webbrowsersite.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / MS / Internal / Controls / webbrowsersite.cs / 1305600 / webbrowsersite.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
//
// Description: 
//      WebBrowserSite is a sub-class of ActiveXSite. 
//      Used to implement IDocHostUIHandler.
// 
//      Copied from WebBrowser.cs in [....]
//
// History
//      06/16/05 - marka - Created 
//      04/24/08 - [....] - Implemented hosting the WebOC in the browser process for IE 7+ Protected Mode.
// 
//----------------------------------------------------------------------------- 

using System; 
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows; 
using MS.Win32;
using System.Security ; 
using MS.Internal.Interop; 
using MS.Internal.PresentationFramework;
using System.Windows.Controls; 
using System.Windows.Interop;
using System.Windows.Input;
using System.Windows.Threading;
using System.Threading; 

using IComDataObject = System.Runtime.InteropServices.ComTypes.IDataObject; 
 
namespace MS.Internal.Controls
{ 
    //
    // WebBrowserSite class:
    //
    /// 
    /// 
    /// Provides a default WebBrowserSite implementation for use in the CreateWebBrowserSite 
    /// method in the WebBrowser class. 
    /// 
    ///  
    /// WebOCHostedInBrowserProcess - defense in depth:
    ///   These interface implementations are exposed across a security boundary. We must not allow a
    ///   compromised low-integrity-level browser process to gain elevation of privilege via our process or
    ///   tamper with its state. (Attacking the WebOC via this interface is not interesting, because the WebOC 
    ///   is directly accessible in the browser process.) Each interface implementation method must be
    ///   carefully reviewed to ensure that it cannot be abused by disclosing protected resources or by passing 
    ///   malicious data to it. 
    /// 
    ///  
    /// THREADING ISSUE: When WebBrowser.IsWebOCHostedInBrowserProcess, calls on the interfaces implemented here
    ///   (and on ActiveXSite) arrive on RPC worker threads. This is because CLR objects don't like to stick to
    ///   STA threads. Fortunately, most of the current implementation methods are okay to be called on any thread.
    ///   And if not, switching to the WebBrowser object's thread via the Dispatcher is usually possible & safe. 
    ///   In a few scenarios, when we need to call a WebOC method from one of these callback interfaces, we get
    ///   RPC_E_CANTCALLOUT_ININPUTSYNCCALL, which happens because the CLR actually tries to switch to the right 
    ///   thread to make the COM call, but that thread is already blocked on an outgoing call (to the WebOC). 
    ///   One example is IOleInPlaceSite.OnInPlaceActivate().
    ///   These failures are silent and safely ignorable for now. If this threading issue becomes more troubling, 
    ///   a solution like ActiveXHelper.CreateIDispatchSTAForwarder() is possible.
    /// 
    internal class WebBrowserSite : ActiveXSite,
        UnsafeNativeMethods.IDocHostUIHandler, 
        UnsafeNativeMethods.IOleControlSite // partial override
    { 
        /// 
        /// 
        ///     WebBrowser implementation of ActiveXSite. Used to override GetHostInfo. 
        ///     and "turn on" our redirect notifications.
        /// 
        /// 
        ///     Critical - calls base class ctor which is critical. 
        /// 
        [ SecurityCritical ] 
        internal WebBrowserSite(WebBrowser host) : base(host) 
        {
        } 


        #region IDocHostUIHandler Implementation
 
        int UnsafeNativeMethods.IDocHostUIHandler.ShowContextMenu(int dwID, NativeMethods.POINT pt, object pcmdtReserved, object pdispReserved)
        { 
 
