RFR: JDK-8243454 - Redundant code for executable jar file manifests except SplashScreen-Image

[Lance Andersen]

Hi Philipp,

I have not looked at this in detail yet, but the changes you are proposing would require a CSR and probably an update to the JAR specification

I am not  sure of the history as to why this was done, perhaps others might know.  I think this would be good to know as part of considering this change/

Best,
Lance

> On May 17, 2020, at 5:53 AM, Philipp Kunz <philipp.kunz at paratix.ch> wrote:
> 
> Hi,
> Essentially the same patch as last time [1] but this time with a bug
> number [2].The patch does not include the updated UnicodeTest.jar which
> I created with
> ../jtreg-5.0-b01/bin/jtreg -va -nr -jdk:build/linux-x86_64-server-
> release/images/jdk/ -Xshare:off
> test/jdk/tools/launcher/UnicodeTest.javacp
> JTwork/scratch/UnicodeTest.jar test/jdk/tools/launcher/
> Regards,Philipp
> [1] 
> https://mail.openjdk.java.net/pipermail/core-libs-dev/2020-January/064190.html[2
> ] https://bugs.openjdk.java.net/browse/JDK-8243454
> 
> On Sat, 2020-01-04 at 11:00 +0100, Philipp Kunz wrote:
>> Hi,
>> When I tried to improve Unicode support in JAR manifests in [1],
>> independent of what will happen with that, I found that there are not
>> only Manifest and Attributes classes parsing manifests but also some
>> c code which parses "SplashScreen-Image" attribute and also used to
>> parse some other attributes such as "Main-Class" and others.
>> There already are tests for splash screen images but those existing
>> ones work with the "-splash" command line option and not with the
>> "SplashScreen-Image" manifest attribute. I found "SplashScreen-Image" 
>> manifest attribute not yet covered with a test and extended the
>> existing UnicodeTest accordingly, see attached patch which confirmed
>> that the "SplashScreen-Image" manifest attribute already fully
>> supports Unicode.
>> Support for "JRE-Version" manifest attribute and "-jre-restrict-
>> search" and "-jre-no-restrict-search" command line attributes has
>> already been removed earlier already and the relevant lines of code
>> determining the main class from the manifest when launching have
>> already been moved to or near LauncherHelper::getMainClassFromJar in
>> earlier versions, apparently leaving them with no use any longer in
>> java.c, java.h, manifest_info.h, and parse_manifest.c, I figure.
>> Hence, I propose to remove those parts as in the attached patch.
>> This leaves manifest_info.h and parse_manifest.c with "SplashScreen-
>> Image" as the only attribute parsed there. Certainly it would be a
>> different change but anyway it might be worth a consideration to move
>> the code opening the splash screen image to LauncherHelper or a
>> similar appropriate place in Java which would allow to remove quite a
>> number of some lines of c code, provided it could be acceptable to
>> show the splash screen image slightly later.
>> There is no existing related bug and I didn't find a new one. It
>> would be nice to have "SplashScreen-Image" manifest attribute covered
>> with a test and there is some potential for cleaning up unused code
>> which certainly is not urgent at all and I would not know how
>> desirable this really is. Also I'm not sure whether it's better or
>> not to add SPLASHSCREEN_IMAGE to Attributes.Name.KNOWN_NAMES.
>> Any opinion about to how to proceed with this, if at all or would
>> someone sponsor this patch?
>> Regards,Philipp
>> 
>> [1] 
>> https://mail.openjdk.java.net/pipermail/core-libs-dev/2019-December/064149.html
>> 
> <20200517-splashscreenimageunicodetestwithoutunicodetestjar.patch>

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