| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package org.apache.geronimo.javamail.util; |
| |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| /** |
| * An implementation of an OutputStream that performs MIME linebreak |
| * canonicalization and "byte-stuff" so that data content does not get mistaken |
| * for a message data-end marker (CRLF.CRLF)l |
| * |
| * @version $Rev$ $Date$ |
| */ |
| public class MIMEOutputStream extends OutputStream { |
| |
| // the wrappered output stream. |
| protected OutputStream out; |
| |
| // last character we handled...used to recongnize line breaks. |
| protected int lastWrite = -1; |
| |
| // a flag to indicate we've just processed a line break. This is used for |
| // byte stuffing purposes. This |
| // is initially true, because if the first character of the content is a |
| // period, we need to byte-stuff |
| // immediately. |
| protected boolean atLineBreak = true; |
| |
| /** |
| * Create an output stream that writes to the target output stream. |
| * |
| * @param out |
| * The wrapped output stream. |
| */ |
| public MIMEOutputStream(OutputStream out) { |
| this.out = out; |
| } |
| |
| // in order for this to work, we only need override the single character |
| // form, as the others |
| // funnel through this one by default. |
| public void write(int ch) throws IOException { |
| // if this is a CR character, always write out a full sequence, and |
| // remember that we just did this. |
| if (ch == '\r') { |
| out.write((byte) '\r'); |
| out.write((byte) '\n'); |
| // we've just taken a break; |
| atLineBreak = true; |
| } |
| // if this is a new line, then we need to determine if this is a loner |
| // or part of a CRLF sequence. |
| else if (ch == '\n') { |
| // is this a lone ranger? |
| if (lastWrite != '\r') { |
| // write the full CRLF sequence. |
| out.write((byte) '\r'); |
| out.write((byte) '\n'); |
| } |
| // regardless of whether we wrote something or not, we're still at a |
| // line break. |
| atLineBreak = true; |
| } |
| // potential byte-stuffing situation? |
| else if (ch == '.') { |
| // ok, this is a potential stuff situation. Did we just have a line |
| // break? Double up the character. |
| if (atLineBreak) { |
| out.write('.'); |
| } |
| out.write('.'); |
| atLineBreak = false; |
| } else { |
| // just write this out and flip the linebreak flag. |
| out.write(ch); |
| atLineBreak = false; |
| } |
| // remember this last one for CRLF tracking purposes. |
| lastWrite = ch; |
| } |
| } |