/
BlockingCollection.cs
1755 lines (1607 loc) · 100 KB
/
BlockingCollection.cs
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
//
// BlockingCollection.cs
//
// A class that implements the bounding and blocking functionality while abstracting away
// the underlying storage mechanism. This file also contains BlockingCollection's
// associated debugger view type.
//
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
using System.Collections.Generic;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Runtime.Versioning;
using System.Threading;
namespace System.Collections.Concurrent
{
/// <summary>
/// Provides blocking and bounding capabilities for thread-safe collections that
/// implement <see cref="System.Collections.Concurrent.IProducerConsumerCollection{T}"/>.
/// </summary>
/// <remarks>
/// <see cref="System.Collections.Concurrent.IProducerConsumerCollection{T}"/> represents a collection
/// that allows for thread-safe adding and removing of data.
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> is used as a wrapper
/// for an <see cref="System.Collections.Concurrent.IProducerConsumerCollection{T}"/> instance, allowing
/// removal attempts from the collection to block until data is available to be removed. Similarly,
/// a <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> can be created to enforce
/// an upper-bound on the number of data elements allowed in the
/// <see cref="System.Collections.Concurrent.IProducerConsumerCollection{T}"/>; addition attempts to the
/// collection may then block until space is available to store the added items. In this manner,
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> is similar to a traditional
/// blocking queue data structure, except that the underlying data storage mechanism is abstracted
/// away as an <see cref="System.Collections.Concurrent.IProducerConsumerCollection{T}"/>.
/// </remarks>
/// <typeparam name="T">Specifies the type of elements in the collection.</typeparam>
[UnsupportedOSPlatform("browser")]
[DebuggerTypeProxy(typeof(BlockingCollectionDebugView<>))]
[DebuggerDisplay("Count = {Count}, Type = {_collection}")]
public class BlockingCollection<T> : IEnumerable<T>, ICollection, IDisposable, IReadOnlyCollection<T>
{
private IProducerConsumerCollection<T> _collection;
private int _boundedCapacity;
private const int NON_BOUNDED = -1;
private SemaphoreSlim? _freeNodes;
private SemaphoreSlim _occupiedNodes;
private bool _isDisposed;
private CancellationTokenSource _consumersCancellationTokenSource;
private CancellationTokenSource _producersCancellationTokenSource;
private volatile int _currentAdders;
private const int COMPLETE_ADDING_ON_MASK = unchecked((int)0x80000000);
#region Properties
/// <summary>Gets the bounded capacity of this <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> instance.</summary>
/// <value>The bounded capacity of this collection, or -1 if no bound was supplied.</value>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
public int BoundedCapacity
{
get
{
CheckDisposed();
return _boundedCapacity;
}
}
/// <summary>Gets whether this <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been marked as complete for adding.</summary>
/// <value>Whether this collection has been marked as complete for adding.</value>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
public bool IsAddingCompleted
{
get
{
CheckDisposed();
return (_currentAdders == COMPLETE_ADDING_ON_MASK);
}
}
/// <summary>Gets whether this <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been marked as complete for adding and is empty.</summary>
/// <value>Whether this collection has been marked as complete for adding and is empty.</value>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
public bool IsCompleted
{
get
{
CheckDisposed();
return (IsAddingCompleted && (_occupiedNodes.CurrentCount == 0));
}
}
/// <summary>Gets the number of items contained in the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.</summary>
/// <value>The number of items contained in the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.</value>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
public int Count
{
get
{
CheckDisposed();
return _occupiedNodes.CurrentCount;
}
}
/// <summary>Gets a value indicating whether access to the <see cref="System.Collections.ICollection"/> is synchronized.</summary>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
bool ICollection.IsSynchronized
{
get
{
CheckDisposed();
return false;
}
}
/// <summary>
/// Gets an object that can be used to synchronize access to the <see
/// cref="System.Collections.ICollection"/>. This property is not supported.
/// </summary>
/// <exception cref="System.NotSupportedException">The SyncRoot property is not supported.</exception>
object ICollection.SyncRoot
{
get
{
throw new NotSupportedException(SR.ConcurrentCollection_SyncRoot_NotSupported);
}
}
#endregion
/// <summary>Initializes a new instance of the
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>
/// class without an upper-bound.
/// </summary>
/// <remarks>
/// The default underlying collection is a <see cref="System.Collections.Concurrent.ConcurrentQueue{T}">ConcurrentQueue<T></see>.
/// </remarks>
public BlockingCollection()
: this(new ConcurrentQueue<T>())
{
}
/// <summary>Initializes a new instance of the <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/>
/// class with the specified upper-bound.
/// </summary>
/// <param name="boundedCapacity">The bounded size of the collection.</param>
/// <exception cref="System.ArgumentOutOfRangeException">The <paramref name="boundedCapacity"/> is
/// not a positive value.</exception>
/// <remarks>
/// The default underlying collection is a <see cref="System.Collections.Concurrent.ConcurrentQueue{T}">ConcurrentQueue<T></see>.
