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using System.Collections.Specialized;
using System.Text;
using System.Net.Mail;
namespace System.Net.Mime
{
internal class MimeBasePart
{
protected ContentType contentType;
protected ContentDisposition contentDisposition;
HeaderCollection headers;
internal const string defaultCharSet = "utf-8";//"iso-8859-1";
internal MimeBasePart()
{
}
internal static bool ShouldUseBase64Encoding(Encoding encoding){
if (encoding == Encoding.Unicode || encoding == Encoding.UTF8 || encoding == Encoding.UTF32 || encoding == Encoding.BigEndianUnicode) {
return true;
}
return false;
}
//use when the length of the header is not known or if there is no header
internal static string EncodeHeaderValue(string value, Encoding encoding, bool base64Encoding){
return MimeBasePart.EncodeHeaderValue(value, encoding, base64Encoding, 0);
}
//used when the length of the header name itself is known (i.e. Subject : )
internal static string EncodeHeaderValue(string value, Encoding encoding, bool base64Encoding, int headerLength) {
StringBuilder newString = new StringBuilder();
//no need to encode if it's pure ascii
if (IsAscii(value, false)) {
return value;
}
if (encoding == null) {
encoding = Encoding.GetEncoding(MimeBasePart.defaultCharSet);
}
EncodedStreamFactory factory = new EncodedStreamFactory();
IEncodableStream stream = factory.GetEncoderForHeader(encoding, base64Encoding, headerLength);
byte[] buffer = encoding.GetBytes(value);
stream.EncodeBytes(buffer, 0, buffer.Length);
return stream.GetEncodedString();
}
internal static string DecodeHeaderValue(string value) {
if(value == null || value.Length == 0){
return String.Empty;
}
string newValue = String.Empty;
//split strings, they may be folded. If they are, decode one at a time and append the results
string[] substringsToDecode = value.Split(new char[] { '\r', '\n', ' ' }, StringSplitOptions.RemoveEmptyEntries);
foreach (string foldedSubString in substringsToDecode) {
//an encoded string has as specific format in that it must start and end with an
//'=' char and contains five parts, separated by '?' chars.
//the first and last part are therefore '=', the second part is the byte encoding (B or Q)
//the third is the unicode encoding type, and the fourth is encoded message itself. '?' is not valid inside of
//an encoded string other than as a separator for these five parts.
//If this check fails, the string is either not encoded or cannot be decoded by this method
string[] subStrings = foldedSubString.Split('?');
if ((subStrings.Length != 5 || subStrings[0] != "=" || subStrings[4] != "=")) {
return value;
}
string charSet = subStrings[1];
bool base64Encoding = (subStrings[2] == "B");
byte[] buffer = ASCIIEncoding.ASCII.GetBytes(subStrings[3]);
int newLength;
EncodedStreamFactory encoderFactory = new EncodedStreamFactory();
IEncodableStream s = encoderFactory.GetEncoderForHeader(Encoding.GetEncoding(charSet), base64Encoding, 0);
newLength = s.DecodeBytes(buffer, 0, buffer.Length);
Encoding encoding = Encoding.GetEncoding(charSet);
newValue += encoding.GetString(buffer, 0, newLength);
}
return newValue;
}
// Detect the encoding: "=?encoding?BorQ?content?="
// "=?utf-8?B?RmlsZU5hbWVf55CG0Y3Qq9C60I5jw4TRicKq0YIM0Y1hSsSeTNCy0Klh?="; // 3.5
// With the addition of folding in 4.0, there may be multiple lines with encoding, only detect the first:
// "=?utf-8?B?RmlsZU5hbWVf55CG0Y3Qq9C60I5jw4TRicKq0YIM0Y1hSsSeTNCy0Klh?=\r\n =?utf-8?B??=";
internal static Encoding DecodeEncoding(string value) {
if (value == null || value.Length == 0){
return null;
}
