Add tweaker loaderHEADmaster

1 files changed, 200 insertions, 0 deletions

diff --git a/tweaker/src/main/java/net/hypixel/modapi/tweaker/HypixelModAPITweaker.java b/tweaker/src/main/java/net/hypixel/modapi/tweaker/HypixelModAPITweaker.java
new file mode 100644
index 0000000..857433c
--- /dev/null
+++ b/tweaker/src/main/java/net/hypixel/modapi/tweaker/HypixelModAPITweaker.java
@@ -0,0 +1,200 @@
+package net.hypixel.modapi.tweaker;
+
+import net.minecraft.launchwrapper.ITweaker;
+import net.minecraft.launchwrapper.Launch;
+import net.minecraft.launchwrapper.LaunchClassLoader;
+import net.minecraftforge.fml.relauncher.CoreModManager;
+import org.apache.commons.io.IOUtils;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.nio.file.Files;
+import java.util.List;
+import java.util.Objects;
+import java.util.Properties;
+
+/**
+ * A tweaker class to automatically load the hypixel mod api while resolving conflicts
+ * from multiple mods providing a copy. This saves users from having to download the
+ * mod api separately.
+ */
+public class HypixelModAPITweaker implements ITweaker {
+
+	public static final String VERSION_NAME;
+	public static final long VERSION;
+
+	static {
+		// Load version information from the .properties generated by the gradle task generateVersionInfo
+		Properties properties = new Properties();
+		try {
+			properties.load(HypixelModAPITweaker.class.getResourceAsStream("/hypixel-mod-api-bundled.properties"));
+		} catch (IOException e) {
+			e.printStackTrace();
+		}
+		VERSION_NAME = properties.getProperty("version", "0.0.0.0");
+		String[] versionComponents = VERSION_NAME.split("\\.");
+		assert versionComponents.length == 4;
+		// We pack each of the four version components into a long.
+		// To do so we use the biggest number that can fit 4 times into a long:
+		//noinspection ConstantValue
+		assert Math.pow(10000, 4) < Long.MAX_VALUE;
+		long version = 0;
+		for (int i = 0; i < 4; i++) {
+			version *= 10000;
+			version += Long.parseLong(versionComponents[i]);
+		}
+		VERSION = version;
+	}
+
+	public static final String BUNDLED_JAR_NAME = "HypixelModAPI-" + VERSION_NAME + ".jar";
+
+	/**
+	 * This is the key which is used in the {@link Launch#blackboard} to perform
+	 * version negotiation.
+	 *
+	 * @see #getBlackboardVersion()
+	 * @see #offerVersionToBlackboard()
+	 */
+	public static final String VERSION_KEY = "net.hypixel.mod-api.version:1";
+
+	private boolean hasOfferedVersion = false;
+
+	/**
+	 * Get the current version declared on the blackboard.
+	 * The blackboard allows us to store arbitrary values. We store an int indicating the max version installed.
+	 *
+	 * @see #VERSION_KEY
+	 */
+	public static long getBlackboardVersion() {
+		Object blackboardVersion = Launch.blackboard.get(VERSION_KEY);
+		// In case nobody has declared a version on the blackboard yet, we return an incredibly outdated past version
+		if (blackboardVersion == null) return Long.MIN_VALUE;
+		// In case we later switch to another version format we declare any non-integer as an incredibly advanced future version
+		if (!(blackboardVersion instanceof Long)) return Long.MAX_VALUE;
+		return (Long) blackboardVersion;
+	}
+
+	/**
+	 * Inject our API jar into forge if we are the highest available version.
+	 *
+	 * @see #injectAPI()
+	 */
+	private void tryInjectAPI() {
+		// If the maximum installed version isn't our version return
+		if (getBlackboardVersion() != VERSION) return;
+		// If we didn't offer to install this version return
+		if (!hasOfferedVersion) return;
+
+		injectAPI();
+	}
+
+	/**
+	 * Unpacks the actual API file into a temporary folder from where it can be loaded.
