[OT] MultiByteFileStream (was: Re: [Vm-dev] VM Maker: CMakeVMMaker-StasenkoIgor.104.mcz)

[Igor Stasenko]

On 17 May 2011 13:50, Levente Uzonyi <leves at elte.hu> wrote:
>
> On Tue, 17 May 2011, Igor Stasenko wrote:
>
>>
>> On 16 May 2011 20:21, Levente Uzonyi <leves at elte.hu> wrote:
>>>
>>> On Mon, 16 May 2011, squeak-dev-noreply at lists.squeakfoundation.org wrote:
>>>
>>>>
>>>> Igor Stasenko uploaded a new version of CMakeVMMaker to project VM
>>>> Maker:
>>>> http://www.squeaksource.com/VMMaker/CMakeVMMaker-StasenkoIgor.104.mcz
>>>>
>>>> ==================== Summary ====================
>>>>
>>>> Name: CMakeVMMaker-StasenkoIgor.104
>>>> Author: StasenkoIgor
>>>> Time: 16 May 2011, 10:33:56 am
>>>> UUID: 68959e6f-18b1-304c-a3de-2b84a1f2c93b
>>>> Ancestors: CMakeVMMaker-IgorStasenko.103
>>>>
>>>> workaround the MultiByteCrapStream, which converting line endings twice
>>>> on
>>>> windows.
>>>
>>> It's not crap, just broken.
>>
>> Well, i don't know better wording for seeing the mess in this
>> implementation. It contains too much bells and whistles and therefore
>> its very easy to break it.
>
> Tests can greatly decrease the chance of breaking it.
>

yes, i submitted a test yesterday.
http://code.google.com/p/pharo/issues/detail?id=4236

it written in a way to reproduce an issue when running on any system
(not just Windows).

>>
>> I don't understand why it patching the UTF8Converter and turns it into
>> line-ending converter..
>> as to me, UTF8Converter have nothing to do with line ends, and such
>> abuse of text converters should be strictly prohibited.
>
> The reason is performance, and the implementation is transparent. It also
> simplifies MultiByteFileStream.
>

what about clarity? The problem is that this code is so optimized that
it is no longer transparent. It is opaque for my eyes.
I cannot fix it, because it looks very brittle and it is hard to get
what it does, with all those branches, ifNotNils etc etc in almost
every method there.

And i cannot be sure if my fix won't break something else, because
there is no clear separation of concerns:

 - use UTF8Converter for utf8 conversion and NOTHING else.
 - and let stream to filter input and replace cr character(s) to
whatever it wants them to be


And what about simplification?

Do you think this is how a _simple_ method should look like?

nextPut: aCharacter
	aCharacter isInteger
		ifTrue: [ ^ super nextPut: aCharacter ].
	(wantsLineEndConversion == true and: [ lineEndConvention notNil ])
"#doConversion is inlined here"
		 ifTrue: [
			aCharacter = Cr
				ifTrue: [ converter nextPutAll: (LineEndStrings at:
lineEndConvention) toStream: self ]
				ifFalse: [ converter nextPut: aCharacter toStream: self ].
			^aCharacter ].
	^ self converter nextPut: aCharacter toStream: self

4 branches.. while i, by following your premise, would expect a single
line here:

nextPut: aCharacter
   ^ converter nextPut: aCharacter toStream: self

because if you decided to delegate line ends conversion to converter
(for whatever reason) , then you don't have to do anything outside of
it.

>>
>>> I'll integrate the fix for it into Squeak soon.
>>> If you're impatient you can fix it yourself, or use something else.
>>>
>>
>> Well, i can't use something else, because its VMMaker which using
>> CrLfFileStream for producing source files output.
>> Maybe it worth to just use FileStream in binary mode and deal with
>> line ends internally, to not leave chance for
>> clever text streams to interfere.
>
> CrLfFileStream is not used, since Squeak 3.x. References to it should be
> rewritten to use FileStream instead. Using binary mode to work around a bug
> is bad idea, fixing the bug is the way to go.
>

But why you stating false statements? CrLfFileStream is used, at least
by VMMaker.
And i was never took a deep look on a file streams to clearly say if
it still used or can be removed.

So, can you clarify, can we deprecate and then completely remove
CrLfFileStream from image
and fix all references to it with FileStream instead?
Because i like putting useless cra.. (err stuff) into trash bin.

>> But then again, it means time, which i haven't because i was focused
>> on completely different problem.
>
> I'll upload my fix to Squeak Trunk this week. Applying the changes to Pharo
> probably won't work out of the box, because IIRC some issues were solved
> differently in the past.
>

i'm not sure.

>
> Levente
>



-- 
Best regards,
Igor Stasenko AKA sig.