
+ /// The enumerator returned from the dictionary is safe to use concurrently with
+ /// reads and writes to the dictionary, however it does not represent a moment-in-time snapshot
+ /// of the dictionary. The contents exposed through the enumerator may contain modifications
+ /// made to the dictionary after <see cref="GetEnumerator"/> was called.
+ /// </remarks>
+ public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
+ {
+ Node[] buckets = m_tables.m_buckets;
+
+ for (int i = 0; i < buckets.Length; i++)
+ {
+ // The Volatile.Read ensures that the load of the fields of 'current' doesn't move before the load from buckets[i].
+ Node current = Volatile.Read<Node>(ref buckets[i]);
+
+ while (current != null)
+ {
+ yield return new KeyValuePair<TKey, TValue>(current.m_key, current.m_value);
+ current = current.m_next;
+ }
+ }
+ }
+
+ /// <summary>
+ /// Shared internal implementation for inserts and updates.
+ /// If key exists, we always return false; and if updateIfExists == true we force update with value;
+ /// If key doesn't exist, we always add value and return true;
+ /// </summary>
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "Reviewed for thread safety")]
+ private bool TryAddInternal(TKey key, TValue value, bool updateIfExists, bool acquireLock, out TValue resultingValue)
+ {
+ while (true)
+ {
+ int bucketNo, lockNo;
+ int hashcode;
+
+ Tables tables = m_tables;
+ IEqualityComparer<TKey> comparer = tables.m_comparer;
+ hashcode = comparer.GetHashCode(key);
+ GetBucketAndLockNo(hashcode, out bucketNo, out lockNo, tables.m_buckets.Length, tables.m_locks.Length);
+
+ bool resizeDesired = false;
+ bool lockTaken = false;
+#if FEATURE_RANDOMIZED_STRING_HASHING
+#if !FEATURE_CORECLR
+ bool resizeDueToCollisions = false;
+#endif // !FEATURE_CORECLR
+#endif
+
+ try
+ {
+ if (acquireLock)
+ Monitor.Enter(tables.m_locks[lockNo], ref lockTaken);
+
+ // If the table just got resized, we may not be holding the right lock, and must retry.
+ // This should be a rare occurence.
+ if (tables != m_tables)
+ {
+ continue;
+ }
+
+#if FEATURE_RANDOMIZED_STRING_HASHING
+#if !FEATURE_CORECLR
+ int collisionCount = 0;
+#endif // !FEATURE_CORECLR
+#endif
+
+ // Try to find this key in the bucket
+ Node prev = null;
+ for (Node node = tables.m_buckets[bucketNo]; node != null; node = node.m_next)
+ {
+ Assert((prev == null && node == tables.m_buckets[bucketNo]) || prev.m_next == node);
+ if (comparer.Equals(node.m_key, key))
+ {
+ // The key was found in the dictionary. If updates are allowed, update the value for that key.
+ // We need to create a new node for the update, in order to support TValue types that cannot
+ // be written atomically, since lock-free reads may be happening concurrently.
+ if (updateIfExists)
+ {
+ if (s_isValueWriteAtomic)
+ {
+ node.m_value = value;
+ }
+ else
+ {
+ Node newNode = new Node(node.m_key, value, hashcode, node.m_next);
+ if (prev == null)
+ {
+ tables.m_buckets[bucketNo] = newNode;
+ }
+ else
+ {
+ prev.m_next = newNode;
+ }
+ }
+ resultingValue = value;
+ }
+ else
+ {
+ resultingValue = node.m_value;
+ }
+ return false;
+ }
+ prev = node;
+
+#if FEATURE_RANDOMIZED_STRING_HASHING
+#if !FEATURE_CORECLR
+ collisionCount++;
+#endif // !FEATURE_CORECLR
+#endif
+ }
+
+#if FEATURE_RANDOMIZED_STRING_HASHING
+#if !FEATURE_CORECLR
+ if(collisionCount > HashHelpers.HashCollisionThreshold && HashHelpers.IsWellKnownEqualityComparer(comparer))
+ {
+ resizeDesired = true;
+ resizeDueToCollisions = true;
+ }
+#endif // !FEATURE_CORECLR
+#endif
+
+ // The key was not found in the bucket. Insert the key-value pair.
+ Volatile.Write<Node>(ref tables.m_buckets[bucketNo], new Node(key, value, hashcode, tables.m_buckets[bucketNo]));
+ checked
+ {
+ tables.m_countPerLock[lockNo]++;
+ }
+
+ //
+ // If the number of elements guarded by this lock has exceeded the budget, resize the bucket table.
+ // It is also possible that GrowTable will increase the budget but won't resize the bucket table.
+ // That happens if the bucket table is found to be poorly utilized due to a bad hash function.
+ //
+ if (tables.m_countPerLock[lockNo] > m_budget)
+ {
+ resizeDesired = true;
+ }
+ }
+ finally
+ {
+ if (lockTaken)
+ Monitor.Exit(tables.m_locks[lockNo]);
+ }
+
+ //
+ // The fact that we got here means that we just performed an insertion. If necessary, we will grow the table.
+ //
+ // Concurrency notes:
+ // - Notice that we are not holding any locks at when calling GrowTable. This is necessary to prevent deadlocks.
+ // - As a result, it is possible that GrowTable will be called unnecessarily. But, GrowTable will obtain lock 0
+ // and then verify that the table we passed to it as the argument is still the current table.
+ //
+ if (resizeDesired)
+ {
+#if FEATURE_RANDOMIZED_STRING_HASHING
+#if !FEATURE_CORECLR
+ if (resizeDueToCollisions)
+ {
+ GrowTable(tables, (IEqualityComparer<TKey>)HashHelpers.GetRandomizedEqualityComparer(comparer), true, m_keyRehashCount);
+ }
+ else
+#endif // !FEATURE_CORECLR
+ {
+ GrowTable(tables, tables.m_comparer, false, m_keyRehashCount);
+ }
+#else
+ GrowTable(tables, tables.m_comparer, false, m_keyRehashCount);
+#endif
+ }
+
+ resultingValue = value;
+ return true;
+ }
+ }
+
+ /// <summary>
+ /// Gets or sets the value associated with the specified key.
