/*
* Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.server;
import java.io.ByteArrayInputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.net.Socket;
import java.sql.SQLException;
import java.util.ArrayList;
import org.h2.api.ErrorCode;
import org.h2.command.Command;
import org.h2.engine.ConnectionInfo;
import org.h2.engine.Constants;
import org.h2.engine.Engine;
import org.h2.engine.Session;
import org.h2.engine.SessionRemote;
import org.h2.engine.SysProperties;
import org.h2.expression.Parameter;
import org.h2.expression.ParameterInterface;
import org.h2.expression.ParameterRemote;
import org.h2.jdbc.JdbcSQLException;
import org.h2.message.DbException;
import org.h2.result.ResultColumn;
import org.h2.result.ResultInterface;
import org.h2.store.LobStorageInterface;
import org.h2.util.IOUtils;
import org.h2.util.SmallLRUCache;
import org.h2.util.SmallMap;
import org.h2.util.StringUtils;
import org.h2.value.Transfer;
import org.h2.value.Value;
import org.h2.value.ValueLobDb;
/**
* One server thread is opened per client connection.
*/
public class TcpServerThread implements Runnable {
protected final Transfer transfer;
private final TcpServer server;
private Session session;
private boolean stop;
private Thread thread;
private Command commit;
private final SmallMap cache = new SmallMap(SysProperties.SERVER_CACHED_OBJECTS); //默认缓存64个对象
private final SmallLRUCache<Long, CachedInputStream> lobs =
SmallLRUCache.newInstance(Math.max(
SysProperties.SERVER_CACHED_OBJECTS,
SysProperties.SERVER_RESULT_SET_FETCH_SIZE * 5));
private final int threadId;
private int clientVersion;
private String sessionId;
TcpServerThread(Socket socket, TcpServer server, int id) {
this.server = server;
this.threadId = id;
transfer = new Transfer(null);
transfer.setSocket(socket);
}
private void trace(String s) {
server.trace(this + " " + s);
}
@Override
public void run() {
try {
transfer.init();
trace("Connect");
// TODO server: should support a list of allowed databases
// and a list of allowed clients
try {
//如果没有加-tcpAllowOthers参数，那么只接受本地连接
if (!server.allow(transfer.getSocket())) {
throw DbException.get(ErrorCode.REMOTE_CONNECTION_NOT_ALLOWED);
}
int minClientVersion = transfer.readInt();
if (minClientVersion < Constants.TCP_PROTOCOL_VERSION_6) {
throw DbException.get(ErrorCode.DRIVER_VERSION_ERROR_2,
"" + clientVersion, "" + Constants.TCP_PROTOCOL_VERSION_6);
} else if (minClientVersion > Constants.TCP_PROTOCOL_VERSION_16) {
throw DbException.get(ErrorCode.DRIVER_VERSION_ERROR_2,
"" + clientVersion, "" + Constants.TCP_PROTOCOL_VERSION_16);
}
int maxClientVersion = transfer.readInt();
if (maxClientVersion >= Constants.TCP_PROTOCOL_VERSION_16) {
clientVersion = Constants.TCP_PROTOCOL_VERSION_16;
} else {
clientVersion = minClientVersion;
}
transfer.setVersion(clientVersion);
String db = transfer.readString();
String originalURL = transfer.readString();
if (db == null && originalURL == null) {
String targetSessionId = transfer.readString();
int command = transfer.readInt();
stop = true;
if (command == SessionRemote.SESSION_CANCEL_STATEMENT) {
// cancel a running statement
int statementId = transfer.readInt();
server.cancelStatement(targetSessionId, statementId);
} else if (command == SessionRemote.SESSION_CHECK_KEY) {
// check if this is the correct server
db = server.checkKeyAndGetDatabaseName(targetSessionId);
if (!targetSessionId.equals(db)) {
transfer.writeInt(SessionRemote.STATUS_OK);
} else {
transfer.writeInt(SessionRemote.STATUS_ERROR);
}
}
}
//启动TcpServer时加"-baseDir"或者像这样System.setProperty("h2.baseDir", "E:\\H2\\baseDir")
String baseDir = server.getBaseDir();
if (baseDir == null) {
baseDir = SysProperties.getBaseDir();
}
//例如启动TcpServer时，指定了"-key mydb mydatabase"，
//如果db变量是mydb，那么实际上就是mydatabase，相当于做一次映射
//如果db变量不是mydb，那么抛错: org.h2.jdbc.JdbcSQLException: Wrong user name or password [28000-170]
db = server.checkKeyAndGetDatabaseName(db);
ConnectionInfo ci = new ConnectionInfo(db);
