+
−/*
+
− * SPDX-License-Identifier: MPL-2.0
+
− *
+
− * This Source Code Form is subject to the terms of the Mozilla Public
+
− * License, v. 2.0.  If a copy of the MPL was not distributed with this
+
− * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
− *
+
− * Copyright 2024, 2025 MonetDB Foundation;
+
− * Copyright August 2008 - 2023 MonetDB B.V.;
+
− * Copyright 1997 - July 2008 CWI.
+
− */
+
−
+
−package org.monetdb.mcl.net;
+
−
+
−import java.io.BufferedInputStream;
+
−import java.io.BufferedOutputStream;
+
−import java.io.FileWriter;
+
−import java.io.FilterInputStream;
+
−import java.io.FilterOutputStream;
+
−import java.io.IOException;
+
−import java.io.InputStream;
+
−import java.io.OutputStream;
+
−import java.io.Writer;
+
−import java.net.*;
+
−import java.nio.charset.StandardCharsets;
+
−import java.security.MessageDigest;
+
−import java.security.NoSuchAlgorithmException;
+
−import java.util.*;
+
−
+
−import javax.net.ssl.SSLException;
+
−
+
−import org.monetdb.mcl.MCLException;
+
−import org.monetdb.mcl.io.BufferedMCLReader;
+
−import org.monetdb.mcl.io.BufferedMCLWriter;
+
−import org.monetdb.mcl.io.LineType;
+
−import org.monetdb.mcl.parser.MCLParseException;
+
−
+
−/**
+
− * A Socket for communicating with the MonetDB database in MAPI block
+
− * mode.
+
− *
+
− * The MapiSocket implements the protocol specifics of the MAPI block
+
− * mode protocol, and interfaces it as a socket that delivers a
+
− * BufferedReader and a BufferedWriter.  Because logging in is an
+
− * integral part of the MAPI protocol, the MapiSocket performs the login
+
− * procedure.  Like the Socket class, various options can be set before
+
− * calling the connect() method to influence the login process.  Only
+
− * after a successful call to connect() the BufferedReader and
+
− * BufferedWriter can be retrieved.
+
− *
+
− * For each line read, it is determined what type of line it is
+
− * according to the MonetDB MAPI protocol.  This results in a line to be
+
− * PROMPT, HEADER, RESULT, ERROR or UNKNOWN.  Use the getLineType()
+
− * method on the BufferedMCLReader to retrieve the type of the last
+
− * line read.
+
− *
+
− * For debugging purposes a socket level debugging is implemented where
+
− * each and every interaction to and from the MonetDB server is logged
+
− * to a file on disk.
+
− * Incoming messages are prefixed by "RX" (received by the driver),
+
− * outgoing messages by "TX" (transmitted by the driver).  Special
+
− * decoded non-human readable messages are prefixed with "RD" and "TD"
+
− * instead.  Following this two char prefix, a timestamp follows as the
+
− * number of milliseconds since the UNIX epoch.  The rest of the line is
+
− * a String representation of the data sent or received.
+
− *
+
− * The general use of this Socket must be seen only in the full context
+
− * of a MAPI connection to a server.  It has the same ingredients as a
+
− * normal Socket, allowing for seamless plugging.
+
− * <pre>
+
− *    Socket   \     /  InputStream  ----&gt; (BufferedMCL)Reader
+
− *              &gt; o &lt;
+
− *  MapiSocket /     \ OutputStream  ----&gt; (BufferedMCL)Writer
+
− * </pre>
+
− * The MapiSocket allows to retrieve Streams for communicating.  They
+
− * are interfaced, so they can be chained in any way.  While the Socket
+
− * transparently deals with how data is sent over the wire, the actual
+
− * data read needs to be interpreted, for which a Reader/Writer
+
− * interface is most sufficient.  In particular the BufferedMCL*
+
− * implementations of those interfaces supply some extra functionality
+
− * geared towards the format of the data.
+
− *
+
− * @author Fabian Groffen
+
− * @version 4.4
+
− * @see org.monetdb.mcl.io.BufferedMCLReader
+
− * @see org.monetdb.mcl.io.BufferedMCLWriter
+
− */
+
−public final class MapiSocket {
+
−	/* an even number of NUL bytes used during the handshake */
+
−	private static final byte[] NUL_BYTES = new byte[]{ 0, 0, 0, 0, 0, 0, 0, 0 };
+
−
+
−	/* A mapping between hash algorithm names as used in the MAPI
+
−	 * protocol, and the names by which the Java runtime knows them.
+
−	 */
+
−	private static final String[][] KNOWN_ALGORITHMS = new String[][] {
+
−			{"SHA512", "SHA-512"},
+
−			{"SHA384", "SHA-384"},
+
−			{"SHA256", "SHA-256"},
+
−			// should we deprecate this by now?
+
−			{"SHA1", "SHA-1"},
+
−	};
+
−
+
−	// MUST be lowercase!
+
−	private static final char[] HEXDIGITS = "0123456789abcdef".toCharArray();
+
−
+
−	/** Connection parameters */
+
−	private Target target;
+
−	/** The TCP Socket to mserver */
+
−	private Socket con;
+
−	/** Stream from the Socket for reading */
+
−	private BlockInputStream fromMonet;
+
−	/** Stream from the Socket for writing */
+
−	private OutputStream toMonet;
+
−	/** MCLReader on the InputStream */
+
−	private BufferedMCLReader reader;
+
−	/** MCLWriter on the OutputStream */
+
−	private BufferedMCLWriter writer;
+
−	/** protocol version of the connection */
+
−	private int version;
+
−	private boolean supportsClientInfo;
+
−
+
−	/** Whether we should follow redirects.
+
−	 * Not sure why this needs to be separate
+
−	 * from 'ttl' but someone someday explicitly documented setTtl
+
−	 * with 'to disable completely, use followRedirects' so
+
−	 * apparently there is a use case.
+
−	 */
+
−	private boolean followRedirects = true;
+
−	/** How many redirections do we follow until we're fed up with it? */
+
−	private int ttl = 10;
+
−
+
−	/** The Writer for the debug log-file */
+
−	private Writer log;
+
−
+
−	/** The blocksize (hardcoded in compliance with MonetDB common/stream/stream.h) */
+
−	public final static int BLOCK = 8190;
+
−
+
−	/** A short in two bytes for holding the block size in bytes */
+
−	private final byte[] blklen = new byte[2];
+
−
+
−	/**
+
−	 * Constructs a new MapiSocket.
+
−	 */
+
−	public MapiSocket() {
+
−		target = new Target();
+
−		con = null;
+
−	}
+
−
+
−	/**
+
−	 * Sets the database to connect to.  If database is null, a
+
−	 * connection is made to the default database of the server.  This
+
−	 * is also the default.
+
−	 *
+
−	 * @param db the database
+
−	 */
+
−	public void setDatabase(final String db) {
+
−		target.setDatabase(db);
+
−	}
+
−
+
−	/**
+
−	 * Sets the language to use for this connection.
+
−	 *
+
−	 * @param lang the language
+
−	 */
+
−	public void setLanguage(final String lang) {
+
−		target.setLanguage(lang);
+
−	}
+
−
+
−	/**
+
−	 * Sets the hash method to use.  Note that this method is intended
+
−	 * for debugging purposes.  Setting a hash method can yield in
+
−	 * connection failures.  Multiple hash methods can be given by
+
−	 * separating the hashes by commas.
+
−	 * DON'T USE THIS METHOD if you don't know what you're doing.
