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added more exception handling and ensure implementation code

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This commit is contained in:
hyunghwan.chung
2016-06-23 15:35:28 +00:00
parent 9c2c0ea6c2
commit 544ee2b4ae
3 changed files with 212 additions and 62 deletions
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2
stix/kernel/Apex.st
View File

@ -312,7 +312,7 @@
('### EXCEPTION NOT HANDLED #### ', exception class name, ' - ', exception messageText) dump. ('### EXCEPTION NOT HANDLED #### ', exception class name, ' - ', exception messageText) dump.
## TODO: debug the current process???? " ## TODO: debug the current process???? "
## TODO: ensure to execute ensure blocks as well.... ## TODO: ensure to execute ensure blocks as well....
Processor activeProcess terminate. ####Processor activeProcess terminate.
} }
} }

266
stix/kernel/Context.st
View File

@ -14,12 +14,12 @@
^self.sender ^self.sender
} }
#method isExceptionHandlerContext #method isExceptionContext
{ {
^false ^false
} }
#method hasEnsureBlock #method isEnsureContext
{ {
^false ^false
} }
@ -29,42 +29,117 @@
^nil ^nil
} }
#method findExceptionHandlerContext #method findExceptionContext
{ {
| ctx | | ctx |
ctx := self. ctx := self.
[ ctx isExceptionHandlerContext ifTrue: [^ctx]. [ ctx notNil ] whileTrue: [
ctx := ctx sender. (ctx isExceptionContext) ifTrue: [^ctx].
ctx isNil ] whileFalse. ctx := ctx sender.
].
^nil ^nil
} }
#method findExceptionHandlerBlock #method findEnsureContextAbove: sentinel
{ {
^nil | ctx |
ctx := self.
[ ctx notNil and: [ctx ~~ sentinel] ] whileTrue: [
(ctx isEnsureContext) ifTrue: [^ctx].
ctx := ctx sender.
].
^nil
} }
#method handleException: exception
#method hasSender: context
{ {
| excblk retval posact | | s |
(self == context) ifTrue: [^false].
s := self.sender.
[ s isNil ] whileFalse: [
(s == context) ifTrue: [^true].
s := s sender.
].
^false
}
## position of the temporary variable 'active' in MethodContext>>on:do. #method isDead
## for this code to work, it must be the last temporary variable in the method. {
posact := (self basicSize) - 1. ^self.ip < 0
}
excblk := self findExceptionHandlerBlock: (exception class). #method terminate
(excblk isNil or: [(self basicAt: posact) not]) ifTrue: [ {
^self.sender findExceptionHandlerContext handleException: exception self.sender := nil.
self.ip = -1;
}
#method terminateTo: prevctx
{
| ctx sctx |
(self hasSender: prevctx) ifTrue: [
ctx := self.sender.
[ctx ~~ prevctx] whileTrue: [
sctx := ctx sender.
ctx terminate.
ctx := sctx.
]
].
self.sender := prevctx.
}
#method resume: retval through: context
{
| ctx |
self isDead ifTrue: ["TODO: cannot return" 'CANNOT RETURN' dump.].
ctx := context.
[ ctx notNil ] whileTrue: [
| donepos |
donepos := ctx basicSize - 1.
(ctx basicAt: donepos) ifFalse: [
| ensblk |
ctx basicAt: donepos put: true.
ensblk := ctx ensureBlock.
thisContext terminateTo: ctx.
ensblk value.
].
ctx := ctx findEnsureContextAbove: self.
]. ].
exception handlerContext: self. thisContext terminateTo: self.
^retval
}
self basicAt: posact put: false. #method unwindTo: context return: retval
[ retval := excblk value: exception ] ensure: [ {
self basicAt: posact put: true ## -------------------------------------------------------------------
## <<private>>
## private: called by VM upon unwinding
## -------------------------------------------------------------------
| ctx stop |
ctx := self.
stop := false.
[stop] whileFalse: [
| eb |
eb := ctx ensureBlock.
(eb notNil) ifTrue: [
| donepos |
donepos := ctx basicSize - 1.
(ctx basicAt: donepos) ifFalse: [
ctx basicAt: donepos put: true.
eb value.
].
].
stop := (ctx == context).
ctx := ctx sender.
]. ].
##self return: retval. ^retval
} }
} }
@ -98,16 +173,15 @@
^self.sp. ^self.sp.
} }
#method sp: anInteger #method sp: new_sp
{ {
self.sp := anInteger. self.sp := new_sp
} }
#method pc: aPC sp: aSP #method pc: new_pc sp: new_sp
{ {
self.ip := aPC. self.ip := new_pc.
self.sp := aSP. self.sp := new_sp.
##sp := sp - 1.
} }
#method method #method method
@ -115,13 +189,13 @@
^self.method ^self.method
} }
#method isExceptionHandlerContext #method isExceptionContext
{ {
## 10 - STIX_METHOD_PREAMBLE_EXCEPTION in VM. ## 10 - STIX_METHOD_PREAMBLE_EXCEPTION in VM.
^self.method preambleCode == 10. ^self.method preambleCode == 10.
} }
#method hasEnsureBlock #method isEnsureContext
{ {
## 10 - STIX_METHOD_PREAMBLE_ENSURE in VM. ## 10 - STIX_METHOD_PREAMBLE_ENSURE in VM.
^self.method preambleCode == 11 ^self.method preambleCode == 11
@ -129,14 +203,13 @@
#method ensureBlock #method ensureBlock
{ {
## TODO: 9 is the number of named instance variables of a context. ## TODO: change 8 to a constant when stix is enhanced to support constant definition
## TODO: change 9 to a constant when stix is enhanced to support constant definition
(self.method preambleCode == 11) ifFalse: [^nil]. (self.method preambleCode == 11) ifFalse: [^nil].
^self basicAt: 8. ^self basicAt: 8.
} }
#method findExceptionHandlerBlock: anExceptionClass
#method findExceptionHandlerFor: exception_class
{ {
## find an exception handler block for a given exception class. ## find an exception handler block for a given exception class.
## ##
@ -146,7 +219,7 @@
## basicAt: 8 must be the on: argument. ## basicAt: 8 must be the on: argument.
## basicAt: 9 must be the do: argument ## basicAt: 9 must be the do: argument
(self isExceptionHandlerContext) ifTrue: [ (self isExceptionContext) ifTrue: [
| bound exc | | bound exc |
## NOTE: if on:do: has a temporary varible, bound must be adjusted to reflect it. ## NOTE: if on:do: has a temporary varible, bound must be adjusted to reflect it.
bound := self basicSize - 1. bound := self basicSize - 1.
@ -154,26 +227,64 @@