+ /// </summary>
+ /// <param name="key">The key of the value to get or set.</param>
+ /// <value>The value associated with the specified key. If the specified key is not found, a get
+ /// operation throws a
+ /// <see cref="T:Sytem.Collections.Generic.KeyNotFoundException"/>, and a set operation creates a new
+ /// element with the specified key.</value>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.Collections.Generic.KeyNotFoundException">The property is retrieved and
+ /// <paramref name="key"/>
+ /// does not exist in the collection.</exception>
+ public TValue this[TKey key]
+ {
+ get
+ {
+ TValue value;
+ if (!TryGetValue(key, out value))
+ {
+ throw new KeyNotFoundException();
+ }
+ return value;
+ }
+ set
+ {
+ if (key == null) throw new ArgumentNullException("key");
+ TValue dummy;
+ TryAddInternal(key, value, true, true, out dummy);
+ }
+ }
+
+ /// <summary>
+ /// Gets the number of key/value pairs contained in the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>.
+ /// </summary>
+ /// <exception cref="T:System.OverflowException">The dictionary contains too many
+ /// elements.</exception>
+ /// <value>The number of key/value paris contained in the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>.</value>
+ /// <remarks>Count has snapshot semantics and represents the number of items in the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// at the moment when Count was accessed.</remarks>
+ public int Count
+ {
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "ConcurrencyCop just doesn't know about these locks")]
+ get
+ {
+ int count = 0;
+
+ int acquiredLocks = 0;
+ try
+ {
+ // Acquire all locks
+ AcquireAllLocks(ref acquiredLocks);
+
+ // Compute the count, we allow overflow
+ for (int i = 0; i < m_tables.m_countPerLock.Length; i++)
+ {
+ count += m_tables.m_countPerLock[i];
+ }
+
+ }
+ finally
+ {
+ // Release locks that have been acquired earlier
+ ReleaseLocks(0, acquiredLocks);
+ }
+
+ return count;
+ }
+ }
+
+ /// <summary>
+ /// Adds a key/value pair to the <see cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// if the key does not already exist.
+ /// </summary>
+ /// <param name="key">The key of the element to add.</param>
+ /// <param name="valueFactory">The function used to generate a value for the key</param>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="valueFactory"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.OverflowException">The dictionary contains too many
+ /// elements.</exception>
+ /// <returns>The value for the key. This will be either the existing value for the key if the
+ /// key is already in the dictionary, or the new value for the key as returned by valueFactory
+ /// if the key was not in the dictionary.</returns>
+ public TValue GetOrAdd(TKey key, Func<TKey, TValue> valueFactory)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+ if (valueFactory == null) throw new ArgumentNullException("valueFactory");
+
+ TValue resultingValue;
+ if (TryGetValue(key, out resultingValue))
+ {
+ return resultingValue;
+ }
+ TryAddInternal(key, valueFactory(key), false, true, out resultingValue);
+ return resultingValue;
+ }
+
+ /// <summary>
+ /// Adds a key/value pair to the <see cref="ConcurrentDictionary{TKey,TValue}"/>
+ /// if the key does not already exist.
+ /// </summary>
+ /// <param name="key">The key of the element to add.</param>
+ /// <param name="value">the value to be added, if the key does not already exist</param>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.OverflowException">The dictionary contains too many
+ /// elements.</exception>
+ /// <returns>The value for the key. This will be either the existing value for the key if the
+ /// key is already in the dictionary, or the new value if the key was not in the dictionary.</returns>
+ public TValue GetOrAdd(TKey key, TValue value)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+
+ TValue resultingValue;
+ TryAddInternal(key, value, false, true, out resultingValue);
+ return resultingValue;
+ }
+
+ /// <summary>
+ /// Adds a key/value pair to the <see cref="ConcurrentDictionary{TKey,TValue}"/> if the key does not already
+ /// exist, or updates a key/value pair in the <see cref="ConcurrentDictionary{TKey,TValue}"/> if the key
+ /// already exists.
+ /// </summary>
+ /// <param name="key">The key to be added or whose value should be updated</param>
+ /// <param name="addValueFactory">The function used to generate a value for an absent key</param>
+ /// <param name="updateValueFactory">The function used to generate a new value for an existing key
+ /// based on the key's existing value</param>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="addValueFactory"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="updateValueFactory"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.OverflowException">The dictionary contains too many
+ /// elements.</exception>
+ /// <returns>The new value for the key. This will be either be the result of addValueFactory (if the key was
+ /// absent) or the result of updateValueFactory (if the key was present).</returns>
+ public TValue AddOrUpdate(TKey key, Func<TKey, TValue> addValueFactory, Func<TKey, TValue, TValue> updateValueFactory)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+ if (addValueFactory == null) throw new ArgumentNullException("addValueFactory");
+ if (updateValueFactory == null) throw new ArgumentNullException("updateValueFactory");
+
+ TValue newValue, resultingValue;
+ while (true)
+ {
+ TValue oldValue;
+ if (TryGetValue(key, out oldValue))
+ //key exists, try to update
+ {
+ newValue = updateValueFactory(key, oldValue);
+ if (TryUpdate(key, newValue, oldValue))
+ {
+ return newValue;
+ }
+ }
+ else //try add
+ {
+ newValue = addValueFactory(key);
+ if (TryAddInternal(key, newValue, false, true, out resultingValue))
+ {
+ return resultingValue;
+ }
+ }
+ }
+ }
+
+ /// <summary>
+ /// Adds a key/value pair to the <see cref="ConcurrentDictionary{TKey,TValue}"/> if the key does not already
+ /// exist, or updates a key/value pair in the <see cref="ConcurrentDictionary{TKey,TValue}"/> if the key
+ /// already exists.