/// </remarks>
public BlockingCollection(int boundedCapacity)
: this(new ConcurrentQueue<T>(), boundedCapacity)
{
}
/// <summary>Initializes a new instance of the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>
/// class with the specified upper-bound and using the provided
/// <see cref="System.Collections.Concurrent.IProducerConsumerCollection{T}"/> as its underlying data store.</summary>
/// <param name="collection">The collection to use as the underlying data store.</param>
/// <param name="boundedCapacity">The bounded size of the collection.</param>
/// <exception cref="System.ArgumentNullException">The <paramref name="collection"/> argument is
/// null.</exception>
/// <exception cref="System.ArgumentOutOfRangeException">The <paramref name="boundedCapacity"/> is not a positive value.</exception>
/// <exception cref="System.ArgumentException">The supplied <paramref name="collection"/> contains more values
/// than is permitted by <paramref name="boundedCapacity"/>.</exception>
public BlockingCollection(IProducerConsumerCollection<T> collection, int boundedCapacity)
{
ArgumentNullException.ThrowIfNull(collection);
ArgumentOutOfRangeException.ThrowIfNegativeOrZero(boundedCapacity);
int count = collection.Count;
if (count > boundedCapacity)
{
throw new ArgumentException(SR.BlockingCollection_ctor_CountMoreThanCapacity);
}
Initialize(collection, boundedCapacity, count);
}
/// <summary>Initializes a new instance of the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>
/// class without an upper-bound and using the provided
/// <see cref="System.Collections.Concurrent.IProducerConsumerCollection{T}"/> as its underlying data store.</summary>
/// <param name="collection">The collection to use as the underlying data store.</param>
/// <exception cref="System.ArgumentNullException">The <paramref name="collection"/> argument is
/// null.</exception>
public BlockingCollection(IProducerConsumerCollection<T> collection)
{
ArgumentNullException.ThrowIfNull(collection);
Initialize(collection, NON_BOUNDED, collection.Count);
}
/// <summary>Initializes the BlockingCollection instance.</summary>
/// <param name="collection">The collection to use as the underlying data store.</param>
/// <param name="boundedCapacity">The bounded size of the collection.</param>
/// <param name="collectionCount">The number of items currently in the underlying collection.</param>
[MemberNotNull(nameof(_collection))]
[MemberNotNull(nameof(_consumersCancellationTokenSource))]
[MemberNotNull(nameof(_producersCancellationTokenSource))]
[MemberNotNull(nameof(_occupiedNodes))]
private void Initialize(IProducerConsumerCollection<T> collection, int boundedCapacity, int collectionCount)
{
Debug.Assert(boundedCapacity > 0 || boundedCapacity == NON_BOUNDED);
_collection = collection;
_boundedCapacity = boundedCapacity;
_isDisposed = false;
_consumersCancellationTokenSource = new CancellationTokenSource();
_producersCancellationTokenSource = new CancellationTokenSource();
if (boundedCapacity == NON_BOUNDED)
{
_freeNodes = null;
}
else
{
Debug.Assert(boundedCapacity > 0);
_freeNodes = new SemaphoreSlim(boundedCapacity - collectionCount);
}
_occupiedNodes = new SemaphoreSlim(collectionCount);
}
/// <summary>
/// Adds the item to the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.
/// </summary>
/// <param name="item">The item to be added to the collection. The value can be a null reference.</param>
/// <exception cref="System.InvalidOperationException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been marked
/// as complete with regards to additions.</exception>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection didn't accept the item.</exception>
/// <remarks>
/// If a bounded capacity was specified when this instance of
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> was initialized,
/// a call to Add may block until space is available to store the provided item.
/// </remarks>
public void Add(T item)
{
#if DEBUG
bool tryAddReturnValue =
#endif
TryAddWithNoTimeValidation(item, Timeout.Infinite, CancellationToken.None);
#if DEBUG
Debug.Assert(tryAddReturnValue, "TryAdd() was expected to return true.");
#endif
}
/// <summary>
/// Adds the item to the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.
/// A <see cref="System.OperationCanceledException"/> is thrown if the <see cref="CancellationToken"/> is
/// canceled.
/// </summary>
/// <param name="item">The item to be added to the collection. The value can be a null reference.</param>
/// <param name="cancellationToken">A cancellation token to observe.</param>
/// <exception cref="OperationCanceledException">If the <see cref="CancellationToken"/> is canceled.</exception>
/// <exception cref="System.InvalidOperationException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been marked
/// as complete with regards to additions.</exception>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection didn't accept the item.</exception>
/// <remarks>
/// If a bounded capacity was specified when this instance of
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> was initialized,
/// a call to <see cref="Add(T,System.Threading.CancellationToken)"/> may block until space is available to store the provided item.
/// </remarks>
public void Add(T item, CancellationToken cancellationToken)
{
#if DEBUG
bool tryAddReturnValue =
#endif
TryAddWithNoTimeValidation(item, Timeout.Infinite, cancellationToken);
#if DEBUG
Debug.Assert(tryAddReturnValue, "TryAdd() was expected to return true.");
#endif
}
/// <summary>
/// Attempts to add the specified item to the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.
