"

 COPYRIGHT (c) 1999 by eXept Software AG

              All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

"{ Package: 'stx:libbasic' }"

GenericException subclass:#NoHandlerError

	instanceVariableNames:''

	classVariableNames:'EmergencyHandler'

	poolDictionaries:''

	category:'Kernel-Exceptions-Errors'

!

!NoHandlerError class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1999 by eXept Software AG

              All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    NoHandlerError is raised, if there is no exception handler

    or default action for an exception.

    The parameter is the unhandled exception.

    [Class variables:]

        EmergencyHandler <Block>    this block is evaluated, if no handler was defined

                                    for a signal (i.e. this one is responsible for the

                                    unhandled exception debugger).

                                    Having this being a block allows to globally catch

                                    these errors - even when no enclosing handler-scope

                                    around the erronous code exists.

                                    (as the catch/through does).

    [see also:]

        GenericException 

        (``Exception handling and signals'': programming/exceptions.html)

"

!

examples

"

    The emergencyHandler stuff is very useful, to prevent endUser applications

    from entering the debugger.

    Some commonly used (useful) emergency handlers are provided in the

    'useful handlers' section; try them to learn more

    (especially, the mailingHandler is fun).

    Of course, these are only examples - you may define your own handler

    block and pass it to the #emergencyHandler: method.

    BTW: the Launchers 'source & debugger' settings menu allows you

         to install either a default or the notifying handler.

    A handler which shows a box, then aborts - (no more debuggers):

                                                                [exBegin]

        NoHandlerError emergencyHandler:(NoHandlerError abortingEmergencyHandler)

                                                                [exEnd]

    A handler which aborts - (no box, no debugger):

                                                                [exBegin]

        NoHandlerError emergencyHandler:[:ex | AbortSignal raise]

                                                                [exEnd]

    try some exception (for demonstration, in some other process):

                                                                [exBegin]

        [

            #(1 2 3) at:4

        ] fork.

                                                                [exEnd]

    cleanup (switch back to the regular handler, which enters the debugger):

                                                                [exBegin]

        NoHandlerError emergencyHandler:nil

                                                                [exEnd]

    A handler which shows a warnBox and asks for debugging:

                                                                [exBegin]

        NoHandlerError emergencyHandler:(NoHandlerError notifyingEmergencyHandler)

                                                                [exEnd]

    A handler which dumps information to a file (watch the file 'errorTrace.stx'):

                                                                [exBegin]

        NoHandlerError emergencyHandler:(NoHandlerError dumpingEmergencyHandler)

                                                                [exEnd]

    A handler which sends you mail:

                                                                [exBegin]

        NoHandlerError emergencyHandler:(NoHandlerError mailingEmergencyHandler)

                                                                [exEnd]

"

! !

!NoHandlerError class methodsFor:'initialization'!

initialize

    NotifierString := 'unhandled exception'.

    "

     self initialize

    "

! !

!NoHandlerError class methodsFor:'accessing emergencyHandler'!

emergencyHandler

    "return the handler used for unhandled exceptions.

     If no EmergencyHandler has been set, a handler which enters the 

     debugger is returned.

     The debugger is opened by asking the signal for a debug action,

     this allows to provide other debuggers in specialized (subclass-instances)

     of Signal (if that is ever needed)"

    "

     set it up, when called the first time

    "

    EmergencyHandler isNil ifTrue:[

        EmergencyHandler := [:ex |

            "

             sending it to the signal allows per-signal specific

             debuggers to be implemented in the future

             (for example, segv in primitive code could show things 

              on the C-level ..)

            "

            ex signal openDebuggerOnException:ex.

            "if we arrive here, the debugger did proceed.

             the value returned by #openDebuggerOnException: is the exceptions value ..."

        ]

    ].

    ^ EmergencyHandler

!

emergencyHandler:aOneArgBlock

    "set the handler used for unhandled exceptions.

     The default (a nil-handler) leads to a debugger to be shown."

    EmergencyHandler := aOneArgBlock

    "ST-80 behavior of first showing a notifier:

     (I prefer to get right into the debugger, though)

     NoHandlerError

        emergencyHandler:

            [:ex | self errorNotify:ex description ]

    "

    "ST-X behavior of going right into the debugger:

     NoHandlerError

        emergencyHandler:nil

    "

    "automatically aborting current operation, on error:

     (may be useful for end-user apps; make certain, 

      you have abortSignal handlers at appropriate places)

     NoHandlerError

        emergencyHandler:

            [:ex | AbortOperationRequest raise. ex return. ]

    "

    "finally, traditional language system behavior; dump core ;-)

     NoHandlerError

        emergencyHandler:

            [:ex | Smalltalk exitWithCoreDump. ]

    "

    "Modified: 15.1.1997 / 20:49:06 / cg"

! !

