Misc. cleanup and minor optimisations (#3)

- Reduced the number of allocating lambdas and object allocations
- Avoided double `DownloadAssets#getAssetDest()` calls on cache miss
- Drastically simplified `JarVersionInfo#hello`
- Use `MethodHandles#publicLookup`
    - Requires the main method to be public, in a public class and in a package that is unconditionally open (if in a module), but faster to obtain than a `MethodHandles#lookup`

Author: PaintNinja

src/main/java/net/minecraftforge/launcher/DownloadAssets.java

@@ -12,6 +12,7 @@
 import net.minecraftforge.util.logging.Log;
 
 import java.io.File;
+import java.util.Map;
 
 /** Handles downloading assets for Minecraft. */
 final class DownloadAssets {
@@ -29,35 +30,34 @@ static void download(String repo, File assetsDir, MinecraftVersion versionJson)
         if (!objectsDir.exists() && !objectsDir.mkdirs())
             throw new IllegalStateException("Failed to create objects directory: " + objectsDir);
 
-        index.objects.forEach((name, asset) -> {
-            File file = new File(objectsDir, getAssetDest(asset.hash));
+        for (Map.Entry<String, AssetsIndex.Asset> entry : index.objects.entrySet()) {
+            String name = entry.getKey();
+            AssetsIndex.Asset asset = entry.getValue();
+            String assetDest = getAssetDest(asset.hash);
+            File file = new File(objectsDir, assetDest);
             if (file.exists()) {
                 Log.debug("Considering existing file with size " + file.length() + " and hash " + asset.hash + " for " + name);
                 if (file.length() == asset.size && HashFunction.SHA1.sneakyHash(file).equals(asset.hash)) {
                     Log.debug("Hash and size check succeeded. Skipping.");
-                    return;
+                    continue;
                 }
             }
 
             // We need to download assets? Release the log so the consumer is aware.
             Log.release();
             try {
                 Log.info("Downloading missing asset: " + name);
-                DownloadUtils.downloadFile(file, getAssetDownloadUrl(repo, asset.hash));
+                DownloadUtils.downloadFile(file, repo + assetDest);
             } catch (Exception e) {
                 throw new IllegalStateException("Failed to download " + name, e);
             }
-        });
+        }
     }
 
     private static String getAssetDest(String hash) {
         return hash.substring(0, 2) + "/" + hash;
     }
 
-    private static String getAssetDownloadUrl(String repo, String hash) {
-        return repo + getAssetDest(hash);
-    }
-
     private static File downloadIndex(MinecraftVersion versionJson, File assetsDir) {
         File index = new File(assetsDir, "indexes/" + versionJson.assetIndex.id + ".json");
         if (index.exists() && HashFunction.SHA1.sneakyHash(index).equals(versionJson.assetIndex.sha1)) {

src/main/java/net/minecraftforge/launcher/JarVersionInfo.java

@@ -20,7 +20,6 @@
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
-import java.util.Arrays;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 
@@ -82,7 +81,8 @@ private static Launcher run(String[] args) throws Throwable {
             .accepts("main", "The main class to run")
             .withRequiredArg().ofType(String.class);
 
-        JarVersionInfo.of(Main.class).hello(Log::info, false, true);
+        Package pkg = Main.class.getPackage();
+        Log.info(pkg.getImplementationTitle() + " " + pkg.getImplementationVersion());
 
         SplitArgs split = new SplitArgs(args);
 
@@ -118,15 +118,17 @@ private static Launcher run(String[] args) throws Throwable {
         MethodHandle mainMethod;
         try {
             Class<?> main = Class.forName(mainClass);
-            mainMethod = MethodHandles.lookup().findStatic(main, "main", MethodType.methodType(void.class, String[].class));
+            mainMethod = MethodHandles.publicLookup().findStatic(main, "main", MethodType.methodType(void.class, String[].class));
         } catch (ClassNotFoundException | NoSuchMethodException | IllegalAccessException e) {
             throw new IllegalStateException("Could not find main class!", e);
         }
 
         Log.info("Sanitizing Minecraft arguments");
-        Arrays.asList(split.mc).replaceAll(s -> s
-            .replace("{asset_index}", versionJson.assetIndex.id)
-            .replace("{assets_root}", assets.getAbsolutePath()));
+        for (int i = 0; i < split.mc.length; i++) {
+            split.mc[i] = split.mc[i]
+                .replace("{asset_index}", versionJson.assetIndex.id)
+                .replace("{assets_root}", assets.getAbsolutePath());
+        }
 
         return new Launcher(mainClass, mainMethod, split.mc);
     }
@@ -155,7 +157,13 @@ private static final class SplitArgs {
 
         private SplitArgs(String[] args) {
             // we're looking for the first "--"
-            int splitIdx = Arrays.asList(args).indexOf("--");
+            int splitIdx = -1;
+            for (int i = 0; i < args.length; i++) {
+                if (args[i].equals("--")) {
+                    splitIdx = i;
+                    break;
+                }
+            }
 
             if (splitIdx < 0) {
                 this.sl = args;