Avoid allocating unused prefix/localName in XmlCharCheckingReader.Val…

…idateQName (#54836)
dotnet · Jun 29, 2021 · 39e8a6e · 39e8a6e
1 parent 72047c5
commit 39e8a6e
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Showing 2 changed files with 13 additions and 4 deletions.
diff --git a/src/libraries/System.Private.Xml/src/System/Xml/Core/XmlCharCheckingReader.cs b/src/libraries/System.Private.Xml/src/System/Xml/Core/XmlCharCheckingReader.cs
@@ -624,8 +624,7 @@ private void CheckWhitespace(string value)
 
         private void ValidateQName(string name)
         {
-            string prefix, localName;
-            ValidateNames.ParseQNameThrow(name, out prefix, out localName);
+            ValidateNames.ParseQNameThrow(name);
         }
 
         private void ValidateQName(string prefix, string localName)

diff --git a/src/libraries/System.Private.Xml/src/System/Xml/ValidateNames.cs b/src/libraries/System.Private.Xml/src/System/Xml/ValidateNames.cs
@@ -261,9 +261,9 @@ internal static int ParseQName(string s, int offset, out int colonOffset)
 
         /// <summary>
         /// Calls parseQName and throws exception if the resulting name is not a valid QName.
-        /// Returns the prefix and local name parts.
+        /// Returns the colon offset in the name.
         /// </summary>
-        internal static void ParseQNameThrow(string s, out string prefix, out string localName)
+        internal static int ParseQNameThrow(string s)
         {
             int colonOffset;
             int len = ParseQName(s, 0, out colonOffset);
@@ -274,6 +274,16 @@ internal static void ParseQNameThrow(string s, out string prefix, out string loc
                 ThrowInvalidName(s, 0, len);
             }
 
+            return colonOffset;
+        }
+
+        /// <summary>
+        /// Calls parseQName and throws exception if the resulting name is not a valid QName.
+        /// Returns the prefix and local name parts.
+        /// </summary>
+        internal static void ParseQNameThrow(string s, out string prefix, out string localName)
+        {
+            int colonOffset = ParseQNameThrow(s);
             if (colonOffset != 0)
             {
                 prefix = s.Substring(0, colonOffset);