/// </summary>
/// <param name="item">The item to be added to the collection.</param>
/// <returns>true if the <paramref name="item"/> could be added; otherwise, false.</returns>
/// <exception cref="System.InvalidOperationException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been marked
/// as complete with regards to additions.</exception>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection didn't accept the item.</exception>
public bool TryAdd(T item)
{
return TryAddWithNoTimeValidation(item, 0, CancellationToken.None);
}
/// <summary>
/// Attempts to add the specified item to the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.
/// </summary>
/// <param name="item">The item to be added to the collection.</param>
/// <param name="timeout">A <see cref="System.TimeSpan"/> that represents the number of milliseconds
/// to wait, or a <see cref="System.TimeSpan"/> that represents -1 milliseconds to wait indefinitely.
/// </param>
/// <returns>true if the <paramref name="item"/> could be added to the collection within
/// the alloted time; otherwise, false.</returns>
/// <exception cref="System.InvalidOperationException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been marked
/// as complete with regards to additions.</exception>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.ArgumentOutOfRangeException"><paramref name="timeout"/> is a negative number
/// other than -1 milliseconds, which represents an infinite time-out -or- timeout is greater than
/// <see cref="int.MaxValue"/>.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection didn't accept the item.</exception>
public bool TryAdd(T item, TimeSpan timeout)
{
ValidateTimeout(timeout);
return TryAddWithNoTimeValidation(item, (int)timeout.TotalMilliseconds, CancellationToken.None);
}
/// <summary>
/// Attempts to add the specified item to the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.
/// </summary>
/// <param name="item">The item to be added to the collection.</param>
/// <param name="millisecondsTimeout">The number of milliseconds to wait, or <see
/// cref="System.Threading.Timeout.Infinite"/> (-1) to wait indefinitely.</param>
/// <returns>true if the <paramref name="item"/> could be added to the collection within
/// the alloted time; otherwise, false.</returns>
/// <exception cref="System.InvalidOperationException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been marked
/// as complete with regards to additions.</exception>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.ArgumentOutOfRangeException"><paramref name="millisecondsTimeout"/> is a
/// negative number other than -1, which represents an infinite time-out.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection didn't accept the item.</exception>
public bool TryAdd(T item, int millisecondsTimeout)
{
ValidateMillisecondsTimeout(millisecondsTimeout);
return TryAddWithNoTimeValidation(item, millisecondsTimeout, CancellationToken.None);
}
/// <summary>
/// Attempts to add the specified item to the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.
/// A <see cref="System.OperationCanceledException"/> is thrown if the <see cref="CancellationToken"/> is
/// canceled.
/// </summary>
/// <param name="item">The item to be added to the collection.</param>
/// <param name="millisecondsTimeout">The number of milliseconds to wait, or <see
/// cref="System.Threading.Timeout.Infinite"/> (-1) to wait indefinitely.</param>
/// <param name="cancellationToken">A cancellation token to observe.</param>
/// <returns>true if the <paramref name="item"/> could be added to the collection within
/// the alloted time; otherwise, false.</returns>
/// <exception cref="OperationCanceledException">If the <see cref="CancellationToken"/> is canceled.</exception>
/// <exception cref="System.InvalidOperationException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been marked
/// as complete with regards to additions.</exception>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.ArgumentOutOfRangeException"><paramref name="millisecondsTimeout"/> is a
/// negative number other than -1, which represents an infinite time-out.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection didn't accept the item.</exception>
public bool TryAdd(T item, int millisecondsTimeout, CancellationToken cancellationToken)
{
ValidateMillisecondsTimeout(millisecondsTimeout);
return TryAddWithNoTimeValidation(item, millisecondsTimeout, cancellationToken);
}
/// <summary>Adds an item into the underlying data store using its IProducerConsumerCollection<T>.Add
/// method. If a bounded capacity was specified and the collection was full,
/// this method will wait for, at most, the timeout period trying to add the item.
/// If the timeout period was exhausted before successfully adding the item this method will
/// return false.</summary>
/// <param name="item">The item to be added to the collection.</param>
/// <param name="millisecondsTimeout">The number of milliseconds to wait for the collection to accept the item,
/// or Timeout.Infinite to wait indefinitely.</param>
/// <param name="cancellationToken">A cancellation token to observe.</param>
/// <returns>False if the collection remained full till the timeout period was exhausted.True otherwise.</returns>
/// <exception cref="OperationCanceledException">If the <see cref="CancellationToken"/> is canceled.</exception>
/// <exception cref="System.InvalidOperationException">the collection has already been marked
/// as complete with regards to additions.</exception>
/// <exception cref="System.ObjectDisposedException">If the collection has been disposed.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection didn't accept the item.</exception>
private bool TryAddWithNoTimeValidation(T item, int millisecondsTimeout, CancellationToken cancellationToken)
{
CheckDisposed();
cancellationToken.ThrowIfCancellationRequested();
if (IsAddingCompleted)
{
throw new InvalidOperationException(SR.BlockingCollection_Completed);
}
bool waitForSemaphoreWasSuccessful = true;
if (_freeNodes != null)
{
//If the _freeNodes semaphore threw OperationCanceledException then this means that CompleteAdding()
//was called concurrently with Adding which is not supported by BlockingCollection.
