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Import EnumExtensions and JSON converters
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mburumaxwell committed Mar 19, 2024
1 parent a43c1f2 commit 5de536a
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317 changes: 317 additions & 0 deletions src/Tingle.Extensions.Primitives/Converters/EnumConverterHelper.cs
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using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Reflection;
using System.Runtime.Serialization;
using System.Text;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace Tingle.Extensions.Primitives.Converters;

internal static class EnumConverterHelper
{
internal const DynamicallyAccessedMemberTypes RequiredMembersTypes =
DynamicallyAccessedMemberTypes.PublicFields |
DynamicallyAccessedMemberTypes.NonPublicFields;
}

internal class EnumConverterHelper<[DynamicallyAccessedMembers(EnumConverterHelper.RequiredMembersTypes)] TEnum> where TEnum : struct, Enum
{
private readonly struct EnumInfo(string name, TEnum value, ulong raw, string preferred)
{
public string Name { get; } = name;
public TEnum Value { get; } = value;
public ulong Raw { get; } = raw;

public string Preferred { get; } = preferred;

public override string ToString() => $"{Preferred} ({Value})";
}

private readonly bool allowIntegerValues;
[DynamicallyAccessedMembers(EnumConverterHelper.RequiredMembersTypes)]
private readonly Type type = typeof(TEnum);
private readonly TypeCode enumTypeCode;
private readonly bool isFlags;
private readonly Dictionary<TEnum, EnumInfo> mapping;
private readonly Dictionary<string, EnumInfo> lookup;

public EnumConverterHelper(JsonNamingPolicy? namingPolicy, bool allowIntegerValues)
{
this.allowIntegerValues = allowIntegerValues;
enumTypeCode = Type.GetTypeCode(type);
isFlags = type.IsDefined(typeof(FlagsAttribute), true);

var names = type.GetEnumNames();
var builtInValues = type.GetEnumValues();

int numberOfNames = names.Length;

mapping = new Dictionary<TEnum, EnumInfo>(numberOfNames);
lookup = new Dictionary<string, EnumInfo>(numberOfNames, StringComparer.OrdinalIgnoreCase);

var bindings = BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static;
for (int i = 0; i < numberOfNames; i++)
{
var value = (Enum?)builtInValues.GetValue(i);
if (value is null) continue;

var raw = GetEnumValue(enumTypeCode, value);

var name = names[i];
var field = type.GetField(name, bindings)!;

TryGetCustomAttribute<EnumMemberAttribute>(field, true, out var ema);
TryGetCustomAttribute<JsonPropertyNameAttribute>(field, true, out var jpna);
var chosen = ema?.Value ?? jpna?.Name ?? namingPolicy?.ConvertName(name) ?? name;

if (value is not TEnum typed)
throw new NotSupportedException();

var info = new EnumInfo(name, typed, raw, chosen);
mapping[typed] = info;

if (ema?.Value is not null) lookup[ema.Value] = info;
if (jpna?.Name is not null) lookup[jpna.Name] = info;
if (namingPolicy is not null) lookup[namingPolicy.ConvertName(name)] = info;
lookup[name] = info;
lookup[raw.ToString()] = info;
}
}

public TEnum Read(ref Utf8JsonReader reader)
{
JsonTokenType token = reader.TokenType;

if (token is JsonTokenType.String or JsonTokenType.PropertyName)
{
string enumString = reader.GetString()!;

if (lookup.TryGetValue(enumString, out EnumInfo enumInfo))
return enumInfo.Value;

if (isFlags)
{
var calculatedValue = 0UL;

var flagValues = enumString.Split(", ");
foreach (var flagValue in flagValues)
{
// Case sensitive search attempted first.
if (lookup.TryGetValue(flagValue, out enumInfo))
{
calculatedValue |= enumInfo.Raw;
}
else
{
throw ThrowHelper.GenerateJsonException_DeserializeUnableToConvertValue(type, flagValue);
}
}

return (TEnum)Enum.ToObject(type, calculatedValue);
}

throw ThrowHelper.GenerateJsonException_DeserializeUnableToConvertValue(type, enumString);
}

if (token != JsonTokenType.Number || !allowIntegerValues)
{
throw ThrowHelper.GenerateJsonException_DeserializeUnableToConvertValue(type);
}

switch (enumTypeCode)
{
case TypeCode.Int32:
if (reader.TryGetInt32(out int int32))
{
return (TEnum)Enum.ToObject(type, int32);
}
break;
case TypeCode.Int64:
if (reader.TryGetInt64(out long int64))
{
return (TEnum)Enum.ToObject(type, int64);
}
break;
case TypeCode.Int16:
if (reader.TryGetInt16(out short int16))
{
return (TEnum)Enum.ToObject(type, int16);
}
break;
case TypeCode.Byte:
if (reader.TryGetByte(out byte ubyte8))
{
return (TEnum)Enum.ToObject(type, ubyte8);
}
break;
case TypeCode.UInt32:
if (reader.TryGetUInt32(out uint uint32))
{
return (TEnum)Enum.ToObject(type, uint32);
}
break;
case TypeCode.UInt64:
if (reader.TryGetUInt64(out ulong uint64))
{
return (TEnum)Enum.ToObject(type, uint64);
}
break;
case TypeCode.UInt16:
if (reader.TryGetUInt16(out ushort uint16))
{
return (TEnum)Enum.ToObject(type, uint16);
}
break;
case TypeCode.SByte:
if (reader.TryGetSByte(out sbyte byte8))
{
return (TEnum)Enum.ToObject(type, byte8);
}
break;
}

throw ThrowHelper.GenerateJsonException_DeserializeUnableToConvertValue(type);
}

public void Write(Utf8JsonWriter writer, TEnum value)
{
if (mapping.TryGetValue(value, out EnumInfo enumInfo))
{
writer.WriteStringValue(enumInfo.Preferred);
return;
}

ulong rawValue = GetEnumValue(enumTypeCode, value);

if (isFlags)
{
ulong calculatedValue = 0;

var builder = new StringBuilder();
foreach (var kvp in mapping)
{
enumInfo = kvp.Value;
if (!value.HasFlag(enumInfo.Value)) continue;

// Track the value to make sure all bits are represented.
calculatedValue |= enumInfo.Raw;

if (builder.Length > 0) builder.Append(", ");
builder.Append(enumInfo.Preferred);
}
if (calculatedValue == rawValue)
{
string finalName = builder.ToString();
writer.WriteStringValue(finalName);
return;
}
}

if (!allowIntegerValues)
throw new JsonException($"Enum type {type} does not have a mapping for integer value '{rawValue.ToString(CultureInfo.CurrentCulture)}'.");

switch (enumTypeCode)
{
case TypeCode.Int32:
writer.WriteNumberValue((int)rawValue);
break;
case TypeCode.Int64:
writer.WriteNumberValue((long)rawValue);
break;
case TypeCode.Int16:
writer.WriteNumberValue((short)rawValue);
break;
case TypeCode.Byte:
writer.WriteNumberValue((byte)rawValue);
break;
case TypeCode.UInt32:
writer.WriteNumberValue((uint)rawValue);
break;
case TypeCode.UInt64:
writer.WriteNumberValue(rawValue);
break;
case TypeCode.UInt16:
writer.WriteNumberValue((ushort)rawValue);
break;
case TypeCode.SByte:
writer.WriteNumberValue((sbyte)rawValue);
break;
default:
throw new JsonException(); // GetEnumValue should have already thrown.
}
}

public void WritePropertyName(Utf8JsonWriter writer, TEnum value)
{
if (mapping.TryGetValue(value, out EnumInfo enumInfo))
{
writer.WritePropertyName(enumInfo.Preferred);
return;
}

ulong rawValue = GetEnumValue(enumTypeCode, value);

if (isFlags)
{
ulong calculatedValue = 0;

var builder = new StringBuilder();
foreach (var kvp in mapping)
{
enumInfo = kvp.Value;
if (!value.HasFlag(enumInfo.Value)) continue;

// Track the value to make sure all bits are represented.
calculatedValue |= enumInfo.Raw;

if (builder.Length > 0) builder.Append(", ");
builder.Append(enumInfo.Preferred);
}
if (calculatedValue == rawValue)
{
string finalName = builder.ToString();
writer.WritePropertyName(finalName);
return;
}
}
}

internal static ulong GetEnumValue(TypeCode enumTypeCode, object value)
{
return enumTypeCode switch
{
TypeCode.Int32 => (ulong)(int)value,
TypeCode.Int64 => (ulong)(long)value,
TypeCode.Int16 => (ulong)(short)value,
TypeCode.Byte => (byte)value,
TypeCode.UInt32 => (uint)value,
TypeCode.UInt64 => (ulong)value,
TypeCode.UInt16 => (ushort)value,
TypeCode.SByte => (ulong)(sbyte)value,
_ => throw new NotSupportedException($"Enum '{value}' of {enumTypeCode} type is not supported."),
};
}

/// <summary>
/// Tries to retrieve a custom attribute of a specified type that is applied to the member,
/// and optionally inspects the ancestors of that member.
/// </summary>
/// <typeparam name="T">The type of attribute to search for.</typeparam>
/// <param name="element">The member to inspect.</param>
/// <param name="inherit">true to inspect the ancestors of element; otherwise, false.</param>
/// <param name="attribute">A custom attribute that matches T, or null if no such attribute is found.</param>
/// <returns></returns>
/// <exception cref="ArgumentNullException">element is null</exception>
/// <exception cref="NotSupportedException">element is not a constructor, method, property, event, type, or field.</exception>
/// <exception cref="AmbiguousMatchException">More than one of the requested attributes was found.</exception>
/// <exception cref="TypeLoadException">A custom attribute type cannot be loaded.</exception>
internal static bool TryGetCustomAttribute<T>(MemberInfo element, bool inherit, [NotNullWhen(true)] out T? attribute)
where T : Attribute
{
ArgumentNullException.ThrowIfNull(element);

attribute = element.GetCustomAttribute<T>(inherit);
return attribute != null;
}
}
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using System.Net;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace Tingle.Extensions.Primitives.Converters;

/// <summary>
/// <see cref="JsonConverter{T}"/> to convert <see cref="IPAddress"/> to and from strings.
/// </summary>
public class JsonIPAddressConverter : JsonConverter<IPAddress>
{
/// <inheritdoc/>
public override IPAddress? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
{
if (reader.TokenType is not JsonTokenType.String)
{
throw ThrowHelper.GenerateJsonException_DeserializeUnableToConvertValue(typeof(IPAddress));
}

var value = reader.GetString()!;

try
{
return IPAddress.Parse(value);
}
catch (Exception ex)
{
throw ThrowHelper.GenerateJsonException_DeserializeUnableToConvertValue(typeof(IPAddress), value, ex);
}
}

/// <inheritdoc/>
public override void Write(Utf8JsonWriter writer, IPAddress value, JsonSerializerOptions options)
=> writer.WriteStringValue(value.ToString());
}
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#if NET8_0_OR_GREATER
using System.Net;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace Tingle.Extensions.Primitives.Converters;

/// <summary>
/// <see cref="JsonConverter{T}"/> to convert <see cref="IPNetwork"/> to and from strings.
/// </summary>
public class JsonIPNetworkConverter : JsonConverter<IPNetwork>
{
/// <inheritdoc/>
public override IPNetwork Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
{
if (reader.TokenType is not JsonTokenType.String)
{
throw ThrowHelper.GenerateJsonException_DeserializeUnableToConvertValue(typeof(IPNetwork));
}

var value = reader.GetString()!;

try
{
return IPNetwork.Parse(value);
}
catch (Exception ex)
{
throw ThrowHelper.GenerateJsonException_DeserializeUnableToConvertValue(typeof(IPNetwork), value, ex);
}
}

/// <inheritdoc/>
public override void Write(Utf8JsonWriter writer, IPNetwork value, JsonSerializerOptions options)
{
writer.WriteStringValue(value.ToString());
}
}
#endif
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