1 files changed, 105 insertions, 0 deletions
diff --git a/bootstrap_scala/BootstrapScala.java b/bootstrap_scala/BootstrapScala.java
new file mode 100644
index 0000000..fb6bd1e
--- /dev/null
+++ b/bootstrap_scala/BootstrapScala.java
@@ -0,0 +1,105 @@
+import java.io.*;
+import java.lang.reflect.*;
+import java.math.*;
+import java.net.*;
+import java.nio.*;
+import java.nio.file.*;
+import java.security.*;
+import java.util.*;
+import java.util.stream.*;
+import javax.tools.*;
+import javax.xml.bind.annotation.adapters.HexBinaryAdapter;
+
+/*
+This file class allows bootstrapping out of Java into Scala.
+It downloads the Scala jars for the version number given as the first
+argument into the directory given as the second argument and returns
+a classpath String.
+*/
+public class BootstrapScala{
+	public final static Dependency[] dependencies(String target, String scalaVersion){
+		return new Dependency[]{
+			Dependency.scala(target, scalaVersion, "library", "f75e7acabd57b213d6f61483240286c07213ec0e"),
+			Dependency.scala(target, scalaVersion, "compiler","1454c21d39a4d991006a2a47c164f675ea1dafaf"),
+			Dependency.scala(target, scalaVersion, "reflect", "bf1649c9d33da945dea502180855b56caf06288c"),
+			new Dependency(target, "modules/scala-xml_2.11/1.0.5", "scala-xml_2.11-1.0.5", "77ac9be4033768cf03cc04fbd1fc5e5711de2459")
+		};
+	}
+
+	public static void main(String args[]){
+		if(args.length < 2){
+			System.err.println("Usage: bootstrap_scala <scala version> <download directory>");
+			System.exit(1);
+		}
+		Dependency[] ds = dependencies( args[1], args[0] );
+
+		try {
+			new File(args[1]).mkdirs();
+			Arrays.stream(ds).forEach( d -> {
+				download( d.url, d.path, d.hash );
+			});
+			System.out.println(
+				String.join(
+					File.pathSeparator,
+					Arrays.stream(ds).map( d -> d.path.toString() ).toArray(String[]::new)
+				)
+			);
+		} catch (final Exception e) {
+		   throw new RuntimeException(e);
+		}
+	}
+	public static void download(URL urlString, Path target, String sha1){
+		try {
+			final Path unverified = Paths.get(target+".unverified");
+
+			if(!Files.exists(target)){
+				new File(target.toString()).getParentFile().mkdirs();
+				System.err.println("downloading "+urlString);
+				System.err.println("to "+target);
+				InputStream stream = urlString.openStream();
+				Files.copy(stream, unverified, StandardCopyOption.REPLACE_EXISTING);
+				stream.close();
+				String checksum = sha1(Files.readAllBytes(unverified));
+				if(sha1 == null || sha1.toUpperCase().equals(checksum)){
+					Files.move(unverified, target, StandardCopyOption.REPLACE_EXISTING, StandardCopyOption.ATOMIC_MOVE);
+				} else {
+					System.err.println(target + " checksum does not match.\nExpected: |"+sha1+"|\nFound:    |"+checksum+"|");
+					System.exit(1);
+				}
+			}
+		} catch (final Exception e) {
+		   throw new RuntimeException(e);
+		}
+	}
+	public static String sha1(byte[] bytes){
+		try {
+			final MessageDigest sha1 = MessageDigest.getInstance("SHA1");
+			sha1.update( bytes, 0, bytes.length );
+			return (new HexBinaryAdapter()).marshal(sha1.digest());
+		} catch (final Exception e) {
+		   throw new RuntimeException(e);
+		}
+	}
+}
+
+
+class Dependency{
+	URL url;
+	Path path;
+	String hash;
+	public Dependency(String target, String folder, String file, String hash){
+		path = Paths.get(target+file+".jar");
+		try { url = new URL("https://repo1.maven.org/maven2/org/scala-lang/"+folder+"/"+file+".jar"); }
+		catch (final MalformedURLException e) { throw new RuntimeException(e); }
+		hash = hash;
+	}
+	// scala-lang dependency
+	public static Dependency scala(String target, String scalaVersion, String scalaModule, String hash){
+		return new Dependency(
+			target,
+			"scala-"+scalaModule+"/"+scalaVersion,
+			"scala-"+scalaModule+"-"+scalaVersion,
+			hash
+		);
+	}
+}