+ /// </summary>
+ /// <param name="key">The key to be added or whose value should be updated</param>
+ /// <param name="addValue">The value to be added for an absent key</param>
+ /// <param name="updateValueFactory">The function used to generate a new value for an existing key based on
+ /// the key's existing value</param>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="updateValueFactory"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.OverflowException">The dictionary contains too many
+ /// elements.</exception>
+ /// <returns>The new value for the key. This will be either be the result of addValueFactory (if the key was
+ /// absent) or the result of updateValueFactory (if the key was present).</returns>
+ public TValue AddOrUpdate(TKey key, TValue addValue, Func<TKey, TValue, TValue> updateValueFactory)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+ if (updateValueFactory == null) throw new ArgumentNullException("updateValueFactory");
+ TValue newValue, resultingValue;
+ while (true)
+ {
+ TValue oldValue;
+ if (TryGetValue(key, out oldValue))
+ //key exists, try to update
+ {
+ newValue = updateValueFactory(key, oldValue);
+ if (TryUpdate(key, newValue, oldValue))
+ {
+ return newValue;
+ }
+ }
+ else //try add
+ {
+ if (TryAddInternal(key, addValue, false, true, out resultingValue))
+ {
+ return resultingValue;
+ }
+ }
+ }
+ }
+
+
+
+ /// <summary>
+ /// Gets a value that indicates whether the <see cref="ConcurrentDictionary{TKey,TValue}"/> is empty.
+ /// </summary>
+ /// <value>true if the <see cref="ConcurrentDictionary{TKey,TValue}"/> is empty; otherwise,
+ /// false.</value>
+ public bool IsEmpty
+ {
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "ConcurrencyCop just doesn't know about these locks")]
+ get
+ {
+ int acquiredLocks = 0;
+ try
+ {
+ // Acquire all locks
+ AcquireAllLocks(ref acquiredLocks);
+
+ for (int i = 0; i < m_tables.m_countPerLock.Length; i++)
+ {
+ if (m_tables.m_countPerLock[i] != 0)
+ {
+ return false;
+ }
+ }
+ }
+ finally
+ {
+ // Release locks that have been acquired earlier
+ ReleaseLocks(0, acquiredLocks);
+ }
+
+ return true;
+ }
+ }
+
+ #region IDictionary<TKey,TValue> members
+
+ /// <summary>
+ /// Adds the specified key and value to the <see
+ /// cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/>.
+ /// </summary>
+ /// <param name="key">The object to use as the key of the element to add.</param>
+ /// <param name="value">The object to use as the value of the element to add.</param>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.OverflowException">The dictionary contains too many
+ /// elements.</exception>
+ /// <exception cref="T:System.ArgumentException">
+ /// An element with the same key already exists in the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>.</exception>
+ void IDictionary<TKey, TValue>.Add(TKey key, TValue value)
+ {
+ if (!TryAdd(key, value))
+ {
+ throw new ArgumentException(GetResource("ConcurrentDictionary_KeyAlreadyExisted"));
+ }
+ }
+
+ /// <summary>
+ /// Removes the element with the specified key from the <see
+ /// cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/>.
+ /// </summary>
+ /// <param name="key">The key of the element to remove.</param>
+ /// <returns>true if the element is successfully remove; otherwise false. This method also returns
+ /// false if
+ /// <paramref name="key"/> was not found in the original <see
+ /// cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/>.
+ /// </returns>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ bool IDictionary<TKey, TValue>.Remove(TKey key)
+ {
+ TValue throwAwayValue;
+ return TryRemove(key, out throwAwayValue);
+ }
+
+ /// <summary>
+ /// Gets a collection containing the keys in the <see
+ /// cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/>.
+ /// </summary>
+ /// <value>An <see cref="T:System.Collections.Generic.ICollection{TKey}"/> containing the keys in the
+ /// <see cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/>.</value>
+ public ICollection<TKey> Keys
+ {
+ get { return GetKeys(); }
+ }
+
+ /// <summary>
+ /// Gets an <see cref="T:System.Collections.Generic.IEnumerable{TKey}"/> containing the keys of
+ /// the <see cref="T:System.Collections.Generic.IReadOnlyDictionary{TKey,TValue}"/>.
+ /// </summary>
+ /// <value>An <see cref="T:System.Collections.Generic.IEnumerable{TKey}"/> containing the keys of
+ /// the <see cref="T:System.Collections.Generic.IReadOnlyDictionary{TKey,TValue}"/>.</value>
+ IEnumerable<TKey> IReadOnlyDictionary<TKey, TValue>.Keys
+ {
+ get { return GetKeys(); }
+ }
+
+ /// <summary>
+ /// Gets a collection containing the values in the <see
+ /// cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/>.
+ /// </summary>
+ /// <value>An <see cref="T:System.Collections.Generic.ICollection{TValue}"/> containing the values in
+ /// the
+ /// <see cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/>.</value>
+ public ICollection<TValue> Values
+ {
+ get { return GetValues(); }
+ }
+
+ /// <summary>
+ /// Gets an <see cref="T:System.Collections.Generic.IEnumerable{TValue}"/> containing the values
+ /// in the <see cref="T:System.Collections.Generic.IReadOnlyDictionary{TKey,TValue}"/>.
+ /// </summary>
+ /// <value>An <see cref="T:System.Collections.Generic.IEnumerable{TValue}"/> containing the
+ /// values in the <see cref="T:System.Collections.Generic.IReadOnlyDictionary{TKey,TValue}"/>.</value>
+ IEnumerable<TValue> IReadOnlyDictionary<TKey, TValue>.Values
+ {
+ get { return GetValues(); }
+ }
+ #endregion
+
+ #region ICollection<KeyValuePair<TKey,TValue>> Members
+
+ /// <summary>
+ /// Adds the specified value to the <see cref="T:System.Collections.Generic.ICollection{TValue}"/>
+ /// with the specified key.