!NoHandlerError class methodsFor:'useful emergency handlers'!

abortingEmergencyHandler

    "return a block (usable as an emergency handler),

     which aborts after showing a warnBox.

     This is useful for endUser applications."

    ^ [:ex | self warn:'Error: ' , ex description.

             AbortOperationRequest raise

      ]

    "test with (try a few halts or CTRL-C's):

     NoHandlerError emergencyHandler:(NoHandlerError abortingEmergencyHandler)

    "

    "back with:

     NoHandlerError emergencyHandler:(NoHandlerError notifyingEmergencyHandler)

     NoHandlerError emergencyHandler:nil

    "

    "Created: 15.1.1997 / 20:13:06 / cg"

    "Modified: 15.1.1997 / 20:15:02 / cg"

!

dumpingEmergencyHandler

    "return a block (usable as an emergency handler),

     which dumps the stackBacktrace to a trace file and

     aborts after showing a warnBox.

     This is useful, for endUser application, which are still being

     debugged (i.e. the programmers may have a look at the traceFile

     from time to time).

     Notice:

         The code below is just an example; you may want to change the

         name of the error-file in your application

         (but please: copy the code; do not modify here)"

    ^ [:ex |

             |str printedException|

             ex signal == NoHandlerError ifTrue:[

                printedException := ex unhandledException.

             ] ifFalse:[

                printedException := ex

             ].

             "/ user interruption is handled specially:

             "/ allow user to choose between proceeding or aborting

             "/ but never dump that information to the file.

             printedException signal == Object userInterruptSignal ifTrue:[

                  (self confirm:'abort current action ?') ifTrue:[

                      AbortOperationRequest raise

                  ].

                  ex proceedWith:nil

             ].

             "/

             "/ dump it to 'errorTrace.stx'

             "/

             str := 'errorTrace.stx' asFilename appendingWriteStream.

             str nextPutLine:('******************************* '

                              , Timestamp now printString

                              , ' *******************************').

             str cr.

             str nextPutLine:('** Error: ' , printedException description).

             str nextPutLine:('** Signal: ' , printedException signal printString).

             str nextPutLine:('** Parameter: ' , printedException parameter printString).

             str nextPutLine:('** Process: ' , Processor activeProcess printString).

             str nextPutLine:('** Backtrace:').

             str cr.

             printedException suspendedContext fullPrintAllOn:str.

             str cr.

             str cr.

             str close.

             "/ send a line to stdErr

             ('[warning]: ignored error: ' , printedException description) errorPrintCR.

             ('[warning]:    error information appended to ''errorTrace.stx''') errorPrintCR.

             AbortOperationRequest raise

      ]

    "test with (try a few halts or CTRL-C's):

     NoHandlerError emergencyHandler:(NoHandlerError dumpingEmergencyHandler)

    "

    "back with:

     NoHandlerError emergencyHandler:(NoHandlerError notifyingEmergencyHandler)

     NoHandlerError emergencyHandler:nil

    "

    "Created: / 15.1.1997 / 20:14:52 / cg"

    "Modified: / 24.1.1997 / 20:36:21 / cg"

    "Modified: / 4.8.1999 / 08:11:20 / stefan"

!

mailingEmergencyHandler

    "return a block (usable as an emergency handler),

     which shows a warnBox and optionally mails a stackBacktrace to a maintainer.

     This is useful, for endUser application, which are still being

     debugged (i.e. the programmers may have a look at the errors).

     Notice: the stuff here is a demonstration only; it should be modified

             for your particular environment ...

             ... but please: copy the code and modify there;

             leave the stuff below as it is."

    ^ [:ex |

            |str printedException doMail emergencyMailReceiver pipe|

            ex signal == NoHandlerError ifTrue:[

               printedException := ex unhandledException.

            ] ifFalse:[

               printedException := ex

            ].

             "/ user interruption is handled specially:

             "/ allow user to choose between proceeding or aborting

             "/ but never dump that information to the file.

             printedException signal == UserInterrupt ifTrue:[

                  (self confirm:'abort current action ?') ifTrue:[

                      AbortOperationRequest raise

                  ].

                  ex proceedWith:nil

             ].

            "/ somehow get the name of the guy to receive the mail

            "/ you have to implement that yourself.

            "/ emergencyMailReceiver := OneOfYourClass getEmergencyMailReceiver.

            emergencyMailReceiver := OperatingSystem getLoginName.

            emergencyMailReceiver isNil ifTrue:[

                self warn:(printedException description

                           , '\\No mailing to service people possible.') withCRs.

                doMail := false.

