Start porting to Kotlin

.idea/codeStyles/codeStyleConfig.xml

@@ -0,0 +1,5 @@
+<component name="ProjectCodeStyleConfiguration">
+  <state>
+    <option name="PREFERRED_PROJECT_CODE_STYLE" value="Default" />
+  </state>
+</component>

.idea/jarRepositories.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RemoteRepositoriesConfiguration">
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Maven Central repository" />
+      <option name="url" value="https://repo1.maven.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="jboss.community" />
+      <option name="name" value="JBoss Community repository" />
+      <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="BintrayJCenter" />
+      <option name="name" value="BintrayJCenter" />
+      <option name="url" value="https://jcenter.bintray.com/" />
+    </remote-repository>
+  </component>
+</project>

build.gradle

@@ -1,72 +0,0 @@
-plugins {
-    id 'java'
-    id 'application'
-    id 'com.github.johnrengelman.shadow' version '5.0.0'
-    id 'com.palantir.git-version' version '0.11.0'
-    id 'com.github.breadmoirai.github-release' version '2.2.9'
-}
-
-sourceCompatibility = 1.8
-
-dependencies {
-	implementation 'commons-cli:commons-cli:1.4'
-	implementation 'com.moandjiezana.toml:toml4j:0.7.2'
-    // TODO: Implement tests
-    //testImplementation 'junit:junit:4.12'
-    implementation 'com.google.code.gson:gson:2.8.1'
-    implementation 'com.squareup.okio:okio:2.2.2'
-}
-
-repositories {
-    jcenter()
-}
-
-mainClassName = 'link.infra.packwiz.installer.RequiresBootstrap'
-version gitVersion()
-
-jar {
-    manifest {
-        attributes(
-            'Main-Class': 'link.infra.packwiz.installer.RequiresBootstrap',
-            'Implementation-Version': project.version
-        )
-    }
-}
-
-// Commons CLI and Minimal JSON are already included in packwiz-installer-bootstrap
-shadowJar {
-   dependencies {
-       exclude(dependency('commons-cli:commons-cli:1.4'))
-       exclude(dependency('com.eclipsesource.minimal-json:minimal-json:0.9.5'))
-   }
-}
-
-// Used for vscode launch.json
-task copyJar(type: Copy) {
-    from shadowJar
-    rename "packwiz-installer-(.*)\\.jar", "packwiz-installer.jar"
-    into "build/libs/"
-}
-
-build.dependsOn copyJar
-
-if (project.hasProperty("github.token")) {
-    githubRelease {
-        // IntelliJ u ok?
-        //noinspection GroovyAssignabilityCheck
-        owner "comp500"
-        //noinspection GroovyAssignabilityCheck
-        repo "packwiz-installer"
-        //noinspection GroovyAssignabilityCheck
-        tagName "${project.version}"
-        //noinspection GroovyAssignabilityCheck
-        releaseName "Release ${project.version}"
-        //noinspection GroovyAssignabilityCheck
-        draft true
-        //noinspection GroovyAssignabilityCheck
-        token findProperty("github.token") ?: ""
-        releaseAssets = [jar.destinationDirectory.file("packwiz-installer.jar").get()]
-    }
-
-    tasks.githubRelease.dependsOn(build)
-}

build.gradle.kts

@@ -0,0 +1,86 @@
+plugins {
+	java
+	application
+	id("com.github.johnrengelman.shadow") version "5.0.0"
+	id("com.palantir.git-version") version "0.11.0"
+	id("com.github.breadmoirai.github-release") version "2.2.9"
+	kotlin("jvm") version "1.3.61"
+}
+
+java {
+	sourceCompatibility = JavaVersion.VERSION_1_8
+}
+
+dependencies {
+	implementation("commons-cli:commons-cli:1.4")
+	implementation("com.moandjiezana.toml:toml4j:0.7.2")
+	// TODO: Implement tests
+	//testImplementation "junit:junit:4.12"
+	implementation("com.google.code.gson:gson:2.8.1")
+	implementation("com.squareup.okio:okio:2.2.2")
+	implementation(kotlin("stdlib-jdk8"))
+}
+
+repositories {
+	jcenter()
+}
+
+application {
+	mainClassName = "link.infra.packwiz.installer.RequiresBootstrap"
+}
+
+val gitVersion: groovy.lang.Closure<*> by extra
+version = gitVersion()
+
+tasks.jar {
+	manifest {
+		attributes["Main-Class"] = "link.infra.packwiz.installer.RequiresBootstrap"
+		attributes["Implementation-Version"] = project.version
+	}
+}
+
+// Commons CLI and Minimal JSON are already included in packwiz-installer-bootstrap
+tasks.shadowJar {
+	dependencies {
+		exclude(dependency("commons-cli:commons-cli:1.4"))
+		exclude(dependency("com.eclipsesource.minimal-json:minimal-json:0.9.5"))
+	}
+}
+
+// Used for vscode launch.json
+tasks.register<Copy>("copyJar") {
+	from(tasks.shadowJar)
+	rename("packwiz-installer-(.*)\\.jar", "packwiz-installer.jar")
+	into("build/libs/")
+}
+
+tasks.build {
+	dependsOn("copyJar")
+}
+
+if (project.hasProperty("github.token")) {
+	githubRelease {
+		owner("comp500")
+		repo("packwiz-installer")
+		tagName("${project.version}")
+		releaseName("Release ${project.version}")
+		draft(true)
+		token(findProperty("github.token") as String? ?: "")
+		releaseAssets(tasks.jar.get().destinationDirectory.file("packwiz-installer.jar").get())
+	}
+
+	tasks.githubRelease {
+		dependsOn(tasks.build)
+	}
+}
+
+tasks.compileKotlin {
+	kotlinOptions {
+		jvmTarget = "1.8"
+	}
+}
+tasks.compileTestKotlin {
+	kotlinOptions {
+		jvmTarget = "1.8"
+	}
+}

