RFR : 8013528 : (XS) Provide SharedSecrets access to String(char[], boolean) constructor

[Mike Duigou]

On Apr 30 2013, at 23:41 , Peter Levart wrote:

> Hi Mike,
> 
> Some comments about the test...
> 
>   40         String benchmark = "exemplar";
>   41         String constructorCopy = new String(benchmark);
>   42         String jlaCopy = jla.newStringUnsafe(benchmark.toCharArray());
>   43 
>   44         if (constructorCopy == constructorCopy) {
>   45             throw new Error("should be different instances");
>   46         }
> Wouldn't this always throw error? You really wanted to test benchmark == constructorCopy, right?

Argh, yes. I forgot a hg qrefresh before generating the webrev. This was corrected in my local copy.
> To check whether the jlaCopy is really taking the given char array by reference, a test could also do something "illegal" like:
> 
> 
> char[] array = benchmark.toCharArray();
> String jlaCopy = jla.newStringUnsafe(array);
> array[0] = "X"; // ouch!
> String constructorCopy = new String(array);
> 
> if (!constructorCopy.equals(jlaCopy)) { ... }
> 
> Regards, Peter
> 
I have added an "evil" test to check exactly that.

I'm pleased to be able to include you an official reviewer. :-)

Thanks,

Mike

> 
> 
> 
> 2013/5/1 Mike Duigou <mike.duigou at oracle.com>
> Hello all;
> 
> Since this code will be introduced without any usages I decided it was critical to make a stand alone unit test. I've updated the webrev:
> 
> http://cr.openjdk.java.net/~mduigou/JDK-8013528/1/webrev/
> 
> The webrev mistakes my hg copy for a rename... Ignore that. Capturing the provenance of the test file probably isn't critical since the file is repurposed for a different test, but I prefer to have the origin tracked rather than use a non-vcs copy.
> 
> I also made the other changes suggested by reviewers.
> 
> Thanks
> 
> Mike
> 
> On Apr 29 2013, at 21:30 , Mike Duigou wrote:
> 
> > Hello all;
> >
> > This change originated as part of JDK-8006627 (which was also previously split into JDK-8007398 as well). It adds an internal mechanism for performance sensitive usages to create a string from a provided character array without copying that array. This saves both in the allocation (and subsequent GC) as well as the copying of the characters. There are a few places in the JDK that return Strings which can benefit from this change.
> >
> > http://cr.openjdk.java.net/~mduigou/JDK-8013528/0/webrev/
> >
> > Fear not, JDK-8006627 and JDK-8007398 will be revisited... For now it would be to get this change in to allow other potential users to move forward with their changes.
> >
> > Mike
> 
>