JsonEncodedText.cs

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using System.Buffers;
using System.Diagnostics.CodeAnalysis;
using System.Text.Encodings.Web;
 
namespace System.Text.Json;
 
public readonly struct JsonEncodedText : IEquatable<JsonEncodedText>
{
    internal readonly byte[] _utf8Value;
 
    internal readonly string _value;
 
    public ReadOnlySpan<byte> EncodedUtf8Bytes => _utf8Value;
 
    private JsonEncodedText(byte[] utf8Value)
    {
        _value = JsonReaderHelper.GetTextFromUtf8(utf8Value);
        _utf8Value = utf8Value;
    }
 
    public static JsonEncodedText Encode(string value, JavaScriptEncoder? encoder = null)
    {
        if (value == null)
        {
            throw new ArgumentNullException("value");
        }
        return Encode(value.AsSpan(), encoder);
    }
 
    public static JsonEncodedText Encode(ReadOnlySpan<char> value, JavaScriptEncoder? encoder = null)
    {
        if (value.Length == 0)
        {
            return new JsonEncodedText(Array.Empty<byte>());
        }
        return TranscodeAndEncode(value, encoder);
    }
 
    private static JsonEncodedText TranscodeAndEncode(ReadOnlySpan<char> value, JavaScriptEncoder encoder)
    {
        JsonWriterHelper.ValidateValue(value);
        int utf8ByteCount = JsonReaderHelper.GetUtf8ByteCount(value);
        byte[] array = ArrayPool<byte>.Shared.Rent(utf8ByteCount);
        int utf8FromText = JsonReaderHelper.GetUtf8FromText(value, array);
        JsonEncodedText result = EncodeHelper(array.AsSpan(0, utf8FromText), encoder);
        array.AsSpan(0, utf8ByteCount).Clear();
        ArrayPool<byte>.Shared.Return(array);
        return result;
    }
 
    public static JsonEncodedText Encode(ReadOnlySpan<byte> utf8Value, JavaScriptEncoder? encoder = null)
    {
        if (utf8Value.Length == 0)
        {
            return new JsonEncodedText(Array.Empty<byte>());
        }
        JsonWriterHelper.ValidateValue(utf8Value);
        return EncodeHelper(utf8Value, encoder);
    }
 
    private static JsonEncodedText EncodeHelper(ReadOnlySpan<byte> utf8Value, JavaScriptEncoder encoder)
    {
        int num = JsonWriterHelper.NeedsEscaping(utf8Value, encoder);
        if (num != -1)
        {
            return new JsonEncodedText(JsonHelpers.EscapeValue(utf8Value, num, encoder));
        }
        return new JsonEncodedText(utf8Value.ToArray());
    }
 
    public bool Equals(JsonEncodedText other)
    {
        if (_value == null)
        {
            return other._value == null;
        }
        return _value.Equals(other._value);
    }
 
    public override bool Equals([NotNullWhen(true)] object? obj)
    {
        if (obj is JsonEncodedText other)
        {
            return Equals(other);
        }
        return false;
    }
 
    public override string ToString()
    {
        return _value ?? string.Empty;
    }
 
    public override int GetHashCode()
    {
        if (_value != null)
        {
            return _value.GetHashCode();
        }
        return 0;
    }
}