File: Core\CSharp\System\Windows\Input\InputProcessorProfiles.cs
Project: wpf\src\PresentationCore.csproj (PresentationCore)
//---------------------------------------------------------------------------
//
// <copyright file=InputProcessorProfiles.cs company=Microsoft>
//    Copyright (C) Microsoft Corporation.  All rights reserved.
// </copyright>
// 
//
// Description: Creates ITfInputProcessorProfiles instances.
//
// History:  
//  07/30/2003 : yutakas - ported from dotnet tree.
//
//---------------------------------------------------------------------------
 
using System;
using System.Runtime.InteropServices;
using System.Security.Permissions;
using System.Threading;
using System.Security;
using MS.Win32;
using MS.Internal;
using System.Diagnostics;
using System.Globalization;
using System.Collections;
 
namespace System.Windows.Input
{
 
    //------------------------------------------------------
    //
    //  InputProcessorProfiles class
    //
    //------------------------------------------------------
 
    /// <summary>
    /// The InputProcessorProfiles class is always associated with 
    /// hwndInputLanguage class.
    /// </summary>
    internal class InputProcessorProfiles
    {
        //------------------------------------------------------
        //
        //  Constructors
        //
        //------------------------------------------------------
 
        /// <summary>
        /// InputProcessorProfiles Constructor;
        /// </summary>
        /// Critical - as this sets the value for _ipp.
        /// Safe - as this just initializes it to null.
        [SecurityCritical, SecurityTreatAsSafe]
        internal InputProcessorProfiles()
        {
            // _ipp is a ValueType, hence no need for new.
            _ipp.Value = null;
            _cookie = UnsafeNativeMethods.TF_INVALID_COOKIE;
        }
 
        //------------------------------------------------------
        //
        //  Internal Methods
        //
        //------------------------------------------------------
 
        #region Internal Methods
 
        /// <summary>
        /// Initialize an interface and notify sink.
        /// </summary>
        /// <SecurityNote>
        /// Critical - calls critical method (inputprocessorprofilesload)
        ///            calls Critical setter on _ipp.Value
        /// </SecurityNote>
        [SecurityCritical]
        internal bool Initialize(object o)
        {
            Debug.Assert(Thread.CurrentThread.GetApartmentState() == ApartmentState.STA, "Initialize called on MTA thread!");
 
            Debug.Assert(_ipp.Value == null, "Initialize called twice");
 
            _ipp.Value = InputProcessorProfilesLoader.Load();
 
            if (_ipp.Value == null)
            {
                return false;
            }
 
            AdviseNotifySink(o);
            return true;
        }
 
        /// <summary>
        /// Initialize an interface and notify sink.
        /// </summary>
        /// <SecurityNote>
        /// Critical - as this calls Marshal.ReleaseComObject(), which has a LinkDemand
        ///            Also calls setter for _ipp.Value.
        /// Safe - as the worst that would happen is NullReference exception when _ipp is accessed.
        ///        Setting _ipp.Value to null is safe.
        /// </SecurityNote>
        [SecurityCritical, SecurityTreatAsSafe]
        internal void Uninitialize()
        {
            Debug.Assert(_ipp.Value != null, "Uninitialize called without initializing");
 
            UnadviseNotifySink();            
            Marshal.ReleaseComObject(_ipp.Value);
            _ipp.Value = null;
        }
 
        #endregion Internal Methods
 
        //------------------------------------------------------
        //
        //  Internal Properties
        //
        //------------------------------------------------------
 
        /// <summary>
        /// Get the current input language of the current thread.
        /// </summary>
        /// <SecurityNote>
        /// Critical - calls unmanaged code to set the input language
        /// TreatAsSafe - it is OK to set the input language, APIs check 
        ///                 to make sure the lang is available.
        /// </SecurityNote>
        internal short CurrentInputLanguage
        {
            [SecurityCritical, SecurityTreatAsSafe]
            set
            {
                if (_ipp.Value != null)
                {
                    if (_ipp.Value.ChangeCurrentLanguage(value) != 0)
                    {
                        //
                        // Under WinXP or W2K3, ITfInputProcessorProfiles::ChangeCurrentLanguage() fails
                        // if there is no thread manager in the current thread. This is Cicero's bug and fixed
                        // for Longhorn.
                        // We need to try ActivateKeyboardLayout() for the case.
                        //
                        IntPtr[] hklList = null;
 