src/main/java/link/infra/packwiz/installer/Main.java

@@ -1,148 +0,0 @@
-package link.infra.packwiz.installer;
-
-import link.infra.packwiz.installer.metadata.SpaceSafeURI;
-import link.infra.packwiz.installer.ui.CLIHandler;
-import link.infra.packwiz.installer.ui.IUserInterface;
-import link.infra.packwiz.installer.ui.InputStateHandler;
-import link.infra.packwiz.installer.ui.InstallWindow;
-import org.apache.commons.cli.*;
-
-import javax.swing.*;
-import java.awt.*;
-import java.net.URISyntaxException;
-
-@SuppressWarnings("unused")
-public class Main {
-
-	// Actual main() is in RequiresBootstrap!
-	@SuppressWarnings("unused")
-	public Main(String[] args) {
-		// Big overarching try/catch just in case everything breaks
-		try {
-			this.startup(args);
-		} catch (Exception e) {
-			e.printStackTrace();
-			EventQueue.invokeLater(() -> {
-				JOptionPane.showMessageDialog(null,
-						"A fatal error occurred: \n" + e.getClass().getCanonicalName() + ": " + e.getMessage(),
-						"packwiz-installer", JOptionPane.ERROR_MESSAGE);
-				System.exit(1);
-			});
-			// In case the eventqueue is broken, exit after 1 minute
-			try {
-				Thread.sleep(60 * 1000);
-			} catch (InterruptedException e1) {
-				// Good, it was already called?
-				return;
-			}
-			System.exit(1);
-		}
-	}
-
-	private void startup(String[] args) {
-		Options options = new Options();
-		addNonBootstrapOptions(options);
-		addBootstrapOptions(options);
-
-		CommandLineParser parser = new DefaultParser();
-		CommandLine cmd = null;
-		try {
-			cmd = parser.parse(options, args);
-		} catch (ParseException e) {
-			e.printStackTrace();
-			try {
-				UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
-			} catch (Exception e1) {
-				// Ignore the exceptions, just continue using the ugly L&F
-			}
-			JOptionPane.showMessageDialog(null, e.getMessage(), "packwiz-installer", JOptionPane.ERROR_MESSAGE);
-			System.exit(1);
-		}
-
-		IUserInterface ui;
-		// if "headless", GUI creation will fail anyway!
-		if (cmd.hasOption("no-gui") || GraphicsEnvironment.isHeadless()) {
-			ui = new CLIHandler();
-		} else {
-			ui = new InstallWindow();
-		}
-
-		String[] unparsedArgs = cmd.getArgs();
-		if (unparsedArgs.length > 1) {
-			ui.handleExceptionAndExit(new RuntimeException("Too many arguments specified!"));
-			return;
-		} else if (unparsedArgs.length < 1) {
-			ui.handleExceptionAndExit(new RuntimeException("URI to install from must be specified!"));
-			return;
-		}
-
-		String title = cmd.getOptionValue("title");
-		if (title != null) {
-			ui.setTitle(title);
-		}
-
-		InputStateHandler inputStateHandler = new InputStateHandler();
-		ui.show(inputStateHandler);
-
-		UpdateManager.Options uOptions = new UpdateManager.Options();
-
-		String side = cmd.getOptionValue("side");
-		if (side != null) {
-			uOptions.side = UpdateManager.Options.Side.from(side);
-		}
-
-		String packFolder = cmd.getOptionValue("pack-folder");
-		if (packFolder != null) {
-			uOptions.packFolder = packFolder;
-		}
-
-		String metaFile = cmd.getOptionValue("meta-file");
-		if (metaFile != null) {
-			uOptions.manifestFile = metaFile;
-		}
-
-		try {
-			uOptions.downloadURI = new SpaceSafeURI(unparsedArgs[0]);
-		} catch (URISyntaxException e) {
-			// TODO: better error message?
-			ui.handleExceptionAndExit(e);
-			return;
-		}
-
-		// Start update process!
-		// TODO: start in SwingWorker?
-		try {
-			ui.executeManager(() -> {
-				try {
-					new UpdateManager(uOptions, ui, inputStateHandler);
-				} catch (Exception e) {
-					// TODO: better error message?
-					ui.handleExceptionAndExit(e);
-				}
-			});
-		} catch (Exception e) {
-			// TODO: better error message?
-			ui.handleExceptionAndExit(e);
-		}
-	}
-
-	// Called by packwiz-installer-bootstrap to set up the help command
-	@SuppressWarnings("WeakerAccess")
-	public static void addNonBootstrapOptions(Options options) {
-		options.addOption("s", "side", true, "Side to install mods from (client/server, defaults to client)");
-		options.addOption(null, "title", true, "Title of the installer window");
-		options.addOption(null, "pack-folder", true, "Folder to install the pack to (defaults to the JAR directory)");
-		options.addOption(null, "meta-file", true, "JSON file to store pack metadata, relative to the pack folder (defaults to packwiz.json)");
-	}
-	
-	// TODO: link these somehow so they're only defined once?
-	private static void addBootstrapOptions(Options options) {
-		options.addOption(null, "bootstrap-update-url", true, "Github API URL for checking for updates");
-		options.addOption(null, "bootstrap-update-token", true, "Github API Access Token, for private repositories");
-		options.addOption(null, "bootstrap-no-update", false, "Don't update packwiz-installer");
-		options.addOption(null, "bootstrap-main-jar", true, "Location of the packwiz-installer JAR file");
-		options.addOption("g", "no-gui", false, "Don't display a GUI to show update progress");
-		options.addOption("h", "help", false, "Display this message"); // Implemented in packwiz-installer-bootstrap!
-	}
-	
-}

