File Structure Changes (#462)

* File Structure changes

* Fix checkstyle

* Fix processed jars

* Fix unpick tests

* Resolve reviews

* Fix merge conflicts

src/main/java/net/fabricmc/loom/LoomRepositoryPlugin.java

@@ -73,13 +73,13 @@ public class LoomRepositoryPlugin implements Plugin<PluginAware> {
 
 		repositories.ivy(repo -> {
 			repo.setUrl(files.getUserCache());
-			repo.patternLayout(layout -> layout.artifact("[revision]/[artifact]-[revision](-[classifier])(.[ext])"));
+			repo.patternLayout(layout -> layout.artifact("[revision]/[artifact](-[classifier])(.[ext])"));
 			repo.metadataSources(IvyArtifactRepository.MetadataSources::artifact);
 		});
 
 		repositories.ivy(repo -> {
 			repo.setUrl(files.getRootProjectPersistentCache());
-			repo.patternLayout(layout -> layout.artifact("[revision]/[artifact]-[revision](-[classifier])(.[ext])"));
+			repo.patternLayout(layout -> layout.artifact("[revision]/[artifact](-[classifier])(.[ext])"));
 			repo.metadataSources(IvyArtifactRepository.MetadataSources::artifact);
 		});
 	}

src/main/java/net/fabricmc/loom/build/mixin/AnnotationProcessorInvoker.java

@@ -82,7 +82,7 @@ public abstract class AnnotationProcessorInvoker<T extends Task> {
 			LoomGradleExtension loom = LoomGradleExtension.get(project);
 			String refmapName = Objects.requireNonNull(MixinApExtension.getMixinInformationContainer(sourceSet)).refmapNameProvider().get();
 			Map<String, String> args = new HashMap<>() {{
-					put(Constants.MixinArguments.IN_MAP_FILE_NAMED_INTERMEDIARY, loom.getMappingsProvider().tinyMappings.getCanonicalPath());
+					put(Constants.MixinArguments.IN_MAP_FILE_NAMED_INTERMEDIARY, loom.getMappingsProvider().tinyMappings.toFile().getCanonicalPath());
 					put(Constants.MixinArguments.OUT_MAP_FILE_NAMED_INTERMEDIARY, loom.getNextMixinMappings().getCanonicalPath());
 					put(Constants.MixinArguments.OUT_REFMAP_FILE, getRefmapDestination(task, refmapName));
 					put(Constants.MixinArguments.DEFAULT_OBFUSCATION_ENV, "named:intermediary");

src/main/java/net/fabricmc/loom/configuration/DependencyProvider.java

@@ -49,6 +49,7 @@ import org.zeroturnaround.zip.ZipUtil;
 
 import net.fabricmc.loom.LoomGradleExtension;
 import net.fabricmc.loom.LoomGradlePlugin;
+import net.fabricmc.loom.configuration.providers.MinecraftProvider;
 import net.fabricmc.loom.extension.LoomFiles;
 
 public abstract class DependencyProvider {
@@ -93,6 +94,10 @@ public abstract class DependencyProvider {
 		return getExtension().getFiles();
 	}
 
+	public MinecraftProvider getMinecraftProvider() {
+		return getExtension().getMinecraftProvider();
+	}
+
 	public boolean isRefreshDeps() {
 		return LoomGradlePlugin.refreshDeps;
 	}

src/main/java/net/fabricmc/loom/configuration/LoomDependencyManager.java

@@ -139,7 +139,7 @@ public class LoomDependencyManager {
 		}
 
 		SourceRemapper sourceRemapper = new SourceRemapper(project, true);
-		String mappingsKey = mappingsProvider.getMappingsKey();
+		String mappingsIdentifier = mappingsProvider.mappingsIdentifier();
 
 		if (extension.getInstallerData() == null) {
 			//If we've not found the installer JSON we've probably skipped remapping Fabric loader, let's go looking
@@ -168,7 +168,7 @@ public class LoomDependencyManager {
 			project.getLogger().warn("fabric-installer.json not found in classpath!");
 		}
 
-		ModCompileRemapper.remapDependencies(project, mappingsKey, extension, sourceRemapper);
+		ModCompileRemapper.remapDependencies(project, mappingsIdentifier, extension, sourceRemapper);
 
 		long start = System.currentTimeMillis();
 

src/main/java/net/fabricmc/loom/configuration/processors/MinecraftProcessedProvider.java

@@ -66,11 +66,11 @@ public class MinecraftProcessedProvider extends MinecraftMappedProvider {
 		}
 
 		getProject().getDependencies().add(Constants.Configurations.MINECRAFT_NAMED,
-				getProject().getDependencies().module("net.minecraft:minecraft:" + getJarVersionString(projectMappedClassifier)));
+				getProject().getDependencies().module("net.minecraft:minecraft-" + projectMappedClassifier + ":" + getMinecraftProvider().minecraftVersion() + "/" + getExtension().getMappingsProvider().mappingsIdentifier()));
 	}
 
 	private void invalidateJars() {
-		File dir = getJarDirectory(getExtension().getFiles().getUserCache(), projectMappedClassifier);
+		File dir = projectMappedJar.getParentFile();
 
 		if (dir.exists()) {
 			getProject().getLogger().warn("Invalidating project jars");
@@ -87,7 +87,8 @@ public class MinecraftProcessedProvider extends MinecraftMappedProvider {
 	public void initFiles(MinecraftProviderImpl minecraftProvider, MappingsProviderImpl mappingsProvider) {
 		super.initFiles(minecraftProvider, mappingsProvider);
 
