Add API to provide cache and data directories

src/main/java/net/fabricmc/loader/api/FabricLoader.java

@@ -236,4 +236,12 @@ static FabricLoader getInstance() {
 	 * @return the launch arguments for the game
 	 */
 	String[] getLaunchArguments(boolean sanitize);
+
+	/**
+	 * Get a {@link ModDirectories} instance, proving access to various cache or data directories.
+	 *
+	 * @param modId the ID of the mod.
+	 * @return A {@link ModDirectories} instance.
+	 */
+	ModDirectories getDirectories(String modId);
 }

src/main/java/net/fabricmc/loader/api/ModDirectories.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2016 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.loader.api;
+
+import java.nio.file.Path;
+
+/**
+ * Provides access to cache or data directories for a mod.
+ *
+ * <p>These directories are unique to the mod id and should not be shared between mods. These directories are not versioned so
+ * special care must be taken to ensure backwards compatibility with older versions of the mod running on the same machine.
+ *
+ * <p>Global directories are shared between all instances of Fabric Loader for the current user of the machine, no matter the game or launcher.
+ *
+ * <p>The cache directories should be used for temporary files that can be regenerated if lost.
+ *
+ * <p>Any sensitive data should be encrypted, and the private key stored in the {@link #getGlobalDataDir()}.
+ *
+ * <p>A sandbox implementation will grant full access to all of these directories, and may not isolate them from other instances.
+ * Code should not be stored and executed from these directories to prevent a sandbox escape.
+ */
+public interface ModDirectories {
+	/**
+	 * Get the local cache directory for the mod.
+	 *
+	 * <p>Note: This directory should not be distributed, for example in a mod pack.
+	 *
+	 * @return A {@link Path} to the cache directory.
+	 */
+	Path getCacheDir();
+
+	/**
+	 * Get the global cache directory for the mod.
+	 *
+	 * @return A {@link Path} to the global cache directory.
+	 */
+	Path getGlobalCacheDir();
+
+	/**
+	 * Get the local data directory for the mod.
+	 *
+	 * @return A {@link Path} to the data directory.
+	 */
+	Path getDataDir();
+
+	/**
+	 * Get the global data directory for the mod.
+	 *
+	 * @return A {@link Path} to the global data directory.
+	 */
+	Path getGlobalDataDir();
+}

src/main/java/net/fabricmc/loader/impl/FabricLoaderImpl.java

@@ -43,6 +43,7 @@
 import net.fabricmc.loader.api.LanguageAdapter;
 import net.fabricmc.loader.api.MappingResolver;
 import net.fabricmc.loader.api.ModContainer;
+import net.fabricmc.loader.api.ModDirectories;
 import net.fabricmc.loader.api.ObjectShare;
 import net.fabricmc.loader.api.entrypoint.EntrypointContainer;
 import net.fabricmc.loader.impl.discovery.ArgumentModCandidateFinder;
@@ -60,10 +61,13 @@
 import net.fabricmc.loader.impl.metadata.DependencyOverrides;
 import net.fabricmc.loader.impl.metadata.EntrypointMetadata;
 import net.fabricmc.loader.impl.metadata.LoaderModMetadata;
+import net.fabricmc.loader.impl.metadata.MetadataVerifier;
 import net.fabricmc.loader.impl.metadata.VersionOverrides;
 import net.fabricmc.loader.impl.util.DefaultLanguageAdapter;
 import net.fabricmc.loader.impl.util.ExceptionUtil;
+import net.fabricmc.loader.impl.util.GlobalDirectories;
 import net.fabricmc.loader.impl.util.LoaderUtil;
+import net.fabricmc.loader.impl.util.ModDirectoriesImpl;
 import net.fabricmc.loader.impl.util.SystemProperties;
 import net.fabricmc.loader.impl.util.log.Log;
 import net.fabricmc.loader.impl.util.log.LogCategory;
@@ -77,7 +81,6 @@ public final class FabricLoaderImpl extends net.fabricmc.loader.FabricLoader {
 	public static final String VERSION = "0.15.11";
 	public static final String MOD_ID = "fabricloader";
 
