support .jar file to be scanned in cli

[maxandersen]

as mentioned in #257 it would be nice to be able to scan jars.

this pr enables it so you can do things like:

jar -jar forbiddenapis.jar -d /Users/manderse/.m2/repository/io/quarkus/quarkus-core/3.18.1/quarkus-core-3.18.1.jar --allowmissingclasses --bundledsignatures jdk-system-out

or in more compact form with jbang (if you done jbang app install forbiddenapis.jar

forbiddenapis -d jbang info jar io.quarkus:quarkus-core:3.18.1 --allowmissingclasses --bundledsignatures jdk-system-out

wdyt? I find this superuseful as i can check any maven artifact or even lib on disk without changing their build.

[uschindler]

There is no need to extract the JAR to a temporary directory. The Checker API can directly consume the InputStream when you pass them one by one. It must just handle a JAR file like a directory. Of course the classfile pattern needs to be applied, too.

So the JAR file must be serially be passed to:

forbidden-apis/src/main/java/de/thetaphi/forbiddenapis/Checker.java

Lines 364 to 374 in 6019f14

	public void addClassToCheck(final InputStream in, String name) throws IOException {
	final ClassReader reader;
	try (final InputStream in_ = in) {
	reader = AsmUtils.readAndPatchClass(in_);
	} catch (IllegalArgumentException iae) {
	throw new IllegalArgumentException(String.format(Locale.ENGLISH,
	"The class file format of '%s' is too recent to be parsed by ASM.", name));
	}
	final ClassMetadata metadata = new ClassMetadata(reader, false, true);
	classesToCheck.put(metadata.getBinaryClassName(), metadata);
	}

I can take your PR as a base, but the implementation is not ideal, so I won't merge this as is. To make this work more modifications are needed.

[maxandersen]

@uschindler I was wondering what could work but as i couldn't get any of my ides to import all the deps via ivy/build.xml I didn't get that far :)

if you can take it from here and make it work right that would be cool - if not let me know and I'll try do it.

[uschindler]

No problem, will fix that. I have some ideas. Basically I would use a ZIPInputStream instead, so the ZIP file is read sequentially. I just have to figure out how to apply the glob-based filtering there, I think its somewhere in plexus-utils to apply it to strings.

[dweiss]

If you stick to NIO then you can use Path as an abstraction for file system files (.class files) and .class files inside ZIP archives (by opening a zip FileSystem [1]).

There is usually some awkwardness in closing zip file systems but they work very well and are robust in my experience. For any downstream code, a Path (and streams) to a file inside a zip archive appears just as a normal filesystem path.

[1] https://docs.oracle.com/en/java/javase/22/docs/api/jdk.zipfs/module-summary.html

[dweiss]

As for globbing, I've also used glob PathMatcher instances on those zip filesystems and they tend to work quite fine. Again: there are some oddities here and there but they do work, generally.