MailAddress.cs

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using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Net.Mime;
using System.Text;
 
namespace System.Net.Mail;
 
public class MailAddress
{
    private readonly Encoding _displayNameEncoding;
 
    private readonly string _displayName;
 
    private readonly string _userName;
 
    private readonly string _host;
 
    private static readonly EncodedStreamFactory s_encoderFactory = new EncodedStreamFactory();
 
    public string DisplayName => _displayName;
 
    public string User => _userName;
 
    public string Host => _host;
 
    public string Address => _userName + "@" + _host;
 
    private string SmtpAddress => "<" + Address + ">";
 
    internal MailAddress(string displayName, string userName, string domain, Encoding displayNameEncoding)
    {
        _host = domain;
        _userName = userName;
        _displayName = displayName;
        _displayNameEncoding = displayNameEncoding ?? Encoding.GetEncoding("utf-8");
    }
 
    public MailAddress(string address)
        : this(address, null, null)
    {
    }
 
    public MailAddress(string address, string? displayName)
        : this(address, displayName, null)
    {
    }
 
    public MailAddress(string address, string? displayName, Encoding? displayNameEncoding)
    {
        (string, string, string, Encoding) parsedData;
        bool flag = TryParse(address, displayName, displayNameEncoding, out parsedData, throwExceptionIfFail: true);
        (_displayName, _userName, _host, _displayNameEncoding) = parsedData;
    }
 
    public static bool TryCreate(string address, [NotNullWhen(true)] out MailAddress? result)
    {
        return TryCreate(address, null, out result);
    }
 
    public static bool TryCreate(string address, string? displayName, [NotNullWhen(true)] out MailAddress? result)
    {
        return TryCreate(address, displayName, null, out result);
    }
 
    public static bool TryCreate(string address, string? displayName, Encoding? displayNameEncoding, [NotNullWhen(true)] out MailAddress? result)
    {
        if (TryParse(address, displayName, displayNameEncoding, out (string, string, string, Encoding) parsedData, throwExceptionIfFail: false))
        {
            result = new MailAddress(parsedData.Item1, parsedData.Item2, parsedData.Item3, parsedData.Item4);
            return true;
        }
        result = null;
        return false;
    }
 
    private static bool TryParse(string address, string displayName, Encoding displayNameEncoding, out (string displayName, string user, string host, Encoding displayNameEncoding) parsedData, bool throwExceptionIfFail)
    {
        if (string.IsNullOrEmpty(address))
        {
            if (throwExceptionIfFail)
            {
                throw (address == null) ? new ArgumentNullException("address") : new ArgumentException(System.SR.Format(System.SR.net_emptystringcall, "address"), "address");
            }
            parsedData = default((string, string, string, Encoding));
            return false;
        }
        if (displayNameEncoding == null)
        {
            displayNameEncoding = Encoding.GetEncoding("utf-8");
        }
        if (displayName == null)
        {
            displayName = string.Empty;
        }
        if (!string.IsNullOrEmpty(displayName))
        {
            if (!MailAddressParser.TryNormalizeOrThrow(displayName, out displayName, throwExceptionIfFail))
            {
                parsedData = default((string, string, string, Encoding));
                return false;
            }
            if (displayName.Length >= 2 && displayName[0] == '"' && displayName[^1] == '"')
            {
                displayName = displayName.Substring(1, displayName.Length - 2);
            }
        }
        if (!MailAddressParser.TryParseAddress(address, out var parsedAddress, throwExceptionIfFail))
        {
            parsedData = default((string, string, string, Encoding));
            return false;
        }
        if (string.IsNullOrEmpty(displayName))
        {
            displayName = parsedAddress.DisplayName;
        }
        parsedData = (displayName: displayName, user: parsedAddress.User, host: parsedAddress.Host, displayNameEncoding: displayNameEncoding);
        return true;
    }
 
    private string GetUser(bool allowUnicode)
    {
        if (!allowUnicode && !MimeBasePart.IsAscii(_userName, permitCROrLF: true))
        {
            throw new SmtpException(System.SR.Format(System.SR.SmtpNonAsciiUserNotSupported, Address));
        }
        return _userName;
    }
 
    private string GetHost(bool allowUnicode)
    {
        string text = _host;
        if (!allowUnicode && !MimeBasePart.IsAscii(text, permitCROrLF: true))
        {
            IdnMapping idnMapping = new IdnMapping();
            try
            {
                text = idnMapping.GetAscii(text);
            }
            catch (ArgumentException innerException)
            {
                throw new SmtpException(System.SR.Format(System.SR.SmtpInvalidHostName, Address), innerException);
            }
        }
        return text;
    }
 
    private string GetAddress(bool allowUnicode)
    {
        return GetUser(allowUnicode) + "@" + GetHost(allowUnicode);
    }
 
    internal string GetSmtpAddress(bool allowUnicode)
    {
        return "<" + GetAddress(allowUnicode) + ">";
    }
 
    public override string ToString()
    {
        if (string.IsNullOrEmpty(DisplayName))
        {
            return Address;
        }
        return "\"" + DisplayName.Replace("\"", "\\\"") + "\" " + SmtpAddress;
    }
 
    public override bool Equals([NotNullWhen(true)] object? value)
    {
        if (value == null)
        {
            return false;
        }
        return ToString().Equals(value.ToString(), StringComparison.InvariantCultureIgnoreCase);
    }
 
    public override int GetHashCode()
    {
        return StringComparer.InvariantCultureIgnoreCase.GetHashCode(ToString());
    }
 
    internal string Encode(int charsConsumed, bool allowUnicode)
    {
        string empty = string.Empty;
        if (!string.IsNullOrEmpty(_displayName))
        {
            if (MimeBasePart.IsAscii(_displayName, permitCROrLF: false) || allowUnicode)
            {
                empty = "\"" + _displayName + "\"";
            }
            else
            {
                IEncodableStream encoderForHeader = s_encoderFactory.GetEncoderForHeader(_displayNameEncoding, useBase64Encoding: false, charsConsumed);
                encoderForHeader.EncodeString(_displayName, _displayNameEncoding);
                empty = encoderForHeader.GetEncodedString();
            }
            return empty + " " + GetSmtpAddress(allowUnicode);
        }
        return GetAddress(allowUnicode);
    }
}