[OpenJDK 2D-Dev] [13] RFR: JDK-8221412: lookupPrintServices() does not always update the list of Windows remote printers

[Alexey Ivanov]

Hi Phil,

On 27/03/2019 00:29, Philip Race wrote:
>
> > The old implementation of getRemotePrintersNames() got the list of 
> both local and remote printers and then filtered out local ones.
>
> The old implementation checked that
> if (info4->Attributes & PRINTER_ATTRIBUTE_NETWORK) { So you don't 
> think this is needed ?

No, I don't.

The old implementation asked for both local and remote printers:
::EnumPrinters(PRINTER_ENUM_LOCAL | PRINTER_ENUM_CONNECTIONS, …

Then it removed local printers from the array.

In getRemotePrintersNames() I ask for remote printers only:
::EnumPrinters(PRINTER_ENUM_CONNECTIONS, …
If the list is not empty, it contains only remote printers. Nothing to 
filter.


Regards,
Alexey

> -phil.
>
> On 3/26/19, 1:22 PM, Alexey Ivanov wrote:
>> Please see the updated webrev:
>> http://cr.openjdk.java.net/~aivanov/8221412/webrev.1/
>>
>> The difference between .0 and .1 is in some minor white-space 
>> adjustments, like parameter alignment.
>>
>> On 26/03/2019 17:01, Alexey Ivanov wrote:
>>> Hi,
>>>
>>> Please review the fix for jdk 13:
>>>
>>> bug: https://bugs.openjdk.java.net/browse/JDK-8221412
>>> webrev: http://cr.openjdk.java.net/~aivanov/8221412/webrev.0/
>>>
>>> Description:
>>> The list of printers is not updated in the situation where there are 
>>> no remote printers on the system and later the user adds a remote 
>>> printer.
>>>
>>> Root cause:
>>> JDK-8153732 [1] added a new thread which polls remote printers on 
>>> the system and updates the list if it detects a change. In this case 
>>> it does not update the print services because of this condition:
>>> 449 if (prevRemotePrinters != null && prevRemotePrinters.length > 0)
>>> prevRemotePrinters is not null but its length is zero because no 
>>> remote printers were initially present on the system.
>>>
>>> Fix:
>>> I removed this if. We have to update the list printers if 
>>> doCompare() returns true. Either prevRemotePrinters or 
>>> currentRemotePrinters, or both can be null; doCompare() handles this 
>>> situation gracefully after JDK-8212202 [2].
>>>
>>> The listener called getRemotePrintersNames() twice: in constructor 
>>> and in run() before entering the first sleep. Now it's done only once.
>>>
>>> I consolidated the implementation of getAllPrinterNames() and 
>>> getRemotePrintersNames(). They were very similar. The old 
>>> implementation of getRemotePrintersNames() got the list of both 
>>> local and remote printers and then filtered out local ones. The new 
>>> implementation gets the list of remote printers only. So the 
>>> difference between the two is limited to the flags passed to 
>>> EnumPrinters.
>>>
>>> If there are no remote printers, the new version 
>>> getRemotePrintersNames() returns null instead of empty array. As 
>>> mentioned earlier, doCompare() handles this situation.
>>>
>>> I'll add the bugid (8221412) to the regression test when fixing 
>>> JDK-8221263 [3]. I'm currently working on it.
>>>
>>>
>>> Thank you in advance.
>>>
>>> Regards,
>>> Alexey
>>>
>>> [1] https://bugs.openjdk.java.net/browse/JDK-8153732
>>> [2] https://bugs.openjdk.java.net/browse/JDK-8212202
>>> [3] https://bugs.openjdk.java.net/browse/JDK-8221263