+
−	 *
+
−	 * @param hash the hash method to use
+
−	 */
+
−	public void setHash(final String hash) {
+
−		target.setHash(hash);
+
−	}
+
−
+
−	/**
+
−	 * Sets whether MCL redirections should be followed or not.  If set
+
−	 * to false, an MCLException will be thrown when a redirect is
+
−	 * encountered during connect.  The default behavior is to
+
−	 * automatically follow redirects.
+
−	 *
+
−	 * @param r whether to follow redirects (true) or not (false)
+
−	 */
+
−	public void setFollowRedirects(final boolean r) {
+
−		this.followRedirects = r;
+
−	}
+
−
+
−	/**
+
−	 * Sets the number of redirects that are followed when
+
−	 * followRedirects is true.  In order to avoid going into an endless
+
−	 * loop due to some evil server, or another error, a maximum number
+
−	 * of redirects that may be followed can be set here.  Note that to
+
−	 * disable the following of redirects you should use
+
−	 * setFollowRedirects.
+
−	 *
+
−	 * @see #setFollowRedirects(boolean r)
+
−	 * @param t the number of redirects before an exception is thrown
+
−	 */
+
−	public void setTTL(final int t) {
+
−		this.ttl = t;
+
−	}
+
−
+
−	/**
+
−	 * Set the SO_TIMEOUT on the underlying Socket.  When for some
+
−	 * reason the connection to the database hangs, this setting can be
+
−	 * useful to break out of this indefinite wait.
+
−	 * This option must be enabled prior to entering the blocking
+
−	 * operation to have effect.
+
−	 *
+
−	 * @param s The specified timeout, in milliseconds.  A timeout
+
−	 *        of zero will disable timeout (i.e., timeout of infinity).
+
−	 * @throws SocketException Issue with the socket
+
−	 */
+
−	public void setSoTimeout(final int s) throws SocketException {
+
−		if (s < 0) {
+
−			throw new IllegalArgumentException("timeout can't be negative");
+
−		}
+
−		target.setSoTimeout(s);
+
−		// limit time to wait on blocking operations
+
−		if (con != null) {
+
−			con.setSoTimeout(s);
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Gets the SO_TIMEOUT from the underlying Socket.
+
−	 *
+
−	 * @return the currently in use timeout in milliseconds
+
−	 * @throws SocketException Issue with the socket
+
−	 */
+
−	public int getSoTimeout() throws SocketException {
+
−		return target.getSoTimeout();
+
−	}
+
−
+
−	/**
+
−	 * Enables/disables debug mode with logging to file
+
−	 *
+
−	 * @param debug Value to set
+
−	 */
+
−	public void setDebug(final boolean debug) {
+
−		target.setDebug(debug);
+
−	}
+
−
+
−	/**
+
−	 * Connects to the given host and port, logging in as the given
+
−	 * user.  If followRedirect is false, a RedirectionException is
+
−	 * thrown when a redirect is encountered.
+
−	 *
+
−	 * @param host the hostname, or null for the loopback address
+
−	 * @param port the port number (must be between 0 and 65535, inclusive)
+
−	 * @param user the username
+
−	 * @param pass the password
+
−	 * @return A List with informational (warning) messages. If this
+
−	 *		list is empty; then there are no warnings.
+
−	 * @throws IOException if an I/O error occurs when creating the socket
+
−	 * @throws SocketException - if there is an error in the underlying protocol, such as a TCP error.
+
−	 * @throws UnknownHostException if the IP address of the host could not be determined
+
−	 * @throws MCLParseException if bogus data is received
+
−	 * @throws MCLException if an MCL related error occurs
+
−	 */
+
−	public List<String> connect(final String host, final int port, final String user, final String pass)
+
−		throws IOException, SocketException, UnknownHostException, MCLParseException, MCLException
+
−	{
+
−		target.setHost(host);
+
−		target.setPort(port);
+
−		target.setUser(user);
+
−		target.setPassword(pass);
+
−		return connect(target, null);
+
−	}
+
−
+
−	public List<String> connect(String url, Properties props) throws URISyntaxException, ValidationError, MCLException, MCLParseException, IOException {
+
−		return connect(new Target(url, props), null);
+
−	}
+
−
+
−	/**
+
−	 * Connect according to the settings in the 'target' parameter.
+
−	 * If followRedirect is false, a RedirectionException is
+
−	 * thrown when a redirect is encountered.
+
−	 *
+
−	 * Some settings, such as the initial reply size, can already be configured
+
−	 * during the handshake, saving a command round-trip later on.
+
−	 * To do so, create and pass a subclass of {@link MapiSocket.OptionsCallback}.
+
−	 *
+
−	 * @param target the connection settings
+
−	 * @param callback will be called if the server allows options to be set during the
+
−	 * initial handshake
+
−	 * @return A List with informational (warning) messages. If this
+
−	 *		list is empty; then there are no warnings.
+
−	 * @throws IOException if an I/O error occurs when creating the socket
+
−	 * @throws SocketException - if there is an error in the underlying protocol, such as a TCP error.
+
−	 * @throws UnknownHostException if the IP address of the host could not be determined
+
−	 * @throws MCLParseException if bogus data is received
+
−	 * @throws MCLException if an MCL related error occurs
+
−	 */
+
−	public List<String> connect(Target target, OptionsCallback callback) throws MCLException, MCLParseException, IOException {
+
−		// get rid of any earlier connection state, including the existing target
+
−		close();
+
−		this.target = target;
+
−
+
−		Target.Validated validated;
+
−		try {
+
−			validated = target.validate();
+
−		} catch (ValidationError e) {
+
−			throw new MCLException(e.getMessage());
+
−		}
+
−
+
−		if (validated.connectScan()) {
+
−			return scanUnixSockets(callback);
+
−		}
+
−
+
−		ArrayList<String> warnings = new ArrayList<>();
+
−		int attempts = 0;
+
−		do {
+
−			boolean ok = false;
+
−			try {
+
−				boolean done = tryConnect(callback, warnings);
+
−				ok = true;
+
−				if (done) {
+
−					return warnings;
+
−				}
+
−			} finally {
+
−				if (!ok)
+
−					close();
+
−			}
+
−		} while (followRedirects && attempts++ < this.ttl);
+
−		throw new MCLException("max redirect count exceeded");
+
−	}
+
−
+
−	private List<String> scanUnixSockets(OptionsCallback callback) throws MCLException, MCLParseException, IOException {
+
−		// Because we do not support Unix Domain sockets, we just go back to connect().
