RFR: 8201274: Launch Single-File Source-Code Programs
maurizio.cimadamore at oracle.com
Fri Apr 13 10:43:28 UTC 2018
One small followup question - the test SourceLauncherTest is not
covering any shebang cases - is that deliberate? I see that those seem
to be covered in the launcher test too, but I wonder if we should have
tests for clearly broken stuff, such as
Another small question - I see that the shebang process essentially
replaces the first line separator with \n - that is probably ok given
that the file is processed internally after that - but I wonder if you
have thought about pros and cons of preserving the original line separator.
On 12/04/18 21:46, Maurizio Cimadamore wrote:
> Looks great - some initial comments (I can't really comment on the
> launcher changes):
> * This logic is efficient:
> int magic = (in.read() << 8) + in.read();
> boolean shebang = magic == (('#' << 8) + '!');
> but convoluted to read; perhaps could be improved slightly by making
> '#' << 8) + '!' a static constant, and comparing against that.
> * I note that the reading logic in general could be simplified, e.g.
> using Files.lines(Path) - but I assume that you wrote the code as is
> for performance reasons (e.g. to avoid creating too many string
> objects) ?
> * I see that both the file manager and the class loader reasonably
> share the same context: a Map<String, byte>. I would make this more
> explicit, by having a Context class, whose state is the map, and then
> have the context provide two methods:
> This way the sharing will be automatic, no need to extract one field
> from one place and pass it over to the other place.
> * Big whohoo for being able to use the enhanced diagnostic framework
> with a couple of tweaks on the makefile - I hope that would have been
> the case when I put in the support, but since we have never done it -
> wasn't 100% sure it would work ;-)
> Overall I like it quite a lot and I think you went for a really clean
> design - kudos!
> On 12/04/18 21:15, Jonathan Gibbons wrote:
>> Please review an initial implementation for the feature described in
>> JEP 330: Launch Single-File Source-Code Programs.
>> The work is described in the JEP and CSR, and falls into various parts:
>> * The part to handle the new command-line options is in the native
>> Java launcher code.
>> * The part to invoke the compiler and subsequently execute the code
>> found in the source file is in a new class in the jdk.compiler
>> * There are some minor Makefile changes, to add support for a new
>> resource file.
>> There are no changes to javac itself.
>> JEP: http://openjdk.java.net/jeps/330
>> JBS: https://bugs.openjdk.java.net/browse/JDK-8201274
>> CSR: https://bugs.openjdk.java.net/browse/JDK-8201275
>> Webrev: http://cr.openjdk.java.net/~jjg/8201274/webrev.00/
>> -- Jon
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