Rewrite Checksum util class (#1304)

* Rewrite Checksum util class as the old one was annoying me.

* Small cleanup in UnpickService

* Test fixes & cleanup

* Fix build

* Fix OfflineModeTest

src/main/java/net/fabricmc/loom/build/nesting/NestableJarGenerationTask.java

@@ -37,7 +37,6 @@ import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-import com.google.common.hash.Hashing;
 import com.google.gson.JsonObject;
 import org.apache.commons.io.FileUtils;
 import org.gradle.api.artifacts.ArtifactView;
@@ -61,6 +60,7 @@ import org.slf4j.LoggerFactory;
 
 import net.fabricmc.loom.LoomGradlePlugin;
 import net.fabricmc.loom.task.AbstractLoomTask;
+import net.fabricmc.loom.util.Checksum;
 import net.fabricmc.loom.util.ZipReprocessorUtil;
 import net.fabricmc.loom.util.fmj.FabricModJsonFactory;
 
@@ -170,9 +170,7 @@ public abstract class NestableJarGenerationTask extends AbstractLoomTask {
 
 		// Fabric Loader can't handle modIds longer than 64 characters
 		if (modId.length() > 64) {
-			String hash = Hashing.sha256()
-					.hashString(modId, StandardCharsets.UTF_8)
-					.toString();
+			String hash = Checksum.of(modId).sha256().hex();
 			modId = modId.substring(0, 50) + hash.substring(0, 14);
 		}
 

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

@@ -275,7 +275,7 @@ public abstract class CompileConfiguration implements Runnable {
 	private LockFile getLockFile() {
 		final LoomGradleExtension extension = LoomGradleExtension.get(getProject());
 		final Path cacheDirectory = extension.getFiles().getUserCache().toPath();
-		final String pathHash = Checksum.projectHash(getProject());
+		final String pathHash = Checksum.of(getProject()).sha1().hex();
 		return new LockFile(
 				cacheDirectory.resolve("." + pathHash + ".lock"),
 				"Lock for cache='%s', project='%s'".formatted(

src/main/java/net/fabricmc/loom/configuration/accesswidener/LocalAccessWidenerEntry.java

@@ -25,7 +25,6 @@
 package net.fabricmc.loom.configuration.accesswidener;
 
 import java.io.IOException;
-import java.io.UncheckedIOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 
@@ -40,11 +39,7 @@ import net.fabricmc.tinyremapper.TinyRemapper;
 
 public record LocalAccessWidenerEntry(Path path, String hash) implements AccessWidenerEntry {
 	public static LocalAccessWidenerEntry create(Path path) {
-		try {
-			return new LocalAccessWidenerEntry(path, Checksum.sha1Hex(path));
-		} catch (IOException e) {
-			throw new UncheckedIOException("Failed to create LocalAccessWidenerEntry", e);
-		}
+		return new LocalAccessWidenerEntry(path, Checksum.of(path).sha1().hex());
 	}
 
 	@Override

src/main/java/net/fabricmc/loom/configuration/mods/ArtifactRef.java

@@ -69,7 +69,7 @@ public interface ArtifactRef {
 		}
 
 		public String version() {
-			return replaceIfNullOrEmpty(artifact.getModuleVersion().getId().getVersion(), () -> Checksum.truncatedSha256(artifact.getFile()));
+			return replaceIfNullOrEmpty(artifact.getModuleVersion().getId().getVersion(), () -> Checksum.of(artifact.getFile()).sha256().hex(10));
 		}
 
 		public String classifier() {

src/main/java/net/fabricmc/loom/configuration/mods/ModConfigurationRemapper.java

@@ -275,7 +275,7 @@ public class ModConfigurationRemapper {
 
 			for (File artifact : files) {
 				final String name = getNameWithoutExtension(artifact.toPath());
-				final String version = replaceIfNullOrEmpty(dependency.getVersion(), () -> Checksum.truncatedSha256(artifact));
+				final String version = replaceIfNullOrEmpty(dependency.getVersion(), () -> Checksum.of(artifact).sha256().hex(10));
 				artifacts.add(new ArtifactRef.FileArtifactRef(artifact.toPath(), group, name, version));
 			}
 		}

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

@@ -25,7 +25,6 @@
 package net.fabricmc.loom.configuration.processors;
 
