walkmc.library.LibraryManager.kt Maven / Gradle / Ivy

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package walkmc.library

import walkmc.*
import walkmc.cache.*
import walkmc.extensions.*
import walkmc.serializer.common.*
import java.io.*
import java.lang.reflect.*
import java.net.*

/**
 * A registry used to store and register libraries.
 */
object LibraryManager : Cache() {
	const val MAVEN_CENTRAL = "https://repo.maven.apache.org/maven2/"
	
	/**
	 * Gets the default folder of the libaries.
	 */
	val folder = newFolder("libraries")
	
	/**
	 * Loads and register all libraries from the default library folder.
	 */
	fun loadAll() = folder
		.files { extension == "jar" }
		.filter { it.nameWithoutExtension !in this }
		.forEach {
			put(it.nameWithoutExtension, it)
			addURLMethod.invoke(mainClassLoader, it.toURI().toURL())
		}
	
	
	/**
	 * Adds and register a new library by the specified [file].
	 */
	fun register(file: File) {
		if (file.nameWithoutExtension in this)
			return
		
		file.copyTo(folder)
		put(file.nameWithoutExtension, file)
		addURLMethod.invoke(mainClassLoader, file.toURI().toURL())
	}
	
	/**
	 * Downloads a jar file from the specified [url] and implements then inside of the library folder.
	 * This alsos register the downloaded file in this registry.
	 */
	fun download(url: String): File {
		val file = Downloader.download(URL(url), folder, true)
		put(file.nameWithoutExtension, file)
		addURLMethod.invoke(mainClassLoader, file.toURI().toURL())
		return file
	}
	
	/**
	 * Downloads a jar file from the maven central and implements then inside of the library folder.
	 * This alsos register the downloaded file in this registry.
	 */
	fun downloadFromMaven(group: String, artifact: String, version: String): File {
		val artifacts = artifact.replace('.', '/')
		val groups = group.replace('.', '/')
		val url = "$MAVEN_CENTRAL$groups/$artifacts/$version/$artifacts-$version.jar"
		return download(url)
	}
}

/**
 * Gets the main class loader.
 */
internal val mainClassLoader by lazy {
	ClassLoader.getSystemClassLoader() as URLClassLoader
}

/**
 * Gets the java method used to add new URL libaries to the classpath.
 */
internal val addURLMethod: Method by lazy {
	URLClassLoader::class.java.getDeclaredMethod("addURL", URL::class.java).apply {
		isAccessible = true
	}
}