-		projectMappedJar = new File(getJarDirectory(getExtension().getFiles().getRootProjectPersistentCache(), projectMappedClassifier), "minecraft-" + getJarVersionString(projectMappedClassifier) + ".jar");
+		projectMappedJar = new File(getDirectories().getRootProjectPersistentCache(), getMinecraftProvider().minecraftVersion() + "/"
+				+ getExtension().getMappingsProvider().mappingsIdentifier() + "/minecraft-" + projectMappedClassifier + ".jar");
 	}
 
 	@Override

src/main/java/net/fabricmc/loom/configuration/providers/LaunchProvider.java

@@ -58,8 +58,8 @@ public class LaunchProvider extends DependencyProvider {
 				.property("fabric.remapClasspathFile", getRemapClasspathFile().getAbsolutePath())
 				.property("log4j.configurationFile", getAllLog4JConfigFiles())
 
-				.property("client", "java.library.path", getDirectories().getNativesDirectory(getExtension().getMinecraftProvider()).getAbsolutePath())
+				.property("client", "java.library.path", getExtension().getMinecraftProvider().nativesDir().getAbsolutePath())
-				.property("client", "org.lwjgl.librarypath", getDirectories().getNativesDirectory(getExtension().getMinecraftProvider()).getAbsolutePath())
+				.property("client", "org.lwjgl.librarypath", getExtension().getMinecraftProvider().nativesDir().getAbsolutePath())
 
 				.argument("client", "--assetIndex")
 				.argument("client", getExtension().getMinecraftProvider().getVersionInfo().assetIndex().fabricId(getExtension().getMinecraftProvider().minecraftVersion()))

src/main/java/net/fabricmc/loom/configuration/providers/MinecraftProvider.java

@@ -24,9 +24,21 @@
 
 package net.fabricmc.loom.configuration.providers;
 
+import java.io.File;
+
 import net.fabricmc.loom.configuration.providers.minecraft.MinecraftVersionMeta;
 
 public interface MinecraftProvider {
+	File workingDir();
+
+	boolean hasCustomNatives();
+
+	File nativesDir();
+
+	File dir(String path);
+
+	File file(String path);
+
 	String minecraftVersion();
 
 	MinecraftVersionMeta getVersionInfo();

src/main/java/net/fabricmc/loom/configuration/providers/MinecraftProviderImpl.java

@@ -53,6 +53,7 @@ public class MinecraftProviderImpl extends DependencyProvider implements Minecra
 	private MinecraftVersionMeta versionInfo;
 	private MinecraftLibraryProvider libraryProvider;
 
+	private File workingDir;
 	private File minecraftJson;
 	private File minecraftClientJar;
 	private File minecraftServerJar;
@@ -112,10 +113,12 @@ public class MinecraftProviderImpl extends DependencyProvider implements Minecra
 	}
 
 	private void initFiles() {
-		minecraftJson = new File(getDirectories().getUserCache(), "minecraft-" + minecraftVersion + "-info.json");
+		workingDir = new File(getDirectories().getUserCache(), minecraftVersion);
-		minecraftClientJar = new File(getDirectories().getUserCache(), "minecraft-" + minecraftVersion + "-client.jar");
+		workingDir.mkdirs();
-		minecraftServerJar = new File(getDirectories().getUserCache(), "minecraft-" + minecraftVersion + "-server.jar");
+		minecraftJson = file("minecraft-info.json");
-		minecraftMergedJar = new File(getDirectories().getUserCache(), "minecraft-" + minecraftVersion + "-merged.jar");
+		minecraftClientJar = file("minecraft-client.jar");
+		minecraftServerJar = file("minecraft-server.jar");
+		minecraftMergedJar = file("minecraft-merged.jar");
 		versionManifestJson = new File(getDirectories().getUserCache(), "version_manifest.json");
 		experimentalVersionsJson = new File(getDirectories().getUserCache(), "experimental_version_manifest.json");
 	}
@@ -257,6 +260,37 @@ public class MinecraftProviderImpl extends DependencyProvider implements Minecra
 		return minecraftMergedJar;
 	}
 
+	@Override
+	public File workingDir() {
+		return workingDir;
+	}
+
+	@Override
+	public boolean hasCustomNatives() {
+		return getProject().getProperties().get("fabric.loom.natives.dir") != null;
+	}
+
+	@Override
+	public File nativesDir() {
+		if (hasCustomNatives()) {
+			return new File((String) getProject().property("fabric.loom.natives.dir"));
+		}
+
+		return dir("natives");
+	}
+
+	@Override
+	public File dir(String path) {
+		File dir = file(path);
+		dir.mkdirs();
+		return dir;
+	}
+
+	@Override
+	public File file(String path) {
+		return new File(workingDir(), path);
+	}
+
 	@Override
 	public String minecraftVersion() {
 		return minecraftVersion;

src/main/java/net/fabricmc/loom/configuration/providers/mappings/GradleMappingContext.java

@@ -62,9 +62,7 @@ public class GradleMappingContext implements MappingContext {
 
 	@Override
 	public File workingDirectory(String name) {
-		File tempDir = new File(mappingsProvider().getMappingsDir().toFile(), workingDirName);
+		return new File(minecraftProvider().dir("layered/working_dir/" + workingDirName), name);
-		tempDir.mkdirs();
-		return new File(tempDir, name);
 	}
 
