/**
 * first <code>@@</code> is included
 */
protected void scanSystemVariable() throws SQLSyntaxErrorException {
    if (ch != '@' || sql[curIndex + 1] != '@') throw err("first char must be @@");
    offsetCache = curIndex + 2;
    sizeCache = 0;
    scanChar(2);
    if (ch == '`') {
        for (++sizeCache;; ++sizeCache) {
            if (scanChar() == '`') {
                ++sizeCache;
                if (scanChar() != '`') {
                    break;
                }
            }
        }
    } else {
        for (; CharTypes.isIdentifierChar(ch); ++sizeCache) {
            scanChar();
        }
    }
    updateStringValue(sql, offsetCache, sizeCache);
    token = MySQLToken.SYS_VAR;
}
 

/**
 * first <code>'('</code> has been consumed. At least one element. Consume last ')' after invocation <br/>
 * <code>'(' expr (',' expr)* ')'</code>
 */
private List<Expression> expressionList(List<Expression> exprList) throws SQLSyntaxErrorException {
    for (;;) {
        Expression expr = expression();
        exprList.add(expr);
        switch (lexer.token()) {
            case PUNC_COMMA:
                lexer.nextToken();
                break;
            case PUNC_RIGHT_PAREN:
                lexer.nextToken();
                return exprList;
            default:
                throw err("unexpected token: " + lexer.token());
        }
    }
}
 

@Override
public SQLStatement preHandle(DumpFileContext context, String stmt) throws SQLSyntaxErrorException {
    SQLStatement sqlStatement = RouteStrategyFactory.getRouteStrategy().parserSQL(stmt);
    String tableName;
    if (sqlStatement instanceof MySqlCreateTableStatement) {
        tableName = StringUtil.removeBackQuote(((MySqlCreateTableStatement) sqlStatement).getTableSource().getName().getSimpleName());
        context.setTable(tableName);
        if (context.getTableType() == TableType.DEFAULT) {
            return null;
        }
        boolean isChanged = preHandleCreateTable(context, sqlStatement);
        return isChanged ? sqlStatement : null;
    } else if (sqlStatement instanceof SQLDropTableStatement) {
        tableName = StringUtil.removeBackQuote(((SQLDropTableStatement) sqlStatement).getTableSources().get(0).getName().getSimpleName());
        context.setTable(tableName);
    } else if (sqlStatement instanceof MySqlLockTableStatement) {
        tableName = StringUtil.removeBackQuote(((MySqlLockTableStatement) sqlStatement).getTableSource().getName().getSimpleName());
        context.setTable(tableName);
    }
    return null;
}
 

/**
 * @return null if there is no hint
 */
private List<IndexHint> hintList() throws SQLSyntaxErrorException {
    IndexHint hint = hint();
    if (hint == null)
        return null;
    List<IndexHint> list;
    IndexHint hint2 = hint();
    if (hint2 == null) {
        list = new ArrayList<IndexHint>(1);
        list.add(hint);
        return list;
    }
    list = new LinkedList<IndexHint>();
    list.add(hint);
    list.add(hint2);
    for (; (hint2 = hint()) != null; list.add(hint2));
    return list;
}
 

/**
 * first <code>'('</code> has been consumed. At least one element. Consume
 * last ')' after invocation <br/>
 * <code>'(' expr (',' expr)* ')'</code>
 */
private List<Expression> expressionList(List<Expression> exprList) throws SQLSyntaxErrorException {
    for (;;) {
        Expression expr = expression();
        exprList.add(expr);
        switch (lexer.token()) {
        case PUNC_COMMA:
            lexer.nextToken();
            break;
        case PUNC_RIGHT_PAREN:
            lexer.nextToken();
            return exprList;
        default:
            throw err("unexpected token: " + lexer.token());
        }
    }
}
 

