Allow building shared libraries

[tomfi]

Is it possible to add the option / flag to build a shared library with this plugin?

When adding the --shared flag to GraalVM it should not require a main-class anymore (https://www.graalvm.org/reference-manual/native-image/ImplementingNativeMethodsInJavaWithSVM/#create-a-shared-library)

At the moment the maven plugin support it quite well but i could not find a good gradle plugin that supports it.

As a workaround i did the following configuration:

nativeImage {
  mainClass = "demo.MainKt"
  executableName = project.name
  arguments(
    "--shared",
  )
}

Where demo.MainKt is a stub:

package demo

fun main() {
}

This results in building a shared library by graalvm as expected.

It would be great if the mainClass and executableName were optional to allow building shared libraries with this plugin without workarounds.

Thanks in advance, this plugin is great 👍

[mike-neck]

The mainClass property cannot be optional, because nativeImage task and generateNativeImageConfig task are sharing the same mainClass property. Without setting mainClass property, the later task(generateNativeImageConfig) will fail. This means that we needs refactoring this plugin for realizing this feature. We have to introduce a convention object with the same interface to nativeImage task.

[mike-neck]

It seems that the shared library feature is limited to Java11 or later.

[mike-neck]

In PR #147

• deprecate mainClass property in nativeImage task
• add buildType {} block to configure the type of build(executable/shared library).

Example configuration of building shared library

nativeImage {
  buildType { BuildTypeSelector build ->
    build.sharedLibrary
  }
}

Example configuration of building executable

nativeImage {
  buildType { BuildTypeSelector build ->
    build.executable { main = 'com.example.Main' }
  }
}

[mike-neck]

The feature will be available at v1.4.0.

[tomfi]

@mike-neck thank you very much :)