 	@Override

src/main/java/net/fabricmc/loom/configuration/providers/mappings/LayeredMappingsDependency.java

@@ -64,7 +64,7 @@ public class LayeredMappingsDependency implements SelfResolvingDependency {
 
 	@Override
 	public Set<File> resolve() {
-		Path mappingsDir = mappingContext.mappingsProvider().getMappingsDir();
+		Path mappingsDir = mappingContext.minecraftProvider().dir("layered").toPath();
 		Path mappingsFile = mappingsDir.resolve(String.format("%s.%s-%s.tiny", GROUP, MODULE, getVersion()));
 
 		if (!Files.exists(mappingsFile) || LoomGradlePlugin.refreshDeps) {

src/main/java/net/fabricmc/loom/configuration/providers/mappings/MappingsProvider.java

@@ -28,7 +28,7 @@ import java.io.File;
 import java.nio.file.Path;
 
 public interface MappingsProvider {
-	Path getMappingsDir();
+	Path mappingsWorkingDir();
 
 	File intermediaryTinyFile();
 }

src/main/java/net/fabricmc/loom/configuration/providers/mappings/MappingsProviderImpl.java

@@ -28,18 +28,18 @@ import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
 import java.net.URL;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.FileSystem;
 import java.nio.file.FileSystems;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.nio.file.Paths;
 import java.nio.file.StandardCopyOption;
+import java.util.Collections;
 import java.util.function.Consumer;
 
-import com.google.common.base.Preconditions;
+import com.google.common.base.Stopwatch;
 import com.google.common.net.UrlEscapers;
 import com.google.gson.JsonObject;
-import org.apache.commons.io.FileUtils;
 import org.apache.tools.ant.util.StringUtils;
 import org.gradle.api.Project;
 import org.zeroturnaround.zip.FileSource;
@@ -59,6 +59,11 @@ import net.fabricmc.loom.util.DeletingFileVisitor;
 import net.fabricmc.loom.util.DownloadUtil;
 import net.fabricmc.mapping.reader.v2.TinyV2Factory;
 import net.fabricmc.mapping.tree.TinyTree;
+import net.fabricmc.mappingio.adapter.MappingNsCompleter;
+import net.fabricmc.mappingio.adapter.MappingSourceNsSwitch;
+import net.fabricmc.mappingio.format.Tiny2Reader;
+import net.fabricmc.mappingio.format.Tiny2Writer;
+import net.fabricmc.mappingio.tree.MemoryMappingTree;
 import net.fabricmc.stitch.Command;
 import net.fabricmc.stitch.commands.CommandProposeFieldNames;
 import net.fabricmc.stitch.commands.tinyv2.CommandMergeTinyV2;
@@ -67,35 +72,26 @@ import net.fabricmc.stitch.commands.tinyv2.CommandReorderTinyV2;
 public class MappingsProviderImpl extends DependencyProvider implements MappingsProvider {
 	public MinecraftMappedProvider mappedProvider;
 
-	public String mappingsName;
+	public String mappingsIdentifier;
-	public String minecraftVersion;
-	public String mappingsVersion;
 
-	private final Path mappingsDir;
+	private Path mappingsWorkingDir;
-	private final Path mappingsStepsDir;
 	private Path intermediaryTiny;
 	private boolean hasRefreshed = false;
 	// The mappings that gradle gives us
 	private Path baseTinyMappings;
 	// The mappings we use in practice
-	public File tinyMappings;
+	public Path tinyMappings;
-	public File tinyMappingsJar;
+	public Path tinyMappingsJar;
-	private File unpickDefinitionsFile;
+	private Path unpickDefinitions;
 	private boolean hasUnpickDefinitions;
 	private UnpickMetadata unpickMetadata;
 
 	public MappingsProviderImpl(Project project) {
 		super(project);
-		mappingsDir = getDirectories().getUserCache().toPath().resolve("mappings");
-		mappingsStepsDir = mappingsDir.resolve("steps");
-	}
-
-	public void clean() throws IOException {
-		FileUtils.deleteDirectory(mappingsDir.toFile());
 	}
 
 	public TinyTree getMappings() throws IOException {
-		return MappingsCache.INSTANCE.get(tinyMappings.toPath());
+		return MappingsCache.INSTANCE.get(tinyMappings);
 	}
 
 	@Override
@@ -107,59 +103,22 @@ public class MappingsProviderImpl extends DependencyProvider implements Mappings
 		String version = dependency.getResolvedVersion();
 		File mappingsJar = dependency.resolveFile().orElseThrow(() -> new RuntimeException("Could not find yarn mappings: " + dependency));
 