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
@@ -113,11 +112,11 @@ public final class MinecraftJarProcessorManager {
 
 	public String getJarHash() {
 		//fabric-loom:mod-javadoc:-1289977000
-		return Checksum.sha1Hex(getCacheValue().getBytes(StandardCharsets.UTF_8)).substring(0, 10);
+		return Checksum.of(getCacheValue()).sha1().hex(10);
 	}
 
 	public String getSourceMappingsHash() {
-		return Checksum.sha1Hex(getCacheValue().getBytes(StandardCharsets.UTF_8));
+		return Checksum.of(getCacheValue()).sha1().hex();
 	}
 
 	public boolean requiresProcessingJar(Path jar) {

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

@@ -124,7 +124,7 @@ public abstract class ModJavadocProcessor implements MinecraftJarProcessor<ModJa
 
 			try {
 				final byte[] data = fabricModJson.getSource().read(javaDocPath);
-				mappingsHash = Checksum.sha1Hex(data);
+				mappingsHash = Checksum.of(data).sha1().hex();
 
 				try (Reader reader = new InputStreamReader(new ByteArrayInputStream(data))) {
 					MappingReader.read(reader, mappings);

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

@@ -25,7 +25,6 @@
 package net.fabricmc.loom.configuration.providers.mappings;
 
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
@@ -115,7 +114,7 @@ public abstract class IntermediaryMappingsProvider extends IntermediateMappingsP
 		if (!LoomGradleExtensionApiImpl.DEFAULT_INTERMEDIARY_URL.equals(urlRaw)) {
 			final String url = getIntermediaryUrl().get().formatted(encodedMcVersion);
 
-			return NAME + "-" + Checksum.sha1Hex(url.getBytes(StandardCharsets.UTF_8));
+			return NAME + "-" + Checksum.of(url).sha1().hex();
 		}
 
 		return NAME;

src/main/java/net/fabricmc/loom/configuration/providers/mappings/utils/LocalFileSpec.java

@@ -29,8 +29,8 @@ import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.Objects;
 
-import net.fabricmc.loom.api.mappings.layered.spec.FileSpec;
 import net.fabricmc.loom.api.mappings.layered.MappingContext;
+import net.fabricmc.loom.api.mappings.layered.spec.FileSpec;
 import net.fabricmc.loom.util.Checksum;
 
 public class LocalFileSpec implements FileSpec {
@@ -48,7 +48,7 @@ public class LocalFileSpec implements FileSpec {
 		}
 
 		// Use the file hash as part of the spec, this means if the input file changes the mappings will be re-generated.
-		return Objects.hash(Arrays.hashCode(Checksum.sha256(file)), file.getAbsolutePath());
+		return Objects.hash(Arrays.hashCode(Checksum.of(file).sha256().digest()), file.getAbsolutePath());
 	}
 
 	@Override

src/main/java/net/fabricmc/loom/configuration/providers/minecraft/verify/MinecraftJarVerification.java

@@ -25,7 +25,6 @@
 package net.fabricmc.loom.configuration.providers.minecraft.verify;
 
 import java.io.IOException;
-import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Map;
 import java.util.function.Function;
@@ -86,9 +85,9 @@ public abstract class MinecraftJarVerification {
 		}
 
 		LOGGER.info("Found executed hash ({}) for known version: {}", expectedHash, version);
-		String hash = Checksum.sha256Hex(Files.readAllBytes(path));
+		Checksum.Result hash = Checksum.of(path).sha256();
 
-		if (hash.equalsIgnoreCase(expectedHash)) {
+		if (hash.matchesStr(expectedHash)) {
 			LOGGER.info("Minecraft {} hash matches known version", path.getFileName());
 			return true;
 		}

src/main/java/net/fabricmc/loom/decompilers/cache/ClassEntry.java

@@ -105,13 +105,13 @@ public record ClassEntry(String name, List<String> innerClasses, List<String> su
 	public String hash(Path root) throws IOException {
 		StringJoiner joiner = new StringJoiner(",");
 
-		joiner.add(Checksum.sha256Hex(Files.readAllBytes(root.resolve(name))));
+		joiner.add(Checksum.of(root.resolve(name)).sha256().hex());
 
 		for (String innerClass : innerClasses) {
-			joiner.add(Checksum.sha256Hex(Files.readAllBytes(root.resolve(innerClass))));
+			joiner.add(Checksum.of(root.resolve(innerClass)).sha256().hex());
 		}
 