CancellationTokenSource? linkedTokenSource = null;
try
{
waitForSemaphoreWasSuccessful = _freeNodes.Wait(0, default);
if (waitForSemaphoreWasSuccessful == false && millisecondsTimeout != 0)
{
linkedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(
cancellationToken, _producersCancellationTokenSource.Token);
waitForSemaphoreWasSuccessful = _freeNodes.Wait(millisecondsTimeout, linkedTokenSource.Token);
}
}
catch (OperationCanceledException)
{
//if cancellation was via external token, throw an OCE
cancellationToken.ThrowIfCancellationRequested();
//if cancellation was via internal token, this indicates invalid use, hence InvalidOpEx.
//Debug.Assert(_ProducersCancellationTokenSource.Token.IsCancellationRequested);
throw new InvalidOperationException
(SR.BlockingCollection_Add_ConcurrentCompleteAdd);
}
finally
{
linkedTokenSource?.Dispose();
}
}
if (waitForSemaphoreWasSuccessful)
{
// Update the adders count if the complete adding was not requested, otherwise
// spins until all adders finish then throw IOE
// The idea behind to spin until all adders finish, is to avoid to return to the caller with IOE while there are still some adders have
// not been finished yet
SpinWait spinner = default;
while (true)
{
int observedAdders = _currentAdders;
if ((observedAdders & COMPLETE_ADDING_ON_MASK) != 0)
{
spinner.Reset();
// CompleteAdding is requested, spin then throw
while (_currentAdders != COMPLETE_ADDING_ON_MASK) spinner.SpinOnce();
throw new InvalidOperationException(SR.BlockingCollection_Completed);
}
if (Interlocked.CompareExchange(ref _currentAdders, observedAdders + 1, observedAdders) == observedAdders)
{
Debug.Assert((observedAdders + 1) <= (~COMPLETE_ADDING_ON_MASK), "The number of concurrent adders thread exceeded the maximum limit.");
break;
}
spinner.SpinOnce(sleep1Threshold: -1);
}
//TryAdd is guaranteed to find a place to add the element. Its return value depends
//on the semantics of the underlying store. Some underlying stores will not add an already
//existing item and thus TryAdd returns false indicating that the size of the underlying
//store did not increase.
bool addingSucceeded = false;
try
{
//The token may have been canceled before the collection had space available, so we need a check after the wait has completed.
//This fixes bug #702328, case 2 of 2.
cancellationToken.ThrowIfCancellationRequested();
addingSucceeded = _collection.TryAdd(item);
if (!addingSucceeded)
throw new InvalidOperationException(SR.BlockingCollection_Add_Failed);
}
finally
{
if (addingSucceeded)
//After adding an element to the underlying storage, signal to the consumers
//waiting on _occupiedNodes that there is a new item added ready to be consumed.
_occupiedNodes.Release();
else
//TryAdd did not result in increasing the size of the underlying store and hence we need
//to increment back the count of the _freeNodes semaphore.
_freeNodes?.Release();
// decrement the adders count
Debug.Assert((_currentAdders & ~COMPLETE_ADDING_ON_MASK) > 0);
Interlocked.Decrement(ref _currentAdders);
}
}
return waitForSemaphoreWasSuccessful;
}
/// <summary>Takes an item from the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.</summary>
/// <returns>The item removed from the collection.</returns>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection was modified
/// outside of this <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instance, or the <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> is empty and has been marked
/// as complete with regards to additions.</exception>
/// <remarks>A call to <see cref="Take()"/> may block until an item is available to be removed.</remarks>
public T Take()
{
T? item;
if (!TryTake(out item, Timeout.Infinite, CancellationToken.None))
{
throw new InvalidOperationException(SR.BlockingCollection_CantTakeWhenDone);
}
return item;
}
/// <summary>Takes an item from the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.</summary>
/// <returns>The item removed from the collection.</returns>
/// <exception cref="OperationCanceledException">If the <see cref="CancellationToken"/> is
/// canceled.</exception>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection was modified
/// outside of this <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instance, or the <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> is empty and has been marked
/// as complete with regards to additions.</exception>
/// <remarks>A call to <see cref="Take(CancellationToken)"/> may block until an item is available to be removed.</remarks>
public T Take(CancellationToken cancellationToken)
{
T? item;
if (!TryTake(out item, Timeout.Infinite, cancellationToken))
{
throw new InvalidOperationException(SR.BlockingCollection_CantTakeWhenDone);
}
return item;
}
/// <summary>
/// Attempts to remove an item from the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.
/// </summary>
/// <param name="item">The item removed from the collection.</param>
/// <returns>true if an item could be removed; otherwise, false.</returns>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection was modified
/// outside of this <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instance.</exception>
public bool TryTake([MaybeNullWhen(false)] out T item)
{
return TryTake(out item, 0, CancellationToken.None);
}
/// <summary>
/// Attempts to remove an item from the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.
/// </summary>
/// <param name="item">The item removed from the collection.</param>
/// <param name="timeout">A <see cref="System.TimeSpan"/> that represents the number of milliseconds
/// to wait, or a <see cref="System.TimeSpan"/> that represents -1 milliseconds to wait indefinitely.