-		this.mappingsName = StringUtils.removeSuffix(dependency.getDependency().getGroup() + "." + dependency.getDependency().getName(), "-unmerged");
+		String mappingsName = StringUtils.removeSuffix(dependency.getDependency().getGroup() + "." + dependency.getDependency().getName(), "-unmerged");
-		this.minecraftVersion = minecraftProvider.minecraftVersion();
+		boolean isV2 = isV2(dependency, mappingsJar);
-
+		this.mappingsIdentifier = createMappingsIdentifier(mappingsName, version, getMappingsClassifier(dependency, isV2));
-		boolean isV2;
-
-		// Only do this for official yarn, there isn't really a way we can get the mc version for all mappings
-		if (dependency.getDependency().getGroup() != null && dependency.getDependency().getGroup().equals("net.fabricmc") && dependency.getDependency().getName().equals("yarn") && dependency.getDependency().getVersion() != null) {
-			String yarnVersion = dependency.getDependency().getVersion();
-			char separator = yarnVersion.contains("+build.") ? '+' : yarnVersion.contains("-") ? '-' : '.';
-			String yarnMinecraftVersion = yarnVersion.substring(0, yarnVersion.lastIndexOf(separator));
-
-			if (!yarnMinecraftVersion.equalsIgnoreCase(minecraftVersion)) {
-				throw new RuntimeException(String.format("Minecraft Version (%s) does not match yarn's minecraft version (%s)", minecraftVersion, yarnMinecraftVersion));
-			}
-
-			// We can save reading the zip file + header by checking the file name
-			isV2 = mappingsJar.getName().endsWith("-v2.jar");
-		} else {
-			isV2 = doesJarContainV2Mappings(mappingsJar.toPath());
-		}
-
-		this.mappingsVersion = version + (isV2 ? "-v2" : "");
 
 		initFiles();
 
-		if (isRefreshDeps()) {
+		if (Files.notExists(tinyMappings) || isRefreshDeps()) {
-			cleanFiles();
-		}
-
-		Files.createDirectories(mappingsDir);
-		Files.createDirectories(mappingsStepsDir);
-
-		String[] depStringSplit = dependency.getDepString().split(":");
-		String jarClassifier = "final";
-
-		if (depStringSplit.length >= 4) {
-			jarClassifier = jarClassifier + depStringSplit[3];
-		}
-
-		tinyMappings = mappingsDir.resolve(StringUtils.removeSuffix(mappingsJar.getName(), ".jar") + ".tiny").toFile();
-		unpickDefinitionsFile = mappingsDir.resolve(StringUtils.removeSuffix(mappingsJar.getName(), ".jar") + ".unpick").toFile();
-		tinyMappingsJar = new File(getDirectories().getUserCache(), mappingsJar.getName().replace(".jar", "-" + jarClassifier + ".jar"));
-
-		if (!tinyMappings.exists() || isRefreshDeps()) {
 			storeMappings(getProject(), minecraftProvider, mappingsJar.toPath());
 		} else {
 			try (FileSystem fileSystem = FileSystems.newFileSystem(mappingsJar.toPath(), (ClassLoader) null)) {
-				extractUnpickDefinitions(fileSystem, unpickDefinitionsFile.toPath());
+				extractUnpickDefinitions(fileSystem, unpickDefinitions);
 			}
 		}
 
-		if (!tinyMappingsJar.exists() || isRefreshDeps()) {
+		if (Files.notExists(tinyMappingsJar) || isRefreshDeps()) {
-			ZipUtil.pack(new ZipEntrySource[] {new FileSource("mappings/mappings.tiny", tinyMappings)}, tinyMappingsJar);
+			ZipUtil.pack(new ZipEntrySource[] {new FileSource("mappings/mappings.tiny", tinyMappings.toFile())}, tinyMappingsJar.toFile());
 		}
 
 		if (hasUnpickDefinitions()) {
@@ -173,7 +132,7 @@ public class MappingsProviderImpl extends DependencyProvider implements Mappings
 			populateUnpickClasspath();
 		}
 
-		addDependency(tinyMappingsJar, Constants.Configurations.MAPPINGS_FINAL);
+		addDependency(tinyMappingsJar.toFile(), Constants.Configurations.MAPPINGS_FINAL);
 
 		LoomGradleExtension extension = getExtension();
 
@@ -198,30 +157,57 @@ public class MappingsProviderImpl extends DependencyProvider implements Mappings
 		mappedProvider.provide(dependency, postPopulationScheduler);
 	}
 
+	private String getMappingsClassifier(DependencyInfo dependency, boolean isV2) {
+		String[] depStringSplit = dependency.getDepString().split(":");
+
+		if (depStringSplit.length >= 4) {
+			return "-" + depStringSplit[3] + (isV2 ? "-v2" : "");
+		}
+
+		return isV2 ? "-v2" : "";
+	}
+
+	private boolean isV2(DependencyInfo dependency, File mappingsJar) throws IOException {
+		String minecraftVersion = getMinecraftProvider().minecraftVersion();
+
+		// Only do this for official yarn, there isn't really a way we can get the mc version for all mappings
+		if (dependency.getDependency().getGroup() != null && dependency.getDependency().getGroup().equals("net.fabricmc") && dependency.getDependency().getName().equals("yarn") && dependency.getDependency().getVersion() != null) {
+			String yarnVersion = dependency.getDependency().getVersion();
+			char separator = yarnVersion.contains("+build.") ? '+' : yarnVersion.contains("-") ? '-' : '.';
+			String yarnMinecraftVersion = yarnVersion.substring(0, yarnVersion.lastIndexOf(separator));
+
+			if (!yarnMinecraftVersion.equalsIgnoreCase(minecraftVersion)) {
+				throw new RuntimeException(String.format("Minecraft Version (%s) does not match yarn's minecraft version (%s)", minecraftVersion, yarnMinecraftVersion));
+			}
+
+			// We can save reading the zip file + header by checking the file name
+			return mappingsJar.getName().endsWith("-v2.jar");
+		} else {
+			return doesJarContainV2Mappings(mappingsJar.toPath());
+		}
+	}
+
 	private void storeMappings(Project project, MinecraftProviderImpl minecraftProvider, Path yarnJar) throws IOException {
 		project.getLogger().info(":extracting " + yarnJar.getFileName());
 
 		try (FileSystem fileSystem = FileSystems.newFileSystem(yarnJar, (ClassLoader) null)) {
 			extractMappings(fileSystem, baseTinyMappings);
-			extractUnpickDefinitions(fileSystem, unpickDefinitionsFile.toPath());
+			extractUnpickDefinitions(fileSystem, unpickDefinitions);
 		}
 