@Override
public void visit(Identifier node) {
    String name = node.getIdTextUpUnescape();
    if (ISequenceVal.SEQ_NEXTVAL.equals(name)) {
        if (node.getParent() == null) {
            throw new TddlNestableRuntimeException(new SQLSyntaxErrorException("SEQUENCE NAME IS NOT EMPTY."));
        }
        name = node.getParent().getIdTextUpUnescape();
        this.columnOrValue = ASTNodeFactory.getInstance().createSequenceValue(name);
    } else {
        IColumn column = ASTNodeFactory.getInstance().createColumn();
        if (node.getParent() != null) { // table.column
            column.setTableName(node.getParent().getIdTextUpUnescape());
        }
        column.setColumnName(node.getIdTextUpUnescape());
        this.columnOrValue = column;
    }
}
 

public MySQLToken nextToken() throws SQLSyntaxErrorException {
    if (tokenCache2 != null) {
        tokenCache2 = null;
        return tokenCache;
    }
    if (tokenCache != null) {
        tokenCache = null;
        return token;
    }
    if (token == MySQLToken.EOF) {
        throw new SQLSyntaxErrorException("eof for sql is already reached, cannot get new token");
    }
    MySQLToken t;
    do {
        skipSeparator();
        t = nextTokenInternal();
    } while (inCStyleComment && inCStyleCommentIgnore || MySQLToken.PUNC_C_STYLE_COMMENT_END == t);
    return t;
}
 

/**
 * @return argument itself if there is no union
 */
protected DMLQueryStatement buildUnionSelect(DMLSelectStatement select) throws SQLSyntaxErrorException {
    if (lexer.token() != KW_UNION) {
        return select;
    }
    DMLSelectUnionStatement union = new DMLSelectUnionStatement(select);
    for (; lexer.token() == KW_UNION;) {
        lexer.nextToken();
        boolean isAll = false;
        switch (lexer.token()) {
            case KW_ALL:
                isAll = true;
            case KW_DISTINCT:
                lexer.nextToken();
                break;
        }
        select = selectPrimary();
        union.addSelect(select, isAll);
    }
    union.setOrderBy(orderBy()).setLimit(limit());
    return union;
}
 

/**
 * <code>higherPRJExpr ( ( '||' | 'OR' ) higherPRJExpr )*</code>
 * 
 * @throws java.sql.SQLSyntaxErrorException
 */
private Expression logicalOrExpression() throws SQLSyntaxErrorException {
    LogicalOrExpression or = null;
    for (Expression expr = logicalXORExpression();;) {
        switch (lexer.token()) {
        case OP_LOGICAL_OR:
        case KW_OR:
            lexer.nextToken();
            if (or == null) {
                or = new LogicalOrExpression();
                or.setCacheEvalRst(cacheEvalRst);
                or.appendOperand(expr);
                expr = or;
            }
            Expression newExpr = logicalXORExpression();
            or.appendOperand(newExpr);
            break;
        default:
            return expr;
        }
    }
}
 

private IndexDefinition indexDefinition() throws SQLSyntaxErrorException {
    IndexDefinition.IndexType indexType = null;
    List<IndexColumnName> columns = new ArrayList<IndexColumnName>(1);
    if (lexer.token() == KW_USING) {
        lexer.nextToken();
        int tp = matchIdentifier("BTREE", "HASH");
        indexType = tp == 0 ? IndexDefinition.IndexType.BTREE : IndexDefinition.IndexType.HASH;
    }
    match(PUNC_LEFT_PAREN);
    for (int i = 0; lexer.token() != PUNC_RIGHT_PAREN; ++i) {
        if (i > 0)
            match(PUNC_COMMA);
        IndexColumnName indexColumnName = indexColumnName();
        columns.add(indexColumnName);
    }
    match(PUNC_RIGHT_PAREN);
    List<IndexOption> options = indexOptions();
    return new IndexDefinition(indexType, columns, options);
}
 

/**
 * first token of this expression has been scanned, not yet consumed
 */
public Expression expression() throws SQLSyntaxErrorException {
    MySQLToken token = lexer.token();
    if (token == null) {
        token = lexer.nextToken();
    }
    if (token == EOF) {
        err("unexpected EOF");
    }
    Expression left = logicalOrExpression();
    if (lexer.token() == OP_ASSIGN) {
        lexer.nextToken();
        Expression right = expression();
        return new AssignmentExpression(left, right).setCacheEvalRst(cacheEvalRst);
    }
    return left;
}
 

public MySQLLexer(char[] sql) throws SQLSyntaxErrorException {
    if ((this.sbuf = sbufRef.get()) == null) {
        this.sbuf = new char[1024];
        sbufRef.set(this.sbuf);
    }
    if (CharTypes.isWhitespace(sql[sql.length - 1])) {
        this.sql = sql;
    } else {
        this.sql = new char[sql.length + 1];
        System.arraycopy(sql, 0, this.sql, 0, sql.length);
    }
    this.eofIndex = this.sql.length - 1;
    this.sql[this.eofIndex] = MySQLLexer.EOI;
    scanChar();
    nextToken();
}
 