## or calcuate the minimum size using the class information. ## or calcuate the minimum size using the class information.
8 to: bound by: 2 do: [ :i | 8 to: bound by: 2 do: [ :i |
exc := self basicAt: i. exc := self basicAt: i.
((anExceptionClass == exc) or: [anExceptionClass inheritsFrom: exc]) ifTrue: [^self basicAt: (i + 1)]. ((exception_class == exc) or: [exception_class inheritsFrom: exc]) ifTrue: [^self basicAt: (i + 1)].
] ]
]. ].
^nil. ^nil.
} }
#method unwindTo: aContext return: anObject #method handleException: exception
{ {
## private: called by VM upon unwinding ## -------------------------------------------------------------------
| ctx eb | ## <<private>>
ctx := self. ## called by Exception>>signal.
[ctx ~~ aContext] whileTrue: [ ## this method only exists in the MethodContext and UndefinedObject.
eb := ctx ensureBlock. ## the caller must make sure that the receiver object is
(eb notNil) ifTrue: [eb value]. ## a method context or nil. Exception>>signal invokes this method
ctx := ctx sender. ## only for an exception context which is a method context. it
]. ## invokes it for nil when no exception context is found.
eb := ctx ensureBlock. ## -------------------------------------------------------------------
(eb notNil) ifTrue: [eb value].
^anObject | excblk retval actpos |
## position of the temporary variable 'active' in MethodContext>>on:do.
## for this code to work, it must be the last temporary variable in the method.
actpos := (self basicSize) - 1.
excblk := self findExceptionHandlerFor: (exception class).
(excblk isNil or: [(self basicAt: actpos) not]) ifTrue: [
## self is an exception context but doesn't have a matching
## exception handler or the exception context is already
## in the middle of evaluation.
^(self.sender findExceptionContext) handleException: exception.
].
exception handlerContext: self.
## -------------------------------------------------------------------
## if an exception occurs within an exception handler block,
## the search will reach this context again as the exception block
## is evaluated before actual unwinding. set the temporary variable
## in the exception context to mask out this context from the search
## list.
## -------------------------------------------------------------------
self basicAt: actpos put: false.
[ retval := excblk value: exception ] ensure: [
self basicAt: actpos put: true
].
##(self.sender isNil) ifTrue: [ "TODO: CANNOT RETURN" ].
## -------------------------------------------------------------------
## return to self.sender which is a caller of the exception context (on:do:)
## pass the first ensure context between thisContext and self.sender.
##
## [ [Exception signal: 'xxx'] ensure: [20] ] on: Exception do: [:ex | ...]
##
## -------------------------------------------------------------------
##^self.sender resume: retval through: (thisContext findEnsureContextAbove: self.sender).
thisContext unwindTo: self.sender return: nil.
Processor return: retval to: self.sender.
} }
} }
@ -392,7 +503,7 @@
| exception_active | | exception_active |
<exception> <exception>
"thisContext isExceptionHandlerContext dump. "thisContext isExceptionContext dump.
(thisContext basicSize) dump. (thisContext basicSize) dump.
(thisContext basicAt: 8) dump. ## this should be anException (thisContext basicAt: 8) dump. ## this should be anException
(thisContext basicAt: 9) dump. ## this should be anExceptionBlock (thisContext basicAt: 9) dump. ## this should be anExceptionBlock
@ -405,19 +516,27 @@
#method on: exc1 do: blk1 on: exc2 do: blk2 #method on: exc1 do: blk1 on: exc2 do: blk2
{ {
| active | | exception_active |
<exception> <exception>
active := true. exception_active := true.
^self value. ^self value.
} }
#method ensure: aBlock #method ensure: aBlock
{ {
| v | | retval done |
<ensure> <ensure>
v := self value.
aBlock value. done := false.
^v retval := self value.
## the temporary variable 'done' may get changed
## during evaluation for exception handling.
done ifFalse: [
done := true.
aBlock value.
].
^retval
} }
#method ifCurtailed: aBlock #method ifCurtailed: aBlock
@ -457,10 +576,42 @@
^self.messageText ^self.messageText
} }
#method signal #method __signal
{ {
self.signalContext := thisContext. self.signalContext := thisContext.
((thisContext sender) findExceptionHandlerContext) handleException: self. ((thisContext sender) findExceptionContext) handleException: self.
}
#method signal
{
| excctx excblk retval actpos |
self.signalContext := thisContext.
excctx := (thisContext sender) findExceptionContext.
[excctx notNil] whileTrue: [
excblk := excctx findExceptionHandlerFor: (self class).
(excblk notNil and:
[actpos := excctx basicSize - 1. excctx basicAt: actpos]) ifTrue: [
self.handlerContext := excctx.
excctx basicAt: actpos put: false.
[ retval := excblk value: self ] ensure: [
excctx basicAt: actpos put: true
].
thisContext unwindTo: (excctx sender) return: nil.
Processor return: retval to: (excctx sender).
].
excctx := (excctx sender) findExceptionContext.
].
## -----------------------------------------------------------------
## FATAL ERROR - no exception handler.
## -----------------------------------------------------------------
thisContext unwindTo: nil return: nil.
('### EXCEPTION NOT HANDLED #### ', self class name, ' - ', self messageText) dump.
## TODO: debug the current process???? "
Processor activeProcess terminate.
} }
#method signal: text #method signal: text
@ -472,7 +623,7 @@
#method pass #method pass
{ {
## pass the exception to the outer context ## pass the exception to the outer context
((self.handlerContext sender) findExceptionHandlerContext) handleException: self. ((self.handlerContext sender) findExceptionContext) handleException: self.
} }
" "
@ -507,7 +658,6 @@ TODO: implement these methods....
] ]
} }
" "
} }
#class NoSuchMessageException(Exception) #class NoSuchMessageException(Exception)