/// </param>
/// <returns>true if an item could be removed from the collection within
/// the alloted time; otherwise, false.</returns>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.ArgumentOutOfRangeException"><paramref name="timeout"/> is a negative number
/// other than -1 milliseconds, which represents an infinite time-out -or- timeout is greater than
/// <see cref="int.MaxValue"/>.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection was modified
/// outside of this <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instance.</exception>
public bool TryTake([MaybeNullWhen(false)] out T item, TimeSpan timeout)
{
ValidateTimeout(timeout);
return TryTakeWithNoTimeValidation(out item, (int)timeout.TotalMilliseconds, CancellationToken.None, null);
}
/// <summary>
/// Attempts to remove an item from the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.
/// </summary>
/// <param name="item">The item removed from the collection.</param>
/// <param name="millisecondsTimeout">The number of milliseconds to wait, or <see
/// cref="System.Threading.Timeout.Infinite"/> (-1) to wait indefinitely.</param>
/// <returns>true if an item could be removed from the collection within
/// the alloted time; otherwise, false.</returns>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.ArgumentOutOfRangeException"><paramref name="millisecondsTimeout"/> is a
/// negative number other than -1, which represents an infinite time-out.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection was modified
/// outside of this <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instance.</exception>
public bool TryTake([MaybeNullWhen(false)] out T item, int millisecondsTimeout)
{
ValidateMillisecondsTimeout(millisecondsTimeout);
return TryTakeWithNoTimeValidation(out item, millisecondsTimeout, CancellationToken.None, null);
}
/// <summary>
/// Attempts to remove an item from the <see cref="System.Collections.Concurrent.BlockingCollection{T}"/>.
/// A <see cref="System.OperationCanceledException"/> is thrown if the <see cref="CancellationToken"/> is
/// canceled.
/// </summary>
/// <param name="item">The item removed from the collection.</param>
/// <param name="millisecondsTimeout">The number of milliseconds to wait, or <see
/// cref="System.Threading.Timeout.Infinite"/> (-1) to wait indefinitely.</param>
/// <param name="cancellationToken">A cancellation token to observe.</param>
/// <returns>true if an item could be removed from the collection within
/// the alloted time; otherwise, false.</returns>
/// <exception cref="OperationCanceledException">If the <see cref="CancellationToken"/> is canceled.</exception>
/// <exception cref="System.ObjectDisposedException">The <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> has been disposed.</exception>
/// <exception cref="System.ArgumentOutOfRangeException"><paramref name="millisecondsTimeout"/> is a
/// negative number other than -1, which represents an infinite time-out.</exception>
/// <exception cref="System.InvalidOperationException">The underlying collection was modified
/// outside of this <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instance.</exception>
public bool TryTake([MaybeNullWhen(false)] out T item, int millisecondsTimeout, CancellationToken cancellationToken)
{
ValidateMillisecondsTimeout(millisecondsTimeout);
return TryTakeWithNoTimeValidation(out item, millisecondsTimeout, cancellationToken, null);
}
/// <summary>Takes an item from the underlying data store using its IProducerConsumerCollection<T>.Take
/// method. If the collection was empty, this method will wait for, at most, the timeout period (if AddingIsCompleted is false)
/// trying to remove an item. If the timeout period was exhausted before successfully removing an item
/// this method will return false.
/// A <see cref="System.OperationCanceledException"/> is thrown if the <see cref="CancellationToken"/> is
/// canceled.
/// </summary>
/// <param name="item">The item removed from the collection.</param>
/// <param name="millisecondsTimeout">The number of milliseconds to wait for the collection to have an item available
/// for removal, or Timeout.Infinite to wait indefinitely.</param>
/// <param name="cancellationToken">A cancellation token to observe.</param>
/// <param name="combinedTokenSource">A combined cancellation token if created, it is only created by GetConsumingEnumerable to avoid creating the linked token
/// multiple times.</param>
/// <returns>False if the collection remained empty till the timeout period was exhausted. True otherwise.</returns>
/// <exception cref="OperationCanceledException">If the <see cref="CancellationToken"/> is canceled.</exception>
/// <exception cref="System.ObjectDisposedException">If the collection has been disposed.</exception>
private bool TryTakeWithNoTimeValidation([MaybeNullWhen(false)] out T item, int millisecondsTimeout, CancellationToken cancellationToken, CancellationTokenSource? combinedTokenSource)
{
CheckDisposed();
item = default(T)!;
cancellationToken.ThrowIfCancellationRequested();
//If the collection is completed then there is no need to wait.
if (IsCompleted)
{
return false;
}
bool waitForSemaphoreWasSuccessful = false;
// set the combined token source to the combinedToken parameter if it is not null (came from GetConsumingEnumerable)
CancellationTokenSource? linkedTokenSource = combinedTokenSource;
try
{
waitForSemaphoreWasSuccessful = _occupiedNodes.Wait(0);
if (waitForSemaphoreWasSuccessful == false && millisecondsTimeout != 0)
{
// create the linked token if it is not created yet
linkedTokenSource ??= CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, _consumersCancellationTokenSource.Token);
waitForSemaphoreWasSuccessful = _occupiedNodes.Wait(millisecondsTimeout, linkedTokenSource.Token);
}
}
//The collection became completed while waiting on the semaphore.
catch (OperationCanceledException)
{
cancellationToken.ThrowIfCancellationRequested();
return false;
}
finally
{
// only dispose the combined token source if we created it here, otherwise the caller (GetConsumingEnumerable) is responsible for disposing it
if (linkedTokenSource != null && combinedTokenSource == null)
{
linkedTokenSource.Dispose();
}
}
if (waitForSemaphoreWasSuccessful)
{
bool removeSucceeded = false;
try
{
//The token may have been canceled before an item arrived, so we need a check after the wait has completed.
