rdblue commented on a change in pull request #1728: URL: https://github.com/apache/iceberg/pull/1728#discussion_r518938209
########## File path: spark3-extensions/src/main/scala/org/apache/spark/sql/catalyst/parser/extensions/IcebergSparkSqlExtensionsParser.scala ########## @@ -0,0 +1,180 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 org.apache.spark.sql.catalyst.parser.extensions + +import org.antlr.v4.runtime._ +import org.antlr.v4.runtime.atn.PredictionMode +import org.antlr.v4.runtime.misc.ParseCancellationException +import org.antlr.v4.runtime.tree.TerminalNodeImpl +import org.apache.spark.sql.AnalysisException +import org.apache.spark.sql.catalyst.{FunctionIdentifier, TableIdentifier} +import org.apache.spark.sql.catalyst.expressions.Expression +import org.apache.spark.sql.catalyst.parser.{ParseErrorListener, ParseException, ParserInterface, UpperCaseCharStream} +import org.apache.spark.sql.catalyst.parser.extensions.IcebergSqlExtensionsParser._ +import org.apache.spark.sql.catalyst.plans.logical.LogicalPlan +import org.apache.spark.sql.catalyst.trees.Origin +import org.apache.spark.sql.internal.{SQLConf, VariableSubstitution} +import org.apache.spark.sql.types.{DataType, StructType} + +class IcebergSparkSqlExtensionsParser(delegate: ParserInterface) extends ParserInterface { + + private lazy val substitutor = new VariableSubstitution(SQLConf.get) + private lazy val astBuilder = new IcebergSqlExtensionsAstBuilder(delegate) + + /** + * Parse a string to a DataType. + */ + override def parseDataType(sqlText: String): DataType = { + delegate.parseDataType(sqlText) + } + + /** + * Parse a string to a raw DataType without CHAR/VARCHAR replacement. + */ + override def parseRawDataType(sqlText: String): DataType = { + delegate.parseRawDataType(sqlText) + } + + /** + * Parse a string to an Expression. + */ + override def parseExpression(sqlText: String): Expression = { + delegate.parseExpression(sqlText) + } + + /** + * Parse a string to a TableIdentifier. + */ + override def parseTableIdentifier(sqlText: String): TableIdentifier = { + delegate.parseTableIdentifier(sqlText) + } + + /** + * Parse a string to a FunctionIdentifier. + */ + override def parseFunctionIdentifier(sqlText: String): FunctionIdentifier = { + delegate.parseFunctionIdentifier(sqlText) + } + + /** + * Parse a string to a multi-part identifier. + */ + override def parseMultipartIdentifier(sqlText: String): Seq[String] = { + delegate.parseMultipartIdentifier(sqlText) + } + + /** + * Creates StructType for a given SQL string, which is a comma separated list of field + * definitions which will preserve the correct Hive metadata. + */ + override def parseTableSchema(sqlText: String): StructType = { + delegate.parseTableSchema(sqlText) + } + + /** + * Parse a string to a LogicalPlan. + */ + override def parsePlan(sqlText: String): LogicalPlan = { + val sqlTextAfterSubstitution = substitutor.substitute(sqlText) + parse(sqlTextAfterSubstitution) { parser => + astBuilder.visit(parser.singleStatement()) match { + case plan: LogicalPlan => plan + case _ => delegate.parsePlan(sqlText) + } + } + } + + protected def parse[T](command: String)(toResult: IcebergSqlExtensionsParser => T): T = { + val lexer = new IcebergSqlExtensionsLexer(new UpperCaseCharStream(CharStreams.fromString(command))) + lexer.removeErrorListeners() + lexer.addErrorListener(ParseErrorListener) + + val tokenStream = new CommonTokenStream(lexer) + val parser = new IcebergSqlExtensionsParser(tokenStream) + parser.addParseListener(IcebergSqlExtensionsPostProcessor) + parser.removeErrorListeners() + parser.addErrorListener(ParseErrorListener) + + try { + try { + // first, try parsing with potentially faster SLL mode + parser.getInterpreter.setPredictionMode(PredictionMode.SLL) + toResult(parser) + } + catch { + case _: ParseCancellationException => + // if we fail, parse with LL mode + tokenStream.seek(0) // rewind input stream + parser.reset() + + // Try Again. + parser.getInterpreter.setPredictionMode(PredictionMode.LL) + toResult(parser) + } + } + catch { + case e: ParseException if e.command.isDefined => + throw e + case e: ParseException => + throw e.withCommand(command) + case e: AnalysisException => + val position = Origin(e.line, e.startPosition) + throw new ParseException(Option(command), e.message, position, position) + } + } +} + +/** + * The post-processor validates & cleans-up the parse tree during the parse process. + */ +// while we reuse ParseErrorListener and ParseException, we have to copy and modify PostProcessor +// as it directly depends on classes generated from the extensions grammar file Review comment: Thanks for updating the comment. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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