Correctly handle file invalidation

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

@@ -7,10 +7,14 @@ import java.io.IOException;
 import java.io.Writer;
 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.HashMap;
+import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.Callable;
 import java.util.concurrent.CompletionService;
 import java.util.concurrent.ConcurrentLinkedQueue;
@@ -142,7 +146,22 @@ public class UpdateManager {
 			return;
 		}
 
-		if (manifest.packFileHash != null && packFileSource.hashIsEqual(manifest.packFileHash)) {
+		ui.submitProgress(new InstallProgress("Checking local files..."));
+
+		List<URI> invalidatedUris = new ArrayList<>();
+		Iterator<Map.Entry<URI, ManifestFile.File>> it = manifest.cachedFiles.entrySet().iterator();
+		while (it.hasNext()) {
+			Map.Entry<URI, ManifestFile.File> entry = it.next();
+			if (entry.getValue().cachedLocation != null) {
+				if (!Files.exists(Paths.get(opts.packFolder, entry.getValue().cachedLocation))) {
+					URI fileUri = entry.getKey();
+					System.out.println("File " + fileUri.toString() + " invalidated, marked for redownloading");
+					invalidatedUris.add(fileUri);
+				}
+			}
+		}
+
+		if (manifest.packFileHash != null && packFileSource.hashIsEqual(manifest.packFileHash) && invalidatedUris.size() == 0) {
 			System.out.println("Modpack is already up to date!");
 			// todo: --force?
 			return;
@@ -152,7 +171,7 @@ public class UpdateManager {
 
 		try {
 			processIndex(HandlerManager.getNewLoc(opts.downloadURI, pf.index.file),
-					HashUtils.getHash(pf.index.hashFormat, pf.index.hash), pf.index.hashFormat, manifest);
+					HashUtils.getHash(pf.index.hashFormat, pf.index.hash), pf.index.hashFormat, manifest, invalidatedUris);
 		} catch (Exception e1) {
 			ui.handleExceptionAndExit(e1);
 		}
@@ -173,8 +192,8 @@ public class UpdateManager {
 		// TODO: implement
 	}
 
-	protected void processIndex(URI indexUri, Hash indexHash, String hashFormat, ManifestFile manifest) {
+	protected void processIndex(URI indexUri, Hash indexHash, String hashFormat, ManifestFile manifest, List<URI> invalidatedUris) {
-		if (manifest.indexFileHash != null && manifest.indexFileHash.equals(indexHash)) {
+		if (manifest.indexFileHash != null && manifest.indexFileHash.equals(indexHash) && invalidatedUris.size() == 0) {
 			System.out.println("Modpack files are already up to date!");
 			return;
 		}
@@ -207,6 +226,25 @@ public class UpdateManager {
 			manifest.cachedFiles = new HashMap<URI, ManifestFile.File>();
 		}
 
+		ui.submitProgress(new InstallProgress("Checking local files..."));
+		Iterator<Map.Entry<URI, ManifestFile.File>> it = manifest.cachedFiles.entrySet().iterator();
+		while (it.hasNext()) {
+			Map.Entry<URI, ManifestFile.File> entry = it.next();
+			if (entry.getValue().cachedLocation != null) {
+				if (!indexFile.files.stream().anyMatch(f -> f.file.equals(entry.getKey()))) {
+					// File has been removed from the index
+					try {
+						Files.deleteIfExists(Paths.get(opts.packFolder, entry.getValue().cachedLocation));
+					} catch (IOException e) {
+						// TODO: should this be shown to the user in some way?
+						e.printStackTrace();
+					}
+					it.remove();
+				}
+			}
+		}
+		ui.submitProgress(new InstallProgress("Comparing new files..."));
+
 		// TODO: progress bar
 		ConcurrentLinkedQueue<Exception> exceptionQueue = new ConcurrentLinkedQueue<Exception>();
 		List<IndexFile.File> newFiles = indexFile.files.stream().map(f -> {
@@ -215,6 +253,9 @@ public class UpdateManager {
 			}
 			return f;
 		}).filter(f -> {
+			if (invalidatedUris.contains(f.file)) {
+				return true;
+			}
 			ManifestFile.File cachedFile = manifest.cachedFiles.get(f.file);
 			Hash newHash;
 			try {
@@ -270,9 +311,11 @@ public class UpdateManager {
 						} catch (Exception e) {}
 					}
 
+					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(Paths.get(opts.packFolder, f.getDestURI().toString()))) {
+						if (Files.exists(destPath)) {
 							return dc;
 						}
 					}
@@ -294,8 +337,8 @@ public class UpdateManager {
 						Okio.buffer(fileSource).readAll(data);
 
 						if (fileSource.hashIsEqual(hash)) {
-							Files.createDirectories(Paths.get(opts.packFolder, f.getDestURI().toString()).getParent());
+							Files.createDirectories(destPath.getParent());
-							Files.copy(data.inputStream(), Paths.get(opts.packFolder, f.getDestURI().toString()), StandardCopyOption.REPLACE_EXISTING);
+							Files.copy(data.inputStream(), destPath, StandardCopyOption.REPLACE_EXISTING);
 						} else {
 							System.out.println("Invalid hash for " + f.getDestURI().toString());
 							System.out.println("Calculated: " + fileSource.getHash());
@@ -303,6 +346,11 @@ public class UpdateManager {
 							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;
@@ -343,6 +391,7 @@ public class UpdateManager {
 						ret.err = e;
 					}
 				}
+				newCachedFile.cachedLocation = ret.file.getDestURI().toString();
 				manifest.cachedFiles.put(ret.file.file, newCachedFile);
 			}
 			// TODO: show errors properly?

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

@@ -16,5 +16,6 @@ public class ManifestFile {
 		public boolean isOptional = false;
 		public boolean optionValue = true;
 		public Hash linkedFileHash = null;
+		public String cachedLocation = null;
 	}
 }