<AWT Dev> [8u] RFR: 8196681: Java Access Bridge logging and debug flags dynamically controlled

[Alex Kashchenko]

Hi Zhengyu,

On 09/16/2019 07:04 PM, Zhengyu Gu wrote:
> Hi Alex,
> 
> On 9/9/19 12:29 PM, Alex Kashchenko wrote:
>> Hi,
>>
>> Please review the code change required to backport JDK-8196681 to 8u.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8196681
>>
>> Original review thread: 
>> http://mail.openjdk.java.net/pipermail/awt-dev/2018-September/014302.html
>>
>> 11u changeset: 
>> https://hg.openjdk.java.net/jdk-updates/jdk11u-dev/rev/af9ad0ae9039
>>
>> Patch does not apply cleanly, because std::chrono is used for 
>> timestamps. And this part of C++11 standard is not supported by VS2010 
>> toolchain that is used for 8u windows builds. The following change 
>> reimplements the same timestamps without std::chrono:
>>
>>
>>   auto getTimeStamp() -> long long {
>> -    using namespace std::chrono;
>> -    auto timeNow = 
>> duration_cast<milliseconds>(steady_clock::now().time_since_epoch());
>> -
>> -    return timeNow.count();
>> +    LARGE_INTEGER freqLarge;
>> +    ::QueryPerformanceFrequency(&freqLarge);
>> +    long long freq = freqLarge.QuadPart;
>> +    LARGE_INTEGER counterLarge;
>> +    ::QueryPerformanceCounter(&counterLarge);
>> +    long long counter = counterLarge.QuadPart;
>> +    long long milliDen = 1000;
>> +    long long whole = (counter / freq) * milliDen;
>> +    long long part = (counter % freq) * milliDen / freq;
>> +    return whole + part;
>>   }
>>
> Would this whole + part calculation just (counter * milliDen) / freq? or 
> you are worry about overflow?
> 
> Otherwise, looks good to me.

Thanks for the review!

Yes, overflow here doesn't matter for milliseconds, but will happen if 
nanoseconds are used.

> 
> [...]
> 


-- 
-Alex