+
−		// target.connectScan() will now return false;
+
−		target.setHost("localhost");
+
−		return connect(target, callback);
+
−	}
+
−
+
−	private boolean tryConnect(OptionsCallback callback, ArrayList<String> warningBuffer) throws MCLException, IOException {
+
−		try {
+
−			// We need a valid target
+
−			Target.Validated validated = target.validate();
+
−			// con will be non-null if the previous attempt ended in a redirect to mapi:monetdb://proxy
+
−			if (con == null)
+
−				connectSocket(validated);
+
−			return handshake(validated, callback, warningBuffer);
+
−		} catch (IOException | MCLException e) {
+
−			close();
+
−			throw e;
+
−		} catch (ValidationError e) {
+
−			close();
+
−			throw new MCLException(e.getMessage());
+
−		}
+
−	}
+
−
+
−	private void connectSocket(Target.Validated validated) throws MCLException, IOException {
+
−		// This method performs steps 2-6 of the procedure outlined in the URL spec
+
−		String tcpHost = validated.connectTcp();
+
−		if (tcpHost.isEmpty()) {
+
−			throw new MCLException("Unix domain sockets are not supported, only TCP");
+
−		}
+
−		int port = validated.connectPort();
+
−		Socket sock = null;
+
−		try {
+
−			sock = new Socket(tcpHost, port);
+
−			sock.setSoTimeout(validated.getSoTimeout());
+
−			sock.setTcpNoDelay(true);
+
−			sock.setKeepAlive(true);
+
−
+
−			sock = wrapTLS(sock, validated);
+
−
+
−			fromMonet = new BlockInputStream(sock.getInputStream());
+
−			toMonet = new BlockOutputStream(sock.getOutputStream());
+
−			reader = new BufferedMCLReader(fromMonet, StandardCharsets.UTF_8);
+
−			writer = new BufferedMCLWriter(toMonet, StandardCharsets.UTF_8);
+
−			writer.registerReader(reader);
+
−			reader.advance();
+
−
+
−			// Only assign to sock when everything went ok so far
+
−			con = sock;
+
−			sock = null;
+
−		} catch (SSLException e) {
+
−			throw new MCLException("SSL error: " + e.getMessage(), e);
+
−		} catch (IOException e) {
+
−			throw new MCLException("Could not connect to " + tcpHost + ":" + port + ": " + e.getMessage(), e);
+
−		} finally {
+
−			if (sock != null)
+
−				try {
+
−					sock.close();
+
−				} catch (IOException e) {
+
−					// ignore
+
−				}
+
−		}
+
−	}
+
−
+
−	private Socket wrapTLS(Socket sock, Target.Validated validated) throws IOException {
+
−		if (validated.getTls())
+
−			return SecureSocket.wrap(validated, sock);
+
−		else {
+
−			// Send an even number of NUL bytes to avoid a deadlock if
+
−			// we're accidentally connecting to a TLS-protected server.
+
−			// The cause of the deadlock is that we speak MAPI and we wait
+
−			// for the server to send a MAPI challenge.
+
−			// However, if the server is trying to set up TLS, it will be
+
−			// waiting for us to send a TLS 'Client Hello' packet.
+
−			// Hence, deadlock.
+
−			// NUL NUL is a no-op in MAPI and will hopefully force an error
+
−			// in the TLS server. This does not always work, some
+
−			// TLS implementations abort on the first NUL, some need more NULs
+
−			// than we are prepared to send here. 8 seems to be a good number.
+
−			sock.getOutputStream().write(NUL_BYTES);
+
−		}
+
−		return sock;
+
−	}
+
−
+
−	private boolean handshake(Target.Validated validated, OptionsCallback callback, ArrayList<String> warnings) throws IOException, MCLException {
+
−		String challenge = reader.getLine();
+
−		reader.advance();
+
−		if (reader.getLineType() != LineType.PROMPT)
+
−			throw new MCLException("Garbage after server challenge: " + reader.getLine());
+
−		String response = challengeResponse(validated, challenge, callback);
+
−		writer.writeLine(response);
+
−		reader.advance();
+
−
+
−		// Process the response lines.
+
−		String redirect = null;
+
−		StringBuilder errors = new StringBuilder();
+
−		while (reader.getLineType() != LineType.PROMPT) {
+
−			switch (reader.getLineType()) {
+
−				case REDIRECT:
+
−					if (redirect == null)
+
−						redirect = reader.getLine(1);
+
−					break;
+
−				case ERROR:
+
−					if (errors.length() > 0)
+
−						errors.append("\n");
+
−					errors.append(reader.getLine(7));  // 7 not 1!
+
−					break;
+
−				case INFO:
+
−					warnings.add(reader.getLine(1));
+
−					break;
+
−				default:
+
−					// ignore??!!
+
−					break;
+
−			}
+
−			reader.advance();
+
−		}
+
−		if (errors.length() > 0)
+
−			throw new MCLException(errors.toString());
+
−
+
−		if (redirect == null)
+
−			return true;   // we're happy
+
−
+
−		// process redirect
+
−		try {
+
−			MonetUrlParser.parse(target, redirect);
+
−		} catch (URISyntaxException | ValidationError e) {
+
−			throw new MCLException("While processing redirect " + redirect + ": " + e.getMessage(), e);
+
−		}
+
−		if (redirect.startsWith("mapi:merovingian://proxy")) {
+
−			// The reader is stuck at LineType.PROMPT but actually the
+
−			// next challenge is already there.
+
−			reader.resetLineType();
+
−			reader.advance();
+
−		} else {
+
−			close();
+
−		}
+
−
+
−		return false;   // we need another go
+
−	}
+
−
+
−	private String challengeResponse(Target.Validated validated, final String challengeLine, OptionsCallback callback) throws MCLException {
+
−		// The challengeLine looks like this:
+
−		//
+
−		// 45IYyVyRnbgEnK92ad:merovingian:9:RIPEMD160,SHA512,SHA384,SHA256,SHA224,SHA1:LIT:SHA512:
+
−		// WgHIibSyH:mserver:9:RIPEMD160,SHA512,SHA384,SHA256,SHA224,SHA1:LIT:SHA512:sql=6:BINARY=1:
+
−		// 0         1       2 3                                          4   5      6     7
+
−
+
−		String[] parts = challengeLine.split(":");
+
−		if (parts.length < 3)
+
−			throw new MCLException("Invalid challenge: expect at least 3 fields");
+
−		String saltPart = parts[0];
+
−		String serverTypePart = parts[1];
+
−		String versionPart = parts[2];
+
−		int version;
+
−		if (versionPart.equals("9"))
+
−			version = 9;
+
−		else
+
−			throw new MCLException("Protocol versions other than 9 are note supported: " + versionPart);
+
−		if (parts.length < 6)
+
−			throw new MCLException("Protocol version " + version + " requires at least 6 fields, found " + parts.length + ": " + challengeLine);
+
−		String serverHashesPart = parts[3];
+
−//		String endianPart = parts[4];
+
−		String passwordHashPart = parts[5];
+
−		String optionsPart = parts.length > 6 ? parts[6] : null;
+
−//		String binaryPart = parts.length > 7 ? parts[7] : null;
+
−
+
−		if (parts.length > 9)
+
−			supportsClientInfo = true;
+
−
+
−		String userResponse;
+
−		String password = target.getPassword();
+
−		if (serverTypePart.equals("merovingian") && !target.getLanguage().equals("control")) {
+
−			userResponse = "merovingian";
+
−			password = "merovingian";
+
−		} else {
+
−			userResponse = target.getUser();
+
−		}
+
−		String optionsResponse = handleOptions(callback, optionsPart);
+
−
+
−		// Response looks like this:
+
−		//
+
−		// LIT:monetdb:{RIPEMD160}f2236256e5a9b20a5ecab4396e36c14f66c3e3c5:sql:demo
+
−		// :FILETRANS:auto_commit=1,reply_size=1000,size_header=0,columnar_protocol=0,time_zone=3600:
+
−		StringBuilder response = new StringBuilder(80);
+
−		response.append("BIG:");
+
−		response.append(userResponse).append(":");
+
−		hashPassword(response, saltPart, password, passwordHashPart, validated.getHash(), serverHashesPart);
+
−		response.append(":");
+
−		response.append(validated.getLanguage()).append(":");
+
−		response.append(validated.getDatabase()).append(":");
+
−		response.append("FILETRANS:");
+
−		response.append(optionsResponse).append(":");
+
−
+
−		return response.toString();
+
−	}
+
−
+
−	private String hashPassword(StringBuilder responseBuffer, String salt, String password, String passwordAlgo, String configuredHashes, String serverSupportedAlgos) throws MCLException {
+
−		// First determine which hash algorithms we can choose from for the challenge response.