-	public static final String CACHE_DIR_NAME = ".fabric"; // relative to game dir
 	private static final String PROCESSED_MODS_DIR_NAME = "processedMods"; // relative to cache dir
 	public static final String REMAPPED_JARS_DIR_NAME = "remappedJars"; // relative to cache dir
 	private static final String TMP_DIR_NAME = "tmp"; // relative to cache dir
@@ -100,6 +103,7 @@ public final class FabricLoaderImpl extends net.fabricmc.loader.FabricLoader {
 	private GameProvider provider;
 	private Path gameDir;
 	private Path configDir;
+	private GlobalDirectories globalDirectories;
 
 	private FabricLoaderImpl() { }
 
@@ -134,6 +138,7 @@ public void setGameProvider(GameProvider provider) {
 	private void setGameDir(Path gameDir) {
 		this.gameDir = gameDir;
 		this.configDir = gameDir.resolve("config");
+		this.globalDirectories = GlobalDirectories.create(getEnvironmentType(), gameDir);
 	}
 
 	@Override
@@ -230,7 +235,7 @@ private void setup() throws ModResolutionException {
 
 		dumpModList(modCandidates);
 
-		Path cacheDir = gameDir.resolve(CACHE_DIR_NAME);
+		Path cacheDir = getDirectories(MOD_ID).getCacheDir();
 		Path outputdir = cacheDir.resolve(PROCESSED_MODS_DIR_NAME);
 
 		// runtime mod remapping
@@ -595,6 +600,15 @@ public String[] getLaunchArguments(boolean sanitize) {
 		return getGameProvider().getLaunchArguments(sanitize);
 	}
 
+	@Override
+	public ModDirectories getDirectories(String modId) {
+		if (!MetadataVerifier.isValidModId(modId)) {
+			throw new IllegalArgumentException("Invalid mod ID: " + modId);
+		}
+
+		return new ModDirectoriesImpl(modId, getGameDir(), globalDirectories);
+	}
+
 	@Override
 	protected Path getModsDirectory0() {
 		String directory = System.getProperty(SystemProperties.MODS_FOLDER);

src/main/java/net/fabricmc/loader/impl/game/GameProviderHelper.java

@@ -189,7 +189,7 @@ public static Map<String, Path> deobfuscate(Map<String, Path> inputFileMap, Stri
 			return inputFileMap;
 		}
 
-		Path deobfJarDir = getDeobfJarDir(gameDir, gameId, gameVersion);
+		Path deobfJarDir = getDeobfJarDir(gameId, gameVersion);
 		List<Path> inputFiles = new ArrayList<>(inputFileMap.size());
 		List<Path> outputFiles = new ArrayList<>(inputFileMap.size());
 		List<Path> tmpFiles = new ArrayList<>(inputFileMap.size());
@@ -247,8 +247,8 @@ public static Map<String, Path> deobfuscate(Map<String, Path> inputFileMap, Stri
 		return ret;
 	}
 
-	private static Path getDeobfJarDir(Path gameDir, String gameId, String gameVersion) {
-		Path ret = gameDir.resolve(FabricLoaderImpl.CACHE_DIR_NAME).resolve(FabricLoaderImpl.REMAPPED_JARS_DIR_NAME);
+	private static Path getDeobfJarDir(String gameId, String gameVersion) {
+		Path ret = FabricLoaderImpl.INSTANCE.getDirectories(FabricLoaderImpl.MOD_ID).getCacheDir().resolve(FabricLoaderImpl.REMAPPED_JARS_DIR_NAME);
 		StringBuilder versionDirName = new StringBuilder();
 
 		if (!gameId.isEmpty()) {

src/main/java/net/fabricmc/loader/impl/metadata/MetadataVerifier.java

@@ -22,6 +22,7 @@
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Objects;
 import java.util.Set;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
@@ -145,4 +146,9 @@ private static void checkModId(String id, String name) throws ParseMetadataExcep
 
 		throw new ParseMetadataException(sw.toString());
 	}
+
+	public static boolean isValidModId(String id) {
+		Objects.requireNonNull(id, "id");
+		return MOD_ID_PATTERN.matcher(id).matches();
+	}
 }

