Improve performance of StringUtils#cleanPath

Author: dreis2211

spring-core/src/main/java/org/springframework/util/StringUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -701,6 +701,10 @@ else if (TOP_PATH.equals(element)) {
 			}
 		}
 
+		// All path elements stayed the same - shortcut
+		if (pathArray.length == pathElements.size()) {
+			return prefix + pathToUse;
+		}
 		// Remaining top paths need to be retained.
 		for (int i = 0; i < tops; i++) {
 			pathElements.add(0, TOP_PATH);

spring-core/src/test/java/org/springframework/util/StringUtilsTests.java

@@ -399,6 +399,7 @@ void cleanPath() {
 		assertThat(StringUtils.cleanPath("file:../")).isEqualTo("file:../");
 		assertThat(StringUtils.cleanPath("file:./../")).isEqualTo("file:../");
 		assertThat(StringUtils.cleanPath("file:.././")).isEqualTo("file:../");
+		assertThat(StringUtils.cleanPath("file:/mypath/spring.factories")).isEqualTo("file:/mypath/spring.factories");
 		assertThat(StringUtils.cleanPath("file:///c:/some/../path/the%20file.txt")).isEqualTo("file:///c:/path/the%20file.txt");
 	}