// ==++==
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--==
/*=============================================================================
**
** Class: Exception
**
**
** Purpose: The base class for all exceptional conditions.
**
** Date: March 11, 1998
**
=============================================================================*/

namespace System {
    using System;
    using System.Runtime.InteropServices;
    using System.Runtime.CompilerServices;
    using System.Diagnostics;
    using System.Text;
    using System.Reflection;
#if SINGULARITY_KERNEL
    using Microsoft.Singularity;
#elif SINGULARITY_PROCESS
    using Microsoft.Singularity.V1.Services;
#endif // SINGULARITY_PROCESS


    //| <include path='docs/doc[@for="Exception"]/*' />
    [RequiredByBartok]
    public class Exception
    {
        //| <include path='docs/doc[@for="Exception.Exception"]/*' />
        public Exception() {
            _message = null;
#if SINGULARITY_KERNEL
            //DebugStub.Break();
#elif SINGULARITY_PROCESS
            //DebugService.Break();
#endif // SINGULARITY_PROCESS
        }

        //| <include path='docs/doc[@for="Exception.Exception1"]/*' />
        public Exception(String message) {
            _message = message;
#if SINGULARITY_KERNEL
            //DebugStub.Break();
#elif SINGULARITY_PROCESS
            //DebugService.Break();
#endif // SINGULARITY_PROCESS
        }

        // Creates a new Exception.  All derived classes should
        // provide this constructor.
        // Note: the stack trace is not started until the exception
        // is thrown
        //
        //| <include path='docs/doc[@for="Exception.Exception2"]/*' />
        public Exception (String message, Exception innerException)
        {
            // TODO: The innerException will be provided by the runtime
            // in the M9 time frame. Until then, we need this method.
            _message = message;
            _innerException = innerException;
        }

        //| <include path='docs/doc[@for="Exception.Message"]/*' />
        public virtual String Message {
               get {
                if (_message == null) {
                    return "Exception_WasThrown";
                } else {
                    return _message;
                }
            }
        }

        private String GetClassName() {
            return this.vtable.vtableType.FullName;
        }

        // Retrieves the lowest exception (inner most) for the given Exception.
        // This will traverse exceptions using the innerException property.
        //
        //| <include path='docs/doc[@for="Exception.GetBaseException"]/*' />
        public virtual Exception GetBaseException()
        {
            Exception inner = InnerException;
            Exception back = this;

            while (inner != null) {
                back = inner;
                inner = inner.InnerException;
            }

            return back;
        }

        // Returns the inner exception contained in this exception
        //
        //| <include path='docs/doc[@for="Exception.InnerException"]/*' />
        public Exception InnerException {
            get { return _innerException; }
        }

        //| <include path='docs/doc[@for="Exception.ToString"]/*' />
        public override String ToString() {
            String message = Message;

            if (_innerException!=null) {
                message = message + " ---> " + _innerException.ToString() + "\r\n" + "   " + "Exception_EndOfInnerExceptionStack";
            }

            return message;
        }

        [AccessedByRuntime("referenced from halasm.asm")]
        internal static unsafe bool IsUnlinkStack(UIntPtr throwAddr) {
            UIntPtr unlinkBegin;
            UIntPtr unlinkLimit;

            fixed (byte *begin = &Microsoft.Singularity.Memory.Stacks.UnlinkStackBegin) {
                unlinkBegin = (UIntPtr)begin;
            }
            fixed (byte *limit = &Microsoft.Singularity.Memory.Stacks.UnlinkStackLimit) {
                unlinkLimit = (UIntPtr)limit;
            }

            if(throwAddr >= unlinkBegin && throwAddr <= unlinkLimit) {
                return true;
            } else {
                return false;
            }
        }

        // The following functions are for tryall support.
        // This is the function actually called by the internal runtime
        [NoLoggingForUndo]
        [RequiredByBartok]
        private Exception internalCloneForUndo() {
            /* this function is not allowed to throw an exception. */
            try {
                return cloneForUndo();
            } catch (Exception ex) {
                return ex;
            }
        }
        // This is the function that users can override

        // BUGBUG: provide a better default (probably deep copy).  The
        // current one does not deal with references well, and so, is
        // not even a good shallow copy (it should at least null out the
        // references).
        virtual protected Exception cloneForUndo() {
            return (Exception)this.MemberwiseClone();
        }

        [AccessedByRuntime("referenced from halexn.cpp")]
        internal String _message;

        private Exception _innerException;

        [AccessedByRuntime("referenced from halexn.cpp")]
        private UIntPtr _throwAddress;

        [AccessedByRuntime("referenced from halexn.cpp")]
        private bool _notifiedDebugger; // True if debugger first chance already thrown.

        //
        public string StackTrace
        {
            get {
                return "<no.stack.trace>";
            }
        }
    }
}