src/main/java/link/infra/packwiz/installer/request/handlers/RequestHandlerGithub.java

@@ -1,90 +0,0 @@
-package link.infra.packwiz.installer.request.handlers;
-
-import link.infra.packwiz.installer.metadata.SpaceSafeURI;
-
-import java.util.HashMap;
-import java.util.Map;
-import java.util.concurrent.locks.ReentrantReadWriteLock;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
-public class RequestHandlerGithub extends RequestHandlerZip {
-	
-	public RequestHandlerGithub() {
-		super(true);
-	}
-
-	@Override
-	public SpaceSafeURI getNewLoc(SpaceSafeURI loc) {
-		return loc;
-	}
-	
-	// TODO: is caching really needed, if HTTPURLConnection follows redirects correctly?
-	private Map<String, SpaceSafeURI> zipUriMap = new HashMap<>();
-	private final ReentrantReadWriteLock zipUriLock = new ReentrantReadWriteLock();
-	private static Pattern repoMatcherPattern = Pattern.compile("/([\\w.-]+/[\\w.-]+).*");
-	
-	private String getRepoName(SpaceSafeURI loc) {
-		Matcher matcher = repoMatcherPattern.matcher(loc.getPath());
-		if (matcher.matches()) {
-			return matcher.group(1);
-		} else {
-			return null;
-		}
-	}
-
-	@Override
-	protected SpaceSafeURI getZipUri(SpaceSafeURI loc) throws Exception {
-		String repoName = getRepoName(loc);
-		String branchName = getBranch(loc);
-		zipUriLock.readLock().lock();
-		SpaceSafeURI zipUri = zipUriMap.get(repoName + "/" + branchName);
-		zipUriLock.readLock().unlock();
-		if (zipUri != null) {
-			return zipUri;
-		}
-		
-		zipUri = new SpaceSafeURI("https://api.github.com/repos/" + repoName + "/zipball/" + branchName);
-		
-		zipUriLock.writeLock().lock();
-		// If another thread sets the value concurrently, use the value of the
-		// thread that first acquired the lock.
-		SpaceSafeURI zipUriInserted = zipUriMap.putIfAbsent(repoName + "/" + branchName, zipUri);
-		if (zipUriInserted != null) {
-			zipUri = zipUriInserted;
-		}
-		zipUriLock.writeLock().unlock();
-		return zipUri;
-	}
-	
-	private static Pattern branchMatcherPattern = Pattern.compile("/[\\w.-]+/[\\w.-]+/blob/([\\w.-]+).*");
-	
-	private String getBranch(SpaceSafeURI loc) {
-		Matcher matcher = branchMatcherPattern.matcher(loc.getPath());
-		if (matcher.matches()) {
-			return matcher.group(1);
-		} else {
-			return null;
-		}
-	}
-
-	@Override
-	protected SpaceSafeURI getLocationInZip(SpaceSafeURI loc) throws Exception {
-		String path = "/" + getRepoName(loc) + "/blob/" + getBranch(loc);
-		return new SpaceSafeURI(loc.getScheme(), loc.getAuthority(), path, null, null).relativize(loc);
-	}
-
-	@Override
-	public boolean matchesHandler(SpaceSafeURI loc) {
-		String scheme = loc.getScheme();
-		if (!("http".equals(scheme) || "https".equals(scheme))) {
-			return false;
-		}
-		if (!"github.com".equals(loc.getHost())) {
-			return false;
-		}
-		// TODO: sanity checks, support for more github urls
-		return true;
-	}
-
-}