+ /// </summary>
+ /// <param name="keyValuePair">The <see cref="T:System.Collections.Generic.KeyValuePair{TKey,TValue}"/>
+ /// structure representing the key and value to add to the <see
+ /// cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/>.</param>
+ /// <exception cref="T:System.ArgumentNullException">The <paramref name="keyValuePair"/> of <paramref
+ /// name="keyValuePair"/> is null.</exception>
+ /// <exception cref="T:System.OverflowException">The <see
+ /// cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/>
+ /// contains too many elements.</exception>
+ /// <exception cref="T:System.ArgumentException">An element with the same key already exists in the
+ /// <see cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/></exception>
+ void ICollection<KeyValuePair<TKey, TValue>>.Add(KeyValuePair<TKey, TValue> keyValuePair)
+ {
+ ((IDictionary<TKey, TValue>)this).Add(keyValuePair.Key, keyValuePair.Value);
+ }
+
+ /// <summary>
+ /// Determines whether the <see cref="T:System.Collections.Generic.ICollection{TKey,TValue}"/>
+ /// contains a specific key and value.
+ /// </summary>
+ /// <param name="keyValuePair">The <see cref="T:System.Collections.Generic.KeyValuePair{TKey,TValue}"/>
+ /// structure to locate in the <see
+ /// cref="T:System.Collections.Generic.ICollection{TValue}"/>.</param>
+ /// <returns>true if the <paramref name="keyValuePair"/> is found in the <see
+ /// cref="T:System.Collections.Generic.ICollection{TKey,TValue}"/>; otherwise, false.</returns>
+ bool ICollection<KeyValuePair<TKey, TValue>>.Contains(KeyValuePair<TKey, TValue> keyValuePair)
+ {
+ TValue value;
+ if (!TryGetValue(keyValuePair.Key, out value))
+ {
+ return false;
+ }
+ return EqualityComparer<TValue>.Default.Equals(value, keyValuePair.Value);
+ }
+
+ /// <summary>
+ /// Gets a value indicating whether the dictionary is read-only.
+ /// </summary>
+ /// <value>true if the <see cref="T:System.Collections.Generic.ICollection{TKey,TValue}"/> is
+ /// read-only; otherwise, false. For <see
+ /// cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/>, this property always returns
+ /// false.</value>
+ bool ICollection<KeyValuePair<TKey, TValue>>.IsReadOnly
+ {
+ get { return false; }
+ }
+
+ /// <summary>
+ /// Removes a key and value from the dictionary.
+ /// </summary>
+ /// <param name="keyValuePair">The <see
+ /// cref="T:System.Collections.Generic.KeyValuePair{TKey,TValue}"/>
+ /// structure representing the key and value to remove from the <see
+ /// cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/>.</param>
+ /// <returns>true if the key and value represented by <paramref name="keyValuePair"/> is successfully
+ /// found and removed; otherwise, false.</returns>
+ /// <exception cref="T:System.ArgumentNullException">The Key property of <paramref
+ /// name="keyValuePair"/> is a null reference (Nothing in Visual Basic).</exception>
+ bool ICollection<KeyValuePair<TKey, TValue>>.Remove(KeyValuePair<TKey, TValue> keyValuePair)
+ {
+ if (keyValuePair.Key == null) throw new ArgumentNullException(GetResource("ConcurrentDictionary_ItemKeyIsNull"));
+
+ TValue throwAwayValue;
+ return TryRemoveInternal(keyValuePair.Key, out throwAwayValue, true, keyValuePair.Value);
+ }
+
+ #endregion
+
+ #region IEnumerable Members
+
+ /// <summary>Returns an enumerator that iterates through the <see
+ /// cref="ConcurrentDictionary{TKey,TValue}"/>.</summary>
+ /// <returns>An enumerator for the <see cref="ConcurrentDictionary{TKey,TValue}"/>.</returns>
+ /// <remarks>
+ /// The enumerator returned from the dictionary is safe to use concurrently with
+ /// reads and writes to the dictionary, however it does not represent a moment-in-time snapshot
+ /// of the dictionary. The contents exposed through the enumerator may contain modifications
+ /// made to the dictionary after <see cref="GetEnumerator"/> was called.
+ /// </remarks>
+ IEnumerator IEnumerable.GetEnumerator()
+ {
+ return ((ConcurrentDictionary<TKey, TValue>)this).GetEnumerator();
+ }
+
+ #endregion
+
+ #region IDictionary Members
+
+ /// <summary>
+ /// Adds the specified key and value to the dictionary.
+ /// </summary>
+ /// <param name="key">The object to use as the key.</param>
+ /// <param name="value">The object to use as the value.</param>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.OverflowException">The dictionary contains too many
+ /// elements.</exception>
+ /// <exception cref="T:System.ArgumentException">
+ /// <paramref name="key"/> is of a type that is not assignable to the key type <typeparamref
+ /// name="TKey"/> of the <see cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/>. -or-
+ /// <paramref name="value"/> is of a type that is not assignable to <typeparamref name="TValue"/>,
+ /// the type of values in the <see cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/>.
+ /// -or- A value with the same key already exists in the <see
+ /// cref="T:System.Collections.Generic.Dictionary{TKey,TValue}"/>.
+ /// </exception>
+ void IDictionary.Add(object key, object value)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+ if (!(key is TKey)) throw new ArgumentException(GetResource("ConcurrentDictionary_TypeOfKeyIncorrect"));
+
+ TValue typedValue;
+ try
+ {
+ typedValue = (TValue)value;
+ }
+ catch (InvalidCastException)
+ {
+ throw new ArgumentException(GetResource("ConcurrentDictionary_TypeOfValueIncorrect"));
+ }
+
+ ((IDictionary<TKey, TValue>)this).Add((TKey)key, typedValue);
+ }
+
+ /// <summary>
+ /// Gets whether the <see cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/> contains an
+ /// element with the specified key.
