<AWT Dev> RFR(XS): 8042416: X11GraphicsEnvironment.isDisplayLocal() throws NoSuchElementException if DISPLAY host has more IP addresses than a local interface

[Volker Simonis]

Thanks Anthony,

Volker

On Wed, May 7, 2014 at 9:03 PM, Anthony Petrov
<anthony.petrov at oracle.com> wrote:
> Hi Volker,
>
> The fix looks fine to me, too.
>
> --
> best regards,
> Anthony
>
>
> On 5/5/2014 10:07 PM, Volker Simonis wrote:
>>
>> Hi,
>>
>> could you please review this tiny fix:
>>
>> http://cr.openjdk.java.net/~simonis/webrevs/8042416/
>> https://bugs.openjdk.java.net/browse/JDK-8042416
>>
>> X11GraphicsEnvironment.isDisplayLocal() calls
>> X11GraphicsEnvironment._isDisplayLocal() whihc in turn iterates over
>> all IP addressees of the DISPLAY host and checks if one of them
>> corresponds to the IP address of a local network interface:
>>
>> for (; interfaces.hasMoreElements();) {
>>      locals = interfaces.nextElement().getInetAddresses();
>>      for (; locals.hasMoreElements();) {
>>          for (int i = 0; i < remAddr.length; i++) {
>>              if (locals.nextElement().equals(remAddr[i])) {
>>                  return Boolean.TRUE;
>>              }
>>          }
>>      }
>> }
>>
>> However it calls locals.nextElement() for each IP address of the
>> DISPLAY host so if the DISPLAY host has more IP addresses than one of
>> the local network interfaces, the check will unexpectedly throw a
>> NoSuchElementException.
>>
>> The solution is simple - just compare every IP-Address of the DISPLAY
>> host against each IP-address of every network interface like so:
>>
>> for (; interfaces.hasMoreElements();) {
>>      locals = interfaces.nextElement().getInetAddresses();
>>      for (; locals.hasMoreElements();) {
>>          final InetAddress localAddr = locals.nextElement();
>>          for (int i = 0; i < remAddr.length; i++) {
>>              if (localsAddr.equals(remAddr[i])) {
>>                  return Boolean.TRUE;
>>              }
>>          }
>>      }
>> }
>>
>> Thank you and best regards,
>> Volker
>>
>>
>> PS: Notice that if we ever want to downport this to jdk8 we need an
>> additional cast like so:
>>
>> final InetAddress localAddr = (InetAddress)locals.nextElement();
>>
>> unless we also downport "8039642: Fix raw and unchecked warnings in
>> sun.awt.*" before this change.
>>
>