+
−		// This defaults to whatever the server offers but may be restricted by the user.
+
−		Set<String> algoSet = new HashSet<>(Arrays.asList(serverSupportedAlgos.split(",")));
+
−		if (!configuredHashes.isEmpty()) {
+
−			String[] allowedList = configuredHashes.toUpperCase().split("[, ]");
+
−			Set<String> allowedSet = new HashSet<>(Arrays.asList(allowedList));
+
−			algoSet.retainAll(allowedSet);
+
−			if (algoSet.isEmpty()) {
+
−				throw new MCLException("None of the hash algorithms in <" + configuredHashes + "> are supported, server only supports <" + serverSupportedAlgos + ">");
+
−			}
+
−		}
+
−
+
−		int maxHashDigits = 512 / 4;
+
−
+
−		// We'll collect the result in the responseBuffer.
+
−		// It will start with '{' HASHNAME '}' followed by hexdigits
+
−
+
−		// This is where we accumulate what will eventually be hashed into the hexdigits above.
+
−		// It consists of the hexadecimal pre-hash of the password,
+
−		// followed by the salt from the server
+
−		StringBuilder intermediate = new StringBuilder(maxHashDigits + salt.length());
+
−
+
−		MessageDigest passwordDigest = pickBestAlgorithm(Collections.singleton(passwordAlgo), null);
+
−		// Here's the password..
+
−		hexhash(intermediate, passwordDigest, password);
+
−		// .. and here's the salt
+
−		intermediate.append(salt);
+
−
+
−		responseBuffer.append('{');
+
−		MessageDigest responseDigest = pickBestAlgorithm(algoSet, responseBuffer);
+
−		// the call above has appended the HASHNAME, now add '}'
+
−		responseBuffer.append('}');
+
−		// pickBestAlgorithm has appended HASHNAME, buffer now contains '{' HASHNAME '}'
+
−		hexhash(responseBuffer, responseDigest, intermediate.toString());
+
−		// response buffer now contains '{' HASHNAME '}' HEX_DIGITS_OF_INTERMEDIATE_BUFFER
+
−
+
−		return responseBuffer.toString();
+
−	}
+
−
+
−	/**
+
−	 * Pick the most preferred digest algorithm and return a MessageDigest instance for that.
+
−	 *
+
−	 * @param algos          the MAPI names of permitted algorithms
+
−	 * @param appendMapiName if not null, append MAPI name of chose algorithm to this buffer
+
−	 * @return instance of the chosen digester
+
−	 * @throws MCLException if none of the options is supported
+
−	 */
+
−	private MessageDigest pickBestAlgorithm(Set<String> algos, StringBuilder appendMapiName) throws MCLException {
+
−		for (String[] choice : KNOWN_ALGORITHMS) {
+
−			String mapiName = choice[0];
+
−			String algoName = choice[1];
+
−			MessageDigest digest;
+
−			if (!algos.contains(mapiName))
+
−				continue;
+
−			try {
+
−				digest = MessageDigest.getInstance(algoName);
+
−			} catch (NoSuchAlgorithmException e) {
+
−				continue;
+
−			}
+
−			// we found a match
+
−			if (appendMapiName != null) {
+
−				appendMapiName.append(mapiName);
+
−			}
+
−			return digest;
+
−		}
+
−		String algoNames = String.join(",", algos);
+
−		throw new MCLException("No supported hash algorithm: " + algoNames);
+
−	}
+
−
+
−	/**
+
−	 * Hash the text into the MessageDigest and append the hexadecimal form of the
+
−	 * resulting digest to buffer.
+
−	 *
+
−	 * @param buffer where the hex digits are appended
+
−	 * @param digest where the hex digits come from after the text has been digested
+
−	 * @param text   text to digest
+
−	 */
+
−	private void hexhash(StringBuilder buffer, MessageDigest digest, String text) {
+
−		byte[] bytes = text.getBytes(StandardCharsets.UTF_8);
+
−		digest.update(bytes);
+
−		byte[] output = digest.digest();
+
−		for (byte b : output) {
+
−			int hi = (b & 0xF0) >> 4;
+
−			int lo = b & 0x0F;
+
−			buffer.append(HEXDIGITS[hi]);
+
−			buffer.append(HEXDIGITS[lo]);
+
−		}
+
−	}
+
−
+
−	private String handleOptions(OptionsCallback callback, String optionsPart) throws MCLException {
+
−		if (callback == null || optionsPart == null || optionsPart.isEmpty())
+
−			return "";
+
−
+
−		StringBuilder buffer = new StringBuilder();
+
−		callback.setBuffer(buffer);
+
−		for (String optlevel : optionsPart.split(",")) {
+
−			int eqindex = optlevel.indexOf('=');
+
−			if (eqindex < 0)
+
−				throw new MCLException("Invalid options part in server challenge: " + optionsPart);
+
−			String lang = optlevel.substring(0, eqindex);
+
−			int level;
+
−			try {
+
−				level = Integer.parseInt(optlevel.substring(eqindex + 1));
+
−			} catch (NumberFormatException e) {
+
−				throw new MCLException("Invalid option level in server challenge: " + optlevel);
+
−			}
+
−			callback.addOptions(lang, level);
+
−		}
+
−
+
−		return buffer.toString();
+
−	}
+
−
+
−	/**
+
−	 * Returns an InputStream that reads from this open connection on
+
−	 * the MapiSocket.
+
−	 *
+
−	 * @return an input stream that reads from this open connection
+
−	 */
+
−	public InputStream getInputStream() {
+
−		return fromMonet;
+
−	}
+
−
+
−	/**
+
−	 * Returns an output stream for this MapiSocket.
+
−	 *
+
−	 * @return an output stream for writing bytes to this MapiSocket
+
−	 */
+
−	public OutputStream getOutputStream() {
+
−		return toMonet;
+
−	}
+
−
+
−	/**
+
−	 * Returns a Reader for this MapiSocket.  The Reader is a
+
−	 * BufferedMCLReader which does protocol interpretation of the
+
−	 * BlockInputStream produced by this MapiSocket.
+
−	 *
+
−	 * @return a BufferedMCLReader connected to this MapiSocket
+
−	 */
+
−	public BufferedMCLReader getReader() {
+
−		return reader;
+
−	}
+
−
+
−	/**
+
−	 * Returns a Writer for this MapiSocket.  The Writer is a
+
−	 * BufferedMCLWriter which produces protocol compatible data blocks
+
−	 * that the BlockOutputStream can properly translate into blocks.
+
−	 *
+
−	 * @return a BufferedMCLWriter connected to this MapiSocket
+
−	 */
+
−	public BufferedMCLWriter getWriter() {
+
−		return writer;
+
−	}
+
−
+
−	/**
+
−	 * Returns the mapi protocol version used by this socket.  The
+
−	 * protocol version depends on the server being used.  Users of the
+
−	 * MapiSocket should check this version to act appropriately.
+
−	 *
+
−	 * @return the mapi protocol version
+
−	 */
+
−	public int getProtocolVersion() {
+
−		return version;
+
−	}
+
−
+
−	/**
+
−	 * Enables logging to a file what is read and written from and to
+
−	 * the server.  Logging can be enabled at any time.  However, it is
+
−	 * encouraged to start debugging before actually connecting the
+
−	 * socket.
+
−	 *
+
−	 * @param filename the name of the file to write to
+
−	 * @throws IOException if the file could not be opened for writing
+
−	 */
+
−	public void debug(final String filename) throws IOException {
+
−		debug(new FileWriter(filename));
+
−	}
+
−
+
−	/**
+
−	 * Enables logging to a stream what is read and written from and to
+
−	 * the server.  Logging can be enabled at any time.  However, it is
+
−	 * encouraged to start debugging before actually connecting the
+
−	 * socket.
