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//------------------------------------------------------------------------------
// <copyright file="ComponentDispatcher.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
using System;
using System.Threading;
using System.Diagnostics.CodeAnalysis;
using System.Security;
using System.Security.Permissions;
using MS.Internal;
using MS.Win32;
using MS.Internal.WindowsBase;
namespace System.Windows.Interop
{
/// <summary>
/// This is the delegate used for registering with the
/// ThreadFilterMessage and ThreadPreprocessMessage Events.
///</summary>
[SuppressMessage("Microsoft.Design", "CA1045:DoNotPassTypesByReference")]
public delegate void ThreadMessageEventHandler(ref MSG msg, ref bool handled);
/// <summary>
/// This is a static class used to share control of the message pump.
/// Whomever is pumping (i.e. calling GetMessage()) will also send
/// the messages to RaiseThreadKeyMessage() which will dispatch them to
/// the ThreadFilterMessage and then (if not handled) to the ThreadPreprocessMessage
/// delegates. That way everyone can be included in the message loop.
/// Currently only Keyboard messages are supported.
/// There are also Events for Idle and facilities for Thread-Modal operation.
///</summary>
public static class ComponentDispatcher
{
static ComponentDispatcher()
{
_threadSlot = Thread.AllocateDataSlot();
}
private static ComponentDispatcherThread CurrentThreadData
{
get
{
ComponentDispatcherThread data;
object obj = Thread.GetData(_threadSlot);
if(null == obj)
{
data = new ComponentDispatcherThread();
Thread.SetData(_threadSlot, data);
}
else
{
data = (ComponentDispatcherThread) obj;
}
return data;
}
}
// Properties
/// <summary>
/// Returns true if one or more components has gone modal.
/// Although once one component is modal a 2nd shouldn't.
///</summary>
/// <remarks>
/// Callers must have UIPermission(PermissionState.Unrestricted) to call this API.
/// </remarks>
/// <SecurityNote>
/// Critical: This is blocked off as defense in depth
/// PublicOk: There is a demand here
/// </SecurityNote>
public static bool IsThreadModal
{
[SecurityCritical]
get
{
SecurityHelper.DemandUnrestrictedUIPermission();
ComponentDispatcherThread data = ComponentDispatcher.CurrentThreadData;
return data.IsThreadModal;
}
}
/// <summary>
/// Returns "current" message. More exactly the last MSG Raised.
///</summary>
/// <remarks>
/// Callers must have UIPermission(PermissionState.Unrestricted) to call this API.
/// </remarks>
/// <SecurityNote>
/// Critical: This is blocked off as defense in depth
/// PublicOk: There is a demand here
/// </SecurityNote>
public static MSG CurrentKeyboardMessage
{
[SecurityCritical]
get
{
SecurityHelper.DemandUnrestrictedUIPermission();
return ComponentDispatcher.CurrentThreadData.CurrentKeyboardMessage;
}
}
/// <summary>
/// Returns "current" message. More exactly the last MSG Raised.
///</summary>
/// <SecurityNote>
/// Critical: This is blocked off as defense in depth
/// </SecurityNote>
internal static MSG UnsecureCurrentKeyboardMessage
{
[FriendAccessAllowed] // Built into Base, used by Core or Framework.
[SecurityCritical]
get
{
return ComponentDispatcher.CurrentThreadData.CurrentKeyboardMessage;
}
[FriendAccessAllowed] // Built into Base, used by Core or Framework.
[SecurityCritical]
set
{
ComponentDispatcher.CurrentThreadData.CurrentKeyboardMessage = value;
}
}
// Methods
/// <summary>
/// A component calls this to go modal. Current thread wide only.
///</summary>
/// <remarks>
/// Callers must have UIPermission(PermissionState.Unrestricted) to call this API.
/// </remarks>
/// <SecurityNote>
/// Critical: This is blocked off as defense in depth
/// PublicOk: There is a demand here
/// </SecurityNote>
[SecurityCritical]
public static void PushModal()
{
SecurityHelper.DemandUnrestrictedUIPermission();
CriticalPushModal();
}
/// <summary>
/// A component calls this to go modal. Current thread wide only.