-		return Checksum.sha256Hex(joiner.toString().getBytes());
+		return Checksum.of(joiner.toString()).sha256().hex();
 	}
 
 	/**
@@ -138,7 +138,7 @@ public record ClassEntry(String name, List<String> innerClasses, List<String> su
 			}
 		}
 
-		return Checksum.sha256Hex(joiner.toString().getBytes());
+		return Checksum.of(joiner.toString()).sha256().hex();
 	}
 
 	public String sourcesFileName() {

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

@@ -409,17 +409,13 @@ public abstract class GenerateSourcesTask extends AbstractLoomTask {
 
 		getLogger().info("Decompile cache data: {}", sj);
 
-		try {
-			return Checksum.sha256Hex(sj.toString().getBytes(StandardCharsets.UTF_8));
-		} catch (IOException e) {
-			throw new UncheckedIOException(e);
-		}
+		return Checksum.of(sj.toString()).sha256().hex();
 	}
 
 	private String getDecompilerCheckKey() {
 		var sj = new StringJoiner(",");
 		sj.add(decompilerOptions.getDecompilerClassName().get());
-		sj.add(Checksum.fileCollectionHash(decompilerOptions.getClasspath()));
+		sj.add(Checksum.of(decompilerOptions.getClasspath()).sha256().hex());
 
 		for (Map.Entry<String, String> entry : decompilerOptions.getOptions().get().entrySet()) {
 			sj.add(entry.getKey() + "=" + entry.getValue());

src/main/java/net/fabricmc/loom/task/service/UnpickService.java

@@ -29,7 +29,6 @@ import java.lang.reflect.InvocationTargetException;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.StringJoiner;
 
 import org.gradle.api.Project;
 import org.gradle.api.artifacts.ConfigurationContainer;
@@ -149,16 +148,11 @@ public class UnpickService extends Service<UnpickService.Options> {
 	}
 
 	public String getUnpickCacheKey() {
-		if (!getOptions().getUnpickDefinitions().isPresent()) {
-			return "";
-		}
-
-		var sj = new StringJoiner(",");
-		sj.add(Checksum.fileHash(getOptions().getUnpickDefinitions().getAsFile().get()));
-		sj.add(Checksum.fileCollectionHash(getOptions().getUnpickConstantJar()));
-		sj.add(Checksum.fileCollectionHash(getOptions().getUnpickRuntimeClasspath()));
-
-		return sj.toString();
+		return Checksum.of(List.of(
+				Checksum.of(getOptions().getUnpickDefinitions().getAsFile().get()),
+				Checksum.of(getOptions().getUnpickConstantJar()),
+				Checksum.of(getOptions().getUnpickRuntimeClasspath())
+		)).sha256().hex();
 	}
 
 	public interface UnpickParams extends WorkParameters {

src/main/java/net/fabricmc/loom/util/CacheKey.java

@@ -24,7 +24,6 @@
 
 package net.fabricmc.loom.util;
 
-import java.nio.charset.StandardCharsets;
 import java.util.function.Supplier;
 
 import com.google.common.base.Suppliers;
@@ -40,7 +39,7 @@ import net.fabricmc.loom.util.gradle.GradleTypeAdapter;
 public abstract class CacheKey {
 	private static final int CHECKSUM_LENGTH = 8;
 	private final transient Supplier<String> jsonSupplier = Suppliers.memoize(() -> GradleTypeAdapter.GSON.toJson(this));
-	private final transient Supplier<String> cacheKeySupplier = Suppliers.memoize(() -> Checksum.sha1Hex(jsonSupplier.get().getBytes(StandardCharsets.UTF_8)).substring(0, CHECKSUM_LENGTH));
+	private final transient Supplier<String> cacheKeySupplier = Suppliers.memoize(() -> Checksum.of(jsonSupplier.get()).sha1().hex(CHECKSUM_LENGTH));
 
 	public static <T> T create(Project project, Class<T> clazz, Action<T> action) {
 		T instance = project.getObjects().newInstance(clazz);

src/main/java/net/fabricmc/loom/util/Checksum.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of fabric-loom, licensed under the MIT License (MIT).
  *
- * Copyright (c) 2016-2020 FabricMC
+ * Copyright (c) 2025 FabricMC
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -26,105 +26,138 @@ package net.fabricmc.loom.util;
 
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
 import java.io.UncheckedIOException;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
 import java.nio.file.Path;
-import java.util.Comparator;
-import java.util.StringJoiner;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.HexFormat;
+import java.util.List;
 
