Xamarin Public Jenkins (auto-signing) 0b4a830db1 Imported Upstream version 4.4.2.4
Former-commit-id: 92904c9c5915c37244316e42ba99e7b934ed7ee2
2016-07-21 09:40:10 +00:00

315 lines
14 KiB
C#

// 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.
using System.Diagnostics;
using System.Runtime.InteropServices;
namespace System.Threading
{
//
// Implementation of ThreadPoolBoundHandle that sits on top of the CLR's ThreadPool and Overlapped infrastructure
//
/// <summary>
/// Represents an I/O handle that is bound to the system thread pool and enables low-level
/// components to receive notifications for asynchronous I/O operations.
/// </summary>
public sealed partial class ThreadPoolBoundHandle : IDisposable
{
private readonly SafeHandle _handle;
private bool _isDisposed;
private ThreadPoolBoundHandle(SafeHandle handle)
{
_handle = handle;
}
/// <summary>
/// Gets the bound operating system handle.
/// </summary>
/// <value>
/// A <see cref="SafeHandle"/> object that holds the bound operating system handle.
/// </value>
public SafeHandle Handle
{
get { return _handle; }
}
/// <summary>
/// Returns a <see cref="ThreadPoolBoundHandle"/> for the specific handle,
/// which is bound to the system thread pool.
/// </summary>
/// <param name="handle">
/// A <see cref="SafeHandle"/> object that holds the operating system handle. The
/// handle must have been opened for overlapped I/O on the unmanaged side.
/// </param>
/// <returns>
/// <see cref="ThreadPoolBoundHandle"/> for <paramref name="handle"/>, which
/// is bound to the system thread pool.
/// </returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="handle"/> is <see langword="null"/>.
/// </exception>
/// <exception cref="ArgumentException">
/// <paramref name="handle"/> has been disposed.
/// <para>
/// -or-
/// </para>
/// <paramref name="handle"/> does not refer to a valid I/O handle.
/// <para>
/// -or-
/// </para>
/// <paramref name="handle"/> refers to a handle that has not been opened
/// for overlapped I/O.
/// <para>
/// -or-
/// </para>
/// <paramref name="handle"/> refers to a handle that has already been bound.
/// </exception>
/// <remarks>
/// This method should be called once per handle.
/// <para>
/// -or-
/// </para>
/// <see cref="ThreadPoolBoundHandle"/> does not take ownership of <paramref name="handle"/>,
/// it remains the responsibility of the caller to call <see cref="SafeHandle.Dispose"/>.
/// </remarks>
public static ThreadPoolBoundHandle BindHandle(SafeHandle handle)
{
if (handle == null)
throw new ArgumentNullException(nameof(handle));
if (handle.IsClosed || handle.IsInvalid)
throw new ArgumentException(SR.Argument_InvalidHandle, nameof(handle));
try
{
// ThreadPool.BindHandle will always return true, otherwise, it throws. See the underlying FCall
// implementation in ThreadPoolNative::CorBindIoCompletionCallback to see the implementation.
bool succeeded = ThreadPool.BindHandle(handle);
Debug.Assert(succeeded);
}
catch (Exception ex)
{ // BindHandle throws ApplicationException on full CLR and Exception on CoreCLR.
// We do not let either of these leak and convert them to ArgumentException to
// indicate that the specified handles are invalid.
if (ex.HResult == System.HResults.E_HANDLE) // Bad handle
throw new ArgumentException(SR.Argument_InvalidHandle, nameof(handle));
if (ex.HResult == System.HResults.E_INVALIDARG) // Handle already bound or sync handle
throw new ArgumentException(SR.Argument_AlreadyBoundOrSyncHandle, nameof(handle));
throw;
}
return new ThreadPoolBoundHandle(handle);
}
/// <summary>
/// Returns an unmanaged pointer to a <see cref="NativeOverlapped"/> structure, specifying
/// a delegate that is invoked when the asynchronous I/O operation is complete, a user-provided
/// object providing context, and managed objects that serve as buffers.
/// </summary>
/// <param name="callback">
/// An <see cref="IOCompletionCallback"/> delegate that represents the callback method
/// invoked when the asynchronous I/O operation completes.