+	 *
+	 * @return the location of the extracted API
+	 */
+	private File unpackAPI() {
+		File extractedFile = new File("hypixel-mod-api/" + BUNDLED_JAR_NAME).getAbsoluteFile();
+		//noinspection ResultOfMethodCallIgnored
+		extractedFile.getParentFile().mkdirs();
+		try (InputStream bundledJar = Objects.requireNonNull(
+				getClass().getResourceAsStream("/" + BUNDLED_JAR_NAME),
+				"Could not find bundled hypixel mod api");
+		     OutputStream outputStream = Files.newOutputStream(extractedFile.toPath())) {
+			IOUtils.copy(bundledJar, outputStream);
+			return extractedFile;
+		} catch (IOException e) {
+			throw new RuntimeException(e);
+		}
+	}
+
+	/**
+	 * @return the jar containing this class
+	 */
+	private File getThisJar() {
+		URL thisJarURL = getClass().getProtectionDomain().getCodeSource().getLocation();
+		if (thisJarURL == null) return null;
+		if (!"file".equals(thisJarURL.getProtocol())) return null;
+		try {
+			return new File(thisJarURL.toURI()).getAbsoluteFile();
+		} catch (URISyntaxException ignored) {
+		}
+		return null;
+	}
+
+	/**
+	 * Inject the API into Forge to be loaded as a mod. This will also extract the JAR.
+	 */
+	private void injectAPI() {
+		CoreModManager.getReparseableCoremods()
+		              .add(unpackAPI().getPath());
+	}
+
+	/**
+	 * Instruct Forge to load the current JAR as a mod.
+	 * By default, Forge does not load mods if they contain a tweaker, only loading the tweaker instead.
+	 * This function will remove this JAR from the list of ignored mods and schedule it to be scanned for mods.
+	 */
+	private void allowModLoading() {
+		File file = getThisJar();
+		if (file != null) {
+			CoreModManager.getReparseableCoremods()
+			              .add(file.getPath());
+			CoreModManager.getIgnoredMods()
+			              .remove(file.getPath());
+		}
+	}
+
+	/**
+	 * Offers our bundled version to the {@link Launch#blackboard}. If there is already a
+	 * higher version than ours installed then this will not do anything. Otherwise, it
+	 * will set {@link #hasOfferedVersion} and increment the version in the blackboard.
+	 *
+	 * @see #VERSION_KEY
+	 */
+	private void offerVersionToBlackboard() {
+		if (getBlackboardVersion() < VERSION) {
+			hasOfferedVersion = true;
+			Launch.blackboard.put(VERSION_KEY, VERSION);
+		}
+	}
+
+	/*
+	 Below here are all the ITweaker methods. The tweaker methods are executed in rounds.
+
+	 1. Run class init and init (constructor) for each tweaker
+	 2. Run acceptOptions for each tweaker
+	 3. Run injectIntoClassLoader for each tweaker
+	 4. If any cascading tweakers have been registered, go back to step 1
+	 5. After there are no new tweakers after an entire round:
+	 6. Run getLaunchArguments for each tweaker
+	 7. Run getLaunchTarget only on the first tweaker found (and execute that class)
+
+	 By first offering our version negotiation in acceptOptions or injectIntoClassloader and
+	 then injection our JARs in getLaunchArguments, we can ensure that every tweaker had time
+	 to make their version announcement heard.
+	 */
+	@Override
+	public void acceptOptions(List<String> args, File gameDir, File assetsDir, String profile) {
+		offerVersionToBlackboard();
+	}
+
+	@Override
+	public void injectIntoClassLoader(LaunchClassLoader classLoader) {
+	}
+
+	@Override
+	public String getLaunchTarget() {
+		return null;
+	}
+
+	@Override
+	public String[] getLaunchArguments() {
+		tryInjectAPI();
+		return new String[0];
+	}
+}