Reverted string utils

Signed-off-by: Mitchell Gale <Mitchell.Gale@improving.com>

common/src/main/java/org/opensearch/sql/common/utils/StringUtils.java

@@ -3,6 +3,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+
 package org.opensearch.sql.common.utils;
 
 import com.google.common.base.Strings;
@@ -11,38 +12,52 @@
 
 public class StringUtils {
   /**
-   * Unquote Identifier which has " or ' as mark. Strings quoted by ' or " with two of these quotes
-   * appearing next to each other in the quote acts as an escape<br>
+   * Unquote any string with mark specified.
+   * @param text string
+   * @param mark quotation mark
+   * @return An unquoted string whose outer pair of (single/double/back-tick) quotes have been
+   *     removed
+   */
+  public static String unquote(String text, String mark) {
+    if (isQuoted(text, mark)) {
+      return text.substring(mark.length(), text.length() - mark.length());
+    }
+    return text;
+  }
+
+  /**
+   * Unquote Identifier which has " or ' or ` as mark.
+   * Strings quoted by ' or " with two of these quotes appearing next to each other in the quote
+   * acts as an escape
    * Example: 'Test''s' will result in 'Test's', similar with those single quotes being replaced
-   * with double quote. Supports escaping quotes (single/double) and escape characters using the `\`
-   * characters.
-   *
+   * with double.
    * @param text string
-   * @return An unquoted string whose outer pair of (single/double) quotes have been removed
+   * @return An unquoted string whose outer pair of (single/double/back-tick) quotes have been
+   *     removed
    */
   public static String unquoteText(String text) {
+
     if (text.length() < 2) {
       return text;
     }
 
-    char enclosingQuote = 0;
+    char enclosingQuote;
     char firstChar = text.charAt(0);
     char lastChar = text.charAt(text.length() - 1);
 
-    if (firstChar != lastChar) {
+    if (firstChar == lastChar
+            && (firstChar == '\''
+            || firstChar == '"'
+            || firstChar == '`')) {
+      enclosingQuote = firstChar;
+    } else {
       return text;
     }
 
-    if (firstChar == '`') {
+    if (enclosingQuote == '`') {
       return text.substring(1, text.length() - 1);
     }
 
-    if (firstChar == lastChar && (firstChar == '\'' || firstChar == '"')) {
-      enclosingQuote = firstChar;
-    } else {
-      return text;
-    }
-
     char currentChar;
     char nextChar;
 
@@ -52,22 +67,21 @@ public static String unquoteText(String text) {
     for (int chIndex = 1; chIndex < text.length() - 1; chIndex++) {
       currentChar = text.charAt(chIndex);
       nextChar = text.charAt(chIndex + 1);
-
-      if ((currentChar == '\\' && (nextChar == '"' || nextChar == '\\' || nextChar == '\''))
-          || (currentChar == nextChar && currentChar == enclosingQuote)) {
+      if (currentChar == enclosingQuote
+              && nextChar == currentChar) {
         chIndex++;
-        currentChar = nextChar;
       }
       textSB.append(currentChar);
     }
+
     return textSB.toString();
   }
 
   /**
    * Unquote Identifier which has ` as mark.
-   *
    * @param identifier identifier that possibly enclosed by double quotes or back ticks
-   * @return An unquoted string whose outer pair of (double/back-tick) quotes have been removed
+   * @return An unquoted string whose outer pair of (double/back-tick) quotes have been
+   *     removed
    */
   public static String unquoteIdentifier(String identifier) {
     if (isQuoted(identifier, "`")) {
@@ -78,15 +92,16 @@ public static String unquoteIdentifier(String identifier) {
   }
 
   /**
-   * Returns a formatted string using the specified format string and arguments, as well as the
-   * {@link Locale#ROOT} locale.
+   * Returns a formatted string using the specified format string and
+   * arguments, as well as the {@link Locale#ROOT} locale.
    *
    * @param format format string
-   * @param args arguments referenced by the format specifiers in the format string
+   * @param args   arguments referenced by the format specifiers in the format string
    * @return A formatted string
    * @throws IllegalFormatException If a format string contains an illegal syntax, a format
-   *     specifier that is incompatible with the given arguments, insufficient arguments given the
-   *     format string, or other illegal conditions.
+   *                                specifier that is incompatible with the given arguments,
+   *                                insufficient arguments given the format string, or other
+   *                                illegal conditions.
    * @see java.lang.String#format(Locale, String, Object...)
    */
   public static String format(final String format, Object... args) {
@@ -96,4 +111,4 @@ public static String format(final String format, Object... args) {
   private static boolean isQuoted(String text, String mark) {
     return !Strings.isNullOrEmpty(text) && text.startsWith(mark) && text.endsWith(mark);
   }
-}
+}