//
// This method attempts reading quoted-string formatted data when the bounding quotes were omitted.
// This is common for e-mail display-names.
//
// Precondition: The index must be within the bounds of the data string.
//
// Return value:
// - The index of the special delimiter provided.
// e.g. In ([email protected], billy box [email protected]), starting at index=19 (x) returns index=9 (,).
// - -1 if the terminating character was not found.
// e.g. In (my name username@domain), starting at index=5 (e) returns index=-1.
//
// A FormatException will be thrown or false is returned if:
// - A non-escaped character is encountered that is not valid in a quoted string. This includes double quotes.
// - A Unicode character is encountered and Unicode has not been allowed.
//
internal static bool TryReadReverseUnQuoted(string data, int index, bool permitUnicode, bool expectCommaDelimiter, out int outIndex, bool throwExceptionIfFail)
{
Debug.Assert(0 <= index && index < data.Length, "Index out of range: " + index + ", " + data.Length);
do
{
// Check for valid whitespace
if (!WhitespaceReader.TryReadFwsReverse(data, index, out index, throwExceptionIfFail))
{
outIndex = default;
return(false);
}
if (index < 0)
{
break;
}
// Check for escaped characters
if (!QuotedPairReader.TryCountQuotedChars(data, index, permitUnicode, out int quotedCharCount, throwExceptionIfFail))
{
outIndex = default;
return(false);
}
if (quotedCharCount > 0)
{
index -= quotedCharCount;
}
// Check for the terminating char
else if (expectCommaDelimiter && data[index] == MailBnfHelper.Comma)
{
break;
}
// Check invalid characters
else if (!IsValidQtext(permitUnicode, data[index]))
{
if (throwExceptionIfFail)
{
throw new FormatException(SR.Format(SR.MailHeaderFieldInvalidCharacter, data[index]));
}
else
{
outIndex = default;
return(false);
}
}
// Valid char
else
{
index--;
}
}while (index >= 0);
outIndex = index;
return(true);
}
//
// This method reads a standard quoted string. Departing from the RFC, Unicode is permitted for display-name.
//
// Preconditions:
// - Index must be within the bounds of the data string.
// - The char at the given index is the initial quote. (data[index] == Quote)
//
// Return value: The next index past the terminating-quote (data[index + 1] == Quote).
// e.g. In (bob "user name"@domain), starting at index=14 (") returns index=3 (space).
//
// A FormatException will be thrown or false is returned if:
// - A non-escaped character is encountered that is not valid in a quoted string.
// - A Unicode character is encountered and Unicode has not been allowed.
// - The final double quote is not found.
//
internal static bool TryReadReverseQuoted(string data, int index, bool permitUnicode, out int outIndex, bool throwExceptionIfFail)
{
Debug.Assert(0 <= index && index < data.Length, "Index out of range: " + index + ", " + data.Length);
// Check for the first bounding quote
Debug.Assert(data[index] == MailBnfHelper.Quote, "Initial char at index " + index + " was not a quote.");
// Skip the bounding quote
index--;
do
{
// Check for valid whitespace
if (!WhitespaceReader.TryReadFwsReverse(data, index, out index, throwExceptionIfFail))
{
outIndex = default;
return(false);
}
if (index < 0)
{
break;
}
// Check for escaped characters
if (!QuotedPairReader.TryCountQuotedChars(data, index, permitUnicode, out int quotedCharCount, throwExceptionIfFail))
{
outIndex = default;
return(false);
}
if (quotedCharCount > 0)
{
// Skip quoted pairs
index -= quotedCharCount;
}
// Check for the terminating quote
else if (data[index] == MailBnfHelper.Quote)
{
// Skip the final bounding quote
outIndex = index - 1;
return(true);
}
// Check invalid characters
else if (!IsValidQtext(permitUnicode, data[index]))
{
if (throwExceptionIfFail)
{
throw new FormatException(SR.Format(SR.MailHeaderFieldInvalidCharacter, data[index]));
}
else
{
outIndex = default;
return(false);
}
}
// Valid char
else
{
index--;
}
}while (index >= 0);
if (throwExceptionIfFail)
{
// We started with a quote, but did not end with one
throw new FormatException(SR.Format(SR.MailHeaderFieldInvalidCharacter, MailBnfHelper.Quote));
}
else
{
outIndex = default;
return(false);
}
}
//
// Parse a single MailAddress, potentially from a list.
//
// Preconditions:
// - Index must be within the bounds of the data string.
// - The data string must not be null or empty
//
// Postconditions:
// - Returns a valid MailAddress object parsed from the string
// - For a single MailAddress index is set to -1
// - For a list data[index] is the comma separator or -1 if the end of the data string was reached.