/// </param>
/// <param name="state">
/// A user-provided object that distinguishes this <see cref="NativeOverlapped"/> from other
/// <see cref="NativeOverlapped"/> instances. Can be <see langword="null"/>.
/// </param>
/// <param name="pinData">
/// An object or array of objects representing the input or output buffer for the operation. Each
/// object represents a buffer, for example an array of bytes. Can be <see langword="null"/>.
/// </param>
/// <returns>
/// An unmanaged pointer to a <see cref="NativeOverlapped"/> structure.
/// </returns>
/// <remarks>
/// <para>
/// The unmanaged pointer returned by this method can be passed to the operating system in
/// overlapped I/O operations. The <see cref="NativeOverlapped"/> structure is fixed in
/// physical memory until <see cref="FreeNativeOverlapped(NativeOverlapped*)"/> is called.
/// </para>
/// <para>
/// The buffer or buffers specified in <paramref name="pinData"/> must be the same as those passed
/// to the unmanaged operating system function that performs the asynchronous I/O.
/// </para>
/// <note>
/// The buffers specified in <paramref name="pinData"/> are pinned for the duration of
/// the I/O operation.
/// </note>
/// </remarks>
/// <exception cref="ArgumentNullException">
/// <paramref name="callback"/> is <see langword="null"/>.
/// </exception>
/// <exception cref="ObjectDisposedException">
/// This method was called after the <see cref="ThreadPoolBoundHandle"/> was disposed.
/// </exception>
public unsafe NativeOverlapped* AllocateNativeOverlapped(IOCompletionCallback callback, object state, object pinData)
{
if (callback == null)
throw new ArgumentNullException(nameof(callback));
EnsureNotDisposed();
ThreadPoolBoundHandleOverlapped overlapped = new ThreadPoolBoundHandleOverlapped(callback, state, pinData, preAllocated: null);
overlapped._boundHandle = this;
return overlapped._nativeOverlapped;
}
/// <summary>
/// Returns an unmanaged pointer to a <see cref="NativeOverlapped"/> structure, using the callback,
/// state, and buffers associated with the specified <see cref="PreAllocatedOverlapped"/> object.
/// </summary>
/// <param name="preAllocated">
/// A <see cref="PreAllocatedOverlapped"/> object from which to create the NativeOverlapped pointer.
/// </param>
/// <returns>
/// An unmanaged pointer to a <see cref="NativeOverlapped"/> structure.
/// </returns>
/// <remarks>
/// <para>
/// The unmanaged pointer returned by this method can be passed to the operating system in
/// overlapped I/O operations. The <see cref="NativeOverlapped"/> structure is fixed in
/// physical memory until <see cref="FreeNativeOverlapped(NativeOverlapped*)"/> is called.
/// </para>
/// </remarks>
/// <exception cref="ArgumentNullException">
/// <paramref name="preAllocated"/> is <see langword="null"/>.
/// </exception>
/// <exception cref="ArgumentException">
/// <paramref name="preAllocated"/> is currently in use for another I/O operation.
/// </exception>
/// <exception cref="ObjectDisposedException">
/// This method was called after the <see cref="ThreadPoolBoundHandle"/> was disposed, or
/// this method was called after <paramref name="preAllocated"/> was disposed.
/// </exception>
/// <seealso cref="PreAllocatedOverlapped"/>
public unsafe NativeOverlapped* AllocateNativeOverlapped(PreAllocatedOverlapped preAllocated)
{
if (preAllocated == null)
throw new ArgumentNullException(nameof(preAllocated));
EnsureNotDisposed();
preAllocated.AddRef();
try
{
ThreadPoolBoundHandleOverlapped overlapped = preAllocated._overlapped;
if (overlapped._boundHandle != null)
throw new ArgumentException(SR.Argument_PreAllocatedAlreadyAllocated, nameof(preAllocated));
overlapped._boundHandle = this;
return overlapped._nativeOverlapped;
}
catch
{
preAllocated.Release();
throw;
}
}
/// <summary>
/// Frees the unmanaged memory associated with a <see cref="NativeOverlapped"/> structure
/// allocated by the <see cref="AllocateNativeOverlapped"/> method.