ci.setOriginalURL(originalURL);
ci.setUserName(transfer.readString());
//password参数的值已经转换成userPasswordHash和filePasswordHash了，
//不能由userPasswordHash和filePasswordHash得到原始的password
ci.setUserPasswordHash(transfer.readBytes());
ci.setFilePasswordHash(transfer.readBytes()); //只有指定"CIPHER"参数时filePasswordHash才是非null的
int len = transfer.readInt();
for (int i = 0; i < len; i++) {
ci.setProperty(transfer.readString(), transfer.readString());
}
// override client's requested properties with server settings
if (baseDir != null) {
ci.setBaseDir(baseDir);
}
if (server.getIfExists()) {
//启动TcpServer时加"-ifExists"，限制只有数据库存在时客户端才能连接，也就是不允许在客户端创建数据库
ci.setProperty("IFEXISTS", "TRUE");
}
transfer.writeInt(SessionRemote.STATUS_OK);
transfer.writeInt(clientVersion);
transfer.flush();
//每建立一个新的Session对象时，把它保存到内存数据库management_db_9092的SESSIONS表
if (clientVersion >= Constants.TCP_PROTOCOL_VERSION_13) {
if (ci.getFilePasswordHash() != null) {
ci.setFileEncryptionKey(transfer.readBytes());
}
}
session = Engine.getInstance().createSession(ci);
transfer.setSession(session);
server.addConnection(threadId, originalURL, ci.getUserName());
trace("Connected");
} catch (Throwable e) {
sendError(e);
stop = true;
}
while (!stop) {
try {
process();
} catch (Throwable e) {
sendError(e);
}
}
trace("Disconnect");
} catch (Throwable e) {
server.traceError(e);
} finally {
close();
}
}
private void closeSession() {
if (session != null) {
RuntimeException closeError = null;
try {
Command rollback = session.prepareLocal("ROLLBACK");
rollback.executeUpdate();
} catch (RuntimeException e) {
closeError = e;
server.traceError(e);
} catch (Exception e) {
server.traceError(e);
}
try {
session.close();
server.removeConnection(threadId);
} catch (RuntimeException e) {
if (closeError == null) {
closeError = e;
server.traceError(e);
}
} catch (Exception e) {
server.traceError(e);
} finally {
session = null;
}
if (closeError != null) {
throw closeError;
}
}
}
/**
* Close a connection.
*/
void close() {
try {
stop = true;
closeSession();
} catch (Exception e) {
server.traceError(e);
} finally {
transfer.close();
trace("Close");
server.remove(this);
}
}
private void sendError(Throwable t) {
try {
SQLException e = DbException.convert(t).getSQLException();
StringWriter writer = new StringWriter();
e.printStackTrace(new PrintWriter(writer));
String trace = writer.toString();
String message;
String sql;
if (e instanceof JdbcSQLException) {
JdbcSQLException j = (JdbcSQLException) e;
message = j.getOriginalMessage();
sql = j.getSQL();
} else {
message = e.getMessage();
sql = null;
}
transfer.writeInt(SessionRemote.STATUS_ERROR).
writeString(e.getSQLState()).writeString(message).
writeString(sql).writeInt(e.getErrorCode()).writeString(trace).flush();
} catch (Exception e2) {
if (!transfer.isClosed()) {
server.traceError(e2);
}
// if writing the error does not work, close the connection
stop = true;
}
}
private void setParameters(Command command) throws IOException {
int len = transfer.readInt();
ArrayList<? extends ParameterInterface> params = command.getParameters();
for (int i = 0; i < len; i++) {
Parameter p = (Parameter) params.get(i);
p.setValue(transfer.readValue());
}
}
//总共18条命令，这里包含16条
//下面这两条在run方法中特殊处理
//SESSION_CANCEL_STATEMENT
//SESSION_CHECK_KEY
//分三种级别，从大到小: SESSION级、COMMAND级、RESULT级
private void process() throws IOException {
int operation = transfer.readInt();
switch (operation) {
case SessionRemote.SESSION_PREPARE_READ_PARAMS:
case SessionRemote.SESSION_PREPARE_READ_PARAMS2:
case SessionRemote.SESSION_PREPARE: {
int id = transfer.readInt();
String sql = transfer.readString();
int old = session.getModificationId();
Command command = session.prepareLocal(sql);
boolean readonly = command.isReadOnly();
cache.addObject(id, command);
boolean isQuery = command.isQuery();
//在Parser中解析sql时会调用org.h2.command.Prepared.setParameterList(ArrayList<Parameter>)
//会保证不为null
transfer.writeInt(getState(old)).writeBoolean(isQuery).