//This fixes bug #702328, case 1 of 2.
cancellationToken.ThrowIfCancellationRequested();
//If an item was successfully removed from the underlying collection.
removeSucceeded = _collection.TryTake(out item);
if (!removeSucceeded)
{
// Check if the collection is empty which means that the collection was modified outside BlockingCollection
throw new InvalidOperationException
(SR.BlockingCollection_Take_CollectionModified);
}
}
finally
{
// removeFaulted implies !removeSucceeded, but the reverse is not true.
if (removeSucceeded)
{
if (_freeNodes != null)
{
Debug.Assert(_boundedCapacity != NON_BOUNDED);
_freeNodes.Release();
}
}
else
{
_occupiedNodes.Release();
}
//Last remover will detect that it has actually removed the last item from the
//collection and that CompleteAdding() was called previously. Thus, it will cancel the semaphores
//so that any thread waiting on them wakes up. Note several threads may call CancelWaitingConsumers
//but this is not a problem.
if (IsCompleted)
{
CancelWaitingConsumers();
}
}
}
return waitForSemaphoreWasSuccessful;
}
/// <summary>
/// Adds the specified item to any one of the specified
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances.
/// </summary>
/// <param name="collections">The array of collections.</param>
/// <param name="item">The item to be added to one of the collections.</param>
/// <returns>The index of the collection in the <paramref name="collections"/> array to which the item was added.</returns>
/// <exception cref="System.ArgumentNullException">The <paramref name="collections"/> argument is
/// null.</exception>
/// <exception cref="System.ArgumentException">The <paramref name="collections"/> argument is
/// a 0-length array or contains a null element, or at least one of collections has been
/// marked as complete for adding.</exception>
/// <exception cref="System.ObjectDisposedException">At least one of the <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances has been disposed.</exception>
/// <exception cref="System.InvalidOperationException">At least one underlying collection didn't accept the item.</exception>
/// <exception cref="System.ArgumentOutOfRangeException">The count of <paramref name="collections"/> is greater than the maximum size of
/// 62 for STA and 63 for MTA.</exception>
/// <remarks>
/// If a bounded capacity was specified when all of the
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances were initialized,
/// a call to AddToAny may block until space is available in one of the collections
/// to store the provided item.
/// </remarks>
public static int AddToAny(BlockingCollection<T>[] collections, T item)
{
#if DEBUG
int tryAddAnyReturnValue =
#else
return
#endif
TryAddToAny(collections, item, Timeout.Infinite, CancellationToken.None);
#if DEBUG
Debug.Assert(tryAddAnyReturnValue >= 0 && tryAddAnyReturnValue < collections.Length,
"TryAddToAny() was expected to return an index within the bounds of the collections array.");
return tryAddAnyReturnValue;
#endif
}
/// <summary>
/// Adds the specified item to any one of the specified
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances.
/// A <see cref="System.OperationCanceledException"/> is thrown if the <see cref="CancellationToken"/> is
/// canceled.
/// </summary>
/// <param name="collections">The array of collections.</param>
/// <param name="item">The item to be added to one of the collections.</param>
/// <param name="cancellationToken">A cancellation token to observe.</param>
/// <returns>The index of the collection in the <paramref name="collections"/> array to which the item was added.</returns>
/// <exception cref="OperationCanceledException">If the <see cref="CancellationToken"/> is canceled.</exception>
/// <exception cref="System.ArgumentNullException">The <paramref name="collections"/> argument is
/// null.</exception>
/// <exception cref="System.ArgumentException">The <paramref name="collections"/> argument is
/// a 0-length array or contains a null element, or at least one of collections has been
/// marked as complete for adding.</exception>
/// <exception cref="System.ObjectDisposedException">At least one of the <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances has been disposed.</exception>
/// <exception cref="System.InvalidOperationException">At least one underlying collection didn't accept the item.</exception>
/// <exception cref="System.ArgumentOutOfRangeException">The count of <paramref name="collections"/> is greater than the maximum size of
/// 62 for STA and 63 for MTA.</exception>
/// <remarks>
/// If a bounded capacity was specified when all of the
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances were initialized,
/// a call to AddToAny may block until space is available in one of the collections
/// to store the provided item.
