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AspClassic.Scripting/ScopeVariable.cs

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+using System;
+using System.Threading;
+
+namespace AspClassic.Scripting;
+
+public sealed class ScopeVariable : IScopeVariable, IWeakReferencable
+{
+	private object _value;
+
+	private WeakReference _weakref;
+
+	private static readonly object _novalue = new object();
+
+	public bool HasValue => _value != _novalue;
+
+	public WeakReference WeakReference
+	{
+		get
+		{
+			if (_weakref == null)
+			{
+				_weakref = new WeakReference(this);
+			}
+			return _weakref;
+		}
+	}
+
+	internal ScopeVariable()
+	{
+		_value = _novalue;
+	}
+
+	public bool TryGetValue(out dynamic value)
+	{
+		value = _value;
+		if ((object)value != _novalue)
+		{
+			return true;
+		}
+		value = null;
+		return false;
+	}
+
+	public void SetValue(object value)
+	{
+		_value = value;
+	}
+
+	public bool DeleteValue()
+	{
+		return Interlocked.Exchange(ref _value, _novalue) != _novalue;
+	}
+}