RegexConverter
Converts a Regex to and from JSON and BSON.
using Newtonsoft.Json.Bson;
using Newtonsoft.Json.Serialization;
using Newtonsoft.Json.Utilities;
using System;
using System.Runtime.CompilerServices;
using System.Text.RegularExpressions;
namespace Newtonsoft.Json.Converters
{
[System.Runtime.CompilerServices.NullableContext(1)]
[System.Runtime.CompilerServices.Nullable(0)]
public class RegexConverter : JsonConverter
{
private const string PatternName = "Pattern";
private const string OptionsName = "Options";
public override void WriteJson(JsonWriter writer, [System.Runtime.CompilerServices.Nullable(2)] object value, JsonSerializer serializer)
{
if (value == null)
writer.WriteNull();
else {
Regex regex = (Regex)value;
BsonWriter bsonWriter = writer as BsonWriter;
if (bsonWriter != null)
WriteBson(bsonWriter, regex);
else
WriteJson(writer, regex, serializer);
}
}
private bool HasFlag(RegexOptions options, RegexOptions flag)
{
return (options & flag) == flag;
}
private void WriteBson(BsonWriter writer, Regex regex)
{
string str = null;
if (HasFlag(regex.Options, RegexOptions.IgnoreCase))
str += "i";
if (HasFlag(regex.Options, RegexOptions.Multiline))
str += "m";
if (HasFlag(regex.Options, RegexOptions.Singleline))
str += "s";
str += "u";
if (HasFlag(regex.Options, RegexOptions.ExplicitCapture))
str += "x";
writer.WriteRegex(regex.ToString(), str);
}
private void WriteJson(JsonWriter writer, Regex regex, JsonSerializer serializer)
{
DefaultContractResolver defaultContractResolver = serializer.ContractResolver as DefaultContractResolver;
writer.WriteStartObject();
writer.WritePropertyName((defaultContractResolver != null) ? defaultContractResolver.GetResolvedPropertyName("Pattern") : "Pattern");
writer.WriteValue(regex.ToString());
writer.WritePropertyName((defaultContractResolver != null) ? defaultContractResolver.GetResolvedPropertyName("Options") : "Options");
serializer.Serialize(writer, regex.Options);
writer.WriteEndObject();
}
[return: System.Runtime.CompilerServices.Nullable(2)]
public override object ReadJson(JsonReader reader, Type objectType, [System.Runtime.CompilerServices.Nullable(2)] object existingValue, JsonSerializer serializer)
{
switch (reader.TokenType) {
case JsonToken.StartObject:
return ReadRegexObject(reader, serializer);
case JsonToken.String:
return ReadRegexString(reader);
case JsonToken.Null:
return null;
default:
throw JsonSerializationException.Create(reader, "Unexpected token when reading Regex.");
}
}
private object ReadRegexString(JsonReader reader)
{
string text = (string)reader.Value;
if (text.Length > 0 && text[0] == '/') {
int num = text.LastIndexOf('/');
if (num > 0) {
string pattern = text.Substring(1, num - 1);
RegexOptions regexOptions = MiscellaneousUtils.GetRegexOptions(text.Substring(num + 1));
return new Regex(pattern, regexOptions);
}
}
throw JsonSerializationException.Create(reader, "Regex pattern must be enclosed by slashes.");
}
private Regex ReadRegexObject(JsonReader reader, JsonSerializer serializer)
{
string text = null;
RegexOptions? nullable = null;
while (reader.Read()) {
switch (reader.TokenType) {
case JsonToken.PropertyName: {
string a = reader.Value.ToString();
if (!reader.Read())
throw JsonSerializationException.Create(reader, "Unexpected end when reading Regex.");
if (string.Equals(a, "Pattern", StringComparison.OrdinalIgnoreCase))
text = (string)reader.Value;
else if (string.Equals(a, "Options", StringComparison.OrdinalIgnoreCase)) {
nullable = serializer.Deserialize<RegexOptions>(reader);
} else {
reader.Skip();
}
break;
}
case JsonToken.EndObject:
if (text == null)
throw JsonSerializationException.Create(reader, "Error deserializing Regex. No pattern found.");
return new Regex(text, nullable.GetValueOrDefault());
}
}
throw JsonSerializationException.Create(reader, "Unexpected end when reading Regex.");
}
public override bool CanConvert(Type objectType)
{
if (objectType.get_Name() == "Regex")
return IsRegex(objectType);
return false;
}
[MethodImpl(MethodImplOptions.NoInlining)]
private bool IsRegex(Type objectType)
{
return (object)objectType == typeof(Regex);
}
}
}