string[] subStrings = value.Split('?', '\r', '\n');
if ((subStrings.Length < 5 || subStrings[0] != "=" || subStrings[4] != "=")) {
return null;
}
string charSet = subStrings[1];
return Encoding.GetEncoding(charSet);
}
internal static bool IsAscii(string value, bool permitCROrLF) {
if (value == null)
throw new ArgumentNullException("value");
foreach (char c in value) {
if ((int)c > 0x7f) {
return false;
}
if (!permitCROrLF && (c=='\r' || c=='\n')) {
return false;
}
}
return true;
}
internal static bool IsAnsi(string value, bool permitCROrLF) {
if (value == null)
throw new ArgumentNullException("value");
foreach (char c in value) {
if ((int)c > 0xff) {
return false;
}
if (!permitCROrLF && (c=='\r' || c=='\n')) {
return false;
}
}
return true;
}
internal string ContentID {
get {
return Headers[MailHeaderInfo.GetString(MailHeaderID.ContentID)];
}
set {
if (string.IsNullOrEmpty(value))
{
Headers.Remove(MailHeaderInfo.GetString(MailHeaderID.ContentID));
}
else
{
Headers[MailHeaderInfo.GetString(MailHeaderID.ContentID)] = value;
}
}
}
internal string ContentLocation
{
get
{
return Headers[MailHeaderInfo.GetString(MailHeaderID.ContentLocation)];
}
set
{
if (string.IsNullOrEmpty(value))
{
Headers.Remove(MailHeaderInfo.GetString(MailHeaderID.ContentLocation));
}
else
{
Headers[MailHeaderInfo.GetString(MailHeaderID.ContentLocation)] = value;
}
}
}
internal NameValueCollection Headers
{
get {
//persist existing info before returning
if (headers == null)
headers = new HeaderCollection();
if (contentType == null){
contentType = new ContentType();
}
contentType.PersistIfNeeded(headers,false);
if (contentDisposition != null)
contentDisposition.PersistIfNeeded(headers,false);
return headers;
}
}
internal ContentType ContentType{
get{
if (contentType == null){
contentType = new ContentType();
}
return contentType;
}
set {
if (value == null)
throw new ArgumentNullException("value");
contentType = value;
contentType.PersistIfNeeded((HeaderCollection)Headers,true);
}
}
internal void PrepareHeaders(bool allowUnicode) {
contentType.PersistIfNeeded((HeaderCollection)Headers, false);
headers.InternalSet(MailHeaderInfo.GetString(MailHeaderID.ContentType), contentType.Encode(allowUnicode));
if (contentDisposition != null) {
contentDisposition.PersistIfNeeded((HeaderCollection)Headers, false);
headers.InternalSet(MailHeaderInfo.GetString(MailHeaderID.ContentDisposition),
contentDisposition.Encode(allowUnicode));
}
}
internal virtual void Send(BaseWriter writer, bool allowUnicode) {
throw new NotImplementedException();
}
internal virtual IAsyncResult BeginSend(BaseWriter writer, AsyncCallback callback,
bool allowUnicode, object state) {
throw new NotImplementedException();
}
internal void EndSend(IAsyncResult asyncResult) {
if (asyncResult == null) {
throw new ArgumentNullException("asyncResult");
}
LazyAsyncResult castedAsyncResult = asyncResult as MimePartAsyncResult;
if (castedAsyncResult == null || castedAsyncResult.AsyncObject != this) {
throw new ArgumentException(SR.GetString(SR.net_io_invalidasyncresult), "asyncResult");
}
if (castedAsyncResult.EndCalled) {
throw new InvalidOperationException(SR.GetString(SR.net_io_invalidendcall, "EndSend"));
}
castedAsyncResult.InternalWaitForCompletion();
castedAsyncResult.EndCalled = true;
if (castedAsyncResult.Result is Exception) {
throw (Exception)castedAsyncResult.Result;
}
}
internal class MimePartAsyncResult: LazyAsyncResult {
internal MimePartAsyncResult(MimeBasePart part, object state, AsyncCallback callback):base(part,state,callback) {
}
}
}
}
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