+ /// </summary>
+ /// <param name="key">The key to locate in the <see
+ /// cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/>.</param>
+ /// <returns>true if the <see cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/> contains
+ /// an element with the specified key; otherwise, false.</returns>
+ /// <exception cref="T:System.ArgumentNullException"> <paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ bool IDictionary.Contains(object key)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+
+ return (key is TKey) && ((ConcurrentDictionary<TKey, TValue>)this).ContainsKey((TKey)key);
+ }
+
+ /// <summary>Provides an <see cref="T:System.Collections.Generics.IDictionaryEnumerator"/> for the
+ /// <see cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/>.</summary>
+ /// <returns>An <see cref="T:System.Collections.Generics.IDictionaryEnumerator"/> for the <see
+ /// cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/>.</returns>
+ IDictionaryEnumerator IDictionary.GetEnumerator()
+ {
+ return new DictionaryEnumerator(this);
+ }
+
+ /// <summary>
+ /// Gets a value indicating whether the <see
+ /// cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/> has a fixed size.
+ /// </summary>
+ /// <value>true if the <see cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/> has a
+ /// fixed size; otherwise, false. For <see
+ /// cref="T:System.Collections.Generic.ConcurrentDictionary{TKey,TValue}"/>, this property always
+ /// returns false.</value>
+ bool IDictionary.IsFixedSize
+ {
+ get { return false; }
+ }
+
+ /// <summary>
+ /// Gets a value indicating whether the <see
+ /// cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/> is read-only.
+ /// </summary>
+ /// <value>true if the <see cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/> is
+ /// read-only; otherwise, false. For <see
+ /// cref="T:System.Collections.Generic.ConcurrentDictionary{TKey,TValue}"/>, this property always
+ /// returns false.</value>
+ bool IDictionary.IsReadOnly
+ {
+ get { return false; }
+ }
+
+ /// <summary>
+ /// Gets an <see cref="T:System.Collections.ICollection"/> containing the keys of the <see
+ /// cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/>.
+ /// </summary>
+ /// <value>An <see cref="T:System.Collections.ICollection"/> containing the keys of the <see
+ /// cref="T:System.Collections.Generic.IDictionary{TKey,TValue}"/>.</value>
+ ICollection IDictionary.Keys
+ {
+ get { return GetKeys(); }
+ }
+
+ /// <summary>
+ /// Removes the element with the specified key from the <see
+ /// cref="T:System.Collections.IDictionary"/>.
+ /// </summary>
+ /// <param name="key">The key of the element to remove.</param>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ void IDictionary.Remove(object key)
+ {
+ if (key == null) throw new ArgumentNullException("key");
+
+ TValue throwAwayValue;
+ if (key is TKey)
+ {
+ this.TryRemove((TKey)key, out throwAwayValue);
+ }
+ }
+
+ /// <summary>
+ /// Gets an <see cref="T:System.Collections.ICollection"/> containing the values in the <see
+ /// cref="T:System.Collections.IDictionary"/>.
+ /// </summary>
+ /// <value>An <see cref="T:System.Collections.ICollection"/> containing the values in the <see
+ /// cref="T:System.Collections.IDictionary"/>.</value>
+ ICollection IDictionary.Values
+ {
+ get { return GetValues(); }
+ }
+
+ /// <summary>
+ /// Gets or sets the value associated with the specified key.
+ /// </summary>
+ /// <param name="key">The key of the value to get or set.</param>
+ /// <value>The value associated with the specified key, or a null reference (Nothing in Visual Basic)
+ /// if <paramref name="key"/> is not in the dictionary or <paramref name="key"/> is of a type that is
+ /// not assignable to the key type <typeparamref name="TKey"/> of the <see
+ /// cref="T:System.Collections.Generic.ConcurrentDictionary{TKey,TValue}"/>.</value>
+ /// <exception cref="T:System.ArgumentNullException"><paramref name="key"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.ArgumentException">
+ /// A value is being assigned, and <paramref name="key"/> is of a type that is not assignable to the
+ /// key type <typeparamref name="TKey"/> of the <see
+ /// cref="T:System.Collections.Generic.ConcurrentDictionary{TKey,TValue}"/>. -or- A value is being
+ /// assigned, and <paramref name="key"/> is of a type that is not assignable to the value type
+ /// <typeparamref name="TValue"/> of the <see
+ /// cref="T:System.Collections.Generic.ConcurrentDictionary{TKey,TValue}"/>
+ /// </exception>
+ object IDictionary.this[object key]
+ {
+ get
+ {
+ if (key == null) throw new ArgumentNullException("key");
+
+ TValue value;
+ if (key is TKey && this.TryGetValue((TKey)key, out value))
+ {
+ return value;
+ }
+
+ return null;
+ }
+ set
+ {
+ if (key == null) throw new ArgumentNullException("key");
+
+ if (!(key is TKey)) throw new ArgumentException(GetResource("ConcurrentDictionary_TypeOfKeyIncorrect"));
+ if (!(value is TValue)) throw new ArgumentException(GetResource("ConcurrentDictionary_TypeOfValueIncorrect"));
+
+ ((ConcurrentDictionary<TKey, TValue>)this)[(TKey)key] = (TValue)value;
+ }
+ }
+
+ #endregion
+
+ #region ICollection Members
+
+ /// <summary>
+ /// Copies the elements of the <see cref="T:System.Collections.ICollection"/> to an array, starting
+ /// at the specified array index.