/**
 * <code>higherPRJExpr ( ( '||' | 'OR' ) higherPRJExpr )*</code>
 * 
 * @throws SQLSyntaxErrorException
 */
private Expression logicalOrExpression() throws SQLSyntaxErrorException {
    LogicalOrExpression or = null;
    for (Expression expr = logicalXORExpression();;) {
        switch (lexer.token()) {
            case OP_LOGICAL_OR:
            case KW_OR:
                lexer.nextToken();
                if (or == null) {
                    or = new LogicalOrExpression();
                    or.setCacheEvalRst(cacheEvalRst);
                    or.appendOperand(expr);
                    expr = or;
                }
                Expression newExpr = logicalXORExpression();
                or.appendOperand(newExpr);
                break;
            default:
                return expr;
        }
    }
}
 

/**
 * first <code>'('</code> has been consumed. At least one element. Consume
 * last ')' after invocation <br/>
 * <code>'(' expr (',' expr)* ')'</code>
 */
private List<Expression> expressionList(List<Expression> exprList) throws SQLSyntaxErrorException {
    for (;;) {
        Expression expr = expression();
        exprList.add(expr);
        switch (lexer.token()) {
            case PUNC_COMMA:
                lexer.nextToken();
                break;
            case PUNC_RIGHT_PAREN:
                lexer.nextToken();
                return exprList;
            default:
                throw err("unexpected token: " + lexer.token());
        }
    }
}
 

@Override
public RouteResultset route(SchemaConfig schema, int sqlType, String realSQL, ServerConnection sc,
                            LayerCachePool cachePool, String hintSQLValue, int hintSqlType, Map hintMap)
        throws SQLException {

    RouteResultset rrs = routeStrategy.route(schema, hintSqlType,
            hintSQLValue, sc, cachePool);

    if (rrs.isNeedOptimizer()) {
        throw new SQLSyntaxErrorException("Complex SQL not supported in hint");
    }
    // replace the sql of RRS
    if (ServerParse.CALL == sqlType) {
        rrs.setCallStatement(true);
    }

    RouteResultsetNode[] oldRsNodes = rrs.getNodes();
    RouteResultsetNode[] newRrsNodes = new RouteResultsetNode[oldRsNodes.length];
    for (int i = 0; i < newRrsNodes.length; i++) {
        newRrsNodes[i] = new RouteResultsetNode(oldRsNodes[i].getName(), sqlType, realSQL);
    }
    rrs.setNodes(newRrsNodes);

    return rrs;
}
 

@Override
public SQLStatement parserSQL(String originSql) throws SQLSyntaxErrorException {
    SQLStatementParser parser = new MySqlStatementParser(originSql);

    /**
     * thrown SQL SyntaxError if parser error
     */
    try {
        List<SQLStatement> list = parser.parseStatementList();
        if (list.size() > 1) {
            throw new SQLSyntaxErrorException("MultiQueries is not supported,use single query instead ");
        }
        return list.get(0);
    } catch (Exception t) {
        LOGGER.info("routeNormalSqlWithAST", t);
        if (t.getMessage() != null) {
            throw new SQLSyntaxErrorException(t.getMessage());
        } else {
            throw new SQLSyntaxErrorException(t);
        }
    }
}
 

private IndexColumnName indexColumnName() throws SQLSyntaxErrorException {
    // col_name [(length)] [ASC | DESC]
    Identifier colName = identifier();
    Expression len = null;
    if (lexer.token() == PUNC_LEFT_PAREN) {
        lexer.nextToken();
        len = exprParser.expression();
        match(PUNC_RIGHT_PAREN);
    }
    switch (lexer.token()) {
        case KW_ASC:
            lexer.nextToken();
            return new IndexColumnName(colName, len, true);
        case KW_DESC:
            lexer.nextToken();
            return new IndexColumnName(colName, len, false);
        default:
            return new IndexColumnName(colName, len, true);
    }
}
 