                        int count = (int)SafeNativeMethods.GetKeyboardLayoutList(0, null);
                        if (count > 1) 
                        {
                            hklList = new IntPtr[count];
 
                            count = SafeNativeMethods.GetKeyboardLayoutList(count, hklList);
 
                            int i;
                            for (i = 0; (i < hklList.Length) && (i < count); i++)
                            {
                                if (value == (short)hklList[i])
                                {
                                    SafeNativeMethods.ActivateKeyboardLayout(new HandleRef(this,hklList[i]), 0);
                                    break;
                                }
                            }
                        }
                    }
                }
            }
        }
 
        /// <summary>
        /// Get the list of the input languages that are available in the
        /// current thread.
        /// </summary>
        /// <SecurityNote>
        /// Critical - calls unmanaged code to query the languages on the system
        /// TreatAsSafe - it is OK to disclose the available languages on the system
        /// </SecurityNote>
        internal ArrayList InputLanguageList
        {
            [SecurityCritical, SecurityTreatAsSafe]
             get
             {
                 int nCount;
                 IntPtr langids;
 
                 // ITfInputProcessorProfiles::GetLanguageList returns the pointer that was allocated by
                 // CoTaskMemAlloc().
                 _ipp.Value.GetLanguageList(out langids, out nCount);
 
                 ArrayList arrayLang = new ArrayList();
 
                 int sizeOfShort = Marshal.SizeOf(typeof(short));
 
                 for (int i = 0; i < nCount; i++)
                 {
                     // Unmarshal each langid from short array.
                     short langid = (short)Marshal.PtrToStructure((IntPtr)((Int64)langids + sizeOfShort * i), typeof(short));
                     arrayLang.Add(new CultureInfo(langid));
                 }
 
                 // Call CoTaskMemFree().
                 Marshal.FreeCoTaskMem(langids);
 
                 return arrayLang;
             }
        }
 
 
        //------------------------------------------------------
        //
        //  Private Methods
        //
        //------------------------------------------------------
        
        /// <summary>
        /// This advices the input language notify sink to
        /// ITfInputProcessorProfile.
        /// </summary>
        /// <SecurityNote>
        ///     Critical: This calls into ITfSource which is an interop COM call
        /// </SecurityNote>
        [SecurityCritical]
        private void AdviseNotifySink(object o)
        {
            Debug.Assert(_cookie == UnsafeNativeMethods.TF_INVALID_COOKIE, "Cookie is already set.");
 
            UnsafeNativeMethods.ITfSource source = _ipp.Value as UnsafeNativeMethods.ITfSource;
 
            // workaround because I can't pass a ref to a readonly constant
            Guid guid = UnsafeNativeMethods.IID_ITfLanguageProfileNotifySink;
 
            source.AdviseSink(ref guid, o, out _cookie);
        }
 
        /// <summary>
        /// This unadvises the sink.
        /// </summary>
        /// <SecurityNote>
        /// Critical - As this elevates to invoke UnadviseSink on ITfSource.
        /// Safe - as the worst that'll happen is that we'll lose some text framework notifications.
        ///        Note that _ipp is marked SecurityCritical for set.
        /// </SecurityNote>
        [SecurityCritical, SecurityTreatAsSafe]
        private void UnadviseNotifySink()
        {
            Debug.Assert(_cookie != UnsafeNativeMethods.TF_INVALID_COOKIE, "Cookie is not set.");
 
            UnsafeNativeMethods.ITfSource source = _ipp.Value as UnsafeNativeMethods.ITfSource;
 
            source.UnadviseSink(_cookie);
 
            _cookie = UnsafeNativeMethods.TF_INVALID_COOKIE;
        }
 
        //------------------------------------------------------
        //
        //  Private Fields
        //
        //------------------------------------------------------
                
        // The reference to ITfInputProcessorProfile.
        /// <SecurityNote>
        /// Critical - Field for Critical Type.
        /// </SecurityNote>
        [SecurityCritical]
        private SecurityCriticalDataForSet<UnsafeNativeMethods.ITfInputProcessorProfiles> _ipp;
 
        // The cookie for the advised sink.
        private int _cookie;
    }
}