|
using System;
using System.Runtime.InteropServices;
using Pfz.DataTypes;
namespace Pfz.Caching
{
/// <summary>
/// This class is a GCHandle wrapper that allows you to reference other objects
/// using WeakReference, Strong or other reference types.
/// It has a dispose and a destructor, but it is NOT thread safe, in the sense
/// that changing the type or disposing from many threads can cause exceptions.
/// Even not being thread-safe, this class is abort-safe.
/// </summary>
public sealed class ThreadUnsafeReference<T>:
IReference<T>,
ICloneable<ThreadUnsafeReference<T>>,
IEquatable<ThreadUnsafeReference<T>>,
IDisposable
{
private GCHandle _handle;
/// <summary>
/// Creates a new empty reference.
/// </summary>
public ThreadUnsafeReference():
this(default(T), GCHandleType.Weak)
{
}
/// <summary>
/// Creates a new reference using the given value and handle type.
/// </summary>
public ThreadUnsafeReference(T value, GCHandleType handleType)
{
try
{
}
finally
{
_handle = GCHandle.Alloc(value, handleType);
}
_handleType = handleType;
}
/// <summary>
/// Frees the handle.
/// </summary>
~ThreadUnsafeReference()
{
var handle = _handle;
if (handle.IsAllocated)
handle.Free();
}
/// <summary>
/// Frees the handle immediatelly.
/// </summary>
public void Dispose()
{
var handle = _handle;
if (handle.IsAllocated)
{
try
{
}
finally
{
_handle = new GCHandle();
handle.Free();
}
}
GC.SuppressFinalize(this);
}
/// <summary>
/// Gets or sets the value pointed by the handle.
/// </summary>
public T Value
{
get
{
return (T)_handle.Target;
}
set
{
_handle.Target = value;
}
}
private GCHandleType _handleType;
/// <summary>
/// Gets or sets the handle type.
/// </summary>
public GCHandleType HandleType
{
get
{
return _handleType;
}
set
{
if (value == _handleType)
return;
GCHandle oldHandle = _handle;
try
{
}
finally
{
// this block must be executed completelly or must not be executed.
_handle = GCHandle.Alloc(_handle.Target, value);
_handleType = value;
oldHandle.Free();
}
}
}
/// <summary>
/// Gets the data of this Reference.
/// </summary>
public ReferenceData<T> GetData()
{
return new ReferenceData<T>((T)_handle.Target, _handleType);
}
/// <summary>
/// Sets the data of this reference.
/// </summary>
public void Set(GCHandleType handleType, T value)
{
if (handleType == _handleType)
_handle.Target = value;
else
{
GCHandle oldHandle = _handle;
try
{
}
finally
{
// this block must be executed completelly or must not be executed.
_handle = GCHandle.Alloc(value, handleType);
_handleType = handleType;
oldHandle.Free();
}
}
}
/// <summary>
/// Gets the HashCode of the Value.
/// </summary>
public override int GetHashCode()
{
var value = Value;
if (value == null)
return 0;
return value.GetHashCode();
}
/// <summary>
/// Compares the Value of this reference with the value of another reference.
/// </summary>
public override bool Equals(object obj)
{
var other = obj as ThreadUnsafeReference<T>;
if (other != null)
return Equals(other);
return false;
}
/// <summary>
/// Compares the Value of this reference with the value of another reference.
/// </summary>
public bool Equals(ThreadUnsafeReference<T> other)
{
if (other == null)
return false;
return object.Equals(Value, other.Value);
}
#region IValueContainer Members
object IValueContainer.Value
{
get
{
return _handle.Target;
}
set
{
Value = (T)value;
}
}
#endregion
#region ICloneable<ThreadUnsafeReference<T>> Members
/// <summary>
/// Creates a copy of this reference.
/// </summary>
public ThreadUnsafeReference<T> Clone()
{
return new ThreadUnsafeReference<T>((T)_handle.Target, _handleType);
}
#endregion
#region ICloneable Members
object ICloneable.Clone()
{
return Clone();
}
#endregion
#region IReference Members
void IReference.Set(GCHandleType handleType, object value)
{
Set(handleType, (T)value);
}
IReferenceData IReference.GetData()
{
return GetData();
}
#endregion
}
}
|
By viewing downloads associated with this article you agree to the Terms of Service and the article's licence.
If a file you wish to view isn't highlighted, and is a text file (not binary), please
let us know and we'll add colourisation support for it.
I started to program computers when I was 11 years old, as a hobbyist, programming in AMOS Basic and Blitz Basic for Amiga.
At 12 I had my first try with assembler, but it was too difficult at the time. Then, in the same year, I learned C and, after learning C, I was finally able to learn assembler (for Motorola 680x0).
Not sure, but probably between 12 and 13, I started to learn C++. I always programmed "in an object oriented way", but using function pointers instead of virtual methods.
At 15 I started to learn Pascal at school and to use Delphi. At 16 I started my first internship (using Delphi). At 18 I started to work professionally using C++ and since then I've developed my programming skills as a professional developer in C++ and C#, generally creating libraries that help other developers do their work easier, faster and with less errors.
Want more info or simply want to contact me?
Take a look at:
http://paulozemek.azurewebsites.net/
Or e-mail me at: paulozemek@outlook.com
Codeproject MVP 2012, 2015 & 2016
Microsoft MVP 2013-2014 (in October 2014 I started working at Microsoft, so I can't be a Microsoft MVP anymore).