6
stix/lib/exec.c
View File

@ -3921,7 +3921,7 @@ return -1;
{ {
/* returning from a method */ /* returning from a method */
STIX_ASSERT (STIX_CLASSOF(stix, stix->active_context) == stix->_method_context); STIX_ASSERT (STIX_CLASSOF(stix, stix->active_context) == stix->_method_context);
stix->ip = STIX_SMOOI_MIN; stix->ip = -1;
} }
else else
{ {
@ -3953,7 +3953,7 @@ return -1;
/* cannot return from a method that has returned already */ /* cannot return from a method that has returned already */
STIX_ASSERT (STIX_CLASSOF(stix, stix->active_context->origin) == stix->_method_context); STIX_ASSERT (STIX_CLASSOF(stix, stix->active_context->origin) == stix->_method_context);
STIX_ASSERT (stix->active_context->origin->ip == STIX_SMOOI_TO_OOP(STIX_SMOOI_MIN)); STIX_ASSERT (stix->active_context->origin->ip == STIX_SMOOI_TO_OOP(-1));
STIX_LOG0 (stix, STIX_LOG_IC | STIX_LOG_ERROR, "Error - cannot return from dead context\n"); STIX_LOG0 (stix, STIX_LOG_IC | STIX_LOG_ERROR, "Error - cannot return from dead context\n");
stix->errnum = STIX_EINTERN; /* TODO: can i make this error catchable at the stix level? */ stix->errnum = STIX_EINTERN; /* TODO: can i make this error catchable at the stix level? */
@ -3961,7 +3961,7 @@ return -1;
non_local_return_ok: non_local_return_ok:
/*STIX_DEBUG2 (stix, "NON_LOCAL RETURN OK TO... %p %p\n", stix->active_context->origin, stix->active_context->origin->sender);*/ /*STIX_DEBUG2 (stix, "NON_LOCAL RETURN OK TO... %p %p\n", stix->active_context->origin, stix->active_context->origin->sender);*/
stix->active_context->origin->ip = STIX_SMOOI_TO_OOP(STIX_SMOOI_MIN); stix->active_context->origin->ip = STIX_SMOOI_TO_OOP(-1);
} }
STIX_ASSERT (STIX_CLASSOF(stix, stix->active_context->origin) == stix->_method_context); STIX_ASSERT (STIX_CLASSOF(stix, stix->active_context->origin) == stix->_method_context);