/*
 * Copyright 2016 The Netty Project
 *
 * The Netty Project 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 io.netty.handler.codec.smtp;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufUtil;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageEncoder;
import io.netty.util.internal.UnstableApi;

import java.util.Iterator;
import java.util.List;
import java.util.RandomAccess;

Encoder for SMTP requests.
/** * Encoder for SMTP requests. */
@UnstableApi public final class SmtpRequestEncoder extends MessageToMessageEncoder<Object> { private static final int CRLF_SHORT = ('\r' << 8) | '\n'; private static final byte SP = ' '; private static final ByteBuf DOT_CRLF_BUFFER = Unpooled.unreleasableBuffer( Unpooled.directBuffer(3).writeByte('.').writeByte('\r').writeByte('\n')); private boolean contentExpected; @Override public boolean acceptOutboundMessage(Object msg) throws Exception { return msg instanceof SmtpRequest || msg instanceof SmtpContent; } @Override protected void encode(ChannelHandlerContext ctx, Object msg, List<Object> out) throws Exception { if (msg instanceof SmtpRequest) { final SmtpRequest req = (SmtpRequest) msg; if (contentExpected) { if (req.command().equals(SmtpCommand.RSET)) { contentExpected = false; } else { throw new IllegalStateException("SmtpContent expected"); } } boolean release = true; final ByteBuf buffer = ctx.alloc().buffer(); try { req.command().encode(buffer); writeParameters(req.parameters(), buffer); ByteBufUtil.writeShortBE(buffer, CRLF_SHORT); out.add(buffer); release = false; if (req.command().isContentExpected()) { contentExpected = true; } } finally { if (release) { buffer.release(); } } } if (msg instanceof SmtpContent) { if (!contentExpected) { throw new IllegalStateException("No SmtpContent expected"); } final ByteBuf content = ((SmtpContent) msg).content(); out.add(content.retain()); if (msg instanceof LastSmtpContent) { out.add(DOT_CRLF_BUFFER.retainedDuplicate()); contentExpected = false; } } } private static void writeParameters(List<CharSequence> parameters, ByteBuf out) { if (parameters.isEmpty()) { return; } out.writeByte(SP); if (parameters instanceof RandomAccess) { final int sizeMinusOne = parameters.size() - 1; for (int i = 0; i < sizeMinusOne; i++) { ByteBufUtil.writeAscii(out, parameters.get(i)); out.writeByte(SP); } ByteBufUtil.writeAscii(out, parameters.get(sizeMinusOne)); } else { final Iterator<CharSequence> params = parameters.iterator(); for (;;) { ByteBufUtil.writeAscii(out, params.next()); if (params.hasNext()) { out.writeByte(SP); } else { break; } } } } }