@Override public synchronized int readLob( long lobId, byte[] hmac, long offset, byte[] buff, int off, int length) { for (int i = 0, count = 0; i < transferList.size(); i++) { Transfer transfer = transferList.get(i); try { traceOperation("LOB_READ", (int) lobId); transfer.writeInt(SessionRemote.LOB_READ); transfer.writeLong(lobId); if (clientVersion >= Constants.TCP_PROTOCOL_VERSION_12) { transfer.writeBytes(hmac); } transfer.writeLong(offset); transfer.writeInt(length); done(transfer); length = transfer.readInt(); if (length <= 0) { return length; } transfer.readBytes(buff, off, length); return length; } catch (IOException e) { removeServer(e, i--, ++count); } } return 1; }
private Transfer initTransfer(ConnectionInfo ci, String db, String server) throws IOException { Socket socket = NetUtils.createSocket(server, Constants.DEFAULT_TCP_PORT, ci.isSSL()); Transfer trans = new Transfer(this); trans.setSocket(socket); trans.setSSL(ci.isSSL()); trans.init(); trans.writeInt(Constants.TCP_PROTOCOL_VERSION_6); trans.writeInt(Constants.TCP_PROTOCOL_VERSION_15); trans.writeString(db); trans.writeString(ci.getOriginalURL()); trans.writeString(ci.getUserName()); trans.writeBytes(ci.getUserPasswordHash()); trans.writeBytes(ci.getFilePasswordHash()); String[] keys = ci.getKeys(); trans.writeInt(keys.length); for (String key : keys) { trans.writeString(key).writeString(ci.getProperty(key)); } try { done(trans); clientVersion = trans.readInt(); trans.setVersion(clientVersion); if (clientVersion >= Constants.TCP_PROTOCOL_VERSION_14) { if (ci.getFileEncryptionKey() != null) { trans.writeBytes(ci.getFileEncryptionKey()); } } trans.writeInt(SessionRemote.SESSION_SET_ID); trans.writeString(sessionId); done(trans); if (clientVersion >= Constants.TCP_PROTOCOL_VERSION_15) { autoCommit = trans.readBoolean(); } else { autoCommit = true; } return trans; } catch (DbException e) { trans.close(); throw e; } }
// 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: { 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(); ArrayList<? extends ParameterInterface> params = command.getParameters(); transfer .writeInt(getState(old)) .writeBoolean(isQuery) .writeBoolean(readonly) .writeInt(params.size()); if (operation == SessionRemote.SESSION_PREPARE_READ_PARAMS) { 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; } 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).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(); InputStream lobIn = lobStorage.getInputStream(lobId, 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, 0, length); transfer.writeInt(SessionRemote.STATUS_OK); transfer.writeInt(length); transfer.writeBytes(buff, 0, length); transfer.flush(); break; } default: trace("Unknown operation: " + operation); closeSession(); close(); } }