1 files changed, 43 insertions, 0 deletions

diff --git a/language-web/src/main/js/xtext/HighlightingService.ts b/language-web/src/main/js/xtext/HighlightingService.ts
new file mode 100644
index 00000000..fc3e9e53
--- /dev/null
+++ b/language-web/src/main/js/xtext/HighlightingService.ts
@@ -0,0 +1,43 @@
+import type { EditorStore } from '../editor/EditorStore';
+import type { IHighlightRange } from '../editor/semanticHighlighting';
+import type { UpdateService } from './UpdateService';
+import { getLogger } from '../utils/logger';
+import { isHighlightingResult } from './xtextServiceResults';
+
+const log = getLogger('xtext.ValidationService');
+
+export class HighlightingService {
+  private readonly store: EditorStore;
+
+  private readonly updateService: UpdateService;
+
+  constructor(store: EditorStore, updateService: UpdateService) {
+    this.store = store;
+    this.updateService = updateService;
+  }
+
+  onPush(push: unknown): void {
+    if (!isHighlightingResult(push)) {
+      log.error('Invalid highlighting result', push);
+      return;
+    }
+    const allChanges = this.updateService.computeChangesSinceLastUpdate();
+    const ranges: IHighlightRange[] = [];
+    push.regions.forEach(({ offset, length, styleClasses }) => {
+      if (styleClasses.length === 0) {
+        return;
+      }
+      const from = allChanges.mapPos(offset);
+      const to = allChanges.mapPos(offset + length);
+      if (to <= from) {
+        return;
+      }
+      ranges.push({
+        from,
+        to,
+        classes: styleClasses,
+      });
+    });
+    this.store.updateSemanticHighlighting(ranges);
+  }
+}