private List<Pair<Expression, String>> selectExprList() throws SQLSyntaxErrorException {
    Expression expr = exprParser.expression();
    String alias = as();
    List<Pair<Expression, String>> list;
    if (lexer.token() == PUNC_COMMA) {
        list = new LinkedList<Pair<Expression, String>>();
        list.add(new Pair<Expression, String>(expr, alias));
    } else {
        list = new ArrayList<Pair<Expression, String>>(1);
        list.add(new Pair<Expression, String>(expr, alias));
        return list;
    }
    for (; lexer.token() == PUNC_COMMA; list.add(new Pair<Expression, String>(expr, alias))) {
        lexer.nextToken();
        expr = exprParser.expression();
        alias = as();
    }
    return list;
}
 

/**
 * @param expectTextUppercase must be upper-case
 * @return index (start from 0) of expected text which is first matched. -1 if none is matched.
 */
protected int equalsIdentifier(String... expectTextUppercases) throws SQLSyntaxErrorException {
    if (lexer.token() == MySQLToken.IDENTIFIER) {
        String id = lexer.stringValueUppercase();
        for (int i = 0; i < expectTextUppercases.length; ++i) {
            if (expectTextUppercases[i].equals(id)) {
                return i;
            }
        }
    }
    return -1;
}
 

/**
 * @return {@link QueryExpression} or {@link InExpressionList}
 */
private Expression rightOprandOfIn() throws SQLSyntaxErrorException {
    match(PUNC_LEFT_PAREN);
    if (KW_SELECT == lexer.token()) {
        QueryExpression subq = subQuery();
        match(PUNC_RIGHT_PAREN);
        return subq;
    }
    return new InExpressionList(expressionList(new LinkedList<Expression>())).setCacheEvalRst(cacheEvalRst);
}
 

/**
 * Create SQLSyntaxErrorException with null Throwable
 */
@Test
public void test8() {
    SQLSyntaxErrorException ex = new SQLSyntaxErrorException((Throwable)null);
    assertTrue(ex.getMessage() == null
            && ex.getSQLState() == null
            && ex.getCause() == null
            && ex.getErrorCode() == 0);
}
 

private static SQLStatement parseSQL(String stmt) throws SQLSyntaxErrorException {
    SQLStatementParser parser = new MySqlStatementParser(stmt);
    try {
        return parser.parseStatement();
    } catch (Exception t) {
        if (t.getMessage() != null) {
            throw new SQLSyntaxErrorException(t.getMessage());
        } else {
            throw new SQLSyntaxErrorException(t);
        }
    }
}
 

/**
 * Create SQLSyntaxErrorException with null Throwable
 */
@Test
public void test8() {
    SQLSyntaxErrorException ex = new SQLSyntaxErrorException((Throwable)null);
    assertTrue(ex.getMessage() == null
            && ex.getSQLState() == null
            && ex.getCause() == null
            && ex.getErrorCode() == 0);
}
 

/**
 * first token <code>RELEASE</code> is scanned but not yet consumed
 */
public MTSReleaseStatement release() throws SQLSyntaxErrorException {
    match(KW_RELEASE);
    matchIdentifier("SAVEPOINT");
    Identifier id = identifier();
    match(EOF);
    return new MTSReleaseStatement(id);
}
 

/**
 * Serialize a SQLSyntaxErrorException and make sure you can read it back properly
 */
@Test
public void test10() throws Exception {

    SQLSyntaxErrorException e =
            new SQLSyntaxErrorException(reason, state, errorCode, t);
    SQLSyntaxErrorException ex1 =
            createSerializedException(e);
    assertTrue(reason.equals(ex1.getMessage())
            && ex1.getSQLState().equals(state)
            && cause.equals(ex1.getCause().toString())
            && ex1.getErrorCode() == errorCode);
}
 

