perf: avoid null check of parser in CSSTokenProvider

org.eclipse.tm4e.core/src/main/java/org/eclipse/tm4e/core/theme/css/CSSParser.java

@@ -34,7 +34,10 @@
  */
 public class CSSParser {
 
-	private final CSSDocumentHandler handler;
+	protected final CSSDocumentHandler handler = new CSSDocumentHandler();
+
+	protected CSSParser() {
+	}
 
 	public CSSParser(final InputStream source) throws Exception {
 		this(toSource(source));
@@ -55,7 +58,6 @@ public CSSParser(final String source) throws Exception {
 	}
 
 	public CSSParser(final InputSource source, final Parser parser) throws CSSException, IOException {
-		this.handler = new CSSDocumentHandler();
 		parser.setDocumentHandler(handler);
 		parser.setConditionFactory(CSSConditionFactory.INSTANCE);
 		parser.setSelectorFactory(CSSSelectorFactory.INSTANCE);
@@ -84,5 +86,4 @@ public IStyle getBestStyle(final String... names) {
 	public List<IStyle> getStyles() {
 		return handler.getList();
 	}
-
 }

org.eclipse.tm4e.ui/src/main/java/org/eclipse/tm4e/ui/themes/css/CSSTokenProvider.java

@@ -12,7 +12,9 @@
 package org.eclipse.tm4e.ui.themes.css;
 
 import java.io.InputStream;
+import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.eclipse.jdt.annotation.Nullable;
@@ -31,12 +33,24 @@
 
 public class CSSTokenProvider extends AbstractTokenProvider {
 
+	private static class NoopCSSParser extends CSSParser {
+		@Override
+		public List<IStyle> getStyles() {
+			return Collections.emptyList();
+		}
+
+		@Override
+		public @Nullable IStyle getBestStyle(String... names) {
+			return null;
+		}
+	}
+
 	private final Map<IStyle, @Nullable IToken> tokenMaps = new HashMap<>();
 
-	@Nullable
-	private CSSParser parser;
+	private final CSSParser parser;
 
 	public CSSTokenProvider(final InputStream in) {
+		CSSParser parser = null;
 		try {
 			parser = new CSSParser(in);
 			for (final IStyle style : parser.getStyles()) {
@@ -62,6 +76,8 @@ public CSSTokenProvider(final InputStream in) {
 		} catch (final Exception ex) {
 			TMUIPlugin.logError(ex);
 		}
+
+		this.parser = parser == null ? new NoopCSSParser() : parser;
 	}
 
 	@Nullable
@@ -70,10 +86,6 @@ public IToken getToken(@Nullable final String type) {
 		if (type == null)
 			return null;
 
-		final var parser = this.parser;
-		if (parser == null)
-			return null;
-
 		final IStyle style = parser.getBestStyle(StringUtils.splitToArray(type, '.'));
 		if (style == null)
 			return null;
@@ -83,10 +95,6 @@ public IToken getToken(@Nullable final String type) {
 
 	@Nullable
 	private Color getColor(final boolean isForeground, final String... styles) {
-		final var parser = this.parser;
-		if (parser == null)
-			return null;
-
 		final var style = parser.getBestStyle(styles);
 		if (style == null)
 			return null;
@@ -120,7 +128,6 @@ public Color getEditorSelectionForeground() {
 	@Override
 	public Color getEditorSelectionBackground() {
 		return getColor(false, "editor", "selection");
-
 	}
 
 	@Nullable