1 files changed, 82 insertions, 0 deletions

diff --git a/editors/code/src/highlighting.ts b/editors/code/src/highlighting.ts
new file mode 100644
index 000000000..e2ac4d629
--- /dev/null
+++ b/editors/code/src/highlighting.ts
@@ -0,0 +1,82 @@
+import * as vscode from 'vscode';
+import * as lc from 'vscode-languageclient';
+
+import { Server } from './server';
+
+export interface Decoration {
+    range: lc.Range;
+    tag: string;
+}
+
+export class Highlighter {
+    private static initDecorations(): Map<string, vscode.TextEditorDecorationType> {
+        const decor = (color: string) => vscode.window.createTextEditorDecorationType({ color });
+
+        const decorations: Iterable<[string, vscode.TextEditorDecorationType]> = [
+            ['background', decor('#3F3F3F')],
+            ['error', vscode.window.createTextEditorDecorationType({
+                borderColor: 'red',
+                borderStyle: 'none none dashed none',
+            })],
+            ['comment', decor('#7F9F7F')],
+            ['string', decor('#CC9393')],
+            ['keyword', decor('#F0DFAF')],
+            ['function', decor('#93E0E3')],
+            ['parameter', decor('#94BFF3')],
+            ['builtin', decor('#DD6718')],
+            ['text', decor('#DCDCCC')],
+            ['attribute', decor('#BFEBBF')],
+            ['literal', decor('#DFAF8F')],
+        ];
+
+        return new Map<string, vscode.TextEditorDecorationType>(decorations);
+    }
+
+    private decorations: (Map<string, vscode.TextEditorDecorationType> | null) = null;
+
+    public removeHighlights() {
+        if (this.decorations == null) {
+            return;
+        }
+
+        // Decorations are removed when the object is disposed
+        for (const decoration of this.decorations.values()) {
+            decoration.dispose();
+        }
+
+        this.decorations = null;
+    }
+
+    public setHighlights(
+        editor: vscode.TextEditor,
+        highlights: Decoration[],
+    ) {
+        // Initialize decorations if necessary
+        //
+        // Note: decoration objects need to be kept around so we can dispose them
+        // if the user disables syntax highlighting
+        if (this.decorations == null) {
+            this.decorations = Highlighter.initDecorations();
+        }
+
+        const byTag: Map<string, vscode.Range[]> = new Map();
+        for (const tag of this.decorations.keys()) {
+            byTag.set(tag, []);
+        }
+
+        for (const d of highlights) {
+            if (!byTag.get(d.tag)) {
+                continue;
+            }
+            byTag.get(d.tag)!.push(
+                Server.client.protocol2CodeConverter.asRange(d.range),
+            );
+        }
+
+        for (const tag of byTag.keys()) {
+            const dec = this.decorations.get(tag) as vscode.TextEditorDecorationType;
+            const ranges = byTag.get(tag)!;
+            editor.setDecorations(dec, ranges);
+        }
+    }
+}