src/main/java/link/infra/packwiz/installer/request/handlers/RequestHandlerHTTP.java

@@ -1,29 +0,0 @@
-package link.infra.packwiz.installer.request.handlers;
-
-import link.infra.packwiz.installer.metadata.SpaceSafeURI;
-import link.infra.packwiz.installer.request.IRequestHandler;
-import okio.Okio;
-import okio.Source;
-
-import java.net.URLConnection;
-
-public class RequestHandlerHTTP implements IRequestHandler {
-
-	@Override
-	public boolean matchesHandler(SpaceSafeURI loc) {
-		String scheme = loc.getScheme();
-		return "http".equals(scheme) || "https".equals(scheme);
-	}
-
-	@Override
-	public Source getFileSource(SpaceSafeURI loc) throws Exception {
-		URLConnection conn = loc.toURL().openConnection();
-		// TODO: when do we send specific headers??? should there be a way to signal this?
-		// github *sometimes* requires it, sometimes not!
-		//conn.addRequestProperty("Accept", "application/octet-stream");
-		// 30 second read timeout
-		conn.setReadTimeout(30 * 1000);
-		return Okio.source(conn.getInputStream());
-	}
-
-}

src/main/java/link/infra/packwiz/installer/request/handlers/RequestHandlerZip.java