@Test
public void testTRIMWithAliasNegative() throws Exception {
    try {
        String sql = "select trim (leading.c) from a as leading";
        methodWatcher.executeQuery(sql);
        Assert.fail("Query is expected to fail with syntax error!");
    } catch (SQLSyntaxErrorException e) {
        Assert.assertEquals(SQLState.LANG_SYNTAX_ERROR, e.getSQLState());
    }
}
 

public void testLoadDataColumnsSet() throws SQLSyntaxErrorException {

        {
            String sql = "LOAD DATA CONCURRENT LOCAL INFILE 'd:/data.txt' REPLACE INTO TABLE XXXX CHARACTER SET utf8 FIELDS TERMINATED BY '\\t' ENCLOSED BY '' ESCAPED BY '\\\\' LINES STARTING BY '' TERMINATED BY '\\n' ignore 2 lines (id,name,address)";
            SQLStatement stmt = SQLParserDelegate.parse(sql);
            String output = output2MySQL(stmt, sql);
            Assert.assertEquals("LOAD DATA CONCURRENT LOCAL INFILE 'd:/data.txt' REPLACE INTO TABLE XXXXCHARACTER SET utf8 COLUMNS TERMINATED BY '\\t' ENCLOSED BY '' ESCAPED BY '\\\\' LINESSTARTING BY '' TERMINATED BY '\\n' IGNORE 2 LINES (ID, NAME, ADDRESS) ",
                output);
        }

    }
 

/**
 * first '(' has been consumed
 */
private Timestampdiff timestampdiff() throws SQLSyntaxErrorException {
    IntervalPrimary.Unit unit = intervalPrimaryUnit();
    match(PUNC_COMMA);
    Expression interval = expression();
    match(PUNC_COMMA);
    Expression expr = expression();
    match(PUNC_RIGHT_PAREN);
    List<Expression> argument = new ArrayList<Expression>(2);
    argument.add(interval);
    argument.add(expr);
    Timestampdiff func = new Timestampdiff(unit, argument);
    func.setCacheEvalRst(cacheEvalRst);
    return func;
}
 

/**
 * first '(' has been consumed
 */
private Timestampdiff timestampdiff() throws SQLSyntaxErrorException {
    IntervalPrimary.Unit unit = intervalPrimaryUnit();
    match(PUNC_COMMA);
    Expression interval = expression();
    match(PUNC_COMMA);
    Expression expr = expression();
    match(PUNC_RIGHT_PAREN);
    List<Expression> argument = new ArrayList<Expression>(2);
    argument.add(interval);
    argument.add(expr);
    Timestampdiff func = new Timestampdiff(unit, argument);
    func.setCacheEvalRst(cacheEvalRst);
    return func;
}
 

/**
 * tableRule标签结构：
 * <tableRule name="sharding-by-month">
 *     <rule>
 *         <columns>create_date</columns>
 *         <algorithm>partbymonth</algorithm>
 *     </rule>
 * </tableRule>
 * @param root
 * @throws SQLSyntaxErrorException
    */
private void loadTableRules(Element root) throws SQLSyntaxErrorException {
	//获取每个tableRule标签
	NodeList list = root.getElementsByTagName("tableRule");
	for (int i = 0, n = list.getLength(); i < n; ++i) {
		Node node = list.item(i);
		if (node instanceof Element) {
			Element e = (Element) node;
			//先判断是否重复
			String name = e.getAttribute("name");
			if (tableRules.containsKey(name)) {
				throw new ConfigException("table rule " + name
						+ " duplicated!");
			}
			//获取rule标签
			NodeList ruleNodes = e.getElementsByTagName("rule");
			int length = ruleNodes.getLength();
			if (length > 1) {
				throw new ConfigException("only one rule can defined :"
						+ name);
			}
			//目前只处理第一个，未来可能有多列复合逻辑需求
			//RuleConfig是保存着rule与function对应关系的对象
			RuleConfig rule = loadRule((Element) ruleNodes.item(0));
			String funName = rule.getFunctionName();
			//判断function是否存在，获取function
			AbstractPartitionAlgorithm func = functions.get(funName);
			if (func == null) {
				throw new ConfigException("can't find function of name :"
						+ funName);
			}
			rule.setRuleAlgorithm(func);
			//保存到tableRules
			tableRules.put(name, new TableRuleConfig(name, rule));
		}
	}
}