/****************************************************************
* 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.james.protocols.pop3.core;
import java.io.IOException;
import java.io.InputStream;
import java.io.SequenceInputStream;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Set;
import org.apache.james.protocols.api.ProtocolSession.State;
import org.apache.james.protocols.api.Request;
import org.apache.james.protocols.api.Response;
import org.apache.james.protocols.pop3.POP3Response;
import org.apache.james.protocols.pop3.POP3Session;
import org.apache.james.protocols.pop3.POP3StreamResponse;
import org.apache.james.protocols.pop3.mailbox.MessageMetaData;
/**
* Handles TOP command
*/
public class TopCmdHandler extends RetrCmdHandler implements CapaCapability {
private static final Collection<String> COMMANDS = Collections.unmodifiableCollection(Arrays.asList("TOP"));
private static final Set<String> CAPS = Collections.unmodifiableSet(new HashSet<String>(Arrays.asList("TOP")));
private static final Response SYNTAX_ERROR = new POP3Response(POP3Response.ERR_RESPONSE, "Usage: TOP [mail number] [Line number]").immutable();
private static final Response ERROR_MESSAGE_RETR = new POP3Response(POP3Response.ERR_RESPONSE, "Error while retrieving message.").immutable();
/**
* Handler method called upon receipt of a TOP command. This command
* retrieves the top N lines of a specified message in the mailbox.
*
* The expected command format is TOP [mail message number] [number of lines
* to return]
*/
@SuppressWarnings("unchecked")
@Override
public Response onCommand(POP3Session session, Request request) {
String parameters = request.getArgument();
if (parameters == null) {
return SYNTAX_ERROR;
}
String argument = "";
String argument1 = "";
int pos = parameters.indexOf(" ");
if (pos > 0) {
argument = parameters.substring(0, pos);
argument1 = parameters.substring(pos + 1);
}
if (session.getHandlerState() == POP3Session.TRANSACTION) {
int num = 0;
int lines = -1;
try {
num = Integer.parseInt(argument);
lines = Integer.parseInt(argument1);
} catch (NumberFormatException nfe) {
return SYNTAX_ERROR;
}
try {
MessageMetaData data = MessageMetaDataUtils.getMetaData(session, num);
if (data == null) {
StringBuilder responseBuffer = new StringBuilder(64).append("Message (").append(num).append(") does not exist.");
return new POP3Response(POP3Response.ERR_RESPONSE, responseBuffer.toString());
}
List<Long> deletedUidList = (List<Long>) session.getAttachment(POP3Session.DELETED_UID_LIST, State.Transaction);
Long uid = data.getUid();
if (deletedUidList.contains(uid) == false) {
InputStream body = new CountingBodyInputStream(new ExtraDotInputStream(new CRLFTerminatedInputStream(session.getUserMailbox().getMessageBody(uid))), lines);
InputStream headers = session.getUserMailbox().getMessageHeaders(uid);
if (body != null && headers != null) {
return new POP3StreamResponse(POP3Response.OK_RESPONSE, "Message follows", new SequenceInputStream(headers, body));
} else {
StringBuilder exceptionBuffer = new StringBuilder(64).append("Message (").append(num).append(") does not exist.");
return new POP3Response(POP3Response.ERR_RESPONSE, exceptionBuffer.toString());
}
} else {
StringBuilder responseBuffer = new StringBuilder(64).append("Message (").append(num).append(") already deleted.");
return new POP3Response(POP3Response.ERR_RESPONSE, responseBuffer.toString());
}
} catch (IOException ioe) {
return ERROR_MESSAGE_RETR;
} catch (IndexOutOfBoundsException iob) {
StringBuilder exceptionBuffer = new StringBuilder(64).append("Message (").append(num).append(") does not exist.");
return new POP3Response(POP3Response.ERR_RESPONSE, exceptionBuffer.toString());
} catch (NoSuchElementException iob) {
StringBuilder exceptionBuffer = new StringBuilder(64).append("Message (").append(num).append(") does not exist.");
return new POP3Response(POP3Response.ERR_RESPONSE, exceptionBuffer.toString());
}
} else {
return POP3Response.ERR;
}
}
/**
* @see org.apache.james.pop3server.core.CapaCapability#getImplementedCapabilities(org.apache.james.pop3server.POP3Session)
*/
@SuppressWarnings("unchecked")
public Set<String> getImplementedCapabilities(POP3Session session) {
if (session.getHandlerState() == POP3Session.TRANSACTION) {
return CAPS;
} else {
return Collections.EMPTY_SET;
}
}
/**
* @see org.apache.james.protocols.api.handler.CommandHandler#getImplCommands()
*/
@Override
public Collection<String> getImplCommands() {
return COMMANDS;
}
/**
* This {@link InputStream} implementation can be used to limit the body
* lines which will be read from the wrapped {@link InputStream}
*/
private final class CountingBodyInputStream extends InputStream {
private int count = 0;
private int limit = -1;
private int lastChar;
private InputStream in;
/**
*
* @param in
* InputStream to read from
* @param limit
* the lines to read. -1 is used for no limits
*/
public CountingBodyInputStream(InputStream in, int limit) {
this.in = in;
this.limit = limit;
}
@Override
public int read() throws IOException {
if (limit != -1) {
if (count <= limit) {
int a = in.read();
if (lastChar == '\r' && a == '\n') {
count++;
}
lastChar = a;
return a;
} else {
return -1;
}
} else {
return in.read();
}
}
@Override
public long skip(long n) throws IOException {
return in.skip(n);
}
@Override
public int available() throws IOException {
return in.available();
}
@Override
public void close() throws IOException {
in.close();
}
@Override
public void mark(int readlimit) {
// not supported
}
@Override
public void reset() throws IOException {
// do nothing as mark is not supported
}
@Override
public boolean markSupported() {
return false;
}
}
}