@@ -1,169 +0,0 @@
-package link.infra.packwiz.installer.request.handlers;
-
-import link.infra.packwiz.installer.metadata.SpaceSafeURI;
-import okio.Buffer;
-import okio.BufferedSource;
-import okio.Okio;
-import okio.Source;
-
-import java.io.IOException;
-import java.net.URISyntaxException;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.concurrent.locks.ReentrantLock;
-import java.util.concurrent.locks.ReentrantReadWriteLock;
-import java.util.function.Predicate;
-import java.util.zip.ZipEntry;
-import java.util.zip.ZipInputStream;
-
-public abstract class RequestHandlerZip extends RequestHandlerHTTP {
-	
-	private final boolean modeHasFolder;
-	
-	public RequestHandlerZip(boolean modeHasFolder) {
-		this.modeHasFolder = modeHasFolder;
-	}
-	
-	private String removeFolder(String name) {
-		if (modeHasFolder) {
-			return name.substring(name.indexOf("/")+1);
-		} else {
-			return name;
-		}
-	}
-	
-	private class ZipReader {
-		
-		private final ZipInputStream zis;
-		private final Map<SpaceSafeURI, Buffer> readFiles = new HashMap<>();
-		// Write lock implies access to ZipInputStream - only 1 thread must read at a time!
-		final ReentrantLock filesLock = new ReentrantLock();
-		private ZipEntry entry;
-
-		private final BufferedSource zipSource;
-
-		ZipReader(Source zip) {
-			zis = new ZipInputStream(Okio.buffer(zip).inputStream());
-			zipSource = Okio.buffer(Okio.source(zis));
-		}
-		
-		// File lock must be obtained before calling this function
-		private Buffer readCurrFile() throws IOException {
-			Buffer fileBuffer = new Buffer();
-			zipSource.readFully(fileBuffer, entry.getSize());
-			return fileBuffer;
-		}
-		
-		// File lock must be obtained before calling this function
-		private Buffer findFile(SpaceSafeURI loc) throws IOException, URISyntaxException {
-			while (true) {
-				entry = zis.getNextEntry();
-				if (entry == null) {
-					return null;
-				}
-				Buffer data = readCurrFile();
-				SpaceSafeURI fileLoc = new SpaceSafeURI(removeFolder(entry.getName()));
-				if (loc.equals(fileLoc)) {
-					return data;
-				} else {
-					readFiles.put(fileLoc, data);
-				}
-			}
-		}
-		
-		Source getFileSource(SpaceSafeURI loc) throws Exception {
-			filesLock.lock();
-			// Assume files are only read once, allow GC by removing
-			Buffer file = readFiles.remove(loc);
-			if (file != null) {
-				filesLock.unlock();
-				return file;
-			}
-			
-			file = findFile(loc);
-			filesLock.unlock();
-			return file;
-		}
-
-		SpaceSafeURI findInZip(Predicate<SpaceSafeURI> matches) throws Exception {
-			filesLock.lock();
-			for (SpaceSafeURI file : readFiles.keySet()) {
-				if (matches.test(file)) {
-					filesLock.unlock();
-					return file;
-				}
-			}
-			
-			while (true) {
-				entry = zis.getNextEntry();
-				if (entry == null) {
-					filesLock.unlock();
-					return null;
-				}
-				Buffer data = readCurrFile();
-				SpaceSafeURI fileLoc = new SpaceSafeURI(removeFolder(entry.getName()));
-				readFiles.put(fileLoc, data);
-				if (matches.test(fileLoc)) {
-					filesLock.unlock();
-					return fileLoc;
-				}
-			}
-		}
-		
-	}
-	
-	private final Map<SpaceSafeURI, ZipReader> cache = new HashMap<>();
-	private final ReentrantReadWriteLock cacheLock = new ReentrantReadWriteLock();
-	
-	protected abstract SpaceSafeURI getZipUri(SpaceSafeURI loc) throws Exception;
-	
-	protected abstract SpaceSafeURI getLocationInZip(SpaceSafeURI loc) throws Exception;
-	
-	@Override
-	public abstract boolean matchesHandler(SpaceSafeURI loc);
-
-	@Override
-	public Source getFileSource(SpaceSafeURI loc) throws Exception {
-		SpaceSafeURI zipUri = getZipUri(loc);
-		cacheLock.readLock().lock();
-		ZipReader zr = cache.get(zipUri);
-		cacheLock.readLock().unlock();
-		if (zr == null) {
-			cacheLock.writeLock().lock();
-			// Recheck, because unlocking read lock allows another thread to modify it
-			zr = cache.get(zipUri);
-			if (zr == null) {
-				Source src = super.getFileSource(zipUri);
-				if (src == null) {
-					cacheLock.writeLock().unlock();
-					return null;
-				}
-				zr = new ZipReader(src);
-				cache.put(zipUri, zr);
-			}
-			cacheLock.writeLock().unlock();
-		}
-		
-		return zr.getFileSource(getLocationInZip(loc));
-	}
-	
-	protected SpaceSafeURI findInZip(SpaceSafeURI loc, Predicate<SpaceSafeURI> matches) throws Exception {
-		SpaceSafeURI zipUri = getZipUri(loc);
-		cacheLock.readLock().lock();
-		ZipReader zr = cache.get(zipUri);
-		cacheLock.readLock().unlock();
-		if (zr == null) {
-			cacheLock.writeLock().lock();
-			// Recheck, because unlocking read lock allows another thread to modify it
-			zr = cache.get(zipUri);
-			if (zr == null) {
-				zr = new ZipReader(super.getFileSource(zipUri));
-				cache.put(zipUri, zr);
-			}
-			cacheLock.writeLock().unlock();
-		}
-		
-		return zr.findInZip(matches);
-	}
-
-}

