Request for code review 6512101: Incorrect encoding in NetworkInterface.getDisplayName()

[Chris Hegarty]

On 11/11/2012 07:03 PM, Dmitry Samersoff wrote:
> Frank,
>
> Changes look good for me.

I admit that I am not an expert in this area, but given the information 
you provided, and I guess you verified this in your environment, the 
conversion would appear reasonable.

> But it might be better to fall back to original behavior if
> MultiByteToWideChar return error, rather than abort.

I agree with Dmitry, fall back would be preferable. Can you make the 
changes and post an updated webrev.

-Chris.

>
> -Dmitry
>
> On 2012-11-07 13:08, Frank Ding wrote:
>> Hi guys,
>>    Could you please take a look at patch below aimed to resolve existing
>> bug http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6512101 ?
>>    http://cr.openjdk.java.net/~dingxmin/6512101/webrev.01/
>>
>>    I happen to have a Chinese Win 7 environment.  "buggy.png" is current
>> output of test case described in bug system whereas "fixed.png" is the
>> output after the my patch is applied.
>>
>> http://cr.openjdk.java.net/~dingxmin/6512101/buggy.png
>> http://cr.openjdk.java.net/~dingxmin/6512101/fixed.png
>>
>>    The patch simply converts to wide chars encoded in CP_OEMCP by calling
>> MultiByteToWideChar.  We have confirmed a guy from Microsoft who said that
>>
>> BEGIN QUOTE
>> I'm not sure how common it is to call the Java code that results in
>> calling the GetIfTable API but I would guess it does not happen that
>> often. Additionally, if it's rare that the adapter contains the accented
>> characters, it would definitely be quite easy to miss in testing.
>>
>> I have not found any documentation about the encoding of the bDescr
>> string unfortunately. I did, however, debug through the API and located
>> the place where it is generated. It is getting converted from a UTF-16
>> string to a single-byte string using a conversion like this:
>>
>> WideCharToMultiByte(
>> CP_OEMCP,
>> WC_NO_BEST_FIT_CHARS,
>> <source string>,
>> -1,
>> IfRow->bDescr,
>> <size>,
>> NULL,
>> NULL);
>>
>> I have checked the source for Windows Vista, 2008, Windows 7, and
>> Windows 2008 R2. It is using CP_OEMCP in all of them. So using the
>> reverse conversion in your code using CP_OEMCP should be safe.
>> Alternatively, you can use the GetIfTable2 function
>> (http://msdn.microsoft.com/en-us/library/windows/desktop/aa365945^(v=vs.85).aspx
>> ) which returns the same information in the original UTF-16 encoding.
>> END QUOTE
>>
>>    The link below may be helpful to the second param of
>> WideCharToMultiByte.
>> http://blogs.msdn.com/b/oldnewthing/archive/2012/05/04/10300670.aspx
>>
>> You comments are appreciated.
>> Best regards,
>> Frank
>>
>
>