initial commit

cs/src/UpdateLabCode.java

@@ -0,0 +1,173 @@
+/**
+ ** Simple application to update cs/labs.jar to the most recent version.
+ **
+ ** The labs.jar file is fetched from the gitlab.com repository.
+ **/
+
+import java.awt.BorderLayout;
+import java.awt.Dimension;
+import java.awt.FlowLayout;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+import java.util.Arrays;
+import java.util.List;
+import java.util.jar.Attributes;
+import java.util.jar.JarFile;
+import java.util.stream.Collectors;
+
+import javax.swing.JButton;
+import javax.swing.JFrame;
+import javax.swing.JLabel;
+import javax.swing.JPanel;
+import javax.swing.SwingConstants;
+import javax.swing.SwingUtilities;
+import javax.swing.UIManager;
+
+public class UpdateLabCode extends JFrame {
+
+    private static final URI DOWNLOAD_URI = URI.create("https://gitlab.com/api/v4/projects/edaf85%2Fedaf85-labs/repository/files/cs%2Flabs.jar/raw?ref=main");
+
+    private final JLabel messageArea = new JLabel("", SwingConstants.CENTER);
+    private final JPanel buttonArea = new JPanel(new FlowLayout(FlowLayout.RIGHT, 20, 20));
+
+    // -----------------------------------------------------------------------
+
+    public UpdateLabCode() {
+        super("Update lab code (EDAF85, fall 2024)");
+
+        add(messageArea, BorderLayout.CENTER);
+        add(buttonArea, BorderLayout.SOUTH);
+
+        try {
+            List<Path> candidates = Files.walk(Path.of(System.getProperty("user.dir")).getParent())
+                    .filter(Files::isRegularFile)
+                    .filter(f -> f.endsWith(Path.of("cs", "labs.jar")))
+                    .collect(Collectors.toList());
+            if (candidates.size() == 1) {
+                showDialog("Currently using version:    " + getJarVersion(candidates.get(0)),
+                           "Check for update", () -> check(candidates.get(0)));
+            } else {
+                if (candidates.size() != 0) {
+                    System.err.println("*** ERROR: found multiple 'cs/labs.jar', cannot decide which one to use:");
+                    candidates.forEach(System.err::println);
+                }
+                throw new FileNotFoundException("cannot locate 'cs/labs.jar'");
+            }
+        } catch (IOException e) {
+            fail(e);
+        }
+
+        setPreferredSize(new Dimension(600, 150));
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        setResizable(false);
+        pack();
+
+        setLocationRelativeTo(null);
+
+        setVisible(true);
+    }
+
+    private void showDialog(String message, String buttonLabel, Runnable onClick) {
+        SwingUtilities.invokeLater(() -> {
+            messageArea.setText(message);
+            buttonArea.removeAll();
+            buttonArea.repaint();
+            JButton b = new JButton(buttonLabel);
+            b.addActionListener(e -> {
+                b.setEnabled(false);
+                onClick.run();
+            });
+            buttonArea.add(b);
+            getRootPane().setDefaultButton(b);
+        });
+    }
+
+    private void fail(Throwable t) {
+        t.printStackTrace(System.err);
+        showDialog("Error: " + t.getClass().getSimpleName() + " (see console)",
+                   "Quit", () -> System.exit(1));
+    }
+
+    private void check(Path labsJar) {
+        try {
+            messageArea.setText("Checking...");
+
+            Path tempDir = labsJar.getParent().resolve("archive");
+            Files.createDirectories(tempDir);
+
+            Path downloadJar = Files.createTempFile(tempDir, ".download-", ".jar");
+            downloadJar.toFile().deleteOnExit();
+
+            HttpRequest req = HttpRequest.newBuilder(DOWNLOAD_URI).build();
+            HttpClient.newHttpClient()
+                    .sendAsync(req, BodyHandlers.ofFile(downloadJar))
+                    .thenAccept(response -> {
+                        try {
+                            int status = response.statusCode();
+                            if (status != HttpURLConnection.HTTP_OK) {
+                                showDialog("Unexpected status code: " + status,
+                                           "Quit", () -> System.exit(1));
+                            } else if (Arrays.equals(Files.readAllBytes(labsJar), Files.readAllBytes(downloadJar))) { // same content
+                                showDialog("No update available: you are using the latest version    (" + getJarVersion(labsJar) + ")",
+                                           "OK", () -> System.exit(0));
+                            } else if (!getCourseVersion(downloadJar).equals("fall 2024")) {
+                                showDialog("Cannot update: latest update requires repo from " + getCourseVersion(downloadJar),
+                                           "OK", () -> System.exit(0));
+                            } else {
+                                showDialog("Update available:    " + getJarVersion(downloadJar),
+                                           "Update now", () -> updateLabsJar(labsJar, downloadJar, tempDir));
+                            }
+                        } catch (IOException e) {
+                            fail(e);
+                        }
+                    });
+        } catch (IOException e) {
+            fail(e);
+        }
+    }
+
+    private void updateLabsJar(Path labsJar, Path downloadJar, Path tempDir) {
+        try {
+            Path tempFile = Files.createTempFile(tempDir, "labs_jar_", ".old");
+            Files.move(labsJar, tempFile, StandardCopyOption.REPLACE_EXISTING);
+            Files.move(downloadJar, labsJar, StandardCopyOption.REPLACE_EXISTING);
+            showDialog("Success: you are now using the latest version!",
+                       "OK", () -> System.exit(0));
+        } catch (IOException e) {
+            fail(e);
+        }
+    }
+
+    private static String getCourseVersion(Path jar) {
+        try (JarFile f = new JarFile(jar.toFile())) {
+            Attributes a = f.getManifest().getAttributes("common");
+            return (a != null) ? a.getValue(Attributes.Name.SPECIFICATION_VERSION) : "unknown";
+        } catch (IOException e) {
+            return "unknown";
+        }
+    }
+
+    private static String getJarVersion(Path jar) {
+        try (JarFile f = new JarFile(jar.toFile())) {
+            Attributes a = f.getManifest().getAttributes("common");
+            return (a != null) ? a.getValue(Attributes.Name.IMPLEMENTATION_VERSION) : "unknown";
+        } catch (IOException e) {
+            return "unknown";
+        }
+    }
+
+    // -----------------------------------------------------------------------
+
+    public static void main(String[] args) throws Exception {
+        UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
+        SwingUtilities.invokeLater(UpdateLabCode::new);
+    }
+}