src/main/kotlin/link/infra/packwiz/installer/Main.kt

@@ -0,0 +1,123 @@
+package link.infra.packwiz.installer
+
+import link.infra.packwiz.installer.metadata.SpaceSafeURI
+import link.infra.packwiz.installer.ui.CLIHandler
+import link.infra.packwiz.installer.ui.InputStateHandler
+import link.infra.packwiz.installer.ui.InstallWindow
+import org.apache.commons.cli.DefaultParser
+import org.apache.commons.cli.Options
+import org.apache.commons.cli.ParseException
+import java.awt.EventQueue
+import java.awt.GraphicsEnvironment
+import java.net.URISyntaxException
+import javax.swing.JOptionPane
+import javax.swing.UIManager
+import kotlin.system.exitProcess
+
+@Suppress("unused")
+class Main(args: Array<String>) {
+	private fun startup(args: Array<String>) {
+		val options = Options()
+		addNonBootstrapOptions(options)
+		addBootstrapOptions(options)
+
+		val parser = DefaultParser()
+		val cmd = try {
+			parser.parse(options, args)
+		} catch (e: ParseException) {
+			e.printStackTrace()
+			try {
+				UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName())
+			} catch (e1: Exception) {
+				// Ignore the exceptions, just continue using the ugly L&F
+			}
+			JOptionPane.showMessageDialog(null, e.message, "packwiz-installer", JOptionPane.ERROR_MESSAGE)
+			exitProcess(1)
+		}
+
+		// if "headless", GUI creation will fail anyway!
+		val ui = if (cmd.hasOption("no-gui") || GraphicsEnvironment.isHeadless()) {
+			CLIHandler()
+		} else InstallWindow()
+
+		val unparsedArgs = cmd.args
+		if (unparsedArgs.size > 1) {
+			ui.handleExceptionAndExit(RuntimeException("Too many arguments specified!"))
+		} else if (unparsedArgs.isEmpty()) {
+			ui.handleExceptionAndExit(RuntimeException("URI to install from must be specified!"))
+		}
+
+		cmd.getOptionValue("title")?.also {
+			ui.setTitle(it)
+		}
+
+		val inputStateHandler = InputStateHandler()
+		ui.show(inputStateHandler)
+
+		val uOptions = UpdateManager.Options().apply {
+			side = cmd.getOptionValue("side")?.let { UpdateManager.Options.Side.from(it) } ?: side
+			packFolder = cmd.getOptionValue("pack-folder") ?: packFolder
+			manifestFile = cmd.getOptionValue("meta-file") ?: manifestFile
+		}
+
+		try {
+			uOptions.downloadURI = SpaceSafeURI(unparsedArgs[0])
+		} catch (e: URISyntaxException) {
+			// TODO: better error message?
+			ui.handleExceptionAndExit(e)
+		}
+
+		// Start update process!
+		// TODO: start in SwingWorker?
+		try {
+			ui.executeManager {
+				try {
+					UpdateManager(uOptions, ui, inputStateHandler)
+				} catch (e: Exception) { // TODO: better error message?
+					ui.handleExceptionAndExit(e)
+				}
+			}
+		} catch (e: Exception) { // TODO: better error message?
+			ui.handleExceptionAndExit(e)
+		}
+	}
+
+	companion object {
+		// Called by packwiz-installer-bootstrap to set up the help command
+		fun addNonBootstrapOptions(options: Options) {
+			options.addOption("s", "side", true, "Side to install mods from (client/server, defaults to client)")
+			options.addOption(null, "title", true, "Title of the installer window")
+			options.addOption(null, "pack-folder", true, "Folder to install the pack to (defaults to the JAR directory)")
+			options.addOption(null, "meta-file", true, "JSON file to store pack metadata, relative to the pack folder (defaults to packwiz.json)")
+		}
+
+		// TODO: link these somehow so they're only defined once?
+		private fun addBootstrapOptions(options: Options) {
+			options.addOption(null, "bootstrap-update-url", true, "Github API URL for checking for updates")
+			options.addOption(null, "bootstrap-update-token", true, "Github API Access Token, for private repositories")
+			options.addOption(null, "bootstrap-no-update", false, "Don't update packwiz-installer")
+			options.addOption(null, "bootstrap-main-jar", true, "Location of the packwiz-installer JAR file")
+			options.addOption("g", "no-gui", false, "Don't display a GUI to show update progress")
+			options.addOption("h", "help", false, "Display this message") // Implemented in packwiz-installer-bootstrap!
+		}
+	}
+
+	// Actual main() is in RequiresBootstrap!
+	init {
+		// Big overarching try/catch just in case everything breaks
+		try {
+			startup(args)
+		} catch (e: Exception) {
+			e.printStackTrace()
+			EventQueue.invokeLater {
+				JOptionPane.showMessageDialog(null,
+						"A fatal error occurred: \n" + e.javaClass.canonicalName + ": " + e.message,
+						"packwiz-installer", JOptionPane.ERROR_MESSAGE)
+				exitProcess(1)
+			}
+			// In case the EventQueue is broken, exit after 1 minute
+			Thread.sleep(60 * 1000.toLong())
+			exitProcess(1)
+		}
+	}
+}

src/main/kotlin/link/infra/packwiz/installer/request/IRequestHandler.kt

@@ -1,17 +1,16 @@
-package link.infra.packwiz.installer.request;
+package link.infra.packwiz.installer.request
 
-import link.infra.packwiz.installer.metadata.SpaceSafeURI;
+import link.infra.packwiz.installer.metadata.SpaceSafeURI
-import okio.Source;
+import okio.Source
 
 /**
  * IRequestHandler handles requests for locations specified in modpack metadata.
  */
-public interface IRequestHandler {
+interface IRequestHandler {
+	fun matchesHandler(loc: SpaceSafeURI): Boolean
 
