69 lines
2.4 KiB
C#
69 lines
2.4 KiB
C#
//------------------------------------------------------------------------------
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// <copyright file="GCUtil.cs" company="Microsoft">
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// Copyright (c) Microsoft Corporation. All rights reserved.
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// </copyright>
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//------------------------------------------------------------------------------
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namespace System.Web.Util {
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using System;
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using System.Runtime.InteropServices;
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using System.Security.Permissions;
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// Provides helper methods for wrapping managed objects so that they can be passed to and from unmanaged code.
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// Unmanaged code can't actually inspect these objects at all since they're just GCHandles. And these handles
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// cannot be reused (they're single-shot).
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[SecurityPermission(SecurityAction.LinkDemand, UnmanagedCode = true)]
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internal static class GCUtil {
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public static IntPtr RootObject(object obj) {
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return (obj != null)
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? (IntPtr)GCHandle.Alloc(obj)
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: IntPtr.Zero;
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}
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public static object UnrootObject(IntPtr pointer) {
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if (pointer != IntPtr.Zero) {
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GCHandle gcHandle = (GCHandle)pointer;
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if (gcHandle.IsAllocated) {
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object target = gcHandle.Target;
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gcHandle.Free();
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return target;
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}
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}
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return null;
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}
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}
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// This wrapper around a managed object is opaque to SizedReference GC handle
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// and therefore helps with calculating size of only relevant graph of objects
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internal class DisposableGCHandleRef<T> : IDisposable
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where T : class, IDisposable {
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GCHandle _handle;
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[PermissionSet(SecurityAction.Assert, Unrestricted = true)]
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public DisposableGCHandleRef(T t) {
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Debug.Assert(t != null);
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_handle = GCHandle.Alloc(t);
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}
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public T Target {
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[PermissionSet(SecurityAction.Assert, Unrestricted = true)]
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get {
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Debug.Assert(_handle.IsAllocated);
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return (T)_handle.Target;
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}
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}
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[PermissionSet(SecurityAction.Assert, Unrestricted = true)]
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public void Dispose() {
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Target.Dispose();
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Debug.Assert(_handle.IsAllocated);
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if (_handle.IsAllocated) {
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_handle.Free();
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}
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}
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}
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}
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