+
−	 *
+
−	 * @param out to write the log to a print stream
+
−	 * @throws IOException if the file could not be opened for writing
+
−	 */
+
−// disabled as it is not used by JDBC driver code
+
−//	public void debug(PrintStream out) throws IOException {
+
−//		debug(new PrintWriter(out));
+
−//	}
+
−
+
−	/**
+
−	 * Enables logging to a stream what is read and written from and to
+
−	 * the server.  Logging can be enabled at any time.  However, it is
+
−	 * encouraged to start debugging before actually connecting the
+
−	 * socket.
+
−	 *
+
−	 * @param out to write the log to
+
−	 */
+
−	public void debug(final Writer out) {
+
−		log = out;
+
−		setDebug(true);
+
−	}
+
−
+
−	/**
+
−	 * Get the log Writer.
+
−	 *
+
−	 * @return the log writer
+
−	 */
+
−	public Writer getLogWriter() {
+
−		return log;
+
−	}
+
−
+
−	/**
+
−	 * Writes a logline tagged with a timestamp using the given type and message
+
−	 * and optionally flushes afterwards.
+
−	 *
+
−	 * Used for debugging purposes only and represents a message data that is
+
−	 * connected to reading (RD or RX) or writing (TD or TX) to the socket.
+
−	 * R=Receive, T=Transmit, D=Data, X=??
+
−	 *
+
−	 * @param type  message type: either RD, RX, TD or TX
+
−	 * @param message  the message to log
+
−	 * @param flush  whether we need to flush buffered data to the logfile.
+
−	 * @throws IOException if an IO error occurs while writing to the logfile
+
−	 */
+
−	private final void log(final String type, final String message, final boolean flush) throws IOException {
+
−		log.write(type + System.currentTimeMillis() + ": " + message + "\n");
+
−		if (flush)
+
−			log.flush();
+
−	}
+
−
+
−	/**
+
−	 * For internal use
+
−	 *
+
−	 * @param b to enable/disable insert 'fake' newline and prompt
+
−	 * @return previous setting
+
−	 */
+
−	public boolean setInsertFakePrompts(boolean b) {
+
−		return fromMonet.setInsertFakePrompts(b);
+
−	}
+
−
+
−	public boolean isDebug() {
+
−		return target.isDebug();
+
−	}
+
−
+
−	public boolean canClientInfo() {
+
−		return supportsClientInfo;
+
−	}
+
−
+
−
+
−	/**
+
−	 * Inner class that is used to write data on a normal stream as a
+
−	 * blocked stream.  A call to the flush() method will write a
+
−	 * "final" block to the underlying stream.  Non-final blocks are
+
−	 * written as soon as one or more bytes would not fit in the
+
−	 * current block any more.  This allows to write to a block to it's
+
−	 * full size, and then flush it explicitly to have a final block
+
−	 * being written to the stream.
+
−	 */
+
−	final class BlockOutputStream extends FilterOutputStream {
+
−		private int writePos = 0;
+
−		private int blocksize = 0;
+
−		private final byte[] block = new byte[BLOCK];
+
−
+
−		/**
+
−		 * Constructs this BlockOutputStream, backed by the given
+
−		 * OutputStream.  A BufferedOutputStream is internally used.
+
−		 * @param out an OutputStream
+
−		 */
+
−		public BlockOutputStream(final OutputStream out) {
+
−			// always use a buffered stream, even though we know how
+
−			// much bytes to write/read, since this is just faster for
+
−			// some reason
+
−			super(new BufferedOutputStream(out));
+
−		}
+
−
+
−		@Override
+
−		public void flush() throws IOException {
+
−			// write the block (as final) then flush.
+
−			writeBlock(true);
+
−			out.flush();
+
−
+
−			// it's a bit nasty if an exception is thrown from the log,
+
−			// but ignoring it can be nasty as well, so it is decided to
+
−			// let it go so there is feedback about something going wrong
+
−			// it's a bit nasty if an exception is thrown from the log,
+
−			// but ignoring it can be nasty as well, so it is decided to
+
−			// let it go so there is feedback about something going wrong
+
−			if (isDebug()) {
+
−				log.flush();
+
−			}
+
−		}
+
−
+
−		/**
+
−		 * writeBlock puts the data in the block on the stream.  The
+
−		 * boolean last controls whether the block is sent with an
+
−		 * indicator to note it is the last block of a sequence or not.
+
−		 *
+
−		 * @param last whether this is the last block
+
−		 * @throws IOException if writing to the stream failed
+
−		 */
+
−		public void writeBlock(final boolean last) throws IOException {
+
−			if (last) {
+
−				// always fits, because of BLOCK's size
+
−				blocksize = (short)writePos;
+
−				// this is the last block, so encode least
+
−				// significant bit in the first byte (little-endian)
+
−				blklen[0] = (byte)(blocksize << 1 & 0xFF | 1);
+
−				blklen[1] = (byte)(blocksize >> 7);
+
−			} else {
+
−				// always fits, because of BLOCK's size
+
−				blocksize = (short)BLOCK;
+
−				// another block will follow, encode least
+
−				// significant bit in the first byte (little-endian)
+
−				blklen[0] = (byte)(blocksize << 1 & 0xFF);
+
−				blklen[1] = (byte)(blocksize >> 7);
+
−			}
+
−
+
−			out.write(blklen);
+
−			// write the actual block
+
−			out.write(block, 0, writePos);
+
−
+
−			if (isDebug()) {
+
−				if (last) {
+
−					log("TD ", "write final block: " + writePos + " bytes", false);
+
−				} else {
+
−					log("TD ", "write block: " + writePos + " bytes", false);
+
−				}
+
−				log("TX ", new String(block, 0, writePos, StandardCharsets.UTF_8), true);
+
−			}
+
−
+
−			writePos = 0;
+
−		}
+
−
+
−		@Override
+
−		public void write(final int b) throws IOException {
+
−			if (writePos == BLOCK) {
+
−				writeBlock(false);
+
−			}
+
−			block[writePos++] = (byte)b;
+
−		}
+
−
+
−		@Override
+
−		public void write(final byte[] b) throws IOException {
+
−			write(b, 0, b.length);
+
−		}
+
−
+
−		@Override
+
−		public void write(final byte[] b, int off, int len) throws IOException {
+
−			while (len > 0) {
+
−				int t = BLOCK - writePos;
+
−				if (len > t) {
+
−					System.arraycopy(b, off, block, writePos, t);
+
−					off += t;
+
−					len -= t;
+
−					writePos += t;
+
−					writeBlock(false);
+
−				} else {
+
−					System.arraycopy(b, off, block, writePos, len);
+
−					writePos += len;
+
−					break;
+
−				}
+
−			}
+
−		}
+
−
+
−		@Override
+
−		public void close() throws IOException {
+
−			// we don't want the flush() method to be called (default of
+
−			// the FilterOutputStream), so we close manually here
+
−			out.close();
+
−		}
+
−	}
+
−
+
−
+
−	/**
+
−	 * Inner class that is used to make the data on the blocked stream
+
−	 * available as a normal stream.
+
−	 */
+
−	final class BlockInputStream extends FilterInputStream {
+
−		private int readPos = 0;
+
−		private int blockLen = 0;
+
−		private boolean wasEndBlock = false;
+
−		private final byte[] block = new byte[BLOCK + 3]; // \n.\n
+
−		private boolean insertFakePrompts = true;
+
−
+
−		/**
+
−		 * Constructs this BlockInputStream, backed by the given
+
−		 * InputStream.  A BufferedInputStream is internally used.