-import com.google.common.hash.HashCode;
-import com.google.common.hash.Hashing;
-import com.google.common.io.BaseEncoding;
-import com.google.common.io.ByteSource;
-import com.google.common.io.Files;
 import org.gradle.api.Project;
 import org.gradle.api.file.FileCollection;
-import org.gradle.api.logging.Logger;
-import org.gradle.api.logging.Logging;
+import org.jetbrains.annotations.NotNull;
 
-public class Checksum {
-	private static final Logger log = Logging.getLogger(Checksum.class);
+public final class Checksum {
+	public static Checksum of(byte[] data) {
+		return new Checksum(digest -> digest.write(data));
+	}
 
-	public static boolean equals(File file, String checksum) {
-		if (file == null || !file.exists()) {
-			return false;
-		}
+	public static Checksum of(String str) {
+		return new Checksum(digest -> digest.write(str));
+	}
+
+	public static Checksum of(File file) {
+		return of(file.toPath());
+	}
+
+	public static Checksum of(Path file) {
+		return new Checksum(digest -> {
+			try (InputStream is = Files.newInputStream(file)) {
+				is.transferTo(digest);
+			}
+		});
+	}
+
+	public static Checksum of(Project project) {
+		return of(project.getProjectDir().getAbsolutePath() + ":" + project.getPath());
+	}
+
+	public static Checksum of(FileCollection files) {
+		return new Checksum(os -> {
+			for (File file : files) {
+				try (InputStream is = Files.newInputStream(file.toPath())) {
+					is.transferTo(os);
+				}
+			}
+		});
+	}
+
+	public static Checksum of(List<Checksum> others) {
+		return new Checksum(os -> {
+			for (Checksum other : others) {
+				other.consumer.accept(os);
+			}
+		});
+	}
+
+	private final DataConsumer consumer;
+
+	private Checksum(DataConsumer consumer) {
+		this.consumer = consumer;
+	}
+
+	public Result sha1() {
+		return computeResult("SHA-1");
+	}
+
+	public Result sha256() {
+		return computeResult("SHA-256");
+	}
+
+	public Result md5() {
+		return computeResult("MD5");
+	}
+
+	private Result computeResult(String algorithm) {
+		MessageDigest digest;
 
 		try {
-			HashCode hash = Files.asByteSource(file).hash(Hashing.sha1());
-			log.debug("Checksum check: '" + hash.toString() + "' == '" + checksum + "'?");
-			return hash.toString().equals(checksum);
-		} catch (IOException e) {
-			e.printStackTrace();
+			digest = MessageDigest.getInstance(algorithm);
+		} catch (NoSuchAlgorithmException e) {
+			throw new RuntimeException(e);
 		}
 
-		return false;
+		try (MessageDigestOutputStream os = new MessageDigestOutputStream(digest)) {
+			consumer.accept(os);
+		} catch (IOException e) {
+			throw new UncheckedIOException("Failed to compute checksum", e);
+		}
+
+		return new Result(digest.digest());
 	}
 
-	public static byte[] sha256(File file) {
-		try {
-			HashCode hash = Files.asByteSource(file).hash(Hashing.sha256());
-			return hash.asBytes();
-		} catch (IOException e) {
-			throw new UncheckedIOException("Failed to get file hash", e);
+	public record Result(byte[] digest) {
+		public String hex() {
+			return HexFormat.of().formatHex(digest());
+		}
+
+		public String hex(int length) {
+			return hex().substring(0, length);
+		}
+
+		public boolean matchesStr(String other) {
+			return hex().equalsIgnoreCase(other);
 		}
 	}
 
-	public static String sha256Hex(byte[] input) throws IOException {
-		HashCode hash = ByteSource.wrap(input).hash(Hashing.sha256());
-		return Checksum.toHex(hash.asBytes());
+	@FunctionalInterface
+	private interface DataConsumer {
+		void accept(MessageDigestOutputStream os) throws IOException;
 	}
 
-	public static String sha1Hex(Path path) throws IOException {
-		HashCode hash = Files.asByteSource(path.toFile()).hash(Hashing.sha1());
-		return toHex(hash.asBytes());
-	}
+	private static class MessageDigestOutputStream extends OutputStream {
+		private final MessageDigest digest;
 
-	public static String sha1Hex(byte[] input) {
-		try {
-			HashCode hash = ByteSource.wrap(input).hash(Hashing.sha1());
-			return toHex(hash.asBytes());
-		} catch (IOException e) {
-			throw new UncheckedIOException("Failed to hash", e);
+		private MessageDigestOutputStream(MessageDigest digest) {
+			this.digest = digest;
 		}
-	}
 
-	public static String truncatedSha256(File file) {
-		try {
-			HashCode hash = Files.asByteSource(file).hash(Hashing.sha256());
-			return hash.toString().substring(0, 12);
-		} catch (IOException e) {
-			throw new UncheckedIOException("Failed to get file hash of " + file, e);
+		@Override
+		public void write(int b) {
+			digest.update((byte) b);
 		}
-	}
 
-	public static String toHex(byte[] bytes) {
-		return BaseEncoding.base16().lowerCase().encode(bytes);
-	}
-
-	public static String projectHash(Project project) {
-		String str = project.getProjectDir().getAbsolutePath() + ":" + project.getPath();
-		String hex = sha1Hex(str.getBytes(StandardCharsets.UTF_8));
-		return hex.substring(hex.length() - 16);
-	}
-
-	public static String fileHash(File file) {
-		try {
-			return Checksum.sha256Hex(java.nio.file.Files.readAllBytes(file.toPath()));
-		} catch (IOException e) {
-			throw new UncheckedIOException(e);
+		@Override
+		public void write(byte @NotNull[] b, int off, int len) {
+			digest.update(b, off, len);
 		}
-	}
 
-	public static String fileCollectionHash(FileCollection files) {
-		var sj = new StringJoiner(",");
-
-		files.getFiles()
-				.stream()
-				.sorted(Comparator.comparing(File::getAbsolutePath))
-				.map(Checksum::fileHash)
-				.forEach(sj::add);
-
-		return sj.toString();
+		public void write(String string) throws IOException {
+			write(string.getBytes(StandardCharsets.UTF_8));
+		}
 	}
 }

src/main/java/net/fabricmc/loom/util/download/Download.java

@@ -222,7 +222,7 @@ public final class Download {
 				String downloadedHash;
 
 				try {
-					downloadedHash = Checksum.sha1Hex(output);
+					downloadedHash = Checksum.of(output).sha1().hex();
 					Files.deleteIfExists(output);
 				} catch (IOException e) {
 					downloadedHash = "unknown hash";
@@ -357,12 +357,12 @@ public final class Download {
 		String hash = expectedHash.substring(i + 1);
 
 		try {
-			String computedHash = switch (algorithm) {
-			case "sha1" -> Checksum.sha1Hex(path);
+			Checksum.Result computedHash = switch (algorithm) {
+			case "sha1" -> Checksum.of(path).sha1();
 			default -> throw error("Unsupported hash algorithm (%s)", algorithm);
 			};
 
-			return computedHash.equalsIgnoreCase(hash);
+			return computedHash.matchesStr(hash);
 		} catch (IOException e) {
 			throw new UncheckedIOException(e);
 		}

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

@@ -47,7 +47,7 @@ class OfflineModeTest extends Specification implements GradleProjectTestTrait {
             }
 
 			import net.fabricmc.loom.util.Checksum
-			def projectHash = Checksum.projectHash(getProject())
+			def projectHash = Checksum.of(getProject()).sha1().hex()
             println("%%" + projectHash + "%%")
 
             """.stripIndent()

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

@@ -24,17 +24,16 @@
 
 package net.fabricmc.loom.test.integration
 
-import com.google.common.hash.HashCode
-import com.google.common.hash.Hashing
-import com.google.common.io.Files
 import spock.lang.Specification
 import spock.lang.Unroll
 import spock.util.environment.RestoreSystemProperties
 
 import net.fabricmc.loom.test.util.GradleProjectTestTrait
+import net.fabricmc.loom.util.Checksum
 
 import static java.lang.System.setProperty
-import static net.fabricmc.loom.test.LoomTestConstants.*
+import static net.fabricmc.loom.test.LoomTestConstants.DEFAULT_GRADLE
+import static net.fabricmc.loom.test.LoomTestConstants.PRE_RELEASE_GRADLE
 import static org.gradle.testkit.runner.TaskOutcome.SUCCESS
 
 class ReproducibleBuildTest extends Specification implements GradleProjectTestTrait {
@@ -60,7 +59,6 @@ class ReproducibleBuildTest extends Specification implements GradleProjectTestTr
 	}
 
 	String generateMD5(File file) {
-		HashCode hash = Files.asByteSource(file).hash(Hashing.md5())
-		return hash.asBytes().encodeHex() as String
+		return Checksum.of(file).md5().hex()
 	}
 }

src/test/groovy/net/fabricmc/loom/test/unit/ChecksumTest.groovy

@@ -37,7 +37,7 @@ class ChecksumTest extends Specification {
 		project.getProjectDir() >> new File(dir)
 
 		when:
-		def hash = Checksum.projectHash(project)
+		def hash = Checksum.of(project).sha256().hex()
 
 		then:
 		!hash.empty

src/test/groovy/net/fabricmc/loom/test/unit/ZipUtilsTest.groovy

@@ -180,7 +180,7 @@ class ZipUtilsTest extends Specification {
 		then:
 		ZipUtils.unpack(zip, "text.txt") == "hello world".bytes
 		ZipUtils.unpack(zip, "fabric.mod.json") == "Some text".bytes
-		Checksum.sha1Hex(zip) == "1b06cc0aaa65ab2b0d423fe33431ff5bd14bf9c8"
+		Checksum.of(zip).sha1().hex() == "1b06cc0aaa65ab2b0d423fe33431ff5bd14bf9c8"
 
 		where:
 		timezone 			| _
@@ -256,6 +256,6 @@ class ZipUtilsTest extends Specification {
 
 		then:
 		ZipUtils.unpack(zip, "text.txt") == "hello world".bytes
-		Checksum.sha1Hex(zip) == "e699fa52a520553241aac798f72255ac0a912b05"
+		Checksum.of(zip).sha1().hex() == "e699fa52a520553241aac798f72255ac0a912b05"
 	}
 }

src/test/groovy/net/fabricmc/loom/test/unit/download/DownloadFileTest.groovy

@@ -452,6 +452,6 @@ class DownloadFileTest extends DownloadTest {
 				.downloadPath(file)
 
 		then:
-		Checksum.sha1Hex(file) == "8e8c9be5dc27802caba47053d4fdea328f7f89bd"
+		Checksum.of(file).sha1().hex() == "8e8c9be5dc27802caba47053d4fdea328f7f89bd"
 	}
 }

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

@@ -25,7 +25,6 @@
 package net.fabricmc.loom.test.util
 
 import java.nio.file.Path
-import java.security.MessageDigest
 
 import net.fabricmc.loom.LoomGradlePlugin
 import net.fabricmc.loom.configuration.providers.BundleMetadata
@@ -35,6 +34,7 @@ import net.fabricmc.loom.configuration.providers.minecraft.verify.CertificateCha
 import net.fabricmc.loom.configuration.providers.minecraft.verify.JarVerifier
 import net.fabricmc.loom.configuration.providers.minecraft.verify.KnownVersions
 import net.fabricmc.loom.configuration.providers.minecraft.verify.SignatureVerificationFailure
+import net.fabricmc.loom.util.Checksum
 import net.fabricmc.loom.util.Constants
 import net.fabricmc.loom.util.download.Download
 import net.fabricmc.loom.util.download.DownloadExecutor
@@ -109,13 +109,13 @@ class KnownVersionsGenerator {
 		def clientJar = dir.resolve(client.sha1() + ".jar")
 
 		if (!isSigned(clientJar)) {
-			unsignedClientVersions.put(version.id, sha256(clientJar))
+			unsignedClientVersions.put(version.id, Checksum.of(clientJar).sha256().hex())
 		}
 
 		if (server != null) {
 			def serverJar = dir.resolve(server.sha1() + ".jar")
 			if (BundleMetadata.fromJar(serverJar) == null) {
-				unsignedServerVersions.put(version.id, sha256(serverJar))
+				unsignedServerVersions.put(version.id, Checksum.of(serverJar).sha256().hex())
 			}
 		}
 	}
@@ -128,16 +128,4 @@ class KnownVersionsGenerator {
 			return false
 		}
 	}
-
-	static String sha256(Path path) {
-		MessageDigest md = MessageDigest.getInstance("SHA-256")
-		path.withInputStream { inputStream ->
-			byte[] buffer = new byte[8192]
-			int bytesRead
-			while ((bytesRead = inputStream.read(buffer)) != -1) {
-				md.update(buffer, 0, bytesRead)
-			}
-		}
-		return md.digest().encodeHex().toString()
-	}
 }