/// </remarks>
public static int AddToAny(BlockingCollection<T>[] collections, T item, CancellationToken cancellationToken)
{
#if DEBUG
int tryAddAnyReturnValue =
#else
return
#endif
TryAddToAny(collections, item, Timeout.Infinite, cancellationToken);
#if DEBUG
Debug.Assert(tryAddAnyReturnValue >= 0 && tryAddAnyReturnValue < collections.Length,
"TryAddToAny() was expected to return an index within the bounds of the collections array.");
return tryAddAnyReturnValue;
#endif
}
/// <summary>
/// Attempts to add the specified item to any one of the specified
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances.
/// </summary>
/// <param name="collections">The array of collections.</param>
/// <param name="item">The item to be added to one of the collections.</param>
/// <returns>The index of the collection in the <paramref name="collections"/>
/// array to which the item was added, or -1 if the item could not be added.</returns>
/// <exception cref="System.ArgumentNullException">The <paramref name="collections"/> argument is
/// null.</exception>
/// <exception cref="System.ArgumentException">The <paramref name="collections"/> argument is
/// a 0-length array or contains a null element, or at least one of collections has been
/// marked as complete for adding.</exception>
/// <exception cref="System.ObjectDisposedException">At least one of the <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances has been disposed.</exception>
/// <exception cref="System.InvalidOperationException">At least one underlying collection didn't accept the item.</exception>
/// <exception cref="System.ArgumentOutOfRangeException">The count of <paramref name="collections"/> is greater than the maximum size of
/// 62 for STA and 63 for MTA.</exception>
public static int TryAddToAny(BlockingCollection<T>[] collections, T item)
{
return TryAddToAny(collections, item, 0, CancellationToken.None);
}
/// <summary>
/// Attempts to add the specified item to any one of the specified
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances.
/// </summary>
/// <param name="collections">The array of collections.</param>
/// <param name="item">The item to be added to one of the collections.</param>
/// <param name="timeout">A <see cref="System.TimeSpan"/> that represents the number of milliseconds
/// to wait, or a <see cref="System.TimeSpan"/> that represents -1 milliseconds to wait indefinitely.
/// </param>
/// <returns>The index of the collection in the <paramref name="collections"/>
/// array to which the item was added, or -1 if the item could not be added.</returns>
/// <exception cref="System.ArgumentNullException">The <paramref name="collections"/> argument is
/// null.</exception>
/// <exception cref="System.ArgumentException">The <paramref name="collections"/> argument is
/// a 0-length array or contains a null element, or at least one of collections has been
/// marked as complete for adding.</exception>
/// <exception cref="System.ObjectDisposedException">At least one of the <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances has been disposed.</exception>
/// <exception cref="System.ArgumentOutOfRangeException"><paramref name="timeout"/> is a negative number
/// other than -1 milliseconds, which represents an infinite time-out -or- timeout is greater than
/// <see cref="int.MaxValue"/>.</exception>
/// <exception cref="System.InvalidOperationException">At least one underlying collection didn't accept the item.</exception>
/// <exception cref="System.ArgumentOutOfRangeException">The count of <paramref name="collections"/> is greater than the maximum size of
/// 62 for STA and 63 for MTA.</exception>
public static int TryAddToAny(BlockingCollection<T>[] collections, T item, TimeSpan timeout)
{
ValidateTimeout(timeout);
return TryAddToAnyCore(collections, item, (int)timeout.TotalMilliseconds, CancellationToken.None);
}
/// <summary>
/// Attempts to add the specified item to any one of the specified
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances.
/// </summary>
/// <param name="collections">The array of collections.</param>
/// <param name="item">The item to be added to one of the collections.</param>
/// <param name="millisecondsTimeout">The number of milliseconds to wait, or <see
/// cref="System.Threading.Timeout.Infinite"/> (-1) to wait indefinitely.</param> /// <returns>The index of the collection in the <paramref name="collections"/>
/// array to which the item was added, or -1 if the item could not be added.</returns>
/// <exception cref="System.ArgumentNullException">The <paramref name="collections"/> argument is
/// null.</exception>
/// <exception cref="System.ArgumentException">The <paramref name="collections"/> argument is
/// a 0-length array or contains a null element, or at least one of collections has been
/// marked as complete for adding.</exception>
/// <exception cref="System.ObjectDisposedException">At least one of the <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances has been disposed.</exception>
/// <exception cref="System.ArgumentOutOfRangeException"><paramref name="millisecondsTimeout"/> is a
/// negative number other than -1, which represents an infinite time-out.</exception>
/// <exception cref="System.InvalidOperationException">At least one underlying collection didn't accept the item.</exception>
/// <exception cref="System.ArgumentOutOfRangeException">The count of <paramref name="collections"/> is greater than the maximum size of
/// 62 for STA and 63 for MTA.</exception>
public static int TryAddToAny(BlockingCollection<T>[] collections, T item, int millisecondsTimeout)
{
ValidateMillisecondsTimeout(millisecondsTimeout);
return TryAddToAnyCore(collections, item, millisecondsTimeout, CancellationToken.None);
}
/// <summary>
/// Attempts to add the specified item to any one of the specified
/// <see cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances.
/// A <see cref="System.OperationCanceledException"/> is thrown if the <see cref="CancellationToken"/> is
/// canceled.
