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/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.prestosql.sql.parser;
import io.prestosql.sql.tree.Expression;
import io.prestosql.sql.tree.Node;
import io.prestosql.sql.tree.PathSpecification;
import io.prestosql.sql.tree.Statement;
import org.antlr.v4.runtime.BaseErrorListener;
import org.antlr.v4.runtime.CharStreams;
import org.antlr.v4.runtime.CommonToken;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.DefaultErrorStrategy;
import org.antlr.v4.runtime.InputMismatchException;
import org.antlr.v4.runtime.Parser;
import org.antlr.v4.runtime.ParserRuleContext;
import org.antlr.v4.runtime.RecognitionException;
import org.antlr.v4.runtime.Recognizer;
import org.antlr.v4.runtime.Token;
import org.antlr.v4.runtime.atn.PredictionMode;
import org.antlr.v4.runtime.misc.Pair;
import org.antlr.v4.runtime.misc.ParseCancellationException;
import org.antlr.v4.runtime.tree.TerminalNode;
import javax.inject.Inject;
import java.util.Arrays;
import java.util.EnumSet;
import java.util.List;
import java.util.function.Function;
import static java.util.Objects.requireNonNull;
public class SqlParser
{
private static final BaseErrorListener LEXER_ERROR_LISTENER = new BaseErrorListener()
{
@Override
public void syntaxError(Recognizer recognizer, Object offendingSymbol, int line, int charPositionInLine, String message, RecognitionException e)
{
throw new ParsingException(message, e, line, charPositionInLine);
}
};
private static final ErrorHandler PARSER_ERROR_HANDLER = ErrorHandler.builder()
.specialRule(SqlBaseParser.RULE_expression, "")
.specialRule(SqlBaseParser.RULE_booleanExpression, "")
.specialRule(SqlBaseParser.RULE_valueExpression, "")
.specialRule(SqlBaseParser.RULE_primaryExpression, "")
.specialRule(SqlBaseParser.RULE_identifier, "")
.specialRule(SqlBaseParser.RULE_string, "")
.specialRule(SqlBaseParser.RULE_query, "")
.specialRule(SqlBaseParser.RULE_type, "")
.specialToken(SqlBaseLexer.INTEGER_VALUE, "")
.ignoredRule(SqlBaseParser.RULE_nonReserved)
.build();
private final EnumSet allowedIdentifierSymbols;
private boolean enhancedErrorHandlerEnabled;
public SqlParser()
{
this(new SqlParserOptions());
}
@Inject
public SqlParser(SqlParserOptions options)
{
requireNonNull(options, "options is null");
allowedIdentifierSymbols = EnumSet.copyOf(options.getAllowedIdentifierSymbols());
enhancedErrorHandlerEnabled = options.isEnhancedErrorHandlerEnabled();
}
/**
* Consider using {@link #createStatement(String, ParsingOptions)}
*/
@Deprecated
public Statement createStatement(String sql)
{
return createStatement(sql, new ParsingOptions());
}
public Statement createStatement(String sql, ParsingOptions parsingOptions)
{
return (Statement) invokeParser("statement", sql, SqlBaseParser::singleStatement, parsingOptions);
}
/**
* Consider using {@link #createExpression(String, ParsingOptions)}
*/
@Deprecated
public Expression createExpression(String expression)
{
return createExpression(expression, new ParsingOptions());
}
public Expression createExpression(String expression, ParsingOptions parsingOptions)
{
return (Expression) invokeParser("expression", expression, SqlBaseParser::standaloneExpression, parsingOptions);
}
public PathSpecification createPathSpecification(String expression)
{
return (PathSpecification) invokeParser("path specification", expression, SqlBaseParser::standalonePathSpecification, new ParsingOptions());
}
private Node invokeParser(String name, String sql, Function parseFunction, ParsingOptions parsingOptions)
{
try {
SqlBaseLexer lexer = new SqlBaseLexer(new CaseInsensitiveStream(CharStreams.fromString(sql)));
CommonTokenStream tokenStream = new CommonTokenStream(lexer);
SqlBaseParser parser = new SqlBaseParser(tokenStream);
// Override the default error strategy to not attempt inserting or deleting a token.
