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/**************************************************************************\
Copyright Microsoft Corporation. All Rights Reserved.
\**************************************************************************/
namespace Standard
{
using System;
using System.Runtime.ConstrainedExecution;
using System.Runtime.InteropServices;
using System.Security;
using System.Windows;
using System.Windows.Threading;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
/// <SecurityNote>
/// Critical : Should not be created by partially trusted callers because it's finalizer is critical
/// and does not allow partial trust callers.
/// </SecurityNote>
[SecurityCritical]
internal sealed class MessageWindow : CriticalFinalizerObject
{
/// <SecurityNote>
/// Critical : Initializes critical static members
/// <SecurityNote>
[SecurityCritical]
static MessageWindow()
{
}
// Alias this to a static so the wrapper doesn't get GC'd
/// <SecurityNote>
/// Critical : Delegate passed critical data (Win32 messages and parameters) used to control Win32 window behavior
/// <SecurityNote>
[SecurityCritical]
private static readonly WndProc s_WndProc = new WndProc(_WndProc);
/// <SecurityNote>
/// Critical : Provides access to instances of critical MessageWindow type
/// </SecurityNote>
[SecurityCritical]
private static readonly Dictionary<IntPtr, MessageWindow> s_windowLookup = new Dictionary<IntPtr, MessageWindow>();
/// <SecurityNote>
/// Critical : Delegate passed critical data (Win32 messages and parameters) used to control Win32 window behavior
/// <SecurityNote>
[SecurityCritical]
private WndProc _wndProcCallback;
private string _className;
private bool _isDisposed;
Dispatcher _dispatcher;
/// <SecurityNote>
/// Critical : Accesses critical Win32 window handle
/// </SecurityNote>
public IntPtr Handle
{
[SecurityCritical]
get;
[SecurityCritical]
private set;
}
/// <SecurityNote>
/// Critical : P-Invokes to register window class and create win32 window
/// </SecurityNote>
[SecurityCritical]
[SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
public MessageWindow(CS classStyle, WS style, WS_EX exStyle, Rect location, string name, WndProc callback)
{
// A null callback means just use DefWindowProc.
_wndProcCallback = callback;
_className = "MessageWindowClass+" + Guid.NewGuid().ToString();
var wc = new WNDCLASSEX
{
cbSize = Marshal.SizeOf(typeof(WNDCLASSEX)),
style = classStyle,
lpfnWndProc = s_WndProc,
hInstance = NativeMethods.GetModuleHandle(null),
hbrBackground = NativeMethods.GetStockObject(StockObject.NULL_BRUSH),
lpszMenuName = "",
lpszClassName = _className,
};
NativeMethods.RegisterClassEx(ref wc);
GCHandle gcHandle = default(GCHandle);
try
{
gcHandle = GCHandle.Alloc(this);
IntPtr pinnedThisPtr = (IntPtr)gcHandle;
Handle = NativeMethods.CreateWindowEx(
exStyle,
_className,
name,
style,
(int)location.X,
(int)location.Y,
(int)location.Width,
(int)location.Height,
IntPtr.Zero,
IntPtr.Zero,
IntPtr.Zero,
pinnedThisPtr);
}
finally
{
gcHandle.Free();
}
_dispatcher = Dispatcher.CurrentDispatcher;
}
/// <SecurityNote>
/// Critical : Calls critical methods
/// <SecurityNote>
[SecurityCritical]
~MessageWindow()
{
_Dispose(false, false);
}
/// <SecurityNote>
/// Critical : Calls critical methods
/// <SecurityNote>
[SecurityCritical]
public void Release()
{
_Dispose(true, false);
GC.SuppressFinalize(this);
}
// This isn't right if the Dispatcher has already started shutting down.
// It will wind up leaking the class ATOM...
/// <SecurityNote>
/// Critical : Calls critical methods
/// <SecurityNote>
[SecurityCritical]
[SuppressMessage("Microsoft.Usage", "CA1801:ReviewUnusedParameters", MessageId = "disposing")]
private void _Dispose(bool disposing, bool isHwndBeingDestroyed)
{
if (_isDisposed)
{
// Block against reentrancy.
return;
}
_isDisposed = true;
IntPtr hwnd = Handle;
string className = _className;
if (isHwndBeingDestroyed)
{
_dispatcher.BeginInvoke(DispatcherPriority.Normal, (DispatcherOperationCallback)_DestroyWindowCallback, new object [] { IntPtr.Zero, className });
}
else if (Handle != IntPtr.Zero)
{
if (_dispatcher.CheckAccess())
{
_DestroyWindow(hwnd, className);
}
else
{
_dispatcher.BeginInvoke(DispatcherPriority.Normal, (DispatcherOperationCallback)_DestroyWindowCallback, new object [] { hwnd, className });
}
}
s_windowLookup.Remove(hwnd);
_className = null;
Handle = IntPtr.Zero;
}
/// <SecurityNote>
/// Critical : Calls critical methods
/// <SecurityNote>
[SecurityCritical]
private object _DestroyWindowCallback(object arg)
{
object [] args = (object[])arg;
_DestroyWindow((IntPtr)args[0], (string)args[1]);
return null;
}
/// <SecurityNote>
/// Critical : Calls critical methods
/// <SecurityNote>
[SecurityCritical]
[SuppressMessage("Microsoft.Usage", "CA1816:CallGCSuppressFinalizeCorrectly")]
private static IntPtr _WndProc(IntPtr hwnd, WM msg, IntPtr wParam, IntPtr lParam)
{
IntPtr ret = IntPtr.Zero;
MessageWindow hwndWrapper = null;
if (msg == WM.CREATE)
{
var createStruct = (CREATESTRUCT)Marshal.PtrToStructure(lParam, typeof(CREATESTRUCT));
GCHandle gcHandle = GCHandle.FromIntPtr(createStruct.lpCreateParams);
hwndWrapper = (MessageWindow)gcHandle.Target;
s_windowLookup.Add(hwnd, hwndWrapper);
}
else
{
if (!s_windowLookup.TryGetValue(hwnd, out hwndWrapper))
{
return NativeMethods.DefWindowProc(hwnd, msg, wParam, lParam);
}
}
Assert.IsNotNull(hwndWrapper);
WndProc callback = hwndWrapper._wndProcCallback;
if (callback != null)
{
ret = callback(hwnd, msg, wParam, lParam);
}
else
{
ret = NativeMethods.DefWindowProc(hwnd, msg, wParam, lParam);
}
if (msg == WM.NCDESTROY)
{
hwndWrapper._Dispose(true, true);
GC.SuppressFinalize(hwndWrapper);
}
return ret;
}
/// <SecurityNote>
/// Critical : Calls critical methods
/// <SecurityNote>
[SecurityCritical]
private static void _DestroyWindow(IntPtr hwnd, string className)
{
Utility.SafeDestroyWindow(ref hwnd);
NativeMethods.UnregisterClass(className, NativeMethods.GetModuleHandle(null));
}
}
}
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