writeBoolean(readonly);
if (operation == SessionRemote.SESSION_PREPARE_READ_PARAMS2) {
transfer.writeInt(command.getCommandType());
}
ArrayList<? extends ParameterInterface> params = command.getParameters();
transfer.writeInt(params.size());
if (operation != SessionRemote.SESSION_PREPARE) {
for (ParameterInterface p : params) {
ParameterRemote.writeMetaData(transfer, p);
}
}
transfer.flush();
break;
}
case SessionRemote.SESSION_CLOSE: {
stop = true;
closeSession();
transfer.writeInt(SessionRemote.STATUS_OK).flush();
close();
break;
}
case SessionRemote.COMMAND_COMMIT: {
//并不是通过org.h2.jdbc.JdbcConnection.commit()触发，此方法是通过发送COMMIT SQL触发
//触发SessionRemote.COMMAND_COMMIT的是在集群环境下，通过org.h2.engine.SessionRemote.autoCommitIfCluster()触发
if (commit == null) {
commit = session.prepareLocal("COMMIT");
}
int old = session.getModificationId();
commit.executeUpdate();
transfer.writeInt(getState(old)).flush();
break;
}
case SessionRemote.COMMAND_GET_META_DATA: {
int id = transfer.readInt();
int objectId = transfer.readInt();
Command command = (Command) cache.getObject(id, false);
ResultInterface result = command.getMetaData();
cache.addObject(objectId, result);
int columnCount = result.getVisibleColumnCount();
transfer.writeInt(SessionRemote.STATUS_OK).
writeInt(columnCount).writeInt(0);
for (int i = 0; i < columnCount; i++) {
ResultColumn.writeColumn(transfer, result, i);
}
transfer.flush();
break;
}
case SessionRemote.COMMAND_EXECUTE_QUERY: {
int id = transfer.readInt();
int objectId = transfer.readInt();
int maxRows = transfer.readInt();
int fetchSize = transfer.readInt();
Command command = (Command) cache.getObject(id, false);
setParameters(command);
int old = session.getModificationId();
ResultInterface result;
synchronized (session) {
result = command.executeQuery(maxRows, false);
}
cache.addObject(objectId, result);
int columnCount = result.getVisibleColumnCount();
int state = getState(old);
transfer.writeInt(state).writeInt(columnCount);
int rowCount = result.getRowCount();
transfer.writeInt(rowCount);
for (int i = 0; i < columnCount; i++) {
ResultColumn.writeColumn(transfer, result, i);
}
int fetch = Math.min(rowCount, fetchSize);
for (int i = 0; i < fetch; i++) {
sendRow(result);
}
transfer.flush();
break;
}
case SessionRemote.COMMAND_EXECUTE_UPDATE: {
int id = transfer.readInt();
Command command = (Command) cache.getObject(id, false);
//if(command!=null)throw new Error();
setParameters(command);
int old = session.getModificationId();
int updateCount;
synchronized (session) {
updateCount = command.executeUpdate();
}
int status;
if (session.isClosed()) {
status = SessionRemote.STATUS_CLOSED;
stop = true;
} else {
status = getState(old);
}
transfer.writeInt(status).writeInt(updateCount).
writeBoolean(session.getAutoCommit());
transfer.flush();
break;
}
case SessionRemote.COMMAND_CLOSE: {
int id = transfer.readInt();
Command command = (Command) cache.getObject(id, true);
if (command != null) {
command.close();
cache.freeObject(id);
}
break;
}
case SessionRemote.RESULT_FETCH_ROWS: {
int id = transfer.readInt();
int count = transfer.readInt();
ResultInterface result = (ResultInterface) cache.getObject(id, false);
transfer.writeInt(SessionRemote.STATUS_OK);
for (int i = 0; i < count; i++) {
sendRow(result);
}
transfer.flush();
break;
}
case SessionRemote.RESULT_RESET: {
int id = transfer.readInt();
ResultInterface result = (ResultInterface) cache.getObject(id, false);
result.reset();
break;
}
case SessionRemote.RESULT_CLOSE: {
int id = transfer.readInt();
ResultInterface result = (ResultInterface) cache.getObject(id, true);
if (result != null) {
result.close();
cache.freeObject(id);
}
break;
}
case SessionRemote.CHANGE_ID: {
int oldId = transfer.readInt();
int newId = transfer.readInt();
Object obj = cache.getObject(oldId, false);
cache.freeObject(oldId);
cache.addObject(newId, obj);
break;
}
case SessionRemote.SESSION_SET_ID: {
sessionId = transfer.readString();
transfer.writeInt(SessionRemote.STATUS_OK);
transfer.writeBoolean(session.getAutoCommit());
transfer.flush();
break;
}
case SessionRemote.SESSION_SET_AUTOCOMMIT: {
boolean autoCommit = transfer.readBoolean();
session.setAutoCommit(autoCommit);
transfer.writeInt(SessionRemote.STATUS_OK).flush();
break;
}
case SessionRemote.SESSION_HAS_PENDING_TRANSACTION: {
transfer.writeInt(SessionRemote.STATUS_OK).
writeInt(session.hasPendingTransaction() ? 1 : 0).flush();
break;
}
case SessionRemote.LOB_READ: {
long lobId = transfer.readLong();
byte[] hmac;
CachedInputStream in;
boolean verifyMac;
if (clientVersion >= Constants.TCP_PROTOCOL_VERSION_11) {
if (clientVersion >= Constants.TCP_PROTOCOL_VERSION_12) {
hmac = transfer.readBytes();
verifyMac = true;
} else {
hmac = null;
verifyMac = false;
}
in = lobs.get(lobId);
if (in == null && verifyMac) {
in = new CachedInputStream(null);
lobs.put(lobId, in);
}
} else {
verifyMac = false;
hmac = null;
in = lobs.get(lobId);
}
long offset = transfer.readLong();
int length = transfer.readInt();
if (verifyMac) {
transfer.verifyLobMac(hmac, lobId);
}
if (in == null) {
throw DbException.get(ErrorCode.OBJECT_CLOSED);
}
if (in.getPos() != offset) {
LobStorageInterface lobStorage = session.getDataHandler().getLobStorage();
// only the lob id is used
ValueLobDb lob = ValueLobDb.create(Value.BLOB, null, -1, lobId, hmac, -1);
InputStream lobIn = lobStorage.getInputStream(lob, hmac, -1);
in = new CachedInputStream(lobIn);
lobs.put(lobId, in);
lobIn.skip(offset);
}
// limit the buffer size
length = Math.min(16 * Constants.IO_BUFFER_SIZE, length);
byte[] buff = new byte[length];
length = IOUtils.readFully(in, buff, length);
transfer.writeInt(SessionRemote.STATUS_OK);
transfer.writeInt(length);
transfer.writeBytes(buff, 0, length);
transfer.flush();
break;
}
default:
trace("Unknown operation: " + operation);
closeSession();
close();
}
}
private int getState(int oldModificationId) {
if (session.getModificationId() == oldModificationId) {
return SessionRemote.STATUS_OK;
}
return SessionRemote.STATUS_OK_STATE_CHANGED;
}
private void sendRow(ResultInterface result) throws IOException {
if (result.next()) {
transfer.writeBoolean(true);
Value[] v = result.currentRow();
for (int i = 0; i < result.getVisibleColumnCount(); i++) {
if (clientVersion >= Constants.TCP_PROTOCOL_VERSION_12) {
transfer.writeValue(v[i]);
} else {
writeValue(v[i]);
}
}
} else {
transfer.writeBoolean(false);
}
}
private void writeValue(Value v) throws IOException {
if (v.getType() == Value.CLOB || v.getType() == Value.BLOB) {
if (v instanceof ValueLobDb) {
ValueLobDb lob = (ValueLobDb) v;
if (lob.isStored()) {
long id = lob.getLobId();
lobs.put(id, new CachedInputStream(null));
}
}
}
transfer.writeValue(v);
}
void setThread(Thread thread) {
this.thread = thread;
}
Thread getThread() {
return thread;
}
/**
* Cancel a running statement.
*
* @param targetSessionId the session id
* @param statementId the statement to cancel
*/
void cancelStatement(String targetSessionId, int statementId) {
if (StringUtils.equals(targetSessionId, this.sessionId)) {
Command cmd = (Command) cache.getObject(statementId, false);
cmd.cancel();
}
}
/**
* An input stream with a position.
*/
static class CachedInputStream extends FilterInputStream {
private static final ByteArrayInputStream DUMMY =
new ByteArrayInputStream(new byte[0]);
private long pos;
CachedInputStream(InputStream in) {
super(in == null ? DUMMY : in);
if (in == null) {
pos = -1;
}
}
@Override
public int read(byte[] buff, int off, int len) throws IOException {
len = super.read(buff, off, len);
if (len > 0) {
pos += len;
}
return len;
}
@Override
public int read() throws IOException {
int x = in.read();
if (x >= 0) {
pos++;
}
return x;
}
@Override
public long skip(long n) throws IOException {
n = super.skip(n);
if (n > 0) {
pos += n;
}
return n;
}
public long getPos() {
return pos;
}
}
}