support permalinks to lines in source code view (#1472)

This features adjusts the syntax checker to render a little link icon next to a hovered line. When clicked,
a permanent link to this line is created and copied to the user's clipboard. When visiting the link,
the focused row is highlighted.

Co-authored-by: Eduard Heimbuch <eduard.heimbuch@cloudogu.com>

scm-ui/ui-components/src/CopyToClipboard.ts

@@ -0,0 +1,45 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+export default async function copyToClipboard(text: string) {
+  if (navigator.clipboard) {
+    return navigator.clipboard.writeText(text);
+  } else {
+    const textArea = document.createElement("textarea");
+    textArea.value = text;
+    textArea.style.position = "fixed"; //avoid scrolling to bottom
+    document.body.appendChild(textArea);
+    textArea.focus();
+    textArea.select();
+
+    try {
+      document.execCommand("copy");
+      return Promise.resolve();
+    } catch (e) {
+      return Promise.reject(e);
+    } finally {
+      document.body.removeChild(textArea);
+    }
+  }
+}