src/main/java/net/fabricmc/loader/impl/util/GlobalDirectories.java

@@ -0,0 +1,133 @@
+/*
+ * Copyright 2016 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.loader.impl.util;
+
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Locale;
+
+import net.fabricmc.api.EnvType;
+
+public abstract class GlobalDirectories {
+	abstract Path getGlobalCacheRoot();
+
+	abstract Path getGlobalDataRoot();
+
+	public static GlobalDirectories create(EnvType envType, Path gameDir) {
+		switch (envType) {
+		case CLIENT:
+			return Client.create();
+		case SERVER:
+			return new Server(gameDir);
+		default:
+			throw new IllegalStateException();
+		}
+	}
+
+	abstract static class Client extends GlobalDirectories {
+		private final Path cache;
+		private final Path data;
+
+		protected Client(Path cache, Path data) {
+			this.cache = cache;
+			this.data = data;
+		}
+
+		@Override
+		public Path getGlobalCacheRoot() {
+			return cache;
+		}
+
+		@Override
+		public Path getGlobalDataRoot() {
+			return data;
+		}
+
+		static Client create() {
+			final String os = System.getProperty("os.name").toLowerCase(Locale.ROOT);
+
+			if (os.contains("win")) {
+				return new Windows();
+			} else if (os.contains("mac")) {
+				return new MacOS();
+			}
+
+			// Linux or unknown.
+			return new Linux();
+		}
+
+		static final class Windows extends Client {
+			private Windows() {
+				super(getCacheDir(), getDataDir());
+			}
+
+			private static Path getCacheDir() {
+				return Paths.get(System.getenv("LocalAppData"), "net.fabricmc.loader");
+			}
+
+			private static Path getDataDir() {
+				return Paths.get(System.getenv("AppData"), "net.fabricmc.loader");
+			}
+		}
+
+		static final class MacOS extends Client {
+			private MacOS() {
+				super(getCacheDir(), getDataDir());
+			}
+
+			private static Path getCacheDir() {
+				return Paths.get(System.getProperty("user.home"), "Library", "Caches", "net.fabricmc.loader");
+			}
+
+			private static Path getDataDir() {
+				return Paths.get(System.getProperty("user.home"), "Library", "Application Support", "net.fabricmc.loader");
+			}
+		}
+
+		static final class Linux extends Client {
+			private Linux() {
+				super(getCacheDir(), getDataDir());
+			}
+
+			private static Path getCacheDir() {
+				return Paths.get(System.getProperty("user.home"), ".caches", "net.fabricmc.loader");
+			}
+
+			private static Path getDataDir() {
+				return Paths.get(System.getProperty("user.home"), ".config", "net.fabricmc.loader");
+			}
+		}
+	}
+
+	static final class Server extends GlobalDirectories {
+		private final Path gameDir;
+
+		private Server(Path gameDir) {
+			this.gameDir = gameDir;
+		}
+
+		@Override
+		public Path getGlobalCacheRoot() {
+			return gameDir.resolve("fabric-global");
+		}
+
+		@Override
+		public Path getGlobalDataRoot() {
+			return gameDir.resolve("cache-global");
+		}
+	}
+}

src/main/java/net/fabricmc/loader/impl/util/ModDirectoriesImpl.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2016 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.loader.impl.util;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Objects;
+
+import net.fabricmc.loader.api.ModDirectories;
+
+public final class ModDirectoriesImpl implements ModDirectories {
+	private final String modId;
+	private final Path gameDir;
+	private final GlobalDirectories globalDirectories;
+
+	public ModDirectoriesImpl(String modId, Path gameDir, GlobalDirectories globalDirectories) {
+		this.modId = Objects.requireNonNull(modId);
+		this.gameDir = gameDir;
+		this.globalDirectories = Objects.requireNonNull(globalDirectories);
+	}
+
+	@Override
+	public Path getCacheDir() {
+		return ensureDir(gameDir.resolve("cache").resolve(modId));
+	}
+
+	@Override
+	public Path getGlobalCacheDir() {
+		return ensureDir(globalDirectories.getGlobalCacheRoot().resolve(modId));
+	}
+
+	@Override
+	public Path getDataDir() {
+		return ensureDir(gameDir.resolve("fabric").resolve(modId));
+	}
+
+	@Override
+	public Path getGlobalDataDir() {
+		return ensureDir(globalDirectories.getGlobalDataRoot().resolve(modId));
+	}
+
+	private Path ensureDir(Path path) {
+		if (!Files.exists(path)) {
+			try {
+				Files.createDirectories(path);
+			} catch (IOException e) {
+				throw new RuntimeException("Failed to create directory: " + path, e);
+			}
+		}
+
+		return path;
+	}
+}