-		if (baseMappingsAreV2()) {
+		if (areMappingsV2(baseTinyMappings)) {
 			// These are unmerged v2 mappings
-			mergeAndSaveMappings(project, yarnJar);
+			mergeAndSaveMappings(project, baseTinyMappings, tinyMappings);
 		} else {
 			// These are merged v1 mappings
-			if (tinyMappings.exists()) {
+			Files.deleteIfExists(tinyMappings);
-				tinyMappings.delete();
-			}
-
 			project.getLogger().lifecycle(":populating field names");
-			suggestFieldNames(minecraftProvider, baseTinyMappings, tinyMappings.toPath());
+			suggestFieldNames(minecraftProvider, baseTinyMappings, tinyMappings);
 		}
 	}
 
-	private boolean baseMappingsAreV2() throws IOException {
+	private static boolean areMappingsV2(Path path) throws IOException {
-		try (BufferedReader reader = Files.newBufferedReader(baseTinyMappings)) {
+		try (BufferedReader reader = Files.newBufferedReader(path)) {
 			TinyV2Factory.readMetadata(reader);
 			return true;
 		} catch (IllegalArgumentException e) {
@@ -230,7 +216,7 @@ public class MappingsProviderImpl extends DependencyProvider implements Mappings
 		}
 	}
 
-	private boolean doesJarContainV2Mappings(Path path) throws IOException {
+	private static boolean doesJarContainV2Mappings(Path path) throws IOException {
 		try (FileSystem fs = FileSystems.newFileSystem(path, (ClassLoader) null)) {
 			try (BufferedReader reader = Files.newBufferedReader(fs.getPath("mappings", "mappings.tiny"))) {
 				TinyV2Factory.readMetadata(reader);
@@ -241,6 +227,12 @@ public class MappingsProviderImpl extends DependencyProvider implements Mappings
 		}
 	}
 
+	private static void extractMappings(Path jar, Path extractTo) throws IOException {
+		try (FileSystem unmergedIntermediaryFs = FileSystems.newFileSystem(jar, (ClassLoader) null)) {
+			extractMappings(unmergedIntermediaryFs, extractTo);
+		}
+	}
+
 	public static void extractMappings(FileSystem jar, Path extractTo) throws IOException {
 		Files.copy(jar.getPath("mappings/mappings.tiny"), extractTo, StandardCopyOption.REPLACE_EXISTING);
 	}
@@ -279,28 +271,34 @@ public class MappingsProviderImpl extends DependencyProvider implements Mappings
 		);
 	}
 
-	private void extractIntermediary(Path intermediaryJar, Path intermediaryTiny) throws IOException {
+	private void mergeAndSaveMappings(Project project, Path from, Path out) throws IOException {
-		getProject().getLogger().info(":extracting " + intermediaryJar.getFileName());
+		Stopwatch stopwatch = Stopwatch.createStarted();
+		project.getLogger().info(":merging mappings");
 
-		try (FileSystem unmergedIntermediaryFs = FileSystems.newFileSystem(intermediaryJar, (ClassLoader) null)) {
+		MemoryMappingTree tree = new MemoryMappingTree();
-			extractMappings(unmergedIntermediaryFs, intermediaryTiny);
+		MappingSourceNsSwitch sourceNsSwitch = new MappingSourceNsSwitch(tree, MappingNamespace.OFFICIAL.stringValue());
+		readIntermediaryTree().accept(sourceNsSwitch);
+
+		try (BufferedReader reader = Files.newBufferedReader(from, StandardCharsets.UTF_8)) {
+			Tiny2Reader.read(reader, tree);
 		}
+
+		try (Tiny2Writer writer = new Tiny2Writer(Files.newBufferedWriter(out, StandardCharsets.UTF_8), false)) {
+			tree.accept(writer);
+		}
+
+		project.getLogger().info(":merged mappings in " + stopwatch.stop());
 	}
 
-	private void mergeAndSaveMappings(Project project, Path unmergedYarnJar) throws IOException {
+	private MemoryMappingTree readIntermediaryTree() throws IOException {
-		Path unmergedYarn = Paths.get(mappingsStepsDir.toString(), "unmerged-yarn.tiny");
+		MemoryMappingTree tree = new MemoryMappingTree();
-		project.getLogger().info(":extracting " + unmergedYarnJar.getFileName());
+		MappingNsCompleter nsCompleter = new MappingNsCompleter(tree, Collections.singletonMap(MappingNamespace.NAMED.stringValue(), MappingNamespace.INTERMEDIARY.stringValue()), true);
 
