Bug 574519: Always collect WSL entries in a Job

Change-Id: I35abec7ca075bf525e972e4cbc03af4361d1d490

terminal/plugins/org.eclipse.tm.terminal.view.ui/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.tm.terminal.view.ui;singleton:=true
-Bundle-Version: 4.9.0.qualifier
+Bundle-Version: 4.9.1.qualifier
 Bundle-Activator: org.eclipse.tm.terminal.view.ui.activator.UIPlugin
 Bundle-Vendor: %providerName
 Require-Bundle: org.eclipse.core.expressions;bundle-version="3.4.400",

terminal/plugins/org.eclipse.tm.terminal.view.ui/src/org/eclipse/tm/terminal/view/ui/local/showin/detectors/DetectWSL.java

@@ -24,16 +24,19 @@ import java.util.List;
 import java.util.Map;
 import java.util.function.Predicate;
 
+import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.OperationCanceledException;
 import org.eclipse.core.runtime.Platform;
+import org.eclipse.core.runtime.Status;
+import org.eclipse.core.runtime.jobs.Job;
 import org.eclipse.tm.terminal.view.ui.interfaces.IExternalExecutablesProperties;
 import org.eclipse.tm.terminal.view.ui.local.showin.IDetectExternalExecutable;
 
 public class DetectWSL implements IDetectExternalExecutable {
 
-	/**
+	private List<Map<String, String>> result = null;
-	 * Don't access directly, use {@link #getEntries()}
+	private WslDetectJob detectJob = null;
-	 */
-	List<Map<String, String>> result = null;
 
 	@Override
 	public boolean hasEntries() {
@@ -55,57 +58,94 @@ public class DetectWSL implements IDetectExternalExecutable {
 	}
 
 	private synchronized List<Map<String, String>> getEntries() {
-		if (result == null) {
+		// getEntries can be called in many contexts, even from within
-			result = Collections.emptyList();
+		// menu creation (see Bug 574519). Therefore we spawn a job to
-			if (Platform.OS_WIN32.equals(Platform.getOS())) {
+		// get the real entries, which means until the job is done, this
-				String windir = System.getenv("windir"); //$NON-NLS-1$
+		// method will return no entries.
-				if (windir == null) {
+		if (result != null) {
-					return result;
+			return result;
-				}
+		}
-				String wsl = windir + "\\System32\\wsl.exe"; //$NON-NLS-1$
+		if (detectJob == null) {
-				if (!Files.isExecutable(Paths.get(wsl))) {
+			detectJob = new WslDetectJob();
-					return result;
+			detectJob.schedule();
-				}
+		}
-
+		try {
-				ProcessBuilder pb = new ProcessBuilder(wsl, "--list", "--quiet"); //$NON-NLS-1$ //$NON-NLS-2$
+			if (detectJob.join(10, null)) {
-				try {
+				result = detectJob.result;
-					Process process = pb.start();
+				detectJob = null;
-					try (InputStream is = process.getErrorStream()) {
+			} else {
-						// drain the error stream
+				return Collections.emptyList();
-						if (is.readAllBytes().length != 0) {
-							return result;
-						}
-					}
-
-					try (BufferedReader reader = new BufferedReader(
-							new InputStreamReader(process.getInputStream(), StandardCharsets.UTF_16LE))) {
-						result = new ArrayList<>();
-						String line = null;
-						while ((line = reader.readLine()) != null) {
-							String distribution = line.trim();
-							if (distribution.isBlank()) {
-								continue;
-							}
-							// docker-desktop entries are not "real" so shouldn't be shown in UI
-							if (distribution.startsWith("docker-desktop")) { //$NON-NLS-1$
-								continue;
-							}
-
-							String name = distribution + " (WSL)"; //$NON-NLS-1$
-							Map<String, String> m = new HashMap<>();
-							m.put(IExternalExecutablesProperties.PROP_NAME, name);
-							m.put(IExternalExecutablesProperties.PROP_PATH, wsl);
-							m.put(IExternalExecutablesProperties.PROP_ARGS, "--distribution " + distribution); //$NON-NLS-1$
-							m.put(IExternalExecutablesProperties.PROP_TRANSLATE, Boolean.TRUE.toString());
-							result.add(m);
-						}
-					}
-
-				} catch (IOException e) {
-				}
 			}
+		} catch (OperationCanceledException | InterruptedException e) {
+			result = Collections.emptyList();
+			detectJob = null;
 		}
 		return result;
 	}
 
+	private static class WslDetectJob extends Job {
+		private List<Map<String, String>> result = null;
+
+		public WslDetectJob() {
+			super("Detect WSL Instances"); //$NON-NLS-1$
+			setSystem(true);
+		}
+
+		@Override
+		protected IStatus run(IProgressMonitor monitor) {
+			if (result == null) {
+				result = Collections.emptyList();
+				if (Platform.OS_WIN32.equals(Platform.getOS())) {
+					String windir = System.getenv("windir"); //$NON-NLS-1$
+					if (windir == null) {
+						return Status.OK_STATUS;
+					}
+					String wsl = windir + "\\System32\\wsl.exe"; //$NON-NLS-1$
+					if (!Files.isExecutable(Paths.get(wsl))) {
+						return Status.OK_STATUS;
+					}
+
+					ProcessBuilder pb = new ProcessBuilder(wsl, "--list", "--quiet"); //$NON-NLS-1$ //$NON-NLS-2$
+					try {
+						Process process = pb.start();
+						try (InputStream is = process.getErrorStream()) {
+							// drain the error stream
+							if (is.readAllBytes().length != 0) {
+								return Status.OK_STATUS;
+							}
+						}
+
+						try (BufferedReader reader = new BufferedReader(
+								new InputStreamReader(process.getInputStream(), StandardCharsets.UTF_16LE))) {
+							result = new ArrayList<>();
+							String line = null;
+							while ((line = reader.readLine()) != null) {
+								String distribution = line.trim();
+								if (distribution.isBlank()) {
+									continue;
+								}
+								// docker-desktop entries are not "real" so shouldn't be shown in UI
+								if (distribution.startsWith("docker-desktop")) { //$NON-NLS-1$
+									continue;
+								}
+
+								String name = distribution + " (WSL)"; //$NON-NLS-1$
+								Map<String, String> m = new HashMap<>();
+								m.put(IExternalExecutablesProperties.PROP_NAME, name);
+								m.put(IExternalExecutablesProperties.PROP_PATH, wsl);
+								m.put(IExternalExecutablesProperties.PROP_ARGS, "--distribution " + distribution); //$NON-NLS-1$
+								m.put(IExternalExecutablesProperties.PROP_TRANSLATE, Boolean.TRUE.toString());
+								result.add(m);
+							}
+						}
+
+					} catch (IOException e) {
+					}
+				}
+			}
+			return Status.OK_STATUS;
+		}
+
+	}
+
 }