98 lines
2.8 KiB
C#
98 lines
2.8 KiB
C#
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//
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// WeakReference_T.cs
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//
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// Author:
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// Martin Baulig <martin.baulig@xamarin.com>
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//
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// Copyright (c) 2013 Xamarin Inc. (http://www.xamarin.com)
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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using System.Runtime.Serialization;
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using System.Runtime.InteropServices;
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namespace System {
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[SerializableAttribute]
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public sealed class WeakReference<T> : ISerializable
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where T : class
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{
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GCHandle handle;
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bool trackResurrection;
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public WeakReference (T target)
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: this (target, false)
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{
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}
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public WeakReference (T target, bool trackResurrection)
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{
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this.trackResurrection = trackResurrection;
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var handleType = trackResurrection ? GCHandleType.WeakTrackResurrection : GCHandleType.Weak;
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handle = GCHandle.Alloc (target, handleType);
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}
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WeakReference (SerializationInfo info, StreamingContext context)
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{
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if (info == null)
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throw new ArgumentNullException ("info");
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trackResurrection = info.GetBoolean ("TrackResurrection");
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var target = info.GetValue ("TrackedObject", typeof (T));
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var handleType = trackResurrection ? GCHandleType.WeakTrackResurrection : GCHandleType.Weak;
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handle = GCHandle.Alloc (target, handleType);
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}
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public void GetObjectData (SerializationInfo info, StreamingContext context)
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{
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if (info == null)
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throw new ArgumentNullException ("info");
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info.AddValue ("TrackResurrection", trackResurrection);
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if (handle.IsAllocated)
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info.AddValue ("TrackedObject", handle.Target);
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else
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info.AddValue ("TrackedObject", null);
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}
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public void SetTarget (T target)
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{
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handle.Target = target;
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}
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public bool TryGetTarget (out T target)
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{
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if (!handle.IsAllocated) {
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target = null;
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return false;
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}
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target = (T)handle.Target;
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return target != null;
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}
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//Methods
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~WeakReference ()
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{
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handle.Free ();
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}
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}
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}
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