///</summary>
/// <SecurityNote>
/// Critical: This bypasses the demand for unrestricted UIPermission.
/// </SecurityNote>
[SecurityCritical]
internal static void CriticalPushModal()
{
ComponentDispatcherThread data = ComponentDispatcher.CurrentThreadData;
data.PushModal();
}
/// <summary>
/// A component calls this to end being modal.
///</summary>
/// <remarks>
/// Callers must have UIPermission(PermissionState.Unrestricted) to call this API.
/// </remarks>
/// <SecurityNote>
/// Critical: This is blocked off as defense in depth
/// PublicOk: There is a demand here
/// </SecurityNote>
[SecurityCritical]
public static void PopModal()
{
SecurityHelper.DemandUnrestrictedUIPermission();
CriticalPopModal();
}
/// <summary>
/// A component calls this to end being modal.
///</summary>
/// <SecurityNote>
/// Critical: This bypasses the demand for unrestricted UIPermission.
/// </SecurityNote>
[SecurityCritical]
internal static void CriticalPopModal()
{
ComponentDispatcherThread data = ComponentDispatcher.CurrentThreadData;
data.PopModal();
}
/// <summary>
/// The message loop pumper calls this when it is time to do idle processing.
///</summary>
/// <remarks>
/// Callers must have UIPermission(PermissionState.Unrestricted) to call this API.
/// </remarks>
/// <SecurityNote>
/// Critical: This is blocked off as defense in depth
/// PublicOk: There is a demand here
/// </SecurityNote>
[SecurityCritical]
[UIPermissionAttribute(SecurityAction.LinkDemand,Unrestricted=true)]
[SuppressMessage("Microsoft.Design", "CA1030:UseEventsWhereAppropriate")]
public static void RaiseIdle()
{
ComponentDispatcherThread data = ComponentDispatcher.CurrentThreadData;
data.RaiseIdle();
}
/// <summary>
/// The message loop pumper calls this for every keyboard message.
/// </summary>
/// <remarks>
/// Callers must have UIPermission(PermissionState.Unrestricted) to call this API.
/// </remarks>
/// <SecurityNote>
/// Critical: This is blocked off as defense in depth
/// PublicOk: There is a demand here
/// </SecurityNote>
[SecurityCritical]
[SuppressMessage("Microsoft.Design", "CA1030:UseEventsWhereAppropriate")]
[SuppressMessage("Microsoft.Design", "CA1045:DoNotPassTypesByReference")]
[UIPermissionAttribute(SecurityAction.LinkDemand, Unrestricted = true)]
public static bool RaiseThreadMessage(ref MSG msg)
{
ComponentDispatcherThread data = ComponentDispatcher.CurrentThreadData;
return data.RaiseThreadMessage(ref msg);
}
// Events
/// <summary>
/// Components register delegates with this event to handle
/// thread idle processing.
///</summary>
/// <remarks>
/// Callers must have UIPermission(PermissionState.Unrestricted) to call this API.
/// </remarks>
/// <SecurityNote>
/// Critical: This is blocked off as defense in depth
/// PublicOk: There is a demand here
/// </SecurityNote>
public static event EventHandler ThreadIdle
{
[SecurityCritical]
add {
SecurityHelper.DemandUnrestrictedUIPermission();
ComponentDispatcher.CurrentThreadData.ThreadIdle += value;
}
[SecurityCritical]
remove {
SecurityHelper.DemandUnrestrictedUIPermission();
ComponentDispatcher.CurrentThreadData.ThreadIdle -= value;
}
}
/// <summary>
/// Components register delegates with this event to handle
/// Keyboard Messages (first chance processing).
///</summary>
/// <remarks>
/// Callers must have UIPermission(PermissionState.Unrestricted) to call this API.
/// </remarks>
/// <SecurityNote>
/// Critical: This is blocked off as defense in depth
/// PublicOk: There is a demand here
/// </SecurityNote>
[SuppressMessage("Microsoft.Design", "CA1009:DeclareEventHandlersCorrectly")]
public static event ThreadMessageEventHandler ThreadFilterMessage
{
[SecurityCritical]
add {
SecurityHelper.DemandUnrestrictedUIPermission();
ComponentDispatcher.CurrentThreadData.ThreadFilterMessage += value;
}
[SecurityCritical]
remove {
SecurityHelper.DemandUnrestrictedUIPermission();
ComponentDispatcher.CurrentThreadData.ThreadFilterMessage -= value;
}
}
/// <summary>
/// Components register delegates with this event to handle
/// Keyboard Messages (second chance processing).