+ /// </summary>
+ /// <param name="array">The one-dimensional array that is the destination of the elements copied from
+ /// the <see cref="T:System.Collections.ICollection"/>. 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="T:System.ArgumentNullException"><paramref name="array"/> is a null reference
+ /// (Nothing in Visual Basic).</exception>
+ /// <exception cref="T:System.ArgumentOutOfRangeException"><paramref name="index"/> is less than
+ /// 0.</exception>
+ /// <exception cref="T:System.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="T:System.Collections.ICollection"/>
+ /// is greater than the available space from <paramref name="index"/> to the end of the destination
+ /// <paramref name="array"/>.</exception>
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "ConcurrencyCop just doesn't know about these locks")]
+ void ICollection.CopyTo(Array array, int index)
+ {
+ if (array == null) throw new ArgumentNullException("array");
+ if (index < 0) throw new ArgumentOutOfRangeException("index", GetResource("ConcurrentDictionary_IndexIsNegative"));
+
+ int locksAcquired = 0;
+ try
+ {
+ AcquireAllLocks(ref locksAcquired);
+ Tables tables = m_tables;
+
+ int count = 0;
+
+ for (int i = 0; i < tables.m_locks.Length && count >= 0; i++)
+ {
+ count += tables.m_countPerLock[i];
+ }
+
+ if (array.Length - count < index || count < 0) //"count" itself or "count + index" can overflow
+ {
+ throw new ArgumentException(GetResource("ConcurrentDictionary_ArrayNotLargeEnough"));
+ }
+
+ // To be consistent with the behavior of ICollection.CopyTo() in Dictionary<TKey,TValue>,
+ // we recognize three types of target arrays:
+ // - an array of KeyValuePair<TKey, TValue> structs
+ // - an array of DictionaryEntry structs
+ // - an array of objects
+
+ KeyValuePair<TKey, TValue>[] pairs = array as KeyValuePair<TKey, TValue>[];
+ if (pairs != null)
+ {
+ CopyToPairs(pairs, index);
+ return;
+ }
+
+ DictionaryEntry[] entries = array as DictionaryEntry[];
+ if (entries != null)
+ {
+ CopyToEntries(entries, index);
+ return;
+ }
+
+ object[] objects = array as object[];
+ if (objects != null)
+ {
+ CopyToObjects(objects, index);
+ return;
+ }
+
+ throw new ArgumentException(GetResource("ConcurrentDictionary_ArrayIncorrectType"), "array");
+ }
+ finally
+ {
+ ReleaseLocks(0, locksAcquired);
+ }
+ }
+
+ /// <summary>
+ /// Gets a value indicating whether access to the <see cref="T:System.Collections.ICollection"/> is
+ /// synchronized with the SyncRoot.
+ /// </summary>
+ /// <value>true if access to the <see cref="T:System.Collections.ICollection"/> is synchronized
+ /// (thread safe); otherwise, false. For <see
+ /// cref="T:System.Collections.Concurrent.ConcurrentDictionary{TKey,TValue}"/>, this property always
+ /// returns false.</value>
+ bool ICollection.IsSynchronized
+ {
+ get { return false; }
+ }
+
+ /// <summary>
+ /// Gets an object that can be used to synchronize access to the <see
+ /// cref="T:System.Collections.ICollection"/>. This property is not supported.
+ /// </summary>
+ /// <exception cref="T:System.NotSupportedException">The SyncRoot property is not supported.</exception>
+ object ICollection.SyncRoot
+ {
+ get
+ {
+ throw new NotSupportedException(Environment.GetResourceString("ConcurrentCollection_SyncRoot_NotSupported"));
+ }
+ }
+
+ #endregion
+
+ /// <summary>
+ /// Replaces the bucket table with a larger one. To prevent multiple threads from resizing the
+ /// table as a result of a race condition, the Tables instance that holds the table of buckets deemed too
+ /// small is passed in as an argument to GrowTable(). GrowTable() obtains a lock, and then checks
+ /// the Tables instance has been replaced in the meantime or not.
+ /// The <paramref name="rehashCount"/> will be used to ensure that we don't do two subsequent resizes
+ /// because of a collision
+ /// </summary>
+ private void GrowTable(Tables tables, IEqualityComparer<TKey> newComparer, bool regenerateHashKeys, int rehashCount)
+ {
+ int locksAcquired = 0;
+ try
+ {
+ // The thread that first obtains m_locks[0] will be the one doing the resize operation
+ AcquireLocks(0, 1, ref locksAcquired);
+
+ if (regenerateHashKeys && rehashCount == m_keyRehashCount)
+ {
+ // This method is called with regenerateHashKeys==true when we detected
+ // more than HashHelpers.HashCollisionThreshold collisions when adding a new element.
+ // In that case we are in the process of switching to another (randomized) comparer
+ // and we have to re-hash all the keys in the table.
+ // We are only going to do this if we did not just rehash the entire table while waiting for the lock
+ tables = m_tables;
+ }
+ else
+ {
+ // If we don't require a regeneration of hash keys we want to make sure we don't do work when
+ // we don't have to
+ if (tables != m_tables)
+ {
+ // We assume that since the table reference is different, it was already resized (or the budget
+ // was adjusted). If we ever decide to do table shrinking, or replace the table for other reasons,
+ // we will have to revisit this logic.
+ return;
+ }
+
+ // Compute the (approx.) total size. Use an Int64 accumulation variable to avoid an overflow.
+ long approxCount = 0;
+ for (int i = 0; i < tables.m_countPerLock.Length; i++)
+ {
+ approxCount += tables.m_countPerLock[i];
+ }
+
+ //
+ // If the bucket array is too empty, double the budget instead of resizing the table
+ //
+ if (approxCount < tables.m_buckets.Length / 4)
+ {
+ m_budget = 2 * m_budget;
+ if (m_budget < 0)
+ {
+ m_budget = int.MaxValue;
+ }
+
+ return;
+ }
+ }
+ // Compute the new table size. We find the smallest integer larger than twice the previous table size, and not divisible by
+ // 2,3,5 or 7. We can consider a different table-sizing policy in the future.