//
// Throws a FormatException or false is returned if any part of the MailAddress is invalid.
private static bool TryParseAddress(string data, bool expectMultipleAddresses, ref int index, out ParseAddressInfo parseAddressInfo, bool throwExceptionIfFail)
{
Debug.Assert(!string.IsNullOrEmpty(data));
Debug.Assert(index >= 0 && index < data.Length, "Index out of range: " + index + ", " + data.Length);
// Parsed components to be assembled as a MailAddress later
string?displayName;
// Skip comments and whitespace
if (!TryReadCfwsAndThrowIfIncomplete(data, index, out index, throwExceptionIfFail))
{
parseAddressInfo = default;
return(false);
}
// Do we expect angle brackets around the address?
// e.g. ("display name" <user@domain>)
bool expectAngleBracket = false;
if (data[index] == MailBnfHelper.EndAngleBracket)
{
expectAngleBracket = true;
index--;
}
if (!TryParseDomain(data, ref index, out string?domain, throwExceptionIfFail))
{
parseAddressInfo = default;
return(false);
}
// The next character after the domain must be the '@' symbol
if (data[index] != MailBnfHelper.At)
{
if (throwExceptionIfFail)
{
throw new FormatException(SR.MailAddressInvalidFormat);
}
else
{
parseAddressInfo = default;
return(false);
}
}
// Skip the '@' symbol
index--;
if (!TryParseLocalPart(data, ref index, expectAngleBracket, expectMultipleAddresses, out string?localPart, throwExceptionIfFail))
{
parseAddressInfo = default;
return(false);
}
// Check for a matching angle bracket around the address
if (expectAngleBracket)
{
if (index >= 0 && data[index] == MailBnfHelper.StartAngleBracket)
{
index--; // Skip the angle bracket
// Skip whitespace, but leave comments, as they may be part of the display name.
if (!WhitespaceReader.TryReadFwsReverse(data, index, out index, throwExceptionIfFail))
{
parseAddressInfo = default;
return(false);
}
}
else
{
// Mismatched angle brackets
if (throwExceptionIfFail)
{
throw new FormatException(SR.Format(SR.MailHeaderFieldInvalidCharacter,
(index >= 0 ? data[index] : MailBnfHelper.EndAngleBracket)));
}
else
{
parseAddressInfo = default;
return(false);
}
}
}
// Is there anything left to parse?
// There could still be a display name or another address
if (index >= 0 && !(expectMultipleAddresses && data[index] == MailBnfHelper.Comma))
{
if (!TryParseDisplayName(data, ref index, expectMultipleAddresses, out displayName, throwExceptionIfFail))
{
parseAddressInfo = default;
return(false);
}
}
else
{
displayName = string.Empty;
}
parseAddressInfo = new ParseAddressInfo(displayName, localPart, domain);
return(true);
}
//
// Reads a domain literal in reverse
//
// Preconditions:
// - Index must be within the bounds of the data string.
// - The char at the given index is the initial bracket. (data[index] == EndSquareBracket)
//
// Return value:
// - The next index past the terminating bracket (data[index + 1] == StartSquareBracket).
// e.g. In (user@[domain]), starting at index=12 (]) returns index=4 (@).
//
// A FormatException will be thrown or false is returned if:
// - A non-escaped character is encountered that is not valid in a domain literal, including Unicode.
// - The final bracket is not found.
//
internal static bool TryReadReverse(string data, int index, out int outIndex, bool throwExceptionIfFail)
{
Debug.Assert(0 <= index && index < data.Length, "index was outside the bounds of the string: " + index);
Debug.Assert(data[index] == MailBnfHelper.EndSquareBracket, "data did not end with a square bracket");
// Skip the end bracket
index--;
do
{
// Check for valid whitespace
if (!WhitespaceReader.TryReadFwsReverse(data, index, out index, throwExceptionIfFail))
{
outIndex = default;
return(false);
}
if (index < 0)
{
break;
}
// Check for escaped characters
if (!QuotedPairReader.TryCountQuotedChars(data, index, false, out int quotedCharCount, throwExceptionIfFail))
{
outIndex = default;
return(false);
}
if (quotedCharCount > 0)
{
// Skip quoted pairs
index -= quotedCharCount;
}
// Check for the terminating bracket
else if (data[index] == MailBnfHelper.StartSquareBracket)
{
// We're done parsing
outIndex = index - 1;
return(true);
}
// Check for invalid characters
else if (data[index] > MailBnfHelper.Ascii7bitMaxValue || !MailBnfHelper.Dtext[data[index]])
{
if (throwExceptionIfFail)
{
throw new FormatException(SR.Format(SR.MailHeaderFieldInvalidCharacter, data[index]));
}
else
{
outIndex = default;
return(false);
}
}
// Valid char
else
{
index--;
}
}while (index >= 0);
if (throwExceptionIfFail)
{
// We didn't find a matching '[', throw.
throw new FormatException(SR.Format(SR.MailHeaderFieldInvalidCharacter,
MailBnfHelper.EndSquareBracket));
}
else
{
outIndex = default;
return(false);
}
}