+
−		 * @param in an InputStream
+
−		 */
+
−		public BlockInputStream(final InputStream in) {
+
−			// always use a buffered stream, even though we know how
+
−			// much bytes to write/read, since this is just faster for
+
−			// some reason
+
−			super(new BufferedInputStream(in));
+
−		}
+
−
+
−		public boolean setInsertFakePrompts(boolean doFake) {
+
−			boolean old = insertFakePrompts;
+
−			insertFakePrompts = doFake;
+
−			return old;
+
−		}
+
−
+
−		@Override
+
−		public int available() {
+
−			return blockLen - readPos;
+
−		}
+
−
+
−		@Override
+
−		public boolean markSupported() {
+
−			return false;
+
−		}
+
−
+
−		@Override
+
−		public void mark(final int readlimit) {
+
−			throw new AssertionError("Not implemented!");
+
−		}
+
−
+
−		@Override
+
−		public void reset() {
+
−			throw new AssertionError("Not implemented!");
+
−		}
+
−
+
−		/**
+
−		 * Small wrapper to get a blocking variant of the read() method
+
−		 * on the BufferedInputStream.  We want to benefit from the
+
−		 * Buffered pre-fetching, but not dealing with half blocks.
+
−		 * Changing this class to be able to use the partially received
+
−		 * data will greatly complicate matters, while a performance
+
−		 * improvement is debatable given the relatively small size of
+
−		 * our blocks.  Maybe it does speed up on slower links, then
+
−		 * consider this method a quick bug fix/workaround.
+
−		 *
+
−		 * @param b a byte array to store read bytes
+
−		 * @param len number of bytes to read
+
−		 * @return false if reading the block failed due to EOF
+
−		 * @throws IOException if an IO error occurs while reading
+
−		 */
+
−		private boolean _read(final byte[] b, int len) throws IOException {
+
−			int s;
+
−			int off = 0;
+
−			while (len > 0) {
+
−				s = in.read(b, off, len);
+
−				if (s == -1) {
+
−					// if we have read something before, we should have been
+
−					// able to read the whole, so make this fatal
+
−					if (off > 0) {
+
−						if (isDebug()) {
+
−							log("RD ", "the following incomplete block was received:", false);
+
−							log("RX ", new String(b, 0, off, StandardCharsets.UTF_8), true);
+
−						}
+
−						throw new IOException("Read from " +
+
−								con.getInetAddress().getHostName() + ":" +
+
−								con.getPort() + ": Incomplete block read from stream");
+
−					}
+
−					if (isDebug())
+
−						log("RD ", "server closed the connection (EOF)", true);
+
−					return false;
+
−				}
+
−				len -= s;
+
−				off += s;
+
−			}
+
−
+
−			return true;
+
−		}
+
−
+
−		/**
+
−		 * Reads the next block on the stream into the internal buffer,
+
−		 * or writes the prompt in the buffer.
+
−		 *
+
−		 * The blocked stream protocol consists of first a two byte
+
−		 * integer indicating the length of the block, then the
+
−		 * block, followed by another length + block.  The end of
+
−		 * such sequence is put in the last bit of the length, and
+
−		 * hence this length should be shifted to the right to
+
−		 * obtain the real length value first.  We simply fetch
+
−		 * blocks here as soon as they are needed for the stream's
+
−		 * read methods.
+
−		 *
+
−		 * The user-flush, which is an implicit effect of the end of
+
−		 * a block sequence, is communicated beyond the stream by
+
−		 * inserting a prompt sequence on the stream after the last
+
−		 * block.  This method makes sure that a final block ends with a
+
−		 * newline, if it doesn't already, in order to facilitate a
+
−		 * Reader that is possibly chained to this InputStream.
+
−		 *
+
−		 * If the stream is not positioned correctly, hell will break
+
−		 * loose.
+
−		 *
+
−		 * @return blockLen
+
−		 * @throws IOException if an IO error occurs while reading
+
−		 */
+
−		private int readBlock() throws IOException {
+
−			// read next two bytes (short)
+
−			if (!_read(blklen, 2))
+
−				return(-1);
+
−
+
−			// Get the short-value and store its value in blockLen.
+
−			blockLen = (short)(
+
−					(blklen[0] & 0xFF) >> 1 |
+
−					(blklen[1] & 0xFF) << 7
+
−					);
+
−			wasEndBlock = (blklen[0] & 0x1) == 1;
+
−
+
−			readPos = 0;
+
−
+
−			if (isDebug()) {
+
−				if (wasEndBlock) {
+
−					log("RD ", "read final block: " + blockLen + " bytes", false);
+
−				} else {
+
−					log("RD ", "read new block: " + blockLen + " bytes", false);
+
−				}
+
−			}
+
−
+
−			// sanity check to avoid bad servers make us do an ugly
+
−			// stack trace
+
−			if (blockLen > block.length)
+
−				throw new IOException("Server sent a block larger than BLOCKsize: " +
+
−						blockLen + " > " + block.length);
+
−			if (!_read(block, blockLen))
+
−				return -1;
+
−
+
−			if (isDebug())
+
−				log("RX ", new String(block, 0, blockLen, StandardCharsets.UTF_8), true);
+
−
+
−			// if this is the last block, make it end with a newline and prompt
+
−			if (wasEndBlock) {
+
−				// insert 'fake' newline and prompt
+
−				if (insertFakePrompts) {
+
−					if (blockLen > 0 && block[blockLen - 1] != '\n') {
+
−						// to terminate the block in a Reader
+
−						block[blockLen++] = '\n';
+
−					}
+
−					for (byte b : LineType.PROMPT.bytes()) {
+
−						block[blockLen++] = b;
+
−					}
+
−					block[blockLen++] = '\n';
+
−					if (isDebug()) {
+
−						log("RD ", "inserting prompt", true);
+
−					}
+
−				}
+
−			}
+
−
+
−			return blockLen;
+
−		}
+
−
+
−		@Override
+
−		public int read() throws IOException {
+
−			if (available() == 0) {
+
−				if (readBlock() == -1)
+
−					return -1;
+
−			}
+
−
+
−			if (isDebug())
+
−				log("RX ", new String(block, readPos, 1, StandardCharsets.UTF_8), true);
+
−
+
−			return block[readPos++] & 0xFF;
+
−		}
+
−
+
−		@Override
+
−		public int read(final byte[] b) throws IOException {
+
−			return read(b, 0, b.length);
+
−		}
+
−
+
−		@Override
+
−		public int read(final byte[] b, int off, int len) throws IOException {
+
−			int t;
+
−			int size = 0;
+
−			while (size < len) {
+
−				t = available();
+
−				if (t == 0) {
+
−					if (size != 0)
+
−						break;
+
−					if (readBlock() == -1) {
+
−						if (size == 0)
+
−							size = -1;
+
−						break;
+
−					}
+
−					t = available();
+
−				}
+
−				if (len > t) {
+
−					System.arraycopy(block, readPos, b, off, t);
+
−					off += t;
+
−					len -= t;
+
−					readPos += t;
+
−					size += t;
+
−				} else {
+
−					System.arraycopy(block, readPos, b, off, len);
+
−					readPos += len;
+
−					size += len;
+
−					break;
+
−				}
+
−			}
+
−			return size;
+
−		}
+
−
+
−		@Override
+
−		public long skip(final long n) throws IOException {
+
−			long skip = n;
+
−			while (skip > 0) {
+
−				int t = available();
+
−				if (skip > t) {
+
−					skip -= t;
+
−					readPos += t;
+
−					readBlock();
+
−				} else {
+
−					readPos += (int)skip;
+
−					break;
+
−				}
+
−			}
+
−			return n;
+
−		}
+
−
+
−		/**
+
−		 * For internal use
+
−		 * @return new Raw object
+
−		 */
+
−		Raw getRaw() {
+
−			return new Raw();
+
−		}
+
−
+
−		/** An alternative I/O interface that exposes the block based nature of the MAPI protocol */
+
−		final class Raw {
+
−			byte[] getBytes() {
+
−				return block;
+
−			}
+
−
+
−			int getLength() {
+
−				return blockLen;
+
−			}
+
−
+
−			int getPosition() {
+
−				return readPos;
+
−			}
+
−
+
−			int consume(int delta) {
+
−				int pos = readPos;
+
−				readPos += delta;
+
−				return pos;
+
−			}
+
−
+
−			int readBlock() throws IOException {
+
−				boolean wasFaking = setInsertFakePrompts(false);
+
−				try {
+
−					return BlockInputStream.this.readBlock();
+
−				} finally {
+
−					setInsertFakePrompts(wasFaking);
+
−				}
+
−			}
+
−
+
−			boolean wasEndBlock() {
+
−				return wasEndBlock;
+
−			}
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Closes the streams and socket connected to the server if possible.