+ int newLength = 0;
+ bool maximizeTableSize = false;
+ try
+ {
+ checked
+ {
+ // Double the size of the buckets table and add one, so that we have an odd integer.
+ newLength = tables.m_buckets.Length * 2 + 1;
+
+ // Now, we only need to check odd integers, and find the first that is not divisible
+ // by 3, 5 or 7.
+ while (newLength % 3 == 0 || newLength % 5 == 0 || newLength % 7 == 0)
+ {
+ newLength += 2;
+ }
+
+ Assert(newLength % 2 != 0);
+
+ if (newLength > Array.MaxArrayLength)
+ {
+ maximizeTableSize = true;
+ }
+ }
+ }
+ catch (OverflowException)
+ {
+ maximizeTableSize = true;
+ }
+
+ if (maximizeTableSize)
+ {
+ newLength = Array.MaxArrayLength;
+
+ // We want to make sure that GrowTable will not be called again, since table is at the maximum size.
+ // To achieve that, we set the budget to int.MaxValue.
+ //
+ // (There is one special case that would allow GrowTable() to be called in the future:
+ // calling Clear() on the ConcurrentDictionary will shrink the table and lower the budget.)
+ m_budget = int.MaxValue;
+ }
+
+ // Now acquire all other locks for the table
+ AcquireLocks(1, tables.m_locks.Length, ref locksAcquired);
+
+ object[] newLocks = tables.m_locks;
+
+ // Add more locks
+ if (m_growLockArray && tables.m_locks.Length < MAX_LOCK_NUMBER)
+ {
+ newLocks = new object[tables.m_locks.Length * 2];
+ Array.Copy(tables.m_locks, newLocks, tables.m_locks.Length);
+
+ for (int i = tables.m_locks.Length; i < newLocks.Length; i++)
+ {
+ newLocks[i] = new object();
+ }
+ }
+
+ Node[] newBuckets = new Node[newLength];
+ int[] newCountPerLock = new int[newLocks.Length];
+
+ // Copy all data into a new table, creating new nodes for all elements
+ for (int i = 0; i < tables.m_buckets.Length; i++)
+ {
+ Node current = tables.m_buckets[i];
+ while (current != null)
+ {
+ Node next = current.m_next;
+ int newBucketNo, newLockNo;
+ int nodeHashCode = current.m_hashcode;
+
+ if (regenerateHashKeys)
+ {
+ // Recompute the hash from the key
+ nodeHashCode = newComparer.GetHashCode(current.m_key);
+ }
+
+ GetBucketAndLockNo(nodeHashCode, out newBucketNo, out newLockNo, newBuckets.Length, newLocks.Length);
+
+ newBuckets[newBucketNo] = new Node(current.m_key, current.m_value, nodeHashCode, newBuckets[newBucketNo]);
+
+ checked
+ {
+ newCountPerLock[newLockNo]++;
+ }
+
+ current = next;
+ }
+ }
+
+ // If this resize regenerated the hashkeys, increment the count
+ if (regenerateHashKeys)
+ {
+ // We use unchecked here because we don't want to throw an exception if
+ // an overflow happens
+ unchecked
+ {
+ m_keyRehashCount++;
+ }
+ }
+
+ // Adjust the budget
+ m_budget = Math.Max(1, newBuckets.Length / newLocks.Length);
+
+ // Replace tables with the new versions
+ m_tables = new Tables(newBuckets, newLocks, newCountPerLock, newComparer);
+ }
+ finally
+ {
+ // Release all locks that we took earlier
+ ReleaseLocks(0, locksAcquired);
+ }
+ }
+
+ /// <summary>
+ /// Computes the bucket and lock number for a particular key.
+ /// </summary>
+ private void GetBucketAndLockNo(
+ int hashcode, out int bucketNo, out int lockNo, int bucketCount, int lockCount)
+ {
+ bucketNo = (hashcode & 0x7fffffff) % bucketCount;
+ lockNo = bucketNo % lockCount;
+
+ Assert(bucketNo >= 0 && bucketNo < bucketCount);
+ Assert(lockNo >= 0 && lockNo < lockCount);
+ }
+
+ /// <summary>
+ /// The number of concurrent writes for which to optimize by default.
+ /// </summary>
+ private static int DefaultConcurrencyLevel
+ {
+
+ get { return DEFAULT_CONCURRENCY_MULTIPLIER * PlatformHelper.ProcessorCount; }
+ }
+
+ /// <summary>
+ /// Acquires all locks for this hash table, and increments locksAcquired by the number
+ /// of locks that were successfully acquired. The locks are acquired in an increasing
+ /// order.
+ /// </summary>
+ private void AcquireAllLocks(ref int locksAcquired)
+ {
+#if !FEATURE_CORECLR
+ if (CDSCollectionETWBCLProvider.Log.IsEnabled())
+ {
+ CDSCollectionETWBCLProvider.Log.ConcurrentDictionary_AcquiringAllLocks(m_tables.m_buckets.Length);
+ }
+#endif //!FEATURE_CORECLR
+
+ // First, acquire lock 0
+ AcquireLocks(0, 1, ref locksAcquired);
+
+ // Now that we have lock 0, the m_locks array will not change (i.e., grow),
+ // and so we can safely read m_locks.Length.
+ AcquireLocks(1, m_tables.m_locks.Length, ref locksAcquired);
+ Assert(locksAcquired == m_tables.m_locks.Length);
+ }
+
+ /// <summary>
+ /// Acquires a contiguous range of locks for this hash table, and increments locksAcquired
+ /// by the number of locks that were successfully acquired. The locks are acquired in an
+ /// increasing order.
+ /// </summary>
+ private void AcquireLocks(int fromInclusive, int toExclusive, ref int locksAcquired)
+ {
+ Assert(fromInclusive <= toExclusive);
+ object[] locks = m_tables.m_locks;
+
+ for (int i = fromInclusive; i < toExclusive; i++)
+ {
+ bool lockTaken = false;
+ try
+ {
+ Monitor.Enter(locks[i], ref lockTaken);
+ }
+ finally
+ {
+ if (lockTaken)
+ {
+ locksAcquired++;
+ }
+ }
+ }
+ }
+
+ /// <summary>
+ /// Releases a contiguous range of locks.
