Invariant.cs source code in C# .NET

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Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Shared / MS / Internal / Invariant.cs / 1305600 / Invariant.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// File: Invariant.cs
//
// Copyright (C) Microsoft Corporation.  All rights reserved. 
//
// Description: Provides methods that assert an application is in a valid state. 
// 
//---------------------------------------------------------------------------
 
#if WINDOWS_BASE
using MS.Internal.WindowsBase;
#elif DRT
using MS.Internal.Drt; 
#else
#error There is an attempt to use this class from an unexpected assembly. 
#endif 
namespace MS.Internal
{ 
    using System;
    using System.Security;
    using System.Security.Permissions;
    using Microsoft.Win32; 
    using System.Diagnostics;
    using System.Windows; 
 
    /// 
    /// Provides methods that assert an application is in a valid state. 
    /// 
    [FriendAccessAllowed] // Built into Base, used by Framework.
    internal // DO NOT MAKE PUBLIC - See security notes on Assert
        static class Invariant 
    {
        //----------------------------------------------------- 
        // 
        //  Constructors
        // 
        //-----------------------------------------------------

        #region Constructors
 
        /// 
        /// Static ctor.  Initializes the Strict property. 
        ///  
        ///
        /// Critical - this function elevates to read from the registry. 
        /// TreatAsSafe - Not controllable from external input.
        ///               The information stored indicates whether invariant behavior is "strict" or not. Considered safe.
        ///
        [SecurityCritical, SecurityTreatAsSafe] 
        static Invariant()
        { 
            _strict = _strictDefaultValue; 

#if PRERELEASE 
            //
            // Let the user override the inital value of the Strict property from the registry.
            //
 
            new RegistryPermission(RegistryPermissionAccess.Read, "HKEY_LOCAL_MACHINE\\" + RegistryKeys.WPF).Assert();
            try 
            { 
                RegistryKey key = Registry.LocalMachine.OpenSubKey(RegistryKeys.WPF);
 
                if (key != null)
                {
                    object obj = key.GetValue("InvariantStrict");
 
                    if (obj is int)
                    { 
                        _strict = (int)obj != 0; 
                    }
                } 
            }
            finally
            {
                CodeAccessPermission.RevertAll(); 
            }
#endif // PRERELEASE 
        } 

        #endregion Constructors 

        //------------------------------------------------------
        //
        //  Internal Methods 
        //
        //----------------------------------------------------- 
 
        #region Internal Methods
 
        /// 
        /// Checks for a condition and shuts down the application if false.
        /// 
        ///  
        /// If condition is true, does nothing.
        /// 
        /// If condition is false, raises an assert dialog then shuts down the 
        /// process unconditionally.
        ///  
        /// 
        ///     Critical: This code will close the current process
        ///     TreatAsSafe: This code is safe to call.
        ///                  Note that if this code were ever to become public, 
        ///                  we have a potential denial-of-service vulnerability.
        ///                  Passing in false shuts down the process, even in 
        ///                  partial trust.  However, not shutting down in 
        ///                  partial trust is even worse: by definition a false condition
        ///                  means we've hit a bug in avalon code and we cannot safely 
        ///                  continue.
        /// 
        // [SecurityCritical, SecurityTreatAsSafe] - Removed for performance, OK so long as this class remains internal
        internal static void Assert(bool condition) 
        {
            if (!condition) 
            { 
                FailFast(null, null);
            } 
        }

        /// 
        /// Checks for a condition and shuts down the application if false. 
        /// 
        ///  
        /// If condition is true, does nothing. 
        ///
        /// If condition is false, raises an assert dialog then shuts down the 
        /// process unconditionally.
        /// 
        /// 
        /// Message to display before shutting down the application. 
        /// 
        ///  
        ///     Critical: This code will close the current process 
        ///     TreatAsSafe: This code is safe to call.
        ///                  Note that if this code were ever to become public, 
        ///                  we have a potential denial-of-service vulnerability.
        ///                  Passing in false shuts down the process, even in
        ///                  partial trust.  However, not shutting down in
        ///                  partial trust is even worse: by definition a false condition 
        ///                  means we've hit a bug in avalon code and we cannot safely
        ///                  continue. 
        ///  
        // [SecurityCritical, SecurityTreatAsSafe] - Removed for performance, OK so long as this class remains internal
        internal static void Assert(bool condition, string invariantMessage) 
        {
            if (!condition)
            {
                FailFast(invariantMessage, null); 
            }
        } 
 
        /// 
        /// Checks for a condition and shuts down the application if false. 
        /// 
        /// 
        /// If condition is true, does nothing.
        /// 
        /// If condition is false, raises an assert dialog then shuts down the
        /// process unconditionally. 
        ///  
        /// 
        /// Message to display before shutting down the application. 
        /// 
        /// 
        /// Additional message to display before shutting down the application.
        ///  
        /// 
        ///     Critical: This code will close the current process 
        ///     TreatAsSafe: This code is safe to call. 
        ///                  Note that if this code were ever to become public,
        ///                  we have a potential denial-of-service vulnerability. 
        ///                  Passing in false shuts down the process, even in
        ///                  partial trust.  However, not shutting down in
        ///                  partial trust is even worse: by definition a false condition
        ///                  means we've hit a bug in avalon code and we cannot safely 
        ///                  continue.
        ///  
        // [SecurityCritical, SecurityTreatAsSafe] - Removed for performance, OK so long as this class remains internal 
        internal static void Assert(bool condition, string invariantMessage, string detailMessage)
        { 
            if (!condition)
            {
                FailFast(invariantMessage, detailMessage);
            } 
        }
 
