perf(download): skip re-installing loader if identical version patch …

HMCLCore/src/main/java/org/jackhuang/hmcl/download/DefaultDependencyManager.java

@@ -27,9 +27,11 @@
 import org.jackhuang.hmcl.game.Artifact;
 import org.jackhuang.hmcl.game.DefaultGameRepository;
 import org.jackhuang.hmcl.game.GameInstanceManifest;
+import org.jackhuang.hmcl.game.GameInstancePatch;
 import org.jackhuang.hmcl.game.Library;
 import org.jackhuang.hmcl.task.Task;
 import org.jackhuang.hmcl.util.io.FileUtils;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -155,8 +157,75 @@ public Task<GameInstanceManifest> installLibraryAsync(String gameVersion, GameIn
                 .withStage(String.format("hmcl.install.%s:%s", libraryId, libraryVersion));
     }
 
+    /// Checks whether a resolved [Library] belongs to the given loader type.
+    ///
+    /// The mapping must stay consistent with [LibraryAnalyzer.LibraryType]'s
+    /// group-id patterns so that the file-integrity check covers the correct jars.
+    ///
+    /// @param library   a library entry from the resolved launch manifest
+    /// @param libraryId the patch id of the loader (e.g. `"forge"`, `"fabric"`)
+    /// @return `true` if the library's groupId matches the loader
+    private static boolean isLoaderLibrary(Library library, String libraryId) {
+        if (library == null || library.groupId() == null) return false;
+        String groupId = library.groupId().toLowerCase(java.util.Locale.ROOT);
+        String targetId = libraryId.toLowerCase(java.util.Locale.ROOT);
+        return switch (targetId) {
+            case "forge" -> groupId.startsWith("net.minecraftforge");
+            case "neoforge" -> groupId.startsWith("net.neoforged");
+            case "optifine" -> "optifine".equals(groupId) || "net.optifine".equals(groupId);
+            case "fabric" -> groupId.startsWith("net.fabricmc");
+            case "quilt" -> groupId.startsWith("org.quiltmc");
+            case "legacyfabric" -> groupId.startsWith("net.legacyfabric") || groupId.startsWith("net.fabricmc");
+            case "liteloader" -> "com.mumfrey".equals(groupId);
+            case "cleanroom" -> groupId.startsWith("com.cleanroommc") || groupId.startsWith("zone.rong");
+            default -> groupId.contains(targetId);
+        };
+    }
+
+    /// Checks if a matching library patch is already installed for the target instance on disk and intact.
+    ///
+    /// @param baseVersion the base game instance manifest
+    /// @param libraryVersion the remote library version to install
+    /// @return the existing intact matching patch, or `null` if the library is not installed, version mismatches, or files need repair
+    private @Nullable GameInstancePatch getIntactMatchingPatch(GameInstanceManifest baseVersion, RemoteVersion libraryVersion) {
+        if (LibraryAnalyzer.LibraryType.MINECRAFT.getPatchId().equals(libraryVersion.getLibraryId()) || !repository.hasInstance(baseVersion.id())) {
+            return null;
+        }
+
+        try {
+            GameInstanceManifest existingManifest = repository.getInstanceManifest(baseVersion.id());
+            String currentGameVersion = repository.getGameVersion(existingManifest).orElse(null);
+            if (!java.util.Objects.equals(currentGameVersion, libraryVersion.getGameVersion())) {
+                return null;
+            }
+
+            GameInstancePatch matchingPatch = existingManifest.getPatches().stream()
+                    .filter(patch -> libraryVersion.getLibraryId().equals(patch.id())
+                            && java.util.Objects.equals(patch.version(), libraryVersion.getSelfVersion()))
+                    .findFirst()
+                    .orElse(null);
+            if (matchingPatch == null) {
+                return null;
+            }
+
+            GameInstanceManifest.Resolved resolved = repository.getResolvedInstanceManifest(baseVersion.id());
+            boolean needsRepair = resolved.launchManifest().getLibraries().stream()
+                    .filter(lib -> isLoaderLibrary(lib, libraryVersion.getLibraryId()))
+                    .anyMatch(lib -> GameLibrariesTask.shouldDownloadLibrary(repository, existingManifest, lib, true));
+
+            return needsRepair ? null : matchingPatch;
+        } catch (Exception ignored) {
+            return null;
+        }
+    }
+
     @Override
     public Task<GameInstanceManifest> installLibraryAsync(GameInstanceManifest baseVersion, RemoteVersion libraryVersion) {
+        GameInstancePatch matchingPatch = getIntactMatchingPatch(baseVersion, libraryVersion);
+        if (matchingPatch != null) {
+            return Task.completed(baseVersion.addPatch(matchingPatch));
+        }
+
         AtomicReference<GameInstanceManifest> removedLibraryVersion = new AtomicReference<>();
 
         return removeLibraryAsync(baseVersion, libraryVersion.getLibraryId())