feat: auto-reload modified CSS themes

org.eclipse.tm4e.registry/src/main/java/org/eclipse/tm4e/registry/TMResource.java

@@ -19,6 +19,7 @@
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
 
+import org.eclipse.core.runtime.FileLocator;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.jdt.annotation.Nullable;
 
@@ -27,7 +28,7 @@
  */
 public abstract class TMResource implements ITMResource {
 
-	private static final String PLATFORM_PLUGIN = "platform:/plugin/"; //$NON-NLS-1$
+	private static final String PLATFORM_PLUGIN = "platform:/plugin/";
 
 	private String path;
 	private @Nullable String pluginId;
@@ -48,7 +49,7 @@ protected TMResource(final String path) {
 		this.path = path;
 	}
 
-	protected TMResource(final String path, @Nullable final String pluginId) {
+	protected TMResource(final String path, final @Nullable String pluginId) {
 		this.path = path;
 		this.pluginId = pluginId;
 	}
@@ -66,13 +67,24 @@ public String getPath() {
 	@Override
 	@SuppressWarnings("resource")
 	public InputStream getInputStream() throws IOException {
-		return new BufferedInputStream(pluginId != null
-				? new URL(PLATFORM_PLUGIN + pluginId + "/" + path).openStream()
-				: new FileInputStream(new File(path)));
+		return new BufferedInputStream(pluginId == null
+				? new FileInputStream(new File(path))
+				: new URL(PLATFORM_PLUGIN + pluginId + '/' + path).openStream());
+	}
+
+	protected long getLastModified() {
+		try {
+			return new File(pluginId == null
+					? path
+					: FileLocator.resolve(new URL(PLATFORM_PLUGIN + pluginId + '/' + path)).getFile() //
+			).lastModified();
+		} catch (final Exception ex) {
+			return 0;
+		}
 	}
 
 	protected @Nullable String getResourceContent() {
-		try (InputStream in = this.getInputStream()) {
+		try (InputStream in = getInputStream()) {
 			return new String(in.readAllBytes(), StandardCharsets.UTF_8);
 		} catch (final Exception ex) {
 			TMEclipseRegistryPlugin.logError(ex);

org.eclipse.tm4e.ui/src/main/java/org/eclipse/tm4e/ui/themes/Theme.java

@@ -28,7 +28,6 @@
 
 /**
  * {@link ITheme} implementation.
- *
  */
 public class Theme extends TMResource implements ITheme {
 
@@ -137,7 +136,7 @@ public Color getEditorCurrentLineHighlight() {
 
 	@Nullable
 	private ITokenProvider getTokenProvider() {
-		if (tokenProvider == null) {
+		if (tokenProvider == null || isModified()) {
 			try (InputStream in = super.getInputStream()) {
 				tokenProvider = new CSSTokenProvider(in);
 			} catch (final Exception ex) {
@@ -148,6 +147,20 @@ private ITokenProvider getTokenProvider() {
 		return tokenProvider;
 	}
 
+	private long lastModified = -1;
+	private long lastModifiedRecheck = -1;
+
+	private boolean isModified() {
+		final long now = System.currentTimeMillis();
+		if (now > lastModifiedRecheck) {
+			lastModifiedRecheck = now + 5_000;
+			final long oldModified = lastModified;
+			lastModified = getLastModified();
+			return lastModified != oldModified;
+		}
+		return false;
+	}
+
 	@Nullable
 	@Override
 	public String toCSSStyleSheet() {