+
−	 * If an error occurs at closing a resource, it is ignored so as many
+
−	 * resources as possible are closed.
+
−	 */
+
−	public synchronized void close() {
+
−		if (writer != null) {
+
−			try {
+
−				writer.close();
+
−				writer = null;
+
−			} catch (IOException e) { /* ignore it */ }
+
−		}
+
−		if (reader != null) {
+
−			try {
+
−				reader.close();
+
−				reader = null;
+
−			} catch (IOException e) { /* ignore it */ }
+
−		}
+
−		if (toMonet != null) {
+
−			try {
+
−				toMonet.close();
+
−				toMonet = null;
+
−			} catch (IOException e) { /* ignore it */ }
+
−		}
+
−		if (fromMonet != null) {
+
−			try {
+
−				fromMonet.close();
+
−				fromMonet = null;
+
−			} catch (IOException e) { /* ignore it */ }
+
−		}
+
−		if (con != null) {
+
−			try {
+
−				con.close();	// close the socket
+
−				con = null;
+
−			} catch (IOException e) { /* ignore it */ }
+
−		}
+
−		if (isDebug() && log != null && log instanceof FileWriter) {
+
−			try {
+
−				log.close();
+
−				log = null;
+
−			} catch (IOException e) { /* ignore it */ }
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Return an UploadStream for use with for example COPY FROM filename ON CLIENT.
+
−	 *
+
−	 * Building block for {@link org.monetdb.jdbc.MonetConnection.UploadHandler}.
+
−	 *
+
−	 * @param chunkSize chunk size for the upload stream
+
−	 * @return UploadStream new upload stream with the given chunk size
+
−	 */
+
−	public UploadStream uploadStream(int chunkSize) {
+
−		return new UploadStream(chunkSize);
+
−	}
+
−
+
−	/**
+
−	 * Return an UploadStream for use with for example COPY FROM filename ON CLIENT.
+
−	 *
+
−	 * Building block for {@link org.monetdb.jdbc.MonetConnection.UploadHandler}.
+
−	 *
+
−	 * @return UploadStream new upload stream
+
−	 */
+
−	public UploadStream uploadStream() {
+
−		return new UploadStream();
+
−	}
+
−
+
−	/**
+
−	 * Return a DownloadStream for use with for example COPY INTO filename ON CLIENT
+
−	 *
+
−	 * Building block for {@link org.monetdb.jdbc.MonetConnection.DownloadHandler}.
+
−	 *
+
−	 * @param prependCr convert \n to \r\n
+
−	 * @return DownloadStream new download stream
+
−	 */
+
−	public DownloadStream downloadStream(boolean prependCr) {
+
−		return new DownloadStream(fromMonet.getRaw(), toMonet, prependCr);
+
−	}
+
−
+
−
+
−	/**
+
−	 * Stream of data sent to the server
+
−	 *
+
−	 * Building block for {@link org.monetdb.jdbc.MonetConnection.UploadHandler}.
+
−	 *
+
−	 * An UploadStream has a chunk size. Every chunk size bytes, the server gets
+
−	 * the opportunity to abort the upload.
+
−	 */
+
−	public class UploadStream extends FilterOutputStream {
+
−		public final static int DEFAULT_CHUNK_SIZE = 1024 * 1024;
+
−		private final int chunkSize;
+
−		private boolean closed = false;
+
−		private boolean serverCancelled = false;
+
−		private int chunkLeft;
+
−		private byte[] promptBuffer;
+
−		private Runnable cancellationCallback = null;
+
−
+
−		/**
+
−		 * Create an UploadStream with the given chunk size
+
−		 * @param chunkSize chunk size for the upload stream
+
−		 */
+
−		UploadStream(final int chunkSize) {
+
−			super(toMonet);
+
−			if (chunkSize <= 0) {
+
−				throw new IllegalArgumentException("chunk size must be positive");
+
−			}
+
−			this.chunkSize = chunkSize;
+
−			assert LineType.MORE.bytes().length == LineType.FILETRANSFER.bytes().length;
+
−			int promptLen = LineType.MORE.bytes().length;
+
−			promptBuffer = new byte[promptLen + 1];
+
−			chunkLeft = this.chunkSize;
+
−		}
+
−
+
−		/** Create an UploadStream with the default chunk size */
+
−		UploadStream() {
+
−			this(DEFAULT_CHUNK_SIZE);
+
−		}
+
−
+
−		/** Set a callback to be invoked if the server cancels the upload
+
−		 *
+
−		 * @param cancellationCallback callback to call
+
−		 */
+
−		public void setCancellationCallback(final Runnable cancellationCallback) {
+
−			this.cancellationCallback = cancellationCallback;
+
−		}
+
−
+
−		@Override
+
−		public void write(final int b) throws IOException {
+
−			if (serverCancelled) {
+
−				// We have already thrown an exception and apparently that has been ignored.
+
−				// Probably because they're calling print methods instead of write.
+
−				// Throw another one, maybe they'll catch this one.
+
−				throw new IOException("Server aborted the upload");
+
−			}
+
−			handleChunking();
+
−			out.write(b);
+
−			wrote(1);
+
−		}
+
−
+
−		@Override
+
−		public void write(final byte[] b) throws IOException {
+
−			this.write(b, 0, b.length);
+
−		}
+
−
+
−		@Override
+
−		public void write(final byte[] b, int off, int len) throws IOException {
+
−			if (serverCancelled) {
+
−				// We have already thrown an exception and apparently that has been ignored.
+
−				// Probably because they're calling print methods instead of write.
+
−				// Throw another one, maybe they'll catch this one.