        #endregion Internal Methods 

        //------------------------------------------------------ 
        //
        //  Internal Properties
        //
        //------------------------------------------------------ 

        #region Internal Properties 
 
        /// 
        /// Property specifying whether or not the user wants to enable expensive 
        /// verification diagnostics.  The Strict property is rarely used -- only
        /// when performance profiling shows a real problem.
        ///
        /// Default value is false on FRE builds, true on 

 
 

 



 

 
 

 



 
        internal static bool Strict
        { 
            get { return _strict; } 

            set { _strict = value; } 
        }

        #endregion Internal Properties
 
        //-----------------------------------------------------
        // 
        //  Private Methods 
        //
        //------------------------------------------------------ 

        #region Private Methods

        ///  
        ///     Shuts down the process immediately, with no chance for additional
        ///     code to run. 
        /// 
        ///     In debug we raise a Debug.Assert dialog before shutting down.
        ///  
        /// 
        ///     Message to display before shutting down the application.
        /// 
        ///  
        ///     Additional message to display before shutting down the application.
        ///  
        ///  
        ///     Critical: This code will close the current process.
        ///     TreatAsSafe: This code is safe to call. 
        ///         Note that if this code were made to be callable publicly,
        ///         we would have a potential denial-of-service vulnerability.
        /// 
        [SecurityCritical, SecurityTreatAsSafe] 
        private // DO NOT MAKE PUBLIC OR INTERNAL -- See security note
            static void FailFast(string message, string detailMessage) 
        { 
            if (Invariant.IsDialogOverrideEnabled)
            { 
                // This is the override for stress and other automation.
                // Automated systems can't handle a popup-dialog, so let
                // them jump straight into the debugger.
                Debugger.Break(); 
            }
 
            Debug.Assert(false, "Invariant failure: " + message, detailMessage); 

            Environment.FailFast(SR.Get(SRID.InvariantFailure)); 
        }

        #endregion Private Methods
 
        //-----------------------------------------------------
        // 
        //  Private Properties 
        //
        //----------------------------------------------------- 

        #region Private Properties

        // Returns true if the default assert failure dialog has been disabled 
        // on this machine.
        // 
        // The dialog may be disabled by 
        //   Installing a JIT debugger to the [HKEY_LOCAL_MACHINE\Software\Microsoft\.NETFramework]
        //     DbgJITDebugLaunchSetting and DbgManagedDebugger registry keys. 
        ///
        /// Critical - this function elevates to read from the registry.
        /// TreatAsSafe - Not controllable from external input.
        ///               The information stored indicates whether dialog override is available or not. Safe to expose 
        ///
        private static bool IsDialogOverrideEnabled 
        { 
            [SecurityCritical, SecurityTreatAsSafe]
            get 
            {
                RegistryKey key;
                bool enabled;
 
                enabled = false;
 
                //extracting all the data under an elevation. 
                object dbgJITDebugLaunchSettingValue;
                string dbgManagedDebuggerValue; 
                PermissionSet ps = new PermissionSet(PermissionState.None);
                RegistryPermission regPerm = new RegistryPermission(RegistryPermissionAccess.Read, "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\.NetFramework");
                ps.AddPermission(regPerm);
                ps.Assert();//BlessedAssert 
                try
                { 
                    key = Registry.LocalMachine.OpenSubKey("Software\\Microsoft\\.NETFramework"); 
                    dbgJITDebugLaunchSettingValue = key.GetValue("DbgJITDebugLaunchSetting");
                    dbgManagedDebuggerValue = key.GetValue("DbgManagedDebugger") as string; 
                }
                finally
                {
                    PermissionSet.RevertAssert(); 
                }
                // 
                // Check for the enable. 
                //
                if (key != null) 
                {
                    //
                    // Only count the enable if there's a JIT debugger to launch.
                    // 
                    enabled = (dbgJITDebugLaunchSettingValue is int && ((int)dbgJITDebugLaunchSettingValue & 2) != 0);
                    if (enabled) 
                    { 
                        enabled = dbgManagedDebuggerValue != null && dbgManagedDebuggerValue.Length > 0;
                    } 
                }
                return enabled;
            }
        } 

        #endregion Private Properties 
 
        //-----------------------------------------------------
        // 
        //  Private Fields
        //
        //------------------------------------------------------
 
        #region Private Fields
 
        // Property specifying whether or not the user wants to enable expensive 
        // verification diagnostics.
        /// 
        /// Critical - this data member required elevated permissions to be set.
        /// TreatAsSafe - this data indicates whether "strict" invariant mode is to be used. Considered safe
        ///
        [SecurityCritical, SecurityTreatAsSafe] 
        private static bool _strict;
 
        // Used to initialize the default value of _strict in the static ctor. 
        private const bool _strictDefaultValue
#if DEBUG 
            = true;     // Enable strict asserts by default on
#else
            = false;
#endif 

        #endregion Private Fields 
    } 
}
 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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