/// </summary>
/// <param name="collections">The array of collections.</param>
/// <param name="item">The item to be added to one of the collections.</param>
/// <param name="millisecondsTimeout">The number of milliseconds to wait, or <see
/// cref="System.Threading.Timeout.Infinite"/> (-1) to wait indefinitely.</param>
/// <returns>The index of the collection in the <paramref name="collections"/>
/// array to which the item was added, or -1 if the item could not be added.</returns>
/// <param name="cancellationToken">A cancellation token to observe.</param>
/// <exception cref="OperationCanceledException">If the <see cref="CancellationToken"/> is canceled.</exception>
/// <exception cref="System.ArgumentNullException">The <paramref name="collections"/> argument is
/// null.</exception>
/// <exception cref="System.ArgumentException">The <paramref name="collections"/> argument is
/// a 0-length array or contains a null element, or at least one of collections has been
/// marked as complete for adding.</exception>
/// <exception cref="System.ObjectDisposedException">At least one of the <see
/// cref="System.Collections.Concurrent.BlockingCollection{T}"/> instances has been disposed.</exception>
/// <exception cref="System.ArgumentOutOfRangeException"><paramref name="millisecondsTimeout"/> is a
/// negative number other than -1, which represents an infinite time-out.</exception>
/// <exception cref="System.InvalidOperationException">At least one underlying collection didn't accept the item.</exception>
/// <exception cref="System.ArgumentOutOfRangeException">The count of <paramref name="collections"/> is greater than the maximum size of
/// 62 for STA and 63 for MTA.</exception>
public static int TryAddToAny(BlockingCollection<T>[] collections, T item, int millisecondsTimeout, CancellationToken cancellationToken)
{
ValidateMillisecondsTimeout(millisecondsTimeout);
return TryAddToAnyCore(collections, item, millisecondsTimeout, cancellationToken);
}
/// <summary>Adds an item to anyone of the specified collections.
/// A <see cref="System.OperationCanceledException"/> is thrown if the <see cref="CancellationToken"/> is
/// canceled.
/// </summary>
/// <param name="collections">The collections into which the item can be added.</param>
/// <param name="item">The item to be added .</param>
/// <param name="millisecondsTimeout">The number of milliseconds to wait for a collection to accept the
/// operation, or -1 to wait indefinitely.</param>
/// <param name="externalCancellationToken">A cancellation token to observe.</param>
/// <returns>The index into collections for the collection which accepted the
/// adding of the item; -1 if the item could not be added.</returns>
/// <exception cref="OperationCanceledException">If the <see cref="CancellationToken"/> is canceled.</exception>
/// <exception cref="System.ArgumentNullException">If the collections argument is null.</exception>
/// <exception cref="System.ArgumentException">If the collections argument is a 0-length array or contains a
/// null element. Also, if at least one of the collections has been marked complete for adds.</exception>
/// <exception cref="System.ObjectDisposedException">If at least one of the collections has been disposed.</exception>
private static int TryAddToAnyCore(BlockingCollection<T>[] collections, T item, int millisecondsTimeout, CancellationToken externalCancellationToken)
{
ValidateCollectionsArray(collections, true);
const int OPERATION_FAILED = -1;
// Copy the wait time to another local variable to update it
int timeout = millisecondsTimeout;
uint startTime = 0;
if (millisecondsTimeout != Timeout.Infinite)
{
startTime = unchecked((uint)Environment.TickCount);
}
// Fast path for adding if there is at least one unbounded collection
int index = TryAddToAnyFast(collections, item);
if (index > -1)
return index;
// Get wait handles and the tokens for all collections,
// and construct a single combined token from all the tokens,
// add the combined token handle to the handles list
// call WaitAny for all handles
// After WaitAny returns check if the token is cancelled and that caused the WaitAny to return or not
// If the combined token is cancelled, this mean either the external token is cancelled then throw OCE
// or one if the collection is AddingCompleted then throw AE
CancellationToken[] collatedCancellationTokens;
List<WaitHandle> handles = GetHandles(collections, externalCancellationToken, true, out collatedCancellationTokens);
//Loop until one of these conditions is met:
// 1- The operation is succeeded
// 2- The timeout expired for try* versions
// 3- The external token is cancelled, throw
// 4- There is at least one collection marked as adding completed then throw
while (millisecondsTimeout == Timeout.Infinite || timeout >= 0)
{
index = -1;
using (CancellationTokenSource linkedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(collatedCancellationTokens))
{
handles.Add(linkedTokenSource.Token.WaitHandle); // add the combined token to the handles list
//Wait for any collection to become available.
index = WaitHandle.WaitAny(handles.ToArray(), timeout);
handles.RemoveAt(handles.Count - 1); //remove the linked token
if (linkedTokenSource.IsCancellationRequested)
{
externalCancellationToken.ThrowIfCancellationRequested(); //case#3
throw new ArgumentException(SR.BlockingCollection_CantAddAnyWhenCompleted, nameof(collections)); //case#4
}
}
Debug.Assert((index == WaitHandle.WaitTimeout) || (index >= 0 && index < handles.Count));
if (index == WaitHandle.WaitTimeout) //case#2