-	boolean matchesHandler(SpaceSafeURI loc);
+	fun getNewLoc(loc: SpaceSafeURI): SpaceSafeURI {
-	
+		return loc
-	default SpaceSafeURI getNewLoc(SpaceSafeURI loc) {
-		return loc;
 	}
 
 	/**
@@ -21,6 +20,5 @@ public interface IRequestHandler {
 	 * @return The Source containing the data of the file
 	 * @throws Exception Exception if it failed to download a file!!!
 	 */
-	Source getFileSource(SpaceSafeURI loc) throws Exception;
+	fun getFileSource(loc: SpaceSafeURI): Source?
-
 }

src/main/kotlin/link/infra/packwiz/installer/request/handlers/RequestHandlerGithub.kt

@@ -0,0 +1,71 @@
+package link.infra.packwiz.installer.request.handlers
+
+import link.infra.packwiz.installer.metadata.SpaceSafeURI
+import java.util.*
+import java.util.concurrent.locks.ReentrantReadWriteLock
+import java.util.regex.Pattern
+import kotlin.concurrent.read
+import kotlin.concurrent.write
+
+class RequestHandlerGithub : RequestHandlerZip(true) {
+	override fun getNewLoc(loc: SpaceSafeURI): SpaceSafeURI {
+		return loc
+	}
+
+	companion object {
+		private val repoMatcherPattern = Pattern.compile("/([\\w.-]+/[\\w.-]+).*")
+		private val branchMatcherPattern = Pattern.compile("/[\\w.-]+/[\\w.-]+/blob/([\\w.-]+).*")
+	}
+
+	// TODO: is caching really needed, if HTTPURLConnection follows redirects correctly?
+	private val zipUriMap: MutableMap<String, SpaceSafeURI> = HashMap()
+	private val zipUriLock = ReentrantReadWriteLock()
+	private fun getRepoName(loc: SpaceSafeURI): String? {
+		val matcher = repoMatcherPattern.matcher(loc.path)
+		return if (matcher.matches()) {
+			matcher.group(1)
+		} else {
+			null
+		}
+	}
+
+	override fun getZipUri(loc: SpaceSafeURI): SpaceSafeURI {
+		val repoName = getRepoName(loc)
+		val branchName = getBranch(loc)
+
+		zipUriLock.read {
+			zipUriMap["$repoName/$branchName"]
+		}?.let { return it }
+
+		var zipUri = SpaceSafeURI("https://api.github.com/repos/$repoName/zipball/$branchName")
+		zipUriLock.write {
+			// If another thread sets the value concurrently, use the existing value from the
+			// thread that first acquired the lock.
+			zipUri = zipUriMap.putIfAbsent("$repoName/$branchName", zipUri) ?: zipUri
+		}
+		return zipUri
+	}
+
+	private fun getBranch(loc: SpaceSafeURI): String? {
+		val matcher = branchMatcherPattern.matcher(loc.path)
+		return if (matcher.matches()) {
+			matcher.group(1)
+		} else {
+			null
+		}
+	}
+
+	override fun getLocationInZip(loc: SpaceSafeURI): SpaceSafeURI {
+		val path = "/" + getRepoName(loc) + "/blob/" + getBranch(loc)
+		return SpaceSafeURI(loc.scheme, loc.authority, path, null, null).relativize(loc)
+	}
+
+	override fun matchesHandler(loc: SpaceSafeURI): Boolean {
+		val scheme = loc.scheme
+		if (!("http" == scheme || "https" == scheme)) {
+			return false
+		}
+		return "github.com" == loc.host
+		// TODO: sanity checks, support for more github urls
+	}
+}

src/main/kotlin/link/infra/packwiz/installer/request/handlers/RequestHandlerHTTP.kt

@@ -0,0 +1,25 @@
+package link.infra.packwiz.installer.request.handlers
+
+import link.infra.packwiz.installer.metadata.SpaceSafeURI
+import link.infra.packwiz.installer.request.IRequestHandler
+import okio.Source
+import okio.source
+
+open class RequestHandlerHTTP : IRequestHandler {
+	override fun matchesHandler(loc: SpaceSafeURI): Boolean {
+		val scheme = loc.scheme
+		return "http" == scheme || "https" == scheme
+	}
+
+	override fun getFileSource(loc: SpaceSafeURI): Source? {
+		val conn = loc.toURL().openConnection()
+		// TODO: when do we send specific headers??? should there be a way to signal this?
+		// github *sometimes* requires it, sometimes not!
+		//conn.addRequestProperty("Accept", "application/octet-stream");
+		conn.apply {
+			// 30 second read timeout
+			readTimeout = 30 * 1000
+		}
+		return conn.getInputStream().source()
+	}
+}

src/main/kotlin/link/infra/packwiz/installer/request/handlers/RequestHandlerZip.kt