+ /// </summary>
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "Reviewed for thread safety")]
+ private void ReleaseLocks(int fromInclusive, int toExclusive)
+ {
+ Assert(fromInclusive <= toExclusive);
+
+ for (int i = fromInclusive; i < toExclusive; i++)
+ {
+ Monitor.Exit(m_tables.m_locks[i]);
+ }
+ }
+
+ /// <summary>
+ /// Gets a collection containing the keys in the dictionary.
+ /// </summary>
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "ConcurrencyCop just doesn't know about these locks")]
+ private ReadOnlyCollection<TKey> GetKeys()
+ {
+ int locksAcquired = 0;
+ try
+ {
+ AcquireAllLocks(ref locksAcquired);
+ List<TKey> keys = new List<TKey>();
+
+ for (int i = 0; i < m_tables.m_buckets.Length; i++)
+ {
+ Node current = m_tables.m_buckets[i];
+ while (current != null)
+ {
+ keys.Add(current.m_key);
+ current = current.m_next;
+ }
+ }
+
+ return new ReadOnlyCollection<TKey>(keys);
+ }
+ finally
+ {
+ ReleaseLocks(0, locksAcquired);
+ }
+ }
+
+ /// <summary>
+ /// Gets a collection containing the values in the dictionary.
+ /// </summary>
+ [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "ConcurrencyCop just doesn't know about these locks")]
+ private ReadOnlyCollection<TValue> GetValues()
+ {
+ int locksAcquired = 0;
+ try
+ {
+ AcquireAllLocks(ref locksAcquired);
+ List<TValue> values = new List<TValue>();
+
+ for (int i = 0; i < m_tables.m_buckets.Length; i++)
+ {
+ Node current = m_tables.m_buckets[i];
+ while (current != null)
+ {
+ values.Add(current.m_value);
+ current = current.m_next;
+ }
+ }
+
+ return new ReadOnlyCollection<TValue>(values);
+ }
+ finally
+ {
+ ReleaseLocks(0, locksAcquired);
+ }
+ }
+
+ /// <summary>
+ /// A helper method for asserts.
+ /// </summary>
+ [Conditional("DEBUG")]
+ private void Assert(bool condition)
+ {
+ Contract.Assert(condition);
+ }
+
+ /// <summary>
+ /// A helper function to obtain the string for a particular resource key.
+ /// </summary>
+ /// <param name="key"></param>
+ /// <returns></returns>
+ private string GetResource(string key)
+ {
+ Assert(key != null);
+
+ return Environment.GetResourceString(key);
+ }
+
+ /// <summary>
+ /// A node in a singly-linked list representing a particular hash table bucket.
+ /// </summary>
+ private class Node
+ {
+ internal TKey m_key;
+ internal TValue m_value;
+ internal volatile Node m_next;
+ internal int m_hashcode;
+
+ internal Node(TKey key, TValue value, int hashcode, Node next)
+ {
+ m_key = key;
+ m_value = value;
+ m_next = next;
+ m_hashcode = hashcode;
+ }
+ }
+
+ /// <summary>
+ /// A private class to represent enumeration over the dictionary that implements the
+ /// IDictionaryEnumerator interface.
+ /// </summary>
+ private class DictionaryEnumerator : IDictionaryEnumerator
+ {
+ IEnumerator<KeyValuePair<TKey, TValue>> m_enumerator; // Enumerator over the dictionary.
+
+ internal DictionaryEnumerator(ConcurrentDictionary<TKey, TValue> dictionary)
+ {
+ m_enumerator = dictionary.GetEnumerator();
+ }
+
+ public DictionaryEntry Entry
+ {
+ get { return new DictionaryEntry(m_enumerator.Current.Key, m_enumerator.Current.Value); }
+ }
+
+ public object Key
+ {
+ get { return m_enumerator.Current.Key; }
+ }
+
+ public object Value
+ {
+ get { return m_enumerator.Current.Value; }
+ }
+
+ public object Current
+ {
+ get { return this.Entry; }
+ }
+
+ public bool MoveNext()
+ {
+ return m_enumerator.MoveNext();
+ }
+
+ public void Reset()
+ {
+ m_enumerator.Reset();
+ }
+ }
+
+#if !FEATURE_CORECLR
+ /// <summary>
+ /// Get the data array to be serialized
+ /// </summary>
+ [OnSerializing]
+ private void OnSerializing(StreamingContext context)
+ {
+ Tables tables = m_tables;
+
+ // save the data into the serialization array to be saved
+ m_serializationArray = ToArray();
+ m_serializationConcurrencyLevel = tables.m_locks.Length;
+ m_serializationCapacity = tables.m_buckets.Length;
+ m_comparer = (IEqualityComparer<TKey>)HashHelpers.GetEqualityComparerForSerialization(tables.m_comparer);
+ }
+
+ /// <summary>
+ /// Construct the dictionary from a previously serialized one
+ /// </summary>
+ [OnDeserialized]
+ private void OnDeserialized(StreamingContext context)
+ {
+ KeyValuePair<TKey, TValue>[] array = m_serializationArray;
+
+ var buckets = new Node[m_serializationCapacity];
+ var countPerLock = new int[m_serializationConcurrencyLevel];
+
+ var locks = new object[m_serializationConcurrencyLevel];
+ for (int i = 0; i < locks.Length; i++)
+ {
+ locks[i] = new object();
+ }
+
+ m_tables = new Tables(buckets, locks, countPerLock, m_comparer);
+
+ InitializeFromCollection(array);
+ m_serializationArray = null;
+
+ }
+#endif
+ }
+}