RFR(xs): JDK-8152329: jvm should treat the "Multi-Release" jar manifest attribute name as case insensitive

[Jiangli Zhou]

Hi Calvin,

Looks good. Thank you for making the change.

Thanks,
Jiangli

> On Apr 5, 2016, at 5:13 PM, Calvin Cheung <calvin.cheung at oracle.com> wrote:
> 
> 
> 
> On 4/5/16, 1:29 PM, Jiangli Zhou wrote:
>> 
>> Hi Calvin,
>> 
>>> On Apr 5, 2016, at 10:53 AM, Calvin Cheung <calvin.cheung at oracle.com <mailto:calvin.cheung at oracle.com>> wrote:
>>> 
>>> 
>>> 
>>> On 4/5/16, 10:44 AM, Jiangli Zhou wrote:
>>>> 
>>>> Hi Calvin,
>>>> 
>>>> Have you thought about using strcasecmp()? The globalDefinitions_visCPP.hpp defines strcasecmp to _stricmp. So compiler dependency is not an issue. We have existing code that uses strcasecmp() for case insensitive comparison.
>>> I don't think it will work in this situation. It is because the manifest buffer contains all the jar manifest entries, not just the "Multi-Release" entry. In other words, "Multi-Release" isn't at the beginning of the string.
>> 
>> Ok. There is strcasestr(), but it’s a nonstandard extension. I couldn’t find a Windows equivalent for that. Iterating the string to covert each char to lower case is slow although it’s only used in CDS dump time. To make it more efficient, you could add a new field, ‘u1 is_multi_versioned' in ClassPathZipEntry to remember the result so you only need to do the case in-senstive strstr once, instead of everytime when ClassPathZipEntry::open_stream() is called. The new field could have three states, ‘unknown’, ‘yes’ and ‘no’. If it’s ‘unknown’, is_multiple_versioned() opens the manifest, otherwise it can return quickly.
> I've an updated webrev for the above change.
> http://cr.openjdk.java.net/~ccheung/8152329/webrev.02/ <http://cr.openjdk.java.net/~ccheung/8152329/webrev.02/>
> 
> Some testing in progress.
> 
> thanks,
> Calvin
>> 
>> Thanks,
>> Jiangli
>> 
>> 
>>> 
>>> thanks,
>>> Calvin
>>>> 
>>>> // Non-standard stdlib-like stuff:
>>>> inline int strcasecmp(const char *s1, const char *s2) { return _stricmp(s1,s2); }
>>>> 
>>>> Thanks,
>>>> Jiangli
>>>>  
>>>>> On Apr 4, 2016, at 2:07 PM, Calvin Cheung <calvin.cheung at oracle.com <mailto:calvin.cheung at oracle.com>> wrote:
>>>>> 
>>>>> 
>>>>> Please review this small fix for:
>>>>> https://bugs.openjdk.java.net/browse/JDK-8152329 <https://bugs.openjdk.java.net/browse/JDK-8152329>
>>>>> 
>>>>> The fix is to convert the buffer containing the jar manifest into lower case before performing strstr.
>>>>> 
>>>>> webrev: http://cr.openjdk.java.net/~ccheung/8152329/webrev.01/ <http://cr.openjdk.java.net/%7Eccheung/8152329/webrev.01/>
>>>>> 
>>>>> Testing:
>>>>>    JPRT -testset hotspot
>>>>>    The tests under runtime on the platforms built by JPRT.
>>>>> 
>>>>> thanks,
>>>>> Calvin
>>>> 
>> 
>