///</summary>
/// <remarks>
/// Callers must have UIPermission(PermissionState.Unrestricted) to call this API.
/// </remarks>
/// <SecurityNote>
/// Critical: Exposing the raw input enables tampering. (The MSG structure is passed by-ref.)
/// PublicOk: There is a demand here
/// </SecurityNote>
[SuppressMessage("Microsoft.Design", "CA1009:DeclareEventHandlersCorrectly")]
public static event ThreadMessageEventHandler ThreadPreprocessMessage
{
[UIPermissionAttribute(SecurityAction.LinkDemand, Unrestricted = true)]
[SecurityCritical]
add
{
ComponentDispatcher.CurrentThreadData.ThreadPreprocessMessage += value;
}
[UIPermissionAttribute(SecurityAction.LinkDemand, Unrestricted=true)]
[SecurityCritical]
remove {
ComponentDispatcher.CurrentThreadData.ThreadPreprocessMessage -= value;
}
}
/// <summary>
/// Adds the specified handler to the front of the invocation list
/// of the PreprocessMessage event.
/// <summary>
/// <SecurityNote>
/// Critical: Not to expose raw input, which may be destined for a
/// window in another security context. Also, MSG contains a window
/// handle, which we don't want to expose.
/// </SecurityNote>
[SecurityCritical]
internal static void CriticalAddThreadPreprocessMessageHandlerFirst(ThreadMessageEventHandler handler)
{
ComponentDispatcher.CurrentThreadData.AddThreadPreprocessMessageHandlerFirst(handler);
}
/// <summary>
/// Removes the first occurance of the specified handler from the
/// invocation list of the PreprocessMessage event.
/// <summary>
/// <SecurityNote>
/// Critical: Not to expose raw input, which may be destined for a
/// window in another security context. Also, MSG contains a window
/// handle, which we don't want to expose.
/// </SecurityNote>
[SecurityCritical]
internal static void CriticalRemoveThreadPreprocessMessageHandlerFirst(ThreadMessageEventHandler handler)
{
ComponentDispatcher.CurrentThreadData.RemoveThreadPreprocessMessageHandlerFirst(handler);
}
/// <summary>
/// Components register delegates with this event to handle
/// a component on this thread has "gone modal", when previously none were.
///</summary>
/// <remarks>
/// Callers must have UIPermission(PermissionState.Unrestricted) to call this API.
/// </remarks>
/// <SecurityNote>
/// Critical: This is blocked off as defense in depth
/// PublicOk: There is a demand here
/// </SecurityNote>
public static event EventHandler EnterThreadModal
{
[SecurityCritical]
add {
SecurityHelper.DemandUnrestrictedUIPermission();
ComponentDispatcher.CurrentThreadData.EnterThreadModal += value;
}
[SecurityCritical]
remove {
SecurityHelper.DemandUnrestrictedUIPermission();
ComponentDispatcher.CurrentThreadData.EnterThreadModal -= value;
}
}
/// <summary>
/// Components register delegates with this event to handle
/// all components on this thread are done being modal.
///</summary>
/// <remarks>
/// Callers must have UIPermission(PermissionState.Unrestricted) to call this API.
/// </remarks>
/// <SecurityNote>
/// Critical: This is blocked off as defense in depth
/// PublicOk: There is a demand here
/// </SecurityNote>
public static event EventHandler LeaveThreadModal
{
[SecurityCritical]
add
{
SecurityHelper.DemandUnrestrictedUIPermission();
ComponentDispatcher.CurrentThreadData.LeaveThreadModal += value;
}
[SecurityCritical]
remove {
SecurityHelper.DemandUnrestrictedUIPermission();
ComponentDispatcher.CurrentThreadData.LeaveThreadModal -= value;
}
}
// member data
private static System.LocalDataStoreSlot _threadSlot;
}
};
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