-		try (FileSystem unmergedYarnJarFs = FileSystems.newFileSystem(unmergedYarnJar, (ClassLoader) null)) {
+		try (BufferedReader reader = Files.newBufferedReader(getIntermediaryTiny(), StandardCharsets.UTF_8)) {
-			extractMappings(unmergedYarnJarFs, unmergedYarn);
+			Tiny2Reader.read(reader, nsCompleter);
 		}
 
-		Path invertedIntermediary = Paths.get(mappingsStepsDir.toString(), "inverted-intermediary.tiny");
+		return tree;
-		reorderMappings(getIntermediaryTiny(), invertedIntermediary, "intermediary", "official");
-		Path unorderedMergedMappings = Paths.get(mappingsStepsDir.toString(), "unordered-merged.tiny");
-		project.getLogger().info(":merging");
-		mergeMappings(invertedIntermediary, unmergedYarn, unorderedMergedMappings);
-		reorderMappings(unorderedMergedMappings, tinyMappings.toPath(), "official", "intermediary", "named");
 	}
 
 	private void reorderMappings(Path oldMappings, Path newMappings, String... newOrder) {
@@ -341,25 +339,21 @@ public class MappingsProviderImpl extends DependencyProvider implements Mappings
 	}
 
 	private void initFiles() {
-		baseTinyMappings = mappingsDir.resolve(mappingsName + "-tiny-" + minecraftVersion + "-" + mappingsVersion + "-base");
+		mappingsWorkingDir = getMinecraftProvider().dir(mappingsIdentifier).toPath();
+		baseTinyMappings = mappingsWorkingDir.resolve("mappings-base.tiny");
+		tinyMappings = mappingsWorkingDir.resolve("mappings.tiny");
+		tinyMappingsJar = mappingsWorkingDir.resolve("mappings.jar");
+		unpickDefinitions = mappingsWorkingDir.resolve("mappings.unpick");
+
+		if (isRefreshDeps()) {
+			cleanFiles();
+		}
 	}
 
 	public void cleanFiles() {
 		try {
-			if (Files.exists(mappingsStepsDir)) {
+			if (Files.exists(mappingsWorkingDir)) {
-				Files.walkFileTree(mappingsStepsDir, new DeletingFileVisitor());
+				Files.walkFileTree(mappingsWorkingDir, new DeletingFileVisitor());
-			}
-
-			if (Files.exists(baseTinyMappings)) {
-				Files.deleteIfExists(baseTinyMappings);
-			}
-
-			if (tinyMappings != null) {
-				tinyMappings.delete();
-			}
-
-			if (tinyMappingsJar != null) {
-				tinyMappingsJar.delete();
 			}
 		} catch (IOException e) {
 			e.printStackTrace();
@@ -371,40 +365,42 @@ public class MappingsProviderImpl extends DependencyProvider implements Mappings
 		return Constants.Configurations.MAPPINGS;
 	}
 
-	@Override
-	public Path getMappingsDir() {
-		return mappingsDir;
-	}
-
 	public Path getIntermediaryTiny() throws IOException {
 		if (intermediaryTiny == null) {
-			minecraftVersion = getExtension().getMinecraftProvider().minecraftVersion();
+			intermediaryTiny = getMinecraftProvider().file("intermediary-v2.tiny").toPath();
-			Preconditions.checkNotNull(minecraftVersion, "Minecraft version cannot be null");
-
-			intermediaryTiny = mappingsDir.resolve(String.format("intermediary-%s-v2.tiny", minecraftVersion));
 
 			if (!Files.exists(intermediaryTiny) || (isRefreshDeps() && !hasRefreshed)) {
 				hasRefreshed = true;
 
 				// Download and extract intermediary
-				String encodedMinecraftVersion = UrlEscapers.urlFragmentEscaper().escape(minecraftVersion);
+				String encodedMinecraftVersion = UrlEscapers.urlFragmentEscaper().escape(getMinecraftProvider().minecraftVersion());
 				String intermediaryArtifactUrl = getExtension().getIntermediaryUrl(encodedMinecraftVersion);
-				Path intermediaryJar = mappingsDir.resolve("v2-intermediary-" + minecraftVersion + ".jar");
+				File intermediaryJar = getMinecraftProvider().file("intermediary-v2.jar");
-				DownloadUtil.downloadIfChanged(new URL(intermediaryArtifactUrl), intermediaryJar.toFile(), getProject().getLogger());
+				DownloadUtil.downloadIfChanged(new URL(intermediaryArtifactUrl), intermediaryJar, getProject().getLogger());
-
+				extractMappings(intermediaryJar.toPath(), intermediaryTiny);
-				extractIntermediary(intermediaryJar, intermediaryTiny);
 			}
 		}
 
 		return intermediaryTiny;
 	}
 
-	public String getMappingsKey() {
+	@Override
-		return mappingsName + "." + minecraftVersion.replace(' ', '_').replace('.', '_').replace('-', '_') + "." + mappingsVersion;
+	public Path mappingsWorkingDir() {
+		return mappingsWorkingDir;
+	}
+
+	private String createMappingsIdentifier(String mappingsName, String version, String classifier) {
+		//          mappingsName      . mcVersion . version        classifier
+		// Example: net.fabricmc.yarn . 1_16_5    . 1.16.5+build.5 -v2
+		return mappingsName + "." + getMinecraftProvider().minecraftVersion().replace(' ', '_').replace('.', '_').replace('-', '_') + "." + version + classifier;
+	}
+
+	public String mappingsIdentifier() {
+		return mappingsIdentifier;
 	}
 
 	public File getUnpickDefinitionsFile() {
-		return unpickDefinitionsFile;
+		return unpickDefinitions.toFile();
 	}
 
 	public boolean hasUnpickDefinitions() {

src/main/java/net/fabricmc/loom/configuration/providers/minecraft/MinecraftMappedProvider.java