/// </summary>
/// <param name="overlapped">
/// An unmanaged pointer to the <see cref="NativeOverlapped"/> structure to be freed.
/// </param>
/// <remarks>
/// <note type="caution">
/// You must call the <see cref="FreeNativeOverlapped(NativeOverlapped*)"/> method exactly once
/// on every <see cref="NativeOverlapped"/> unmanaged pointer allocated using the
/// <see cref="AllocateNativeOverlapped"/> method.
/// If you do not call the <see cref="FreeNativeOverlapped(NativeOverlapped*)"/> method, you will
/// leak memory. If you call the <see cref="FreeNativeOverlapped(NativeOverlapped*)"/> method more
/// than once on the same <see cref="NativeOverlapped"/> unmanaged pointer, memory will be corrupted.
/// </note>
/// </remarks>
/// <exception cref="ArgumentNullException">
/// <paramref name="overlapped"/> is <see langword="null"/>.
/// </exception>
/// <exception cref="ObjectDisposedException">
/// This method was called after the <see cref="ThreadPoolBoundHandle"/> was disposed.
/// </exception>
public unsafe void FreeNativeOverlapped(NativeOverlapped* overlapped)
{
if (overlapped == null)
throw new ArgumentNullException(nameof(overlapped));
// Note: we explicitly allow FreeNativeOverlapped calls after the ThreadPoolBoundHandle has been Disposed.
ThreadPoolBoundHandleOverlapped wrapper = GetOverlappedWrapper(overlapped, this);
if (wrapper._boundHandle != this)
throw new ArgumentException(SR.Argument_NativeOverlappedWrongBoundHandle, nameof(overlapped));
if (wrapper._preAllocated != null)
wrapper._preAllocated.Release();
else
Overlapped.Free(overlapped);
}
/// <summary>
/// Returns the user-provided object specified when the <see cref="NativeOverlapped"/> instance was
/// allocated using the <see cref="AllocateNativeOverlapped(IOCompletionCallback, object, byte[])"/>.
/// </summary>
/// <param name="overlapped">
/// An unmanaged pointer to the <see cref="NativeOverlapped"/> structure from which to return the
/// asscociated user-provided object.
/// </param>
/// <returns>
/// A user-provided object that distinguishes this <see cref="NativeOverlapped"/>
/// from other <see cref="NativeOverlapped"/> instances, otherwise, <see langword="null"/> if one was
/// not specified when the instance was allocated using <see cref="AllocateNativeOverlapped"/>.
/// </returns>
/// <exception cref="ArgumentNullException">
/// <paramref name="overlapped"/> is <see langword="null"/>.
/// </exception>
public unsafe static object GetNativeOverlappedState(NativeOverlapped* overlapped)
{
if (overlapped == null)
throw new ArgumentNullException(nameof(overlapped));
ThreadPoolBoundHandleOverlapped wrapper = GetOverlappedWrapper(overlapped, null);
Debug.Assert(wrapper._boundHandle != null);
return wrapper._userState;
}
private static unsafe ThreadPoolBoundHandleOverlapped GetOverlappedWrapper(NativeOverlapped* overlapped, ThreadPoolBoundHandle expectedBoundHandle)
{
ThreadPoolBoundHandleOverlapped wrapper;
try
{
wrapper = (ThreadPoolBoundHandleOverlapped)Overlapped.Unpack(overlapped);
}
catch (NullReferenceException ex)
{
throw new ArgumentException(SR.Argument_NativeOverlappedAlreadyFree, nameof(overlapped), ex);
}
return wrapper;
}
public void Dispose()
{
// .NET Native's version of ThreadPoolBoundHandle that wraps the Win32 ThreadPool holds onto
// native resources so it needs to be disposable. To match the contract, we are also disposable.
// We also implement a disposable state to mimic behavior between this implementation and
// .NET Native's version (code written against us, will also work against .NET Native's version).
_isDisposed = true;
}
private void EnsureNotDisposed()
{
if (_isDisposed)
throw new ObjectDisposedException(GetType().ToString());
}
}
}