com.databricks.spark.redshift.TableName.scala Maven / Gradle / Ivy
/*
* Copyright 2015 Databricks
*
* 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 com.databricks.spark.redshift
import scala.collection.mutable.ArrayBuffer
/**
* Wrapper class for representing the name of a Redshift table.
*/
private[redshift] case class TableName(unescapedSchemaName: String, unescapedTableName: String) {
private def quote(str: String) = '"' + str.replace("\"", "\"\"") + '"'
def escapedSchemaName: String = quote(unescapedSchemaName)
def escapedTableName: String = quote(unescapedTableName)
override def toString: String = s"$escapedSchemaName.$escapedTableName"
}
private[redshift] object TableName {
/**
* Parses a table name which is assumed to have been escaped according to Redshift's rules for
* delimited identifiers.
*/
def parseFromEscaped(str: String): TableName = {
def dropOuterQuotes(s: String) =
if (s.startsWith("\"") && s.endsWith("\"")) s.drop(1).dropRight(1) else s
def unescapeQuotes(s: String) = s.replace("\"\"", "\"")
def unescape(s: String) = unescapeQuotes(dropOuterQuotes(s))
splitByDots(str) match {
case Seq(tableName) => TableName("PUBLIC", unescape(tableName))
case Seq(schemaName, tableName) => TableName(unescape(schemaName), unescape(tableName))
case other => throw new IllegalArgumentException(s"Could not parse table name from '$str'")
}
}
/**
* Split by dots (.) while obeying our identifier quoting rules in order to allow dots to appear
* inside of quoted identifiers.
*/
private def splitByDots(str: String): Seq[String] = {
val parts: ArrayBuffer[String] = ArrayBuffer.empty
val sb = new StringBuilder
var inQuotes: Boolean = false
for (c <- str) c match {
case '"' =>
// Note that double quotes are escaped by pairs of double quotes (""), so we don't need
// any extra code to handle them; we'll be back in inQuotes=true after seeing the pair.
sb.append('"')
inQuotes = !inQuotes
case '.' =>
if (!inQuotes) {
parts.append(sb.toString())
sb.clear()
} else {
sb.append('.')
}
case other =>
sb.append(other)
}
if (sb.nonEmpty) {
parts.append(sb.toString())
}
parts
}
}