83 lines
2.7 KiB
C#
83 lines
2.7 KiB
C#
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// ==++==
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//
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// Copyright (c) Microsoft Corporation. All rights reserved.
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//
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// ==--==
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// Verbose runtime tracing
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//#define ENABLE_DEBUG_PRINT
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// This class provides runtime support for managing delegates that may have
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// been passed in to native code.
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//
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// The problem with these delegates is that the GC may move the delegate
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// object without being aware of references from native code. Rather than
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// pinning the objects (which currently operates at a page granularity), we
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// allocate GC-stable indexes ("delegate idxs") which the native code uses in
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// place of the underlying Delegate reference.
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//
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// The entry points from compiled code are:
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//
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// GetCodePtr, which allocates a short function to enter a delegate, passing
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// in the delegate idx.
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//
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// ReleaseCodePtr, which deallocates the function and releases the delegate
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// idx.
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//
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// The NativeDelegateTable is used to map delegate idxs to Delegate references.
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// References from this table are ordinary strong references as far as the GC
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// is concerned.
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namespace System
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{
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using System.Reflection;
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using System.Runtime.InteropServices;
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using System.Runtime.CompilerServices;
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using System.Threading;
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//| <include path='docs/doc[@for="Delegate"]/*' />
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[CCtorIsRunDuringStartup]
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[NoLoggingForUndo]
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[RequiredByBartok]
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public abstract partial class Delegate
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{
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// _method is the MethodInfo representing the target, this is set by
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// InternalCreate.
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[RequiredByBartok]
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private IntPtr _methodPtr;
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// _target is the object we will invoke o
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[RequiredByBartok]
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private Object _target;
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// In the case of a static method passed to a delegate, this field stores
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// whatever _methodPtr would have stored: and _methodPtr points to a
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// small thunk which removes the "this" pointer before going on
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// to _methodPtrAux.
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[RequiredByBartok]
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private IntPtr _methodPtrAux = IntPtr.Zero;
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// Protect the default constructor so you can't build a delegate
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internal Delegate() {}
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//
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// This is just designed to prevent compiler warnings.
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// This field is used from native, but we need to prevent the compiler warnings.
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//
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#if _DEBUG
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private void DontTouchThis() {
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_methodPtr = IntPtr.Zero;
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_target = null;
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}
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#endif
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// Rest of class must define the following two methods:
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// [RequiredByBartok]
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// private static IntPtr GetCodePtr(Delegate d,IntPtr callBackStub);
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// [RequiredByBartok]
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// private static Delegate IdxToDelegate(int idx);
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}
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}
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