Code review request for 6992121: StringBuilder.ensureCapacity(int minCap) throws OutOfMemoryError

[Mandy Chung]

  On 10/18/10 9:24 PM, David Holmes wrote:
> Hi Mandy,
>
> Given you can't actually test ArrayList I would drop it altogether and 
> move the test to java/util/vector/TestEnsureCapacity

But it tests ArrayList.ensureCapacity(Integer.MIN_VALUE) which should 
not throw any exception (the regression throws OutOfMemoryError).  I can 
move it to java/util/vector/TestEnsureCapacity.

Thanks
Mandy

>
> David
>
> Mandy Chung said the following on 10/19/10 14:07:
>>  On 10/18/10 4:54 PM, David Holmes wrote:
>>> Hi Mandy,
>>>
>>> The functional changes seem ok. However the ArrayList test is not 
>>> right because it checks the size not the capacity. The same with the 
>>> Vector test, though at least with Vector you can check capacity().
>>>
>>
>> I missed the Vector.capacity() method.  Thanks.   I updated the test.
>>    http://cr.openjdk.java.net/~mchung/6992121/webrev.01/
>>> I find it odd that ArrayList has a very well defined notion of 
>>> capacity yet no method to query that capacity.
>>>
>>
>> True.  I don't have the history but wonder if this is intentional.
>>
>> Mandy
>>
>>> David
>>>
>>> Mandy Chung said the following on 10/19/10 08:41:
>>>>  Please review the fix for:
>>>>
>>>> 6992121: StringBuilder.ensureCapacity(int minCap) throws 
>>>> OutOfMemoryError with minCap=Integer.MIN_VALUE
>>>>
>>>> Webrev at:
>>>>     http://cr.openjdk.java.net/~mchung/6992121/webrev.00/
>>>>
>>>> This is a regression caused by the changes for 6933217 (Huge arrays 
>>>> handled poorly in core libraries).   The ensureCapacity() method in 
>>>> the StringBuffer, StringBuilder, ArrayList, and Vector classes are 
>>>> a public API that accepts negative numbers.   The following 
>>>> overflow-conscious code:
>>>>
>>>>   if (minimumCapacity - value.length>  0)
>>>>
>>>> considers negative minimumCapacity as overflow case where 
>>>> OutOfMemoryError will be thrown.  So the implementation of the 
>>>> public ensureCapacity() methods need to check if the input argument 
>>>> is positive before doing the above overflow-conscious check.
>>>>
>>>> Thanks
>>>> Mandy
>>