cloud-fan commented on a change in pull request #30412: URL: https://github.com/apache/spark/pull/30412#discussion_r528882090
########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/CharVarcharUtils.scala ########## @@ -0,0 +1,277 @@ +/* + * 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.util + +import scala.collection.mutable + +import org.apache.spark.sql.catalyst.expressions._ +import org.apache.spark.sql.catalyst.parser.CatalystSqlParser +import org.apache.spark.sql.types._ + +object CharVarcharUtils { + + private val CHAR_VARCHAR_TYPE_STRING_METADATA_KEY = "__CHAR_VARCHAR_TYPE_STRING" + + /** + * Replaces CharType/VarcharType with StringType recursively in the given struct type. If a + * top-level StructField's data type is CharType/VarcharType or has nested CharType/VarcharType, + * this method will add the original type string to the StructField's metadata, so that we can + * re-construct the original data type with CharType/VarcharType later when needed. + */ + def replaceCharVarcharWithStringInSchema(st: StructType): StructType = { + StructType(st.map { field => + if (hasCharVarchar(field.dataType)) { + val metadata = new MetadataBuilder().withMetadata(field.metadata) + .putString(CHAR_VARCHAR_TYPE_STRING_METADATA_KEY, field.dataType.sql).build() + field.copy(dataType = replaceCharVarcharWithString(field.dataType), metadata = metadata) + } else { + field + } + }) + } + + /** + * Returns true if the given data type is CharType/VarcharType or has nested CharType/VarcharType. + */ + def hasCharVarchar(dt: DataType): Boolean = { + dt.existsRecursively(f => f.isInstanceOf[CharType] || f.isInstanceOf[VarcharType]) + } + + /** + * Replaces CharType/VarcharType with StringType recursively in the given data type. + */ + def replaceCharVarcharWithString(dt: DataType): DataType = dt match { + case ArrayType(et, nullable) => + ArrayType(replaceCharVarcharWithString(et), nullable) + case MapType(kt, vt, nullable) => + MapType(replaceCharVarcharWithString(kt), replaceCharVarcharWithString(vt), nullable) + case StructType(fields) => + StructType(fields.map { field => + field.copy(dataType = replaceCharVarcharWithString(field.dataType)) + }) + case _: CharType => StringType + case _: VarcharType => StringType + case _ => dt + } + + /** + * Removes the metadata entry that contains the original type string of CharType/VarcharType from + * the given attribute's metadata. + */ + def cleanAttrMetadata(attr: AttributeReference): AttributeReference = { + val cleaned = new MetadataBuilder().withMetadata(attr.metadata) + .remove(CHAR_VARCHAR_TYPE_STRING_METADATA_KEY).build() + attr.withMetadata(cleaned) + } + + /** + * Re-construct the original data type from the type string in the given metadata. + * This is needed when dealing with char/varchar columns/fields. + */ + def getRawType(metadata: Metadata): Option[DataType] = { + if (metadata.contains(CHAR_VARCHAR_TYPE_STRING_METADATA_KEY)) { + Some(CatalystSqlParser.parseRawDataType( + metadata.getString(CHAR_VARCHAR_TYPE_STRING_METADATA_KEY))) + } else { + None + } + } + + /** + * Re-construct the original StructType from the type strings in the metadata of StructFields. + * This is needed when dealing with char/varchar columns/fields. + */ + def getRawSchema(schema: StructType): StructType = { Review comment: removed. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