            //
            // Returning S_FALSE will allow the native control to do default processing, 
            // i.e., execute the shortcut key. Returning S_OK will cancel the context menu
            //

            return NativeMethods.S_FALSE; 
        }
 
        /// 
        ///     Critical - calls critical code.
        ///                If you change this method - you could affect mitigations. 
        ///                 **Needs to be critical.**
        ///     TreatAsSafe - information returned from this method is innocous.
        ///                   lists the set of browser features/options we've enabled.
        /// 
        [ SecurityCritical, SecurityTreatAsSafe ]
        int UnsafeNativeMethods.IDocHostUIHandler.GetHostInfo(NativeMethods.DOCHOSTUIINFO info) 
        { 
            WebBrowser wb = (WebBrowser) Host;
 
            info.dwDoubleClick = (int) NativeMethods.DOCHOSTUIDBLCLICK.DEFAULT;

            //
            // These are the current flags shdocvw uses. Assumed we want the same. 
            //
 
            info.dwFlags = (int) (  NativeMethods.DOCHOSTUIFLAG.DISABLE_HELP_MENU | 
                           NativeMethods.DOCHOSTUIFLAG.DISABLE_SCRIPT_INACTIVE |
                           NativeMethods.DOCHOSTUIFLAG.ENABLE_INPLACE_NAVIGATION | 
                           NativeMethods.DOCHOSTUIFLAG.IME_ENABLE_RECONVERSION |
                           NativeMethods.DOCHOSTUIFLAG.THEME |
                           NativeMethods.DOCHOSTUIFLAG.ENABLE_FORMS_AUTOCOMPLETE |
                           NativeMethods.DOCHOSTUIFLAG.DISABLE_UNTRUSTEDPROTOCOL | 
                           NativeMethods.DOCHOSTUIFLAG.LOCAL_MACHINE_ACCESS_CHECK |
                           NativeMethods.DOCHOSTUIFLAG.ENABLE_REDIRECT_NOTIFICATION | 
                           NativeMethods.DOCHOSTUIFLAG.NO3DOUTERBORDER); 

            return NativeMethods.S_OK; 
        }


        int UnsafeNativeMethods.IDocHostUIHandler.EnableModeless(bool fEnable) 
        {
            return NativeMethods.E_NOTIMPL; 
        } 

 
        int UnsafeNativeMethods.IDocHostUIHandler.ShowUI(int dwID, UnsafeNativeMethods.IOleInPlaceActiveObject activeObject,
                NativeMethods.IOleCommandTarget commandTarget, UnsafeNativeMethods.IOleInPlaceFrame frame,
                UnsafeNativeMethods.IOleInPlaceUIWindow doc)
        { 
            return NativeMethods.E_NOTIMPL;
        } 
 

        int UnsafeNativeMethods.IDocHostUIHandler.HideUI() 
        {
            return NativeMethods.E_NOTIMPL;
        }
 
        int UnsafeNativeMethods.IDocHostUIHandler.UpdateUI() {
            return NativeMethods.E_NOTIMPL; 
        } 
        int UnsafeNativeMethods.IDocHostUIHandler.OnDocWindowActivate(bool fActivate)
        { 
            return NativeMethods.E_NOTIMPL;
        }
        int UnsafeNativeMethods.IDocHostUIHandler.OnFrameWindowActivate(bool fActivate)
        { 
            return NativeMethods.E_NOTIMPL;
        } 
 
        int UnsafeNativeMethods.IDocHostUIHandler.ResizeBorder(NativeMethods.COMRECT rect, UnsafeNativeMethods.IOleInPlaceUIWindow doc, bool fFrameWindow)
        { 
            return NativeMethods.E_NOTIMPL;
        }

        int UnsafeNativeMethods.IDocHostUIHandler.GetOptionKeyPath(string[] pbstrKey, int dw) 
        {
            return NativeMethods.E_NOTIMPL; 
        } 

        int UnsafeNativeMethods.IDocHostUIHandler.GetDropTarget(UnsafeNativeMethods.IOleDropTarget pDropTarget, out UnsafeNativeMethods.IOleDropTarget ppDropTarget) 
        {
            //
            // Set to null no matter what we return, to prevent the marshaller
            // from going crazy if the pointer points to random stuff. 
            ppDropTarget = null;
            return NativeMethods.E_NOTIMPL; 
        } 

