// Parses the domain section of an address. The domain may be in dot-atom format or surrounded by square
// brackets in domain-literal format.
// e.g. <*****@*****.**> or <user@[whatever I want]>
//
// Preconditions:
// - data[index] is just inside of the angle brackets (if any).
//
// Postconditions:
// - data[index] should refer to the '@' symbol
// - returns the parsed domain, including any square brackets for domain-literals
//
// Throws a FormatException or returns false:
// - For invalid un-escaped chars, including Unicode
// - If the start of the data string is reached
private static bool TryParseDomain(string data, ref int index, [NotNullWhen(true)] out string?domain, bool throwExceptionIfFail)
{
// Skip comments and whitespace
if (!TryReadCfwsAndThrowIfIncomplete(data, index, out index, throwExceptionIfFail))
{
domain = default;
return(false);
}
// Mark one end of the domain component
int startingIndex = index;
// Is the domain component in domain-literal format or dot-atom format?
if (data[index] == MailBnfHelper.EndSquareBracket)
{
if (!DomainLiteralReader.TryReadReverse(data, index, out index, throwExceptionIfFail))
{
domain = default;
return(false);
}
}
else
{
if (!DotAtomReader.TryReadReverse(data, index, out index, throwExceptionIfFail))
{
domain = default;
return(false);
}
}
domain = data.Substring(index + 1, startingIndex - index);
// Skip comments and whitespace
if (!TryReadCfwsAndThrowIfIncomplete(data, index, out index, throwExceptionIfFail))
{
return(false);
}
if (!TryNormalizeOrThrow(domain, out domain, throwExceptionIfFail))
{
return(false);
}
return(true);
}
// Parses the local-part section of an address. The local-part may be in dot-atom format or
// quoted-string format. e.g. <user.name@domain> or <"user name"@domain>
// We do not support the obsolete formats of user."name"@domain, "user".name@domain, or "user"."name"@domain.
//
// Preconditions:
// - data[index + 1] is the '@' symbol
//
// Postconditions:
// - data[index] should refer to the '<', if any, otherwise the next non-CFWS char.
// - index == -1 if the beginning of the data string has been reached.
// - returns the parsed local-part, including any bounding quotes around quoted-strings
//
// Throws a FormatException or false is returned:
// - For invalid un-escaped chars, including Unicode
// - If the final value of data[index] is not a valid character to precede the local-part
private static bool TryParseLocalPart(string data, ref int index, bool expectAngleBracket,
bool expectMultipleAddresses, [NotNullWhen(true)] out string?localPart, bool throwExceptionIfFail)
{
// Skip comments and whitespace
if (!TryReadCfwsAndThrowIfIncomplete(data, index, out index, throwExceptionIfFail))
{
localPart = default;
return(false);
}
// Mark the start of the local-part
int startingIndex = index;
// Is the local-part component in quoted-string format or dot-atom format?
if (data[index] == MailBnfHelper.Quote)
{
if (!QuotedStringFormatReader.TryReadReverseQuoted(data, index, true, out index, throwExceptionIfFail))
{
localPart = default;
return(false);
}
}
else
{
if (!DotAtomReader.TryReadReverse(data, index, out index, throwExceptionIfFail))
{
localPart = default;
return(false);
}
// Check that the local-part is properly separated from the next component. It may be separated by a
// comment, whitespace, an expected angle bracket, a quote for the display-name, or an expected comma
// before the next address.
if (index >= 0 &&
!(
MailBnfHelper.IsAllowedWhiteSpace(data[index]) || // < local@domain >
data[index] == MailBnfHelper.EndComment || // <(comment)local@domain>
(expectAngleBracket && data[index] == MailBnfHelper.StartAngleBracket) || // <local@domain>
(expectMultipleAddresses && data[index] == MailBnfHelper.Comma) // local@dom,local@dom
// Note: The following condition is more lax than the RFC. This is done so we could support
// a common invalid formats as shown below.
|| data[index] == MailBnfHelper.Quote // "display"local@domain
)
)
{
if (throwExceptionIfFail)
{
throw new FormatException(SR.Format(SR.MailHeaderFieldInvalidCharacter, data[index]));
}
else
{
localPart = default;
return(false);
}
}
}
localPart = data.Substring(index + 1, startingIndex - index);
if (!WhitespaceReader.TryReadCfwsReverse(data, index, out index, throwExceptionIfFail))
{
return(false);
}
if (!TryNormalizeOrThrow(localPart, out localPart, throwExceptionIfFail))
{
return(false);
}
return(true);
}