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..b8ceed20
--- /dev/null
+++ b/language-web/src/main/js/xtext/HighlightingService.ts
@@ -0,0 +1,43 @@
+import { Decoration } from '@codemirror/view';
+import { Range, RangeSet } from '@codemirror/rangeset';
+
+import type { EditorStore } from '../editor/EditorStore';
+import type { UpdateService } from './UpdateService';
+import { getLogger } from '../utils/logger';
+import { isHighlightingResult } from './xtextServiceResults';
+
+const log = getLogger('xtext.ValidationService');
+
+export class HighlightingService {
+  private store: EditorStore;
+
+  private 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 decorations: Range<Decoration>[] = [];
+    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;
+      }
+      decorations.push(Decoration.mark({
+        class: styleClasses.map((c) => `cmt-problem-${c}`).join(' '),
+      }).range(from, to));
+    });
+    this.store.updateSemanticHighlighting(RangeSet.of(decorations, true));
+  }
+}