From 769f047b0fc7a2835d3e5866a7785e7469e68378 Mon Sep 17 00:00:00 2001
From: Eduard Heimbuch <eduard.heimbuch@cloudogu.com>
Date: Thu, 17 Dec 2020 12:12:10 +0100
Subject: [PATCH] Fix timing problem on jumping to linked line number in source
 view

---
 .../ui-components/src/ErrorNotification.tsx   |  2 +-
 .../ui-components/src/SyntaxHighlighter.tsx   | 34 ++++-------
 .../ui-components/src/useScrollToElement.ts   | 57 +++++++++++++++++++
 3 files changed, 70 insertions(+), 23 deletions(-)
 create mode 100644 scm-ui/ui-components/src/useScrollToElement.ts

diff --git a/scm-ui/ui-components/src/ErrorNotification.tsx b/scm-ui/ui-components/src/ErrorNotification.tsx
index 689b9f1469..9bb685175b 100644
--- a/scm-ui/ui-components/src/ErrorNotification.tsx
+++ b/scm-ui/ui-components/src/ErrorNotification.tsx
@@ -36,7 +36,7 @@ type Props = WithTranslation & {
 const LoginLink: FC = () => {
   const [t] = useTranslation("commons");
   const location = useLocation();
-  const from = encodeURIComponent(location.pathname + location.hash);
+  const from = encodeURIComponent(location.hash ? location.pathname + location.hash : location.pathname);
 
   return <a href={withContextPath(`/login?from=${from}`)}>{t("errorNotification.loginLink")}</a>;
 };
diff --git a/scm-ui/ui-components/src/SyntaxHighlighter.tsx b/scm-ui/ui-components/src/SyntaxHighlighter.tsx
index 8c784c2e90..907ac3f342 100644
--- a/scm-ui/ui-components/src/SyntaxHighlighter.tsx
+++ b/scm-ui/ui-components/src/SyntaxHighlighter.tsx
@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-import React, { FC, useEffect, useState } from "react";
+import React, { FC, useState } from "react";
 
 import { PrismAsyncLight as ReactSyntaxHighlighter } from "react-syntax-highlighter";
 import { defaultLanguage, determineLanguage } from "./languages";
@@ -30,6 +30,7 @@ import highlightingTheme from "./syntax-highlighting";
 import { useLocation } from "react-router-dom";
 import { withContextPath } from "./urls";
 import createSyntaxHighlighterRenderer from "./SyntaxHighlighterRenderer";
+import useScrollToElement from "./useScrollToElement";
 
 const LINE_NUMBER_URL_HASH_REGEX = /^#line-(.*)$/;
 
@@ -44,27 +45,16 @@ const SyntaxHighlighter: FC<Props> = ({ language = defaultLanguage, showLineNumb
   const location = useLocation();
   const [contentRef, setContentRef] = useState<HTMLElement | null>();
 
-  useEffect(() => {
-    const match = location.hash.match(LINE_NUMBER_URL_HASH_REGEX);
-    if (contentRef && match) {
-      const lineNumber = match[1];
-      // We defer the content check until after the syntax-highlighter has rendered
-      setTimeout(() => {
-        let tries = 0;
-        let element = contentRef.querySelector(`#line-${lineNumber}`);
-        if (!element && tries < 10) {
-          setInterval(() => {
-            tries += 1;
-            element = contentRef.querySelector(`#line-${lineNumber}`);
-          }, 200);
-        }
-
-        if (element && element.scrollIntoView) {
-          element.scrollIntoView();
-        }
-      });
-    }
-  }, [value, contentRef]);
+  useScrollToElement(
+    contentRef,
+    () => {
+      const match = location.hash.match(LINE_NUMBER_URL_HASH_REGEX);
+      if (match) {
+        return `#line-${match[1]}`;
+      }
+    },
+    value
+  );
 
   const createLinePermaLink = (lineNumber: number) =>
     window.location.protocol +
diff --git a/scm-ui/ui-components/src/useScrollToElement.ts b/scm-ui/ui-components/src/useScrollToElement.ts
new file mode 100644
index 0000000000..778a69d88b
--- /dev/null
+++ b/scm-ui/ui-components/src/useScrollToElement.ts
@@ -0,0 +1,57 @@
+/*
+ * 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.
+ */
+
+import { useEffect } from "react";
+
+const useScrollToElement = (
+  contentRef: HTMLElement | null | undefined,
+  elementSelectorResolver: () => string | undefined,
+  ...dependencies: any
+) => {
+  useEffect(() => {
+    const elementSelector = elementSelectorResolver();
+    if (contentRef && elementSelector) {
+      // We defer the content check until after the syntax-highlighter has rendered
+      let tries = 0;
+      const intervalId = setInterval(() => {
+        if (tries >= 15) {
+          clearInterval(intervalId);
+        } else {
+          tries++;
+          const element = contentRef.querySelector(elementSelector);
+          if (element && element.scrollIntoView) {
+            clearInterval(intervalId);
+            element.scrollIntoView();
+          }
+        }
+      }, 200);
+
+      return () => {
+        clearInterval(intervalId);
+      };
+    }
+  }, [contentRef, ...dependencies]);
+};
+
+export default useScrollToElement;