+
−				throw new IOException("Server aborted the upload");
+
−			}
+
−			while (len > 0) {
+
−				handleChunking();
+
−				int toWrite = Integer.min(len, chunkLeft);
+
−				out.write(b, off, toWrite);
+
−				off += toWrite;
+
−				len -= toWrite;
+
−				wrote(toWrite);
+
−			}
+
−		}
+
−
+
−		@Override
+
−		public void flush() throws IOException {
+
−			// suppress flushes
+
−		}
+
−
+
−		@Override
+
−		public void close() throws IOException {
+
−			if (closed) {
+
−				return;
+
−			}
+
−			closed = true;
+
−
+
−			if (serverCancelled)
+
−				closeAfterServerCancelled();
+
−			else
+
−				closeAfterSuccesfulUpload();
+
−		}
+
−
+
−		private void closeAfterSuccesfulUpload() throws IOException {
+
−			if (chunkLeft != chunkSize) {
+
−				// flush pending data
+
−				flushAndReadPrompt();
+
−			}
+
−			// send empty block
+
−			out.flush();
+
−			final LineType acknowledgement = readPrompt();
+
−			if (acknowledgement != LineType.FILETRANSFER) {
+
−				throw new IOException("Expected server to acknowledge end of file");
+
−			}
+
−		}
+
−
+
−		private void closeAfterServerCancelled() {
+
−			// nothing to do here, we have already read the error prompt.
+
−		}
+
−
+
−		private void wrote(final int i) {
+
−			chunkLeft -= i;
+
−		}
+
−
+
−		private void handleChunking() throws IOException {
+
−			if (chunkLeft > 0) {
+
−				return;
+
−			}
+
−			flushAndReadPrompt();
+
−		}
+
−
+
−		private void flushAndReadPrompt() throws IOException {
+
−			out.flush();
+
−			chunkLeft = chunkSize;
+
−			final LineType lineType = readPrompt();
+
−			switch (lineType) {
+
−				case MORE:
+
−					return;
+
−				case FILETRANSFER:
+
−					// Note, if the caller is calling print methods instead of write, the IO exception gets hidden.
+
−					// This is unfortunate but there's nothing we can do about it.
+
−					serverCancelled = true;
+
−					if (cancellationCallback != null) {
+
−						cancellationCallback.run();
+
−					}
+
−					throw new IOException("Server aborted the upload");
+
−				default:
+
−					throw new IOException("Expected MORE/DONE from server, got " + lineType);
+
−			}
+
−		}
+
−
+
−		private LineType readPrompt() throws IOException {
+
−			final int nread = fromMonet.read(promptBuffer);
+
−			if (nread != promptBuffer.length || promptBuffer[promptBuffer.length - 1] != '\n') {
+
−				throw new IOException("server return incomplete prompt");
+
−			}
+
−			return LineType.classify(promptBuffer);
+
−		}
+
−	}
+
−
+
−
+
−	/**
+
−	 * Stream of data received from the server
+
−	 *
+
−	 * Building block for {@link org.monetdb.jdbc.MonetConnection.DownloadHandler}.
+
−	 */
+
−	public static class DownloadStream extends InputStream {
+
−		private final BlockInputStream.Raw rawIn;
+
−		private final OutputStream out;
+
−		private final boolean prependCr;
+
−		private boolean endBlockSeen = false;
+
−		private boolean closed = false;
+
−		private boolean newlinePending = false; // used for crlf conversion
+
−
+
−		DownloadStream(BlockInputStream.Raw rawIn, OutputStream out, boolean prependCr) {
+
−			this.rawIn = rawIn;
+
−			this.out = out;
+
−			this.prependCr = prependCr;
+
−		}
+
−
+
−		void nextBlock() throws IOException {
+
−			if (endBlockSeen || closed)
+
−				return;
+
−			final int ret = rawIn.readBlock();
+
−			if (ret < 0 || rawIn.wasEndBlock()) {
+
−				endBlockSeen = true;
+
−			}
+
−		}
+
−
+
−		@Override
+
−		public void close() throws IOException {
+
−			if (closed)
+
−				return;
+
−			closed = true;
+
−			while (!endBlockSeen) {
+
−				nextBlock();
+
−			}
+
−			// Send acknowledgement to server
+
−			out.write('\n');
+
−			out.flush();
+
−			// Do whatever super has to do
+
−			super.close();
+
−		}
+
−
+
−		@Override
+
−		public int read() throws IOException {
+
−			final byte[] buf = { 0 };
+
−			final int nread = read(buf, 0, 1);
+
−			if (nread == 1)
+
−				return buf[0] & 0xFF;
+
−			else
+
−				return -1;
+
−		}
+
−
+
−		@Override
+
−		public int read(final byte[] dest, int off, int len) throws IOException {
+
−			final int origOff = off;
+
−			int end = off + len;
+
−
+
−			while (off < end) {
+
−				// minimum of what's requested and what we have in stock
+
−				int chunk = Integer.min(end - off, rawIn.getLength() - rawIn.getPosition());
+
−				assert chunk >= 0;
+
−				if (chunk == 0) {
+
−					// make progress by fetching more data
+
−					if (endBlockSeen)
+
−						break;
+
−					nextBlock();
+
−					continue;
+
−				}
+
−				// make progress copying some bytes
+
−				if (!prependCr) {
+
−					// no conversion needed, use arraycopy
+
−					System.arraycopy(rawIn.getBytes(), rawIn.getPosition(), dest, off, chunk);
+
−					off += chunk;
+
−					rawIn.consume(chunk);
+
−				} else {
+
−					int chunkEnd = off + chunk;
+
−					if (newlinePending && off < chunkEnd) {
+
−						// we were in the middle of a line ending conversion
+
−						dest[off++] = '\n';
+
−						newlinePending = false;
+
−					}
+
−					while (off < chunkEnd) {
+
−						byte b = rawIn.getBytes()[rawIn.consume(1)];
+
−						if (b != '\n') {
+
−							dest[off++] = b;
+
−						} else if (chunkEnd - off >= 2) {
+
−							dest[off++] = '\r';
+
−							dest[off++] = '\n';
+
−						} else {
+
−							dest[off++] = '\r';
+
−							newlinePending = true;
+
−							break;
+
−						}
+
−					}
+
−				}
+
−			}
+
−
+
−			if (off < end && newlinePending) {
+
−				dest[off++] = '\n';
+
−				newlinePending = false;
+
−			}
+
−
+
−			if (off == origOff && endBlockSeen)
+
−				return -1;
+
−			else
+
−				return off - origOff;
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Callback used during the initial MAPI handshake.
+
−	 *
+
−	 * Newer MonetDB versions allow setting some options during the handshake.
+
−	 * The options are language-specific and each has a 'level'. The server
+
−	 * advertises up to which level options are supported for a given language.
+
−	 * For each language/option combination, {@link #addOptions} will be invoked
+
−	 * during the handshake. This method should call {@link #contribute} for each
+
−	 * option it wants to set.
+
−	 *
+
−	 * At the time of writing, only the 'sql' language supports options,
+
−	 * they are listed in enum mapi_handshake_options_levels in mapi.h.
+
−	 */
+
−	public static abstract class OptionsCallback {
+
−		private StringBuilder buffer;
+
−
+
−		/**
+
−		 * Callback called for each language/level combination supported by the
+
−		 * server. May call {@link #contribute} for options with a level STRICTLY
+
−		 * LOWER than the level passed as a parameter.
+
−		 * @param lang language advertised by the server
+
−		 * @param level one higher than the maximum supported option
+
−		 */
+
−		public abstract void addOptions(String lang, int level);
+
−
+
−		/**
+
−		 * Pass option=value during the handshake
+
−		 * @param field name
+
−		 * @param value int value
+
−		 */
+
−		protected void contribute(String field, int value) {
+
−			if (buffer.length() > 0)
+
−				buffer.append(',');
+
−			buffer.append(field);
+
−			buffer.append('=');
+
−			buffer.append(value);
+
−		}
+
−
+
−		/**
+
−		 * Set the buffer
+
−		 * @param buf a non null StringBuilder object
+
−		 */
+
−		void setBuffer(StringBuilder buf) {
+
−			buffer = buf;
+
−		}
+
−	}
+
−}