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/*
* 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.expressions.codegen
import java.io.ObjectInputStream
import com.esotericsoftware.kryo.{Kryo, KryoSerializable}
import com.esotericsoftware.kryo.io.{Input, Output}
import org.apache.spark.internal.Logging
import org.apache.spark.sql.catalyst.InternalRow
import org.apache.spark.sql.catalyst.expressions._
import org.apache.spark.sql.types.StructType
import org.apache.spark.util.Utils
/**
* Inherits some default implementation for Java from `Ordering[Row]`
*/
class BaseOrdering extends Ordering[InternalRow] {
def compare(a: InternalRow, b: InternalRow): Int = {
throw new UnsupportedOperationException
}
}
/**
* Generates bytecode for an [[Ordering]] of rows for a given set of expressions.
*/
object GenerateOrdering extends CodeGenerator[Seq[SortOrder], Ordering[InternalRow]] with Logging {
protected def canonicalize(in: Seq[SortOrder]): Seq[SortOrder] =
in.map(ExpressionCanonicalizer.execute(_).asInstanceOf[SortOrder])
protected def bind(in: Seq[SortOrder], inputSchema: Seq[Attribute]): Seq[SortOrder] =
in.map(BindReferences.bindReference(_, inputSchema))
/**
* Creates a code gen ordering for sorting this schema, in ascending order.
*/
def create(schema: StructType): BaseOrdering = {
create(schema.zipWithIndex.map { case (field, ordinal) =>
SortOrder(BoundReference(ordinal, field.dataType, nullable = true), Ascending)
})
}
/**
* Generates the code for comparing a struct type according to its natural ordering
* (i.e. ascending order by field 1, then field 2, ..., then field n.
*/
def genComparisons(ctx: CodegenContext, schema: StructType): String = {
val ordering = schema.fields.map(_.dataType).zipWithIndex.map {
case(dt, index) => SortOrder(BoundReference(index, dt, nullable = true), Ascending)
}
genComparisons(ctx, ordering)
}
/**
* Generates the code for ordering based on the given order.
*/
def genComparisons(ctx: CodegenContext, ordering: Seq[SortOrder]): String = {
val comparisons = ordering.map { order =>
val eval = order.child.genCode(ctx)
val asc = order.isAscending
val isNullA = ctx.freshName("isNullA")
val primitiveA = ctx.freshName("primitiveA")
val isNullB = ctx.freshName("isNullB")
val primitiveB = ctx.freshName("primitiveB")
s"""
${ctx.INPUT_ROW} = a;
boolean $isNullA;
${ctx.javaType(order.child.dataType)} $primitiveA;
{
${eval.code}
$isNullA = ${eval.isNull};
$primitiveA = ${eval.value};
}
${ctx.INPUT_ROW} = b;
boolean $isNullB;
${ctx.javaType(order.child.dataType)} $primitiveB;
{
${eval.code}
$isNullB = ${eval.isNull};
$primitiveB = ${eval.value};
}
if ($isNullA && $isNullB) {
// Nothing
} else if ($isNullA) {
return ${
order.nullOrdering match {
case NullsFirst => "-1"
case NullsLast => "1"
}};
} else if ($isNullB) {
return ${
order.nullOrdering match {
case NullