feat: support OSC 52 clipboard writes

lib/components/term.tsx

@@ -18,6 +18,7 @@ import {WebglAddon} from 'xterm-addon-webgl';
 
 import type {TermProps} from '../../typings/hyper';
 import terms from '../terms';
+import {handleOsc52Clipboard} from '../utils/osc52';
 import processClipboard from '../utils/paste';
 import {decorate} from '../utils/plugins';
 
@@ -170,6 +171,13 @@ export default class Term extends React.PureComponent<
 
     this.termOptions = getTermOptions(props);
     this.term = props.term || new Terminal(this.termOptions);
+    this.disposableListeners.push(
+      this.term.parser.registerOscHandler(52, (data) =>
+        handleOsc52Clipboard(data, (text) => {
+          clipboard.writeText(text);
+        })
+      )
+    );
     this.defaultBellSound = new Audio(
       // Source: https://freesound.org/people/altemark/sounds/45759/
       // This sound is released under the Creative Commons Attribution 3.0 Unported

lib/utils/osc52.ts

@@ -0,0 +1,44 @@
+const BASE64_PATTERN = /^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$/;
+
+/**
+ * Decode an OSC 52 system clipboard write.
+ *
+ * Hyper intentionally handles writes only. Clipboard reads would expose the
+ * host clipboard to processes running in the terminal.
+ */
+export function decodeOsc52Clipboard(data: string): string | undefined {
+  const separator = data.indexOf(';');
+  if (separator < 0 || data.slice(0, separator) !== 'c') {
+    return undefined;
+  }
+
+  const encoded = data.slice(separator + 1);
+  if (encoded === '?') {
+    return undefined;
+  }
+
+  if (encoded === '!') {
+    return '';
+  }
+
+  if (!BASE64_PATTERN.test(encoded)) {
+    return undefined;
+  }
+
+  const decoded = Buffer.from(encoded, 'base64');
+  if (decoded.toString('base64') !== encoded) {
+    return undefined;
+  }
+
+  return decoded.toString('utf8');
+}
+
+export function handleOsc52Clipboard(data: string, writeClipboard: (text: string) => void): boolean {
+  const text = decodeOsc52Clipboard(data);
+  if (text === undefined) {
+    return false;
+  }
+
+  writeClipboard(text);
+  return true;
+}

test/unit/osc52.test.ts

@@ -0,0 +1,36 @@
+import test from 'ava';
+
+import {decodeOsc52Clipboard, handleOsc52Clipboard} from '../../lib/utils/osc52';
+
+test('decodes OSC 52 system clipboard writes', (t) => {
+  const encoded = Buffer.from('Olá, Hyper!').toString('base64');
+
+  t.is(decodeOsc52Clipboard(`c;${encoded}`), 'Olá, Hyper!');
+});
+
+test('ignores OSC 52 clipboard reads', (t) => {
+  t.is(decodeOsc52Clipboard('c;?'), undefined);
+});
+
+test('ignores non-system clipboard selections', (t) => {
+  const encoded = Buffer.from('primary').toString('base64');
+
+  t.is(decodeOsc52Clipboard(`p;${encoded}`), undefined);
+});
+
+test('rejects malformed OSC 52 payloads', (t) => {
+  t.is(decodeOsc52Clipboard('c;not-base64'), undefined);
+  t.is(decodeOsc52Clipboard('c;'), '');
+});
+
+test('writes decoded OSC 52 data through the host clipboard', (t) => {
+  let copied = '';
+  const encoded = Buffer.from('from a pane').toString('base64');
+
+  t.true(
+    handleOsc52Clipboard(`c;${encoded}`, (text) => {
+      copied = text;
+    })
+  );
+  t.is(copied, 'from a pane');
+});