@@ -0,0 +1,123 @@
+package link.infra.packwiz.installer.request.handlers
+
+import link.infra.packwiz.installer.metadata.SpaceSafeURI
+import okio.Buffer
+import okio.Source
+import okio.buffer
+import okio.source
+import java.util.*
+import java.util.concurrent.locks.ReentrantLock
+import java.util.concurrent.locks.ReentrantReadWriteLock
+import java.util.function.Predicate
+import java.util.zip.ZipEntry
+import java.util.zip.ZipInputStream
+import kotlin.concurrent.read
+import kotlin.concurrent.withLock
+import kotlin.concurrent.write
+
+abstract class RequestHandlerZip(private val modeHasFolder: Boolean) : RequestHandlerHTTP() {
+	private fun removeFolder(name: String): String {
+		return if (modeHasFolder) {
+			// TODO: replace with proper path checks once switched to Path??
+			name.substring(name.indexOf("/") + 1)
+		} else {
+			name
+		}
+	}
+
+	private inner class ZipReader internal constructor(zip: Source) {
+		private val zis = ZipInputStream(zip.buffer().inputStream())
+		private val readFiles: MutableMap<SpaceSafeURI, Buffer> = HashMap()
+		// Write lock implies access to ZipInputStream - only 1 thread must read at a time!
+		val filesLock = ReentrantLock()
+		private var entry: ZipEntry? = null
+
+		private val zipSource = zis.source().buffer()
+
+		// File lock must be obtained before calling this function
+		private fun readCurrFile(): Buffer {
+			val fileBuffer = Buffer()
+			zipSource.readFully(fileBuffer, entry!!.size)
+			return fileBuffer
+		}
+
+		// File lock must be obtained before calling this function
+		private fun findFile(loc: SpaceSafeURI): Buffer? {
+			while (true) {
+				entry = zis.nextEntry
+				entry?.also {
+					val data = readCurrFile()
+					val fileLoc = SpaceSafeURI(removeFolder(it.name))
+					if (loc == fileLoc) {
+						return data
+					} else {
+						readFiles[fileLoc] = data
+					}
+				} ?: return null
+			}
+		}
+
+		fun getFileSource(loc: SpaceSafeURI): Source? {
+			filesLock.withLock {
+				// Assume files are only read once, allow GC by removing
+				readFiles.remove(loc)?.also { return it }
+				return findFile(loc)
+			}
+		}
+
+		fun findInZip(matches: Predicate<SpaceSafeURI>): SpaceSafeURI? {
+			filesLock.withLock {
+				readFiles.keys.find { matches.test(it) }?.let { return it }
+
+				do {
+					val entry = zis.nextEntry?.also {
+						val data = readCurrFile()
+						val fileLoc = SpaceSafeURI(removeFolder(it.name))
+						readFiles[fileLoc] = data
+						if (matches.test(fileLoc)) {
+							return fileLoc
+						}
+					}
+				} while (entry != null)
+				return null
+			}
+		}
+	}
+
+	private val cache: MutableMap<SpaceSafeURI, ZipReader> = HashMap()
+	private val cacheLock = ReentrantReadWriteLock()
+
+	protected abstract fun getZipUri(loc: SpaceSafeURI): SpaceSafeURI
+	protected abstract fun getLocationInZip(loc: SpaceSafeURI): SpaceSafeURI
+	abstract override fun matchesHandler(loc: SpaceSafeURI): Boolean
+
+	override fun getFileSource(loc: SpaceSafeURI): Source? {
+		val zipUri = getZipUri(loc)
+		var zr = cacheLock.read { cache[zipUri] }
+		if (zr == null) {
+			cacheLock.write {
+				// Recheck, because unlocking read lock allows another thread to modify it
+				zr = cache[zipUri]
+
+				if (zr == null) {
+					val src = super.getFileSource(zipUri) ?: return null
+					zr = ZipReader(src).also { cache[zipUri] = it }
+				}
+			}
+		}
+		return zr?.getFileSource(getLocationInZip(loc))
+	}
+
+	protected fun findInZip(loc: SpaceSafeURI, matches: Predicate<SpaceSafeURI>): SpaceSafeURI? {
+		val zipUri = getZipUri(loc)
+		return (cacheLock.read { cache[zipUri] } ?: cacheLock.write {
+			// Recheck, because unlocking read lock allows another thread to modify it
+			cache[zipUri] ?: run {
+				// Create the ZipReader if it doesn't exist, return null if getFileSource returns null
+				super.getFileSource(zipUri)?.let { ZipReader(it) }
+						?.also { cache[zipUri] = it }
+			}
+		})?.findInZip(matches)
+	}
+
+}