Fix opening legacy files from the pre-open-source era

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.3.0 (2024-02-05)
+### Fixed
+  - Ability to open files from old JDigitalSimulator versions (before open-sourcing, version < 1.*), see the README.md instructions
+
 ## 2.2.0 (2022-06-18)
 ### Added
   - US / ANSI style gate symbols and option to switch in the menu, thanks to Sett17

README.md

@@ -7,10 +7,19 @@ JDigitalSimulator is a platform independent open source Electronic Design Automa
 
 Please download the latest release from the [releases section](https://github.com/kristian/JDigitalSimulator/releases/latest) here on GitHub. Visit the [project homepage](http://kra.lc/projects/jdigitalsimulator/) for some additional information.
 
+Run
+---
+
+To run JDigitalSimulator download the JAR file and run it with:
+```
+java -jar jds-2.x.x.jar
+```
+Note that if you are using a latest Java version (such as Java 21), it will require you to use a `--add-opens java.base/java.io=ALL-UNNAMED` to the command, in order to be able to open legacy files from JDigitalSimulator version > 1.*.
+
 Build
 -----
 
-To build `JDigitalSimulator` on your machine, checkout the repository, `cd` into it, and call:
+To build JDigitalSimulator on your machine, checkout the repository, `cd` into it, and call:
 ```
 mvn clean install
 ```

pom.xml

@@ -4,7 +4,7 @@
 
 	<groupId>lc.kra.jds</groupId>
 	<artifactId>jds</artifactId>
-	<version>2.2.0</version>
+	<version>2.3.0</version>
 
 	<name>JDigitalSimulator</name>
 	<url>http://kra.lc/projects/jdigitalsimulator/</url>
@@ -99,6 +99,7 @@
 								<jdkPreference>preferJre</jdkPreference>
 								<opts>
 									<opt>-Xss4m</opt>
+									<opt>--add-opens java.base/java.io=ALL-UNNAMED</opt>
 								</opts>
 							</jre>
 							<versionInfo>

src/main/java/lc/kra/jds/Simulation.java

@@ -1184,6 +1184,7 @@ public final static Simulation readSimulation(InputStream in, String password) t
 				objectData = objectIn.readObject();
 			} finally { objectIn.close(); }
 		} catch(StreamCorruptedException e) { //cypher required or corrupted input
+			e.printStackTrace();
 			if(password==null||password.isEmpty())
 				throw new PasswordRequiredException();
 			ObjectInputStream objectIn = new LegacyObjectInputStream(new CipherInputStream(in, Utilities.createCipher(Utilities.computeHash(password), Cipher.DECRYPT_MODE)));

src/main/java/lc/kra/jds/Utilities.java

@@ -444,12 +444,29 @@ public AlternateClassLoaderObjectInputStream(InputStream in, ClassLoader alterna
 	public static class LegacyObjectInputStream extends AlternateClassLoaderObjectInputStream {
 		public static final String LEGACY_PACKAGE_PREFIX = "de.ksquared.", PACKAGE_PREFIX = "lc.kra.";
 		public LegacyObjectInputStream(InputStream in) throws IOException {
-			super(in, getSimpleClassLoader()); }
+			super(in, getSimpleClassLoader());
+		}
 		@Override protected ObjectStreamClass readClassDescriptor() throws IOException, ClassNotFoundException {
 			ObjectStreamClass descriptor = super.readClassDescriptor(); String name = descriptor.getName();
-			if(name.contains(LEGACY_PACKAGE_PREFIX)) descriptor = ObjectStreamClass.lookup(Class.forName(replaceLegacyPackage(name), false, alternateClassLoader));
+			if(name.contains(LEGACY_PACKAGE_PREFIX)) {
+				String newName = replaceLegacyPackage(name);
+				try {
+					// Do not return a new ObjectStreamClass looked up from new class definitions, but modify the descriptor read from the stream.
+					// Otherwise some flags could be wrong, like the flag "hasWriteObjectData" when reading objects from 7.6/7.7.
+					Field nameField = ObjectStreamClass.class.getDeclaredField("name");
+					nameField.setAccessible(true);
+					nameField.set(descriptor, newName);
+				} catch (IllegalAccessException | NoSuchFieldException e) {
+					throw new RuntimeException(e);
+				}
+			}
 			return descriptor;
 		}
+		@Override
+		protected Object resolveObject(Object obj) throws IOException {
+			// TODO Auto-generated method stub
+			return super.resolveObject(obj);
+		}
 		public static String replaceLegacyPackage(String name) {
 			return name.replaceFirst("^(\\[L)?"+Pattern.quote(LEGACY_PACKAGE_PREFIX), "$1"+Matcher.quoteReplacement(PACKAGE_PREFIX));
 		}

src/main/java/lc/kra/jds/gui/Application.java

@@ -140,15 +140,15 @@
 /**
  * JDigitalSimulator
  * @author Kristian Kraljic
- * @version 2.2.0
+ * @version 2.3.0
  */
 public class Application extends JFrame {
 	private static final long serialVersionUID = -4693271310855486553L;
 
 	public static final String FILE_EXTENSION = "jdsim";
 	public static File pluginDirectory, currentDirectory;
 
-	private static final String VERSION = "2.2.0", COPYRIGHT = "2010-2022", LINES_OF_CODE = "9.509", WORDS_OF_CODE = "36.133", PAGES_OF_CODE = "245";
+	private static final String VERSION = "2.3.0", COPYRIGHT = "2010-2024", LINES_OF_CODE = "9.509", WORDS_OF_CODE = "36.133", PAGES_OF_CODE = "245";
 
 	private static final String[]
 		TOOLBAR_FRAME_FOCUS = new String[]{"save", "print", "print_level", "simulate", "left", "right", "up", "down", "grid", "secure", "zoom_default", "zoom", "zoom_in", "zoom_out"},