From db67345437d0da12f13731d68faf141e50414e30 Mon Sep 17 00:00:00 2001
From: Andrey Vokin <andrey.vokin@jetbrains.com>
Date: Tue, 18 Sep 2018 15:51:25 +0200
Subject: [PATCH] Introduce method DocumentUtil#getIndent

added test
---
 .../src/com/intellij/util/DocumentUtil.java     |  6 +++---
 .../openapi/editor/DocumentUtilTest.java        | 17 +++++++++++++++++
 2 files changed, 20 insertions(+), 3 deletions(-)
 create mode 100644 platform/platform-tests/testSrc/com/intellij/openapi/editor/DocumentUtilTest.java

diff --git a/platform/core-impl/src/com/intellij/util/DocumentUtil.java b/platform/core-impl/src/com/intellij/util/DocumentUtil.java
index 2df37e06ba38..22b86a70a35c 100644
--- a/platform/core-impl/src/com/intellij/util/DocumentUtil.java
+++ b/platform/core-impl/src/com/intellij/util/DocumentUtil.java
@@ -146,9 +146,9 @@ public final class DocumentUtil {
 
   /**
    * Calculates indent of the line containing {@code offset}
-   * @return amount of characters in indent
+   * @return Whitespaces at the beginning of the line
    */
-  public static int getIndent(@NotNull Document document, int offset) {
+  public static CharSequence getIndent(@NotNull Document document, int offset) {
     int lineOffset = getLineStartOffset(offset, document);
     int result = 0;
     while (lineOffset + result < document.getTextLength() &&
@@ -158,6 +158,6 @@ public final class DocumentUtil {
     if (result + lineOffset > document.getTextLength()) {
       result--;
     }
-    return Math.max(result, 0);
+    return document.getCharsSequence().subSequence(lineOffset, lineOffset + Math.max(result, 0));
   }
 }
diff --git a/platform/platform-tests/testSrc/com/intellij/openapi/editor/DocumentUtilTest.java b/platform/platform-tests/testSrc/com/intellij/openapi/editor/DocumentUtilTest.java
new file mode 100644
index 000000000000..07b8e735c952
--- /dev/null
+++ b/platform/platform-tests/testSrc/com/intellij/openapi/editor/DocumentUtilTest.java
@@ -0,0 +1,17 @@
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.openapi.editor;
+
+import com.intellij.openapi.editor.impl.DocumentImpl;
+import com.intellij.util.DocumentUtil;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class DocumentUtilTest {
+  @Test
+  public void testGetIndent() {
+    final Document doc = new DocumentImpl("line1\n" +
+                                          " \t line2");
+    assertEquals(" \t ", DocumentUtil.getIndent(doc, doc.getTextLength() - 1).toString());
+  }
+}