            ] ifFalse:[

                doMail := self confirm:(printedException description

                                        , '\\Mail error information to the service people ('

                                        , emergencyMailReceiver , ') ?') withCRs

            ].

            doMail ifTrue:[

                str := '' writeStream.

                str nextPutLine:('Error notification from '

                                , OperatingSystem getLoginName

                                , '@'

                                , OperatingSystem getHostName).

                str cr.

                str nextPutLine:('Time: ' , Timestamp now printString).

                str nextPutLine:('Error: ', printedException description).

                str nextPutLine:('Signal: ', printedException signal printString).

                str nextPutLine:('Parameter: ', printedException parameter printString).

                str nextPutLine:('Process: ', Processor activeProcess printString).

                str nextPutLine:'Backtrace:'.

                str cr.

                printedException suspendedContext fullPrintAllOn:str.

                str cr;cr.

                str close.

                pipe := PipeStream

                            writingTo:'mail ', emergencyMailReceiver.

                pipe notNil ifTrue:[

                    pipe nextPutLine:'Subject: automatic error report'.

                    pipe nextPutAll:str contents.

                    pipe cr.

                    pipe close.

                ]

             ].

             AbortOperationRequest raise.

             "not reached"

      ]

    "test with (try a few halts or CTRL-C's):

     NoHandlerError emergencyHandler:(NoHandlerError mailingEmergencyHandler)

    "

    "back with:

     NoHandlerError emergencyHandler:(NoHandlerError notifyingEmergencyHandler)

     NoHandlerError emergencyHandler:nil

    "

    "Created: / 15.1.1997 / 20:14:52 / cg"

    "Modified: / 15.1.1997 / 21:10:28 / cg"

    "Modified: / 4.8.1999 / 08:11:26 / stefan"

!

notifyingEmergencyHandler

    "return a block (usable as an emergency handler for exceptions),

     which does errorNotification before going into the debugger.

     Halts and breakpoints go directly into the debugger (without asking)"

    ^ [:ex |

        |message|

        message := ex descriptionForDebugger.

        (ex signal == NoHandlerError

         and:[(ControlInterrupt handles:ex unhandledException)

         and:[(ControlInterrupt ~~ ex unhandledException signal) ]]) ifTrue:[

            "/ go directly into the debugger ...

            ^ Debugger

                enter:ex returnableSuspendedContext

                withMessage:message

                mayProceed:true

        ].

        "/ ask, and maybe go into the debugger ...

        ^ nil

            errorNotify:message

            from:ex returnableSuspendedContext

            allowDebug:true

      ]

    "test with (NOTE: halt, breakpoints or CTRL-C's still go straight into the debugger):

     NoHandlerError emergencyHandler:(NoHandlerError notifyingEmergencyHandler).

     Object bla.

    "

    "back with:

     NoHandlerError emergencyHandler:nil

    "

    "Modified: / 16.11.2001 / 16:07:05 / cg"

!

notifyingEmergencyHandlerForUserProcesses

    "return a block (usable as an emergency handler for exceptions),

     which does errorNotification before going into the debugger,

     but only for exceptions occurring in user processes;

     systemProcesses are not debugged.

     Halts and breakpoints go directly into the debugger (without asking)"

    ^ [:ex |

        |theException message|

        Processor activeProcessIsSystemProcess ifTrue:[

            'EmergencyHandler [info]: exception cought: ' errorPrint.

            ex signal == NoHandlerError ifTrue:[

                theException := ex unhandledException.

            ] ifFalse:[

                theException := ex

            ].

            theException description errorPrintCR.

            AbortOperationRequest raise.

        ] ifFalse:[

            message := ex descriptionForDebugger.

            (ex signal == NoHandlerError

            and:[ (ControlInterrupt handles:ex unhandledException)

            and:[ (ControlInterrupt ~~ ex unhandledException signal) ]]) ifTrue:[

                "/ go directly into the debugger ...

                ^ Debugger

                    enter:ex returnableSuspendedContext

                    withMessage:message

                    mayProceed:true

            ].

            "/ ask, and maybe go into the debugger ...

            ^ nil

                errorNotify:message

                from:ex returnableSuspendedContext

                allowDebug:true

        ]

      ]

    "test with:

     NoHandlerError emergencyHandler:(NoHandlerError notifyingEmergencyHandlerForUserProcesses)

     Object bla.

    "

    "back with:

     NoHandlerError emergencyHandler:nil

    "

    "Modified: / 16.11.2001 / 16:06:54 / cg"

! !