LoadMethod

Annotates a function that loads the native library:

• In a companion object of a class. It will be called in the parent class's <clinit>.

• In an object. It will be called in the object's <init>.

• At the top level of a file. It will be called in the <clinit> of the file facade class the top-level declarations of that file compile to.

It may optionally have the following String parameters: os, arch, and vendor of a String type:

• If the os: String parameter is present, the OS family will be passed in, or System.getProperty("os.name") if this cannot be determined. These values can be windows, linux, macos, or android. Android is reported from System.getProperty("java.vendor"), since its os.name is Linux like a desktop's. Other OS families will not be determined.

• If the arch: String parameter is present, the normalized System.getProperty("os.arch") will be passed in. That is, instead of something from "x86", "i386", "ia-32", "i686", "x86-64", "x86_64", "amd64", "x64", "arm-v7", "armv7", "arm", "arm32", "aarch64", "arm-v8", "arm64", "riscv32", "rv32", "riscv64", "rv64" the list is shortened to "x86", "x86_64", "aarch32", "aarch64", "riscv32", "riscv64". If arch is not in the list above, it is passed as is.

• If the vendor: String parameter is present, System.getProperty("java.vendor") will be passed to it unchanged.

For example:

class MyClass {
    companion object {
        @LoadMethod
        private fun load(os: String, arch: String) {
            val from = "natives/$os-$arch/${mapLibraryName("native")}"
            val libStream = MyClass::class.java.classLoader.getResourceAsStream(from)
            val lib = Files.createTempFile("lib", from.substringAfter('/')).toFile()
            libStream.use { input -> lib.outputStream().use { output ->
                input.copyTo(output)
            } }
            lib.deleteOnExit()
            System.load(lib.absolutePath)
        }
    }
}

Or at the top level, to load a library bound to top-level external functions, which have no class to inject into:

@LoadMethod
private fun load(os: String, arch: String) {
    System.load("natives/$os-$arch/${mapLibraryName("native")}")
}