        ///  
        ///    Critical: This code access critical member Host.
        ///    TreatAsSafe: The object returned is sandboxed in the managed environment.
        /// 
        [SecurityCritical, SecurityTreatAsSafe] 
        int UnsafeNativeMethods.IDocHostUIHandler.GetExternal(out object ppDispatch)
        { 
            WebBrowser wb = (WebBrowser) Host; 
            ppDispatch = wb.HostingAdaptor.ObjectForScripting;
            return NativeMethods.S_OK; 
        }

        /// 
        /// Called by the WebOC whenever its IOleInPlaceActiveObject::TranslateAccelerator() is called. 
        /// See also the IOleControlSite.TranslateAccelerator() implementation here.
        ///  
        int UnsafeNativeMethods.IDocHostUIHandler.TranslateAccelerator(ref System.Windows.Interop.MSG msg, ref Guid group, int nCmdID) 
        {
            // 
            // Returning S_FALSE will allow the native control to do default processing,
            // i.e., execute the shortcut key. Returning S_OK will cancel the shortcut key.

            /*              WebBrowser wb = (WebBrowser)this.Host; 

            if (!wb.WebBrowserShortcutsEnabled) 
            { 
                int keyCode = (int)msg.wParam | (int)Control.ModifierKeys;
 
                if (msg.message != WindowMessage.WM_CHAR
                        && Enum.IsDefined(typeof(Shortcut), (Shortcut)keyCode)) {
                    return NativeMethods.S_OK;
                } 
                return NativeMethods.S_FALSE;
            } 
            */ 

            return NativeMethods.S_FALSE; 
        }

        int UnsafeNativeMethods.IDocHostUIHandler.TranslateUrl(int dwTranslate, string strUrlIn, out string pstrUrlOut)
        { 
            //
            // Set to null no matter what we return, to prevent the marshaller 
            // from going crazy if the pointer points to random stuff. 
            pstrUrlOut = null;
            return NativeMethods.E_NOTIMPL; 
        }

        int UnsafeNativeMethods.IDocHostUIHandler.FilterDataObject(IComDataObject pDO, out IComDataObject ppDORet)
        { 
            //
            // Set to null no matter what we return, to prevent the marshaller 
            // from going crazy if the pointer points to random stuff. 
            ppDORet = null;
            return NativeMethods.E_NOTIMPL; 
        }

        #endregion
 
        ///  See overview of keyboard input handling in WebBrowser.cs. 
        ///  
        /// Critical: Access the critical Host property. 
        /// TAS: Host is not exposed.
        /// WebOCHostedInBrowserProcess: Potential for input spoofing. Currently we handle only the Tab key, 
        ///     which is safe.
        /// 
        [SecurityCritical, SecurityTreatAsSafe]
        int UnsafeNativeMethods.IOleControlSite.TranslateAccelerator(ref MSG msg, int grfModifiers) 
        {
            // Handle tabbing out of the WebOC 
            if ((WindowMessage)msg.message == WindowMessage.WM_KEYDOWN && (int)msg.wParam == NativeMethods.VK_TAB) 
            {
                FocusNavigationDirection direction = 
                    (grfModifiers & 1/*KEYMOD_SHIFT*/) != 0 ?
                    FocusNavigationDirection.Previous : FocusNavigationDirection.Next;
                // For the WebOCHostedInBrowserProcess case, we need to switch to the right thread.
                Host.Dispatcher.Invoke( 
                    DispatcherPriority.Send, new SendOrPostCallback(MoveFocusCallback), direction);
                return NativeMethods.S_OK; 
            } 
            return NativeMethods.S_FALSE;
        } 

        /// 
        /// Critical: Access the critical Host property.
        /// TAS: Host is not exposed. 
        /// 
        [SecurityCritical, SecurityTreatAsSafe] 
        private void MoveFocusCallback(object direction) 
        {
            Host.MoveFocus(new TraversalRequest((FocusNavigationDirection)direction)); 
        }

    };
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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