-Refactor regex in JSON Path

Src/Newtonsoft.Json.Tests/Linq/JsonPath/JPathParseTests.cs

@@ -315,16 +315,44 @@ namespace Newtonsoft.Json.Tests.Linq.JsonPath
         }
 
         [Test]
-        public void SinglePropertyAndFilterWithRegex()
+        public void SinglePropertyAndFilterWithRegexAndOptions()
         {
             JPath path = new JPath("Blah[ ?( @.name=~/hi/i ) ]");
             Assert.AreEqual(2, path.Filters.Count);
             Assert.AreEqual("Blah", ((FieldFilter)path.Filters[0]).Name);
             BooleanQueryExpression expressions = (BooleanQueryExpression)((QueryFilter)path.Filters[1]).Expression;
-            Assert.AreEqual(QueryOperator.RegExEquals, expressions.Operator);
+            Assert.AreEqual(QueryOperator.RegexEquals, expressions.Operator);
             Assert.AreEqual("/hi/i", (string)(JToken)expressions.Right);
         }
 
+        [Test]
+        public void SinglePropertyAndFilterWithRegex()
+        {
+            JPath path = new JPath("Blah[?(@.title =~ /^.*Sword.*$/)]");
+            Assert.AreEqual(2, path.Filters.Count);
+            Assert.AreEqual("Blah", ((FieldFilter)path.Filters[0]).Name);
+            BooleanQueryExpression expressions = (BooleanQueryExpression)((QueryFilter)path.Filters[1]).Expression;
+            Assert.AreEqual(QueryOperator.RegexEquals, expressions.Operator);
+            Assert.AreEqual("/^.*Sword.*$/", (string)(JToken)expressions.Right);
+        }
+
+        [Test]
+        public void SinglePropertyAndFilterWithEscapedRegex()
+        {
+            JPath path = new JPath(@"Blah[?(@.title =~ /[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g)]");
+            Assert.AreEqual(2, path.Filters.Count);
+            Assert.AreEqual("Blah", ((FieldFilter)path.Filters[0]).Name);
+            BooleanQueryExpression expressions = (BooleanQueryExpression)((QueryFilter)path.Filters[1]).Expression;
+            Assert.AreEqual(QueryOperator.RegexEquals, expressions.Operator);
+            Assert.AreEqual(@"/[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g", (string)(JToken)expressions.Right);
+        }
+
+        [Test]
+        public void SinglePropertyAndFilterWithOpenRegex()
+        {
+            ExceptionAssert.Throws<JsonException>(() => { new JPath(@"Blah[?(@.title =~ /[\"); }, "Path ended with an open regex.");
+        }
+
         [Test]
         public void SinglePropertyAndFilterWithUnknownEscape()
         {

Src/Newtonsoft.Json.Tests/Linq/JsonPath/QueryExpressionTests.cs

@@ -159,11 +159,11 @@ namespace Newtonsoft.Json.Tests.Linq.JsonPath
         }
         
         [Test]
-        public void BooleanExpressionTest_RegExEqualsOperator()
+        public void BooleanExpressionTest_RegexEqualsOperator()
         {
             BooleanQueryExpression e1 = new BooleanQueryExpression
             {
-                Operator = QueryOperator.RegExEquals,
+                Operator = QueryOperator.RegexEquals,
                 Right = new JValue("/foo.*d/"),
                 Left = new List<PathFilter>
                 {
@@ -178,7 +178,7 @@ namespace Newtonsoft.Json.Tests.Linq.JsonPath
 
             BooleanQueryExpression e2 = new BooleanQueryExpression
             {
-                Operator = QueryOperator.RegExEquals,
+                Operator = QueryOperator.RegexEquals,
                 Right = new JValue("/Foo.*d/i"),
                 Left = new List<PathFilter>
                 {
@@ -193,11 +193,11 @@ namespace Newtonsoft.Json.Tests.Linq.JsonPath
         }
 
         [Test]
-        public void BooleanExpressionTest_RegExEqualsOperator_CornerCase()
+        public void BooleanExpressionTest_RegexEqualsOperator_CornerCase()
         {
             BooleanQueryExpression e1 = new BooleanQueryExpression
             {
-                Operator = QueryOperator.RegExEquals,
+                Operator = QueryOperator.RegexEquals,
                 Right = new JValue("/// comment/"),
                 Left = new List<PathFilter>
                 {
@@ -210,7 +210,7 @@ namespace Newtonsoft.Json.Tests.Linq.JsonPath
 
             BooleanQueryExpression e2 = new BooleanQueryExpression
             {
-                Operator = QueryOperator.RegExEquals,
+                Operator = QueryOperator.RegexEquals,
                 Right = new JValue("/<tag>.*</tag>/i"),
                 Left = new List<PathFilter>
                 {

Src/Newtonsoft.Json/Linq/JsonPath/JPath.cs

@@ -719,79 +719,45 @@ namespace Newtonsoft.Json.Linq.JsonPath
 
         private string ReadRegexString()
         {
-            var sb = new StringBuilder("/");
+            int startIndex = _currentIndex;
 
             _currentIndex++;
             while (_currentIndex < _expression.Length)
             {
                 char currentChar = _expression[_currentIndex];
+
+                // handle escaped / character
                 if (currentChar == '\\' && _currentIndex + 1 < _expression.Length)
                 {
-                    _currentIndex++;
-
-                    if (_expression[_currentIndex] == '\'')
-                    {
-                        sb.Append('\'');
-                    }
-                    else if (_expression[_currentIndex] == '\\')
-                    {
-                        sb.Append('\\');
-                    }
-                    else if (_expression[_currentIndex] == '/')
-                    {
-                        sb.Append('/');
-                    }
-                    else
-                    {
-                        throw new JsonException(@"Unknown escape character: \" + _expression[_currentIndex]);
-                    }
-
-                    _currentIndex++;
+                    _currentIndex += 2;
                 }
                 else if (currentChar == '/')
                 {
-                    sb.Append(currentChar);
                     _currentIndex++;
 
-                    string options = ParseRegexOptions();
-                    sb.Append(options);
+                    while (_currentIndex < _expression.Length)
+                    {
+                        currentChar = _expression[_currentIndex];
 
-                    return sb.ToString();
+                        if (char.IsLetter(currentChar))
+                        {
+                            _currentIndex++;
+                        }
+                        else
+                        {
+                            break;
+                        }
+                    }
+
+                    return _expression.Substring(startIndex, _currentIndex - startIndex);
                 }
                 else
                 {
                     _currentIndex++;
-                    sb.Append(currentChar);
                 }
             }
 
-            throw new JsonException("Path ended with an open string.");
-        }
-
-        private string ParseRegexOptions()
-        {
-            var optionsSb = new StringBuilder();
-
-            while (_currentIndex < _expression.Length)
-            {
-                char currentChar = _expression[_currentIndex];
-
-                if (currentChar == 'i'
-                    || currentChar == 'm'
-                    || currentChar == 's'
-                    || currentChar == 'u'
-                    || currentChar == 'x')
-                {
-                    _currentIndex++;
-                    optionsSb.Append(currentChar);
-                }
-                else
-                {
-                    break;
-                }
-            }
-
-            return optionsSb.ToString();
+            throw new JsonException("Path ended with an open regex.");
         }
 
         private bool Match(string s)
@@ -827,7 +793,7 @@ namespace Newtonsoft.Json.Linq.JsonPath
 
             if (Match("=~"))
             {
-                return QueryOperator.RegExEquals;
+                return QueryOperator.RegexEquals;
             }
 
             if (Match("!=") || Match("<>"))

Src/Newtonsoft.Json/Linq/JsonPath/QueryExpression.cs

@@ -24,7 +24,7 @@ namespace Newtonsoft.Json.Linq.JsonPath
         GreaterThanOrEquals = 7,
         And = 8,
         Or = 9,
-        RegExEquals = 10
+        RegexEquals = 10
     }
 
     internal abstract class QueryExpression
@@ -128,7 +128,7 @@ namespace Newtonsoft.Json.Linq.JsonPath
             {
                 switch (Operator)
                 {
-                    case QueryOperator.RegExEquals:
+                    case QueryOperator.RegexEquals:
                         if (RegexEquals(leftValue, rightValue))
                         {
                             return true;
@@ -196,7 +196,7 @@ namespace Newtonsoft.Json.Linq.JsonPath
                 return false;
             }
 
-            var regexText = (string)pattern.Value;
+            string regexText = (string)pattern.Value;
             int patternOptionDelimiterIndex = regexText.LastIndexOf('/');
 
             string patternText = regexText.Substring(1, patternOptionDelimiterIndex - 1);

Src/Newtonsoft.Json/Utilities/MiscellaneousUtils.cs

@@ -154,7 +154,7 @@ namespace Newtonsoft.Json.Utilities
 
         internal static RegexOptions GetRegexOptions(string optionsText)
         {
-            var options = RegexOptions.None;
+            RegexOptions options = RegexOptions.None;
             foreach (char c in optionsText)
             {
                 switch (c)
@@ -176,6 +176,5 @@ namespace Newtonsoft.Json.Utilities
 
             return options;
         }
-
     }
 }