An idea: Add a port layer

[Jing LV]

Hello Henri,

Yes something like that. As far as I understand APR focus on serving 
Apache http server, the portlib for JDK may work for a better JDK. In 
fact there are already many portlibs existing, and we can learn from 
them for a layer for OpenJDK.
I've posted on BSD porting list as well, someone is already interested 
in it. He sugggest we may use a service provider pattern to make it more 
flexible for all kinds of platforms.
Any questions/suggestion/comments are welcome!

于 2011-5-16 21:35, Henri Gomez 写道:
> Do you think about something like Apache does with APR (Apache
> Portable Runtime) ?
>
> 2011/5/15 Jing LV<lvjing at linux.vnet.ibm.com>:
>> Hello MacOS developers,
>>
>> I see on openjdk we'll have more platforms - except MacOS, there is some
>> discussions about AIX. This is great news to the community, as well as a
>> new challenge to the community to manage different native implementation
>> for new added platform as well as early platform. The challenges we may
>> face are:
>> 1. in current implementation, we have native implementation in
>> windows/linux/solaris directory, and create some same jni methods. But
>> actually they have the same or very similar logic. This is not very
>> manageable. If some logic is change we need to modify implementation on
>> all platforms. and may cause some of problem as no one knows all
>> platforms differences, and the platform developers need to understand
>> the logic before the modification, it may be a extra work for developers
>> like MacOS engineers.
>> 2. different platforms offers different system APIs, and even different
>> versions of system have different APIs; in current implementation I see
>> some code like
>> #ifdef someplatform
>> use some API
>> #endif
>> This increases the complexity of the code, and make code ugly. Also the
>> developer may have much trouble to read and modify if necessary.
>> 3. Openjdk is working on project digjaw/modularization, it may meet some
>> trouble if the native API and logic are separated by platform level, not
>> in functional level.
>>
>> I am wondering if a port layer, leave all APIs differences in this
>> layer. The jni developers can use this unified API, like "int write(fd,
>> byte[])" should work on all platforms openjdk supported, including
>> linux, windows, MacOS etc. This may help us the developers:
>> 1. the platform developer can focus on covering the API difference and
>> care nothing of the upper logical - say, e.g, focus on write some given
>> bytes into the give fd, do not care what the fd is and how to deal with
>> the buffers etc, so we will write it only once, and only update for new
>> APIs when necessary. Meanwhile, the classlib developers can use an
>> unified system API and focus on the logic, we write the code once for
>> all platforms. It save time and effort on both side.
>> 2. The code is then clear, no #endif is required, this helps the
>> developer to read and understand, and much easier to modify.
>> 3. it may help to modularize the jdk as well.
>>
>> An new portlib may also have some problems, like modification on the
>> current code, and performance. We need to define the portlayer well, and
>> make excellent build script to avoid performance degradation of the
>> layer. However, in the long run, the portlayer will really help the
>> developers as well as JDK, like some other opensource jdk do.
>>
>> I believe the portlayer would help MacOS developers a lot in code
>> maintenance, and when updating new features. I'd like to listen to your
>> opinions/comments/suggestions on this topic.
>>
>> Thanks!
>>
>> --
>> Best Regards,
>> Jimmy, Jing LV
>>
>>
>>


-- 
Best Regards,
Jimmy, Jing LV