@@ -61,7 +61,7 @@ public class MinecraftMappedProvider extends DependencyProvider {
 
 	@Override
 	public void provide(DependencyInfo dependency, Consumer<Runnable> postPopulationScheduler) throws Exception {
-		if (!getExtension().getMappingsProvider().tinyMappings.exists()) {
+		if (Files.notExists(getExtension().getMappingsProvider().tinyMappings)) {
 			throw new RuntimeException("mappings file not found");
 		}
 
@@ -145,13 +145,13 @@ public class MinecraftMappedProvider extends DependencyProvider {
 
 	protected void addDependencies(DependencyInfo dependency, Consumer<Runnable> postPopulationScheduler) {
 		getProject().getDependencies().add(Constants.Configurations.MINECRAFT_NAMED,
-				getProject().getDependencies().module("net.minecraft:minecraft:" + getJarVersionString("mapped")));
+				getProject().getDependencies().module("net.minecraft:minecraft-mapped:" + getMinecraftProvider().minecraftVersion() + "/" + getExtension().getMappingsProvider().mappingsIdentifier()));
 	}
 
 	public void initFiles(MinecraftProviderImpl minecraftProvider, MappingsProviderImpl mappingsProvider) {
 		this.minecraftProvider = minecraftProvider;
-		minecraftIntermediaryJar = new File(getDirectories().getUserCache(), "minecraft-" + getJarVersionString("intermediary") + ".jar");
+		minecraftIntermediaryJar = new File(getExtension().getMappingsProvider().mappingsWorkingDir().toFile(), "minecraft-intermediary.jar");
-		minecraftMappedJar = new File(getJarDirectory(getDirectories().getUserCache(), "mapped"), "minecraft-" + getJarVersionString("mapped") + ".jar");
+		minecraftMappedJar = new File(getExtension().getMappingsProvider().mappingsWorkingDir().toFile(), "minecraft-mapped.jar");
 	}
 
 	protected File getJarDirectory(File parentDirectory, String type) {
@@ -159,7 +159,7 @@ public class MinecraftMappedProvider extends DependencyProvider {
 	}
 
 	protected String getJarVersionString(String type) {
-		return String.format("%s-%s-%s-%s", minecraftProvider.minecraftVersion(), type, getExtension().getMappingsProvider().mappingsName, getExtension().getMappingsProvider().mappingsVersion);
+		return String.format("%s-%s", type, getExtension().getMappingsProvider().mappingsIdentifier());
 	}
 
 	public File getIntermediaryJar() {
@@ -171,7 +171,7 @@ public class MinecraftMappedProvider extends DependencyProvider {
 	}
 
 	public File getUnpickedJar() {
-		return new File(getJarDirectory(getDirectories().getUserCache(), "mapped"), "minecraft-" + getJarVersionString("unpicked") + ".jar");
+		return new File(getExtension().getMappingsProvider().mappingsWorkingDir().toFile(), "minecraft-unpicked.jar");
 	}
 
 	@Override

src/main/java/net/fabricmc/loom/configuration/providers/minecraft/MinecraftNativesProvider.java

@@ -51,7 +51,7 @@ public class MinecraftNativesProvider {
 		this.project = project;
 		extension = LoomGradleExtension.get(project);
 
-		nativesDir = extension.getFiles().getNativesDirectory(extension.getMinecraftProvider());
+		nativesDir = extension.getMinecraftProvider().nativesDir();
 		jarStore = extension.getFiles().getNativesJarStore();
 	}
 
@@ -60,7 +60,7 @@ public class MinecraftNativesProvider {
 	}
 
 	private void provide() throws IOException {
-		if (extension.getFiles().hasCustomNatives()) {
+		if (extension.getMinecraftProvider().hasCustomNatives()) {
 			if (!nativesDir.exists()) {
 				throw new RuntimeException("Could no find custom natives directory at " + nativesDir.getAbsolutePath());
 			}

src/main/java/net/fabricmc/loom/extension/LoomFiles.java

@@ -29,8 +29,6 @@ import java.io.File;
 import org.gradle.api.Project;
 import org.gradle.api.initialization.Settings;
 
-import net.fabricmc.loom.configuration.providers.MinecraftProvider;
-
 public interface LoomFiles {
 	static LoomFiles create(Project project) {
 		return new LoomFilesProjectImpl(project);
@@ -46,8 +44,6 @@ public interface LoomFiles {
 	File getProjectBuildCache();
 	File getRemappedModCache();
 	File getNativesJarStore();
-	boolean hasCustomNatives();
-	File getNativesDirectory(MinecraftProvider minecraftProvider);
 	File getDefaultLog4jConfigFile();
 	File getDevLauncherConfig();
 	File getUnpickLoggingConfigFile();

src/main/java/net/fabricmc/loom/extension/LoomFilesProjectImpl.java

@@ -29,8 +29,6 @@ import java.util.Objects;
 
 import org.gradle.api.Project;
 
-import net.fabricmc.loom.configuration.providers.MinecraftProvider;
-
 public final class LoomFilesProjectImpl extends LoomFilesBaseImpl {
 	private final Project project;
 
@@ -57,24 +55,4 @@ public final class LoomFilesProjectImpl extends LoomFilesBaseImpl {
 	protected File getBuildDir() {
 		return project.getBuildDir();
 	}
-
-	@Override
-	public boolean hasCustomNatives() {
-		return project.getProperties().get("fabric.loom.natives.dir") != null;
-	}
-
-	@Override
-	public File getNativesDirectory(MinecraftProvider minecraftProvider) {
-		if (hasCustomNatives()) {
-			return new File((String) project.property("fabric.loom.natives.dir"));
-		}
-
-		File natives = new File(getUserCache(), "natives/" + minecraftProvider.minecraftVersion());
-
-		if (!natives.exists()) {
-			natives.mkdirs();
-		}
-
-		return natives;
-	}
 }

src/main/java/net/fabricmc/loom/extension/LoomFilesSettingsImpl.java

@@ -29,8 +29,6 @@ import java.util.Objects;
 
 import org.gradle.api.initialization.Settings;
 
-import net.fabricmc.loom.configuration.providers.MinecraftProvider;
-
 public class LoomFilesSettingsImpl extends LoomFilesBaseImpl {
 	private final Settings settings;
 
@@ -38,16 +36,6 @@ public class LoomFilesSettingsImpl extends LoomFilesBaseImpl {
 		this.settings = Objects.requireNonNull(settings);
 	}
 
-	@Override
-	public boolean hasCustomNatives() {
-		return false;
-	}
-
-	@Override
-	public File getNativesDirectory(MinecraftProvider minecraftProvider) {
-		throw new IllegalStateException("You can not access natives directory from setting stage");
-	}
-
 	@Override
 	protected File getGradleUserHomeDir() {
 		return settings.getGradle().getGradleUserHomeDir();

src/main/java/net/fabricmc/loom/extension/LoomGradleExtensionApiImpl.java

@@ -107,7 +107,7 @@ public abstract class LoomGradleExtensionApiImpl implements LoomGradleExtensionA
 		LayeredMappingSpecBuilder builder = new LayeredMappingSpecBuilder();
 		action.execute(builder);
 		LayeredMappingSpec builtSpec = builder.build();
-		return new LayeredMappingsDependency(new GradleMappingContext(getProject(), "layers_" + builtSpec.getVersion().replace("+", "_").replace(".", "_")), builtSpec, builtSpec.getVersion());
+		return new LayeredMappingsDependency(new GradleMappingContext(getProject(), builtSpec.getVersion().replace("+", "_").replace(".", "_")), builtSpec, builtSpec.getVersion());
 	}
 
 	@Override

src/main/java/net/fabricmc/loom/extension/LoomGradleExtensionImpl.java

@@ -81,7 +81,7 @@ public class LoomGradleExtensionImpl extends LoomGradleExtensionApiImpl implemen
 
 	@Override
 	public synchronized File getNextMixinMappings() {
-		File mixinMapping = new File(getFiles().getProjectBuildCache(), "mixin-map-" + getMinecraftProvider().minecraftVersion() + "-" + getMappingsProvider().mappingsVersion + "." + mixinMappings.size() + ".tiny");
+		File mixinMapping = new File(getFiles().getProjectBuildCache(), "mixin-map-" + getMappingsProvider().mappingsIdentifier() + "." + mixinMappings.size() + ".tiny");
 		mixinMappings.add(mixinMapping);
 		return mixinMapping;
 	}

src/main/java/net/fabricmc/loom/task/GenerateSourcesTask.java

@@ -62,7 +62,7 @@ public class GenerateSourcesTask extends AbstractLoomTask {
 	@TaskAction
 	public void doTask() throws Throwable {
 		int threads = Runtime.getRuntime().availableProcessors();
-		Path javaDocs = getExtension().getMappingsProvider().tinyMappings.toPath();
+		Path javaDocs = getExtension().getMappingsProvider().tinyMappings;
 		Collection<Path> libraries = getProject().getConfigurations().getByName(Constants.Configurations.MINECRAFT_DEPENDENCIES).getFiles()
 						.stream().map(File::toPath).collect(Collectors.toSet());
 

src/test/groovy/net/fabricmc/loom/test/integration/UnpickTest.groovy

@@ -33,7 +33,7 @@ import java.nio.charset.StandardCharsets
 import static org.gradle.testkit.runner.TaskOutcome.SUCCESS
 
 class UnpickTest extends Specification implements ProjectTestTrait {
-	static final String MAPPINGS = "21w13a-mapped-net.fabricmc.yarn-21w13a+build.30-v2"
+	static final String MAPPINGS = "21w13a/net.fabricmc.yarn.21w13a.21w13a+build.30-v2"
 
 	@Override
 	String name() {

src/test/groovy/net/fabricmc/loom/test/util/ProjectTestTrait.groovy

@@ -121,6 +121,6 @@ trait ProjectTestTrait {
 	}
 
 	File getGeneratedSources(String mappings, String gradleVersion = DEFAULT_GRADLE) {
-		return new File(gradleHomeDirectory(gradleVersion), "caches/fabric-loom/${mappings}/minecraft-${mappings}-sources.jar")
+		return new File(gradleHomeDirectory(gradleVersion), "caches/fabric-loom/${mappings}/minecraft-mapped-sources.jar")
 	}
 }