// Otherwise, it messes up error reporting
parser.setErrorHandler(new DefaultErrorStrategy()
{
@Override
public Token recoverInline(Parser recognizer)
throws RecognitionException
{
if (nextTokensContext == null) {
throw new InputMismatchException(recognizer);
}
else {
throw new InputMismatchException(recognizer, nextTokensState, nextTokensContext);
}
}
});
parser.addParseListener(new PostProcessor(Arrays.asList(parser.getRuleNames())));
lexer.removeErrorListeners();
lexer.addErrorListener(LEXER_ERROR_LISTENER);
parser.removeErrorListeners();
if (enhancedErrorHandlerEnabled) {
parser.addErrorListener(PARSER_ERROR_HANDLER);
}
else {
parser.addErrorListener(LEXER_ERROR_LISTENER);
}
ParserRuleContext tree;
try {
// first, try parsing with potentially faster SLL mode
parser.getInterpreter().setPredictionMode(PredictionMode.SLL);
tree = parseFunction.apply(parser);
}
catch (ParseCancellationException ex) {
// if we fail, parse with LL mode
tokenStream.reset(); // rewind input stream
parser.reset();
parser.getInterpreter().setPredictionMode(PredictionMode.LL);
tree = parseFunction.apply(parser);
}
return new AstBuilder(parsingOptions).visit(tree);
}
catch (StackOverflowError e) {
throw new ParsingException(name + " is too large (stack overflow while parsing)");
}
}
private class PostProcessor
extends SqlBaseBaseListener
{
private final List ruleNames;
public PostProcessor(List ruleNames)
{
this.ruleNames = ruleNames;
}
@Override
public void exitQuotedIdentifier(SqlBaseParser.QuotedIdentifierContext context)
{
Token token = context.QUOTED_IDENTIFIER().getSymbol();
if (token.getText().length() == 2) { // empty identifier
throw new ParsingException("Zero-length delimited identifier not allowed", null, token.getLine(), token.getCharPositionInLine());
}
}
@Override
public void exitUnquotedIdentifier(SqlBaseParser.UnquotedIdentifierContext context)
{
String identifier = context.IDENTIFIER().getText();
for (IdentifierSymbol identifierSymbol : EnumSet.complementOf(allowedIdentifierSymbols)) {
char symbol = identifierSymbol.getSymbol();
if (identifier.indexOf(symbol) >= 0) {
throw new ParsingException("identifiers must not contain '" + identifierSymbol.getSymbol() + "'", null, context.IDENTIFIER().getSymbol().getLine(), context.IDENTIFIER().getSymbol().getCharPositionInLine());
}
}
}
@Override
public void exitBackQuotedIdentifier(SqlBaseParser.BackQuotedIdentifierContext context)
{
Token token = context.BACKQUOTED_IDENTIFIER().getSymbol();
throw new ParsingException(
"backquoted identifiers are not supported; use double quotes to quote identifiers",
null,
token.getLine(),
token.getCharPositionInLine());
}
@Override
public void exitDigitIdentifier(SqlBaseParser.DigitIdentifierContext context)
{
Token token = context.DIGIT_IDENTIFIER().getSymbol();
throw new ParsingException(
"identifiers must not start with a digit; surround the identifier with double quotes",
null,
token.getLine(),
token.getCharPositionInLine());
}
@Override
public void exitNonReserved(SqlBaseParser.NonReservedContext context)
{
// we can't modify the tree during rule enter/exit event handling unless we're dealing with a terminal.
// Otherwise, ANTLR gets confused an fires spurious notifications.
if (!(context.getChild(0) instanceof TerminalNode)) {
int rule = ((ParserRuleContext) context.getChild(0)).getRuleIndex();
throw new AssertionError("nonReserved can only contain tokens. Found nested rule: " + ruleNames.get(rule));
}
// replace nonReserved words with IDENT tokens
context.getParent().removeLastChild();
Token token = (Token) context.getChild(0).getPayload();
context.getParent().addChild(new CommonToken(
new Pair<>(token.getTokenSource(), token.getInputStream()),
SqlBaseLexer.IDENTIFIER,
token.getChannel(),
token.getStartIndex(),
token.getStopIndex()));
}
}
}
