Finally, there are no more errors in UpdateManager. Now to actually make it work

.idea/.gitignore

@@ -1,2 +1,4 @@
 # Default ignored files
 /workspace.xml
+
+/uiDesigner.xml

src/main/java/link/infra/packwiz/installer/DownloadTask.java

@@ -2,11 +2,19 @@ package link.infra.packwiz.installer;
 
 import link.infra.packwiz.installer.metadata.IndexFile;
 import link.infra.packwiz.installer.metadata.ManifestFile;
+import link.infra.packwiz.installer.metadata.hash.GeneralHashingSource;
 import link.infra.packwiz.installer.metadata.hash.Hash;
 import link.infra.packwiz.installer.metadata.hash.HashUtils;
 import link.infra.packwiz.installer.ui.IOptionDetails;
+import okio.Buffer;
+import okio.Okio;
+import okio.Source;
 
 import java.net.URI;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -19,15 +27,14 @@ class DownloadTask implements IOptionDetails {
 	private boolean invalidated = false;
 	// If file is new or isOptional changed to true, the option needs to be presented again
 	private boolean newOptional = true;
+	private final UpdateManager.Options.Side downloadSide;
 
-	public DownloadTask(IndexFile.File metadata) {
+	public DownloadTask(IndexFile.File metadata, String defaultFormat, UpdateManager.Options.Side downloadSide) {
 		this.metadata = metadata;
-	}
-
-	public void setDefaultHashFormat(String format) {
 		if (metadata.hashFormat == null || metadata.hashFormat.length() == 0) {
-			metadata.hashFormat = format;
+			metadata.hashFormat = defaultFormat;
 		}
+		this.downloadSide = downloadSide;
 	}
 
 	public void invalidate() {
@@ -37,7 +44,10 @@ class DownloadTask implements IOptionDetails {
 
 	public void updateFromCache(ManifestFile.File cachedFile) {
 		if (failure != null) return;
-		if (cachedFile == null) return;
+		if (cachedFile == null) {
+			this.cachedFile = new ManifestFile.File();
+			return;
+		}
 
 		this.cachedFile = cachedFile;
 
@@ -89,6 +99,78 @@ class DownloadTask implements IOptionDetails {
 		}
 	}
 
+	public void download(String packFolder, URI indexUri) {
+		if (failure != null) return;
+		if (alreadyUpToDate) return;
+		if (metadata.linkedFile != null && !downloadSide.hasSide(metadata.linkedFile.side)) return;
+
+		Path destPath = Paths.get(packFolder, metadata.getDestURI().toString());
+
+		// Don't update files marked with preserve if they already exist on disk
+		if (metadata.preserve) {
+			if (Files.exists(destPath)) {
+				return;
+			}
+		}
+
+		try {
+			Hash hash;
+			String fileHashFormat;
+			if (metadata.linkedFile != null) {
+				hash = metadata.linkedFile.getHash();
+				fileHashFormat = metadata.linkedFile.download.hashFormat;
+			} else {
+				hash = metadata.getHash();
+				fileHashFormat = metadata.hashFormat;
+			}
+
+			Source src = metadata.getSource(indexUri);
+			GeneralHashingSource fileSource = HashUtils.getHasher(fileHashFormat).getHashingSource(src);
+			Buffer data = new Buffer();
+			Okio.buffer(fileSource).readAll(data);
+
+			if (fileSource.hashIsEqual(hash)) {
+				Files.createDirectories(destPath.getParent());
+				Files.copy(data.inputStream(), destPath, StandardCopyOption.REPLACE_EXISTING);
+			} else {
+				// TODO: no more SYSOUT!!!!!!!!!
+				System.out.println("Invalid hash for " + metadata.getDestURI().toString());
+				System.out.println("Calculated: " + fileSource.getHash());
+				System.out.println("Expected:   " + hash);
+				failure = new Exception("Hash invalid!");
+			}
+
+			if (cachedFile.cachedLocation != null && !destPath.equals(Paths.get(packFolder, cachedFile.cachedLocation))) {
+				// Delete old file if location changes
+				Files.delete(Paths.get(packFolder, cachedFile.cachedLocation));
+			}
+		} catch (Exception e) {
+			failure = e;
+		}
+		if (failure == null) {
+			if (cachedFile == null) {
+				cachedFile = new ManifestFile.File();
+			}
+			// Update the manifest file
+			try {
+				cachedFile.hash = metadata.getHash();
+			} catch (Exception e) {
+				failure = e;
+				return;
+			}
+			cachedFile.isOptional = isOptional();
+			cachedFile.cachedLocation = metadata.getDestURI().toString();
+			if (metadata.linkedFile != null) {
+				try {
+					cachedFile.linkedFileHash = metadata.linkedFile.getHash();
+				} catch (Exception e) {
+					failure = e;
+					return;
+				}
+			}
+		}
+	}
+
 	public Exception getException() {
 		return failure;
 	}
@@ -130,10 +212,10 @@ class DownloadTask implements IOptionDetails {
 		this.cachedFile.optionValue = value;
 	}
 
-	public static List<DownloadTask> createTasksFromIndex(IndexFile index) {
+	public static List<DownloadTask> createTasksFromIndex(IndexFile index, String defaultFormat, UpdateManager.Options.Side downloadSide) {
 		ArrayList<DownloadTask> tasks = new ArrayList<>();
 		for (IndexFile.File file : index.files) {
-			tasks.add(new DownloadTask(file));
+			tasks.add(new DownloadTask(file, defaultFormat, downloadSide));
 		}
 		return tasks;
 	}

src/main/java/link/infra/packwiz/installer/UpdateManager.java

@@ -16,16 +16,13 @@ import link.infra.packwiz.installer.request.HandlerManager;
 import link.infra.packwiz.installer.ui.IOptionDetails;
 import link.infra.packwiz.installer.ui.IUserInterface;
 import link.infra.packwiz.installer.ui.InstallProgress;
-import okio.Buffer;
 import okio.Okio;
 import okio.Source;
 
 import java.io.*;
 import java.net.URI;
 import java.nio.file.Files;
-import java.nio.file.Path;
 import java.nio.file.Paths;
-import java.nio.file.StandardCopyOption;
 import java.util.*;
 import java.util.concurrent.*;
 import java.util.stream.Collectors;
@@ -177,6 +174,7 @@ public class UpdateManager {
 		// TODO: update MMC params, java args etc
 
 		manifest.packFileHash = packFileSource.getHash();
+		manifest.cachedSide = opts.side;
 		try (Writer writer = new FileWriter(Paths.get(opts.packFolder, opts.manifestFile).toString())) {
 			gson.toJson(manifest, writer);
 		} catch (IOException e) {
@@ -259,15 +257,24 @@ public class UpdateManager {
 		ui.submitProgress(new InstallProgress("Comparing new files..."));
 
 		// TODO: progress bar, parallelify
-		List<DownloadTask> tasks = DownloadTask.createTasksFromIndex(indexFile);
+		List<DownloadTask> tasks = DownloadTask.createTasksFromIndex(indexFile, indexFile.hashFormat, opts.side);
-		tasks.forEach(f -> f.setDefaultHashFormat(indexFile.hashFormat));
+		// If the side changes, invalidate EVERYTHING just in case
+		// Might not be needed, but done just to be safe
+		boolean invalidateAll = !opts.side.equals(manifest.cachedSide);
 		tasks.forEach(f -> {
-			// TODO: should linkedfile be checked as well? should a getter be used?
+			// TODO: should linkedfile be checked as well? should this be done in the download section?
-			if (invalidatedUris.contains(f.metadata.file)) {
+			if (invalidateAll) {
+				f.invalidate();
+			} else if (invalidatedUris.contains(f.metadata.file)) {
 				f.invalidate();
-			} else {
-				f.updateFromCache(manifest.cachedFiles.get(f.metadata.file));
 			}
+			ManifestFile.File file = manifest.cachedFiles.get(f.metadata.file);
+			if (file != null) {
+				// Ensure the file can be reverted later if necessary - the DownloadTask modifies the file so if it fails we need the old version back
+				file.backup();
+			}
+			// If it is null, the DownloadTask will make a new empty cachedFile
+			f.updateFromCache(file);
 		});
 		tasks.forEach(f -> f.downloadMetadata(indexFile, indexUri));
 
@@ -283,75 +290,17 @@ public class UpdateManager {
 
 		// TODO: different thread pool type?
 		ExecutorService threadPool = Executors.newFixedThreadPool(10);
-		CompletionService<DownloadCompletion> completionService = new ExecutorCompletionService<>(threadPool);
+		CompletionService<DownloadTask> completionService = new ExecutorCompletionService<>(threadPool);
 
-		for (IndexFile.File f : newFiles) {
+		tasks.forEach(t -> {
-			ManifestFile.File cachedFile = manifest.cachedFiles.get(f.file);
 			completionService.submit(() -> {
-				DownloadCompletion dc = new DownloadCompletion();
+				t.download(opts.packFolder, indexUri);
-				dc.file = f;
+				return t;
-
+			});
-				if (cachedFile != null && cachedFile.linkedFileHash != null && f.linkedFile != null) {
-					try {
-						if (cachedFile.linkedFileHash.equals(f.linkedFile.getHash())) {
-							// Do nothing, the file didn't change
-							// TODO: but if the hash of the metafile changed, what did change?????
-							// should this be checked somehow??
-							return dc;
-						}
-					} catch (Exception ignored) {}
-				}
-
-				Path destPath = Paths.get(opts.packFolder, f.getDestURI().toString());
-
-				// Don't update files marked with preserve if they already exist on disk
-				if (f.preserve) {
-					if (Files.exists(destPath)) {
-						return dc;
-					}
-				}
-
-				try {
-					Hash hash;
-					String fileHashFormat;
-					if (f.linkedFile != null) {
-						hash = f.linkedFile.getHash();
-						fileHashFormat = f.linkedFile.download.hashFormat;
-					} else {
-						hash = f.getHash();
-						fileHashFormat = f.hashFormat;
-					}
-
-					Source src = f.getSource(indexUri);
-					GeneralHashingSource fileSource = HashUtils.getHasher(fileHashFormat).getHashingSource(src);
-					Buffer data = new Buffer();
-					Okio.buffer(fileSource).readAll(data);
-
-					if (fileSource.hashIsEqual(hash)) {
-						Files.createDirectories(destPath.getParent());
-						Files.copy(data.inputStream(), destPath, StandardCopyOption.REPLACE_EXISTING);
-					} else {
-						System.out.println("Invalid hash for " + f.getDestURI().toString());
-						System.out.println("Calculated: " + fileSource.getHash());
-						System.out.println("Expected:   " + hash);
-						dc.err = new Exception("Hash invalid!");
-					}
-
-					if (cachedFile != null && !destPath.equals(Paths.get(opts.packFolder, cachedFile.cachedLocation))) {
-						// Delete old file if location changes
-						Files.delete(Paths.get(opts.packFolder, cachedFile.cachedLocation));
-					}
-
-					return dc;
-				} catch (Exception e) {
-					dc.err = e;
-					return dc;
-				}
 		});
-		}
 
-		for (int i = 0; i < newFiles.size(); i++) {
+		for (int i = 0; i < tasks.size(); i++) {
-			DownloadCompletion ret;
+			DownloadTask ret;
 			try {
 				ret = completionService.take().get();
 			} catch (InterruptedException | ExecutionException e) {
@@ -359,57 +308,25 @@ public class UpdateManager {
 				ui.handleException(e);
 				ret = null;
 			}
-			// Update manifest
+			// Update manifest - If there were no errors cachedFile has already been modified in place (good old pass by reference)
-			if (ret != null && ret.err == null && ret.file != null) {
+			if (ret != null && ret.getException() != null) {
-				ManifestFile.File newCachedFile = new ManifestFile.File();
+				manifest.cachedFiles.put(ret.metadata.file, ret.cachedFile.getRevert());
-				try {
-					newCachedFile.hash = ret.file.getHash();
-					if (newCachedFile.hash == null) {
-						throw new Exception("Invalid hash!");
-					}
-				} catch (Exception e) {
-					ret.err = e;
-				}
-				if (ret.file.metafile && ret.file.linkedFile != null) {
-					newCachedFile.isOptional = ret.file.linkedFile.isOptional();
-					if (newCachedFile.isOptional) {
-						newCachedFile.optionValue = ret.file.optionValue;
-					}
-					try {
-						newCachedFile.linkedFileHash = ret.file.linkedFile.getHash();
-					} catch (Exception e) {
-						ret.err = e;
-					}
-				}
-				newCachedFile.cachedLocation = ret.file.getDestURI().toString();
-				manifest.cachedFiles.put(ret.file.file, newCachedFile);
 			}
 			// TODO: show errors properly?
 			String progress;
 			if (ret != null) {
-				if (ret.err != null) {
+				if (ret.getException() != null) {
-					if (ret.file != null) {
+					progress = "Failed to download " + ret.metadata.getName() + ": " + ret.getException().getMessage();
-						progress = "Failed to download " + ret.file.getName() + ": " + ret.err.getMessage();
+					ret.getException().printStackTrace();
 				} else {
-						progress = "Failed to download: " + ret.err.getMessage();
+					progress = "Downloaded " + ret.metadata.getName();
-					}
-					ret.err.printStackTrace();
-				} else if (ret.file != null) {
-					progress = "Downloaded " + ret.file.getName();
-				} else {
-					progress = "Failed to download, unknown reason";
 				}
 			} else {
 				progress = "Failed to download, unknown reason";
 			}
-			ui.submitProgress(new InstallProgress(progress, i + 1, newFiles.size()));
+			ui.submitProgress(new InstallProgress(progress, i + 1, tasks.size()));
 		}
 		// option = false file hashes should be stored to disk, but not downloaded
 		// TODO: don't include optional files in progress????
 	}
-
-	private class DownloadCompletion {
-		Exception err;
-		IndexFile.File file;
-	}
 }

src/main/java/link/infra/packwiz/installer/metadata/ManifestFile.java

@@ -1,5 +1,6 @@
 package link.infra.packwiz.installer.metadata;
 
+import link.infra.packwiz.installer.UpdateManager;
 import link.infra.packwiz.installer.metadata.hash.Hash;
 
 import java.net.URI;
@@ -9,13 +10,31 @@ public class ManifestFile {
 	public Hash packFileHash = null;
 	public Hash indexFileHash = null;
 	public Map<URI, File> cachedFiles;
+	// If the side changes, EVERYTHING invalidates. FUN!!!
+	public UpdateManager.Options.Side cachedSide = UpdateManager.Options.Side.CLIENT;
 
 	public static class File {
+		private transient File revert;
+
 		public Hash hash = null;
 		public Hash linkedFileHash = null;
 		public String cachedLocation = null;
 
 		public boolean isOptional = false;
 		public boolean optionValue = true;
+
+		// When an error occurs, the state needs to be reverted. To do this, I have a crude revert system.
+		public void backup() {
+			revert = new File();
+			revert.hash = hash;
+			revert.linkedFileHash = linkedFileHash;
+			revert.cachedLocation = cachedLocation;
+			revert.isOptional = isOptional;
+			revert.optionValue = optionValue;
+		}
+
+		public File getRevert() {
+			return revert;
+		}
 	}
 }