Support semantic highlighting

Signed-off-by: Yan Zhang <yanzh@microsoft.com>

Author: Eskibear

README.md

@@ -155,9 +155,10 @@ The following settings are supported:
 
   Default launch mode is `Hybrid`. Legacy mode is `Standard`
 
-  New in 0.60.0:
+New in 0.60.0:
 * `java.sources.organizeImports.starThreshold`: Specifies the number of imports added before a star-import declaration is used, default is 99.
 * `java.sources.organizeImports.staticStarThreshold`: Specifies the number of static imports added before a star-import declaration is used, default is 99.
+* `java.semanticHighlighting.enabled`: Enable/disable the [semantic highlighting](https://github.com/microsoft/vscode/wiki/Semantic-Highlighting-Overview). Defaults to `true`.
 
 Troubleshooting
 ===============

package-lock.json

@@ -11,7 +11,7 @@
   "preview": true,
   "enableProposedApi": false,
   "engines": {
-    "vscode": "^1.41.0"
+    "vscode": "^1.44.0"
   },
   "repository": {
     "type": "git",
@@ -526,7 +526,12 @@
         "java.sources.organizeImports.staticStarThreshold": {
           "type": "integer",
           "description": "Specifies the number of static imports added before a star-import declaration is used.",
-          "default": 99,
+          "default": 99
+        },
+        "java.semanticHighlighting.enabled": {
+          "type": "boolean",
+          "default": true,
+          "description": "Enable/disable the semantic highlighting.",
           "scope": "window"
         }
       }
@@ -693,7 +698,7 @@
     "@types/lodash.findindex": "^4.6.6",
     "@types/mocha": "^5.2.5",
     "@types/node": "^8.10.51",
-    "@types/vscode": "^1.41.0",
+    "@types/vscode": "^1.44.0",
     "@types/winston": "^2.4.4",
     "gulp": "^4.0.0",
     "gulp-decompress": "2.0.1",

package.json

@@ -184,4 +184,12 @@ export namespace Commands {
      * Check the input file is a test file or not
      */
     export const IS_TEST_FILE = 'java.project.isTestFile';
+    /**
+     * Temporary command for Semantic Highlighting. To remove when LSP v3.16 is ready.
+     */
+    export const PROVIDE_SEMANTIC_TOKENS = 'java.project.provideSemanticTokens';
+    /**
+     * Temporary command to fetch Semantic Tokens Legend. To remove when LSP v3.16 is ready.
+     */
+    export const GET_SEMANTIC_TOKENS_LEGEND = 'java.project.getSemanticTokensLegend';
 }

src/commands.ts

@@ -32,6 +32,7 @@ import { serverStatus, ServerStatusKind } from './serverStatus';
 import { SyntaxLanguageClient } from './syntaxLanguageClient';
 import { registerClientProviders, ClientHoverProvider } from './providerDispatcher';
 import * as fileEventHandler from './fileEventHandler';
+import { registerSemanticTokensProvider } from './semanticTokenProvider';
 
 let languageClient: LanguageClient;
 const syntaxClient: SyntaxLanguageClient = new SyntaxLanguageClient();
@@ -517,6 +518,9 @@ export function activate(context: ExtensionContext): Promise<ExtensionAPI> {
 			context.subscriptions.push(commands.registerCommand(Commands.CLEAN_WORKSPACE, () => cleanWorkspace(workspacePath)));
 
 			context.subscriptions.push(onConfigurationChange(languageClient, context));
+
+			// temporary implementation Semantic Highlighting before it is part of LSP
+			registerSemanticTokensProvider(context);
 		});
 	});
 }

src/extension.ts

@@ -0,0 +1,57 @@
+import * as vscode from 'vscode';
+import { Commands } from './commands';
+import { getJavaConfiguration } from './utils';
+
+export function registerSemanticTokensProvider(context: vscode.ExtensionContext) {
+	if (isSemanticHTokensEnabled()) {
+		getSemanticTokensLegend().then(legend => {
+			const semanticTokensProviderDisposable = vscode.languages.registerDocumentSemanticTokensProvider({ scheme: 'file', language: 'java' }, semanticTokensProvider, legend);
+			context.subscriptions.push(semanticTokensProviderDisposable);
+			onceSemanticTokenEnabledChange(context, semanticTokensProviderDisposable);
+		});
+	} else {
+		onceSemanticTokenEnabledChange(context, undefined);
+	}
+}
+
+class SemanticTokensProvider implements vscode.DocumentSemanticTokensProvider {
+    async provideDocumentSemanticTokens(document: vscode.TextDocument, token: vscode.CancellationToken): Promise<vscode.SemanticTokens> {
+        const response = await vscode.commands.executeCommand(Commands.EXECUTE_WORKSPACE_COMMAND, Commands.PROVIDE_SEMANTIC_TOKENS, document.uri.toString());
+        if (token.isCancellationRequested) {
+            return undefined;
+        }
+        return response as vscode.SemanticTokens;
+    }
+}
+
+const semanticTokensProvider = new SemanticTokensProvider();
+
+async function getSemanticTokensLegend(): Promise<vscode.SemanticTokensLegend | undefined> {
+    const response = await vscode.commands.executeCommand(Commands.EXECUTE_WORKSPACE_COMMAND, Commands.GET_SEMANTIC_TOKENS_LEGEND) as vscode.SemanticTokensLegend;
+    if (response && response.tokenModifiers !== undefined && response.tokenTypes !== undefined) {
+        return new vscode.SemanticTokensLegend(response.tokenTypes, response.tokenModifiers);
+    }
+    return undefined;
+}
+
+function onceSemanticTokenEnabledChange(context: vscode.ExtensionContext, registeredDisposable?: vscode.Disposable) {
+	const configChangeListener = vscode.workspace.onDidChangeConfiguration(e => {
+		configChangeListener.dispose();
+		if (e.affectsConfiguration('java.semanticHighlighting.enabled')) {
+			if (isSemanticHTokensEnabled()) {
+				// turn on
+				registerSemanticTokensProvider(context);
+			} else if (registeredDisposable) {
+				// turn off
+				registeredDisposable.dispose();
+			}
+			onceSemanticTokenEnabledChange(context);
+		}
+	});
+}
+
+function isSemanticHTokensEnabled(): boolean {
+	const config = getJavaConfiguration();
+	const section = 'semanticHighlighting.enabled';
+	return config.get(section);
+}