RFR: 8201274: Launch Single-File Source-Code Programs (original) (raw)

Maurizio Cimadamore 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

'#'

'#!'

'#!\n'

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.

Cheers Maurizio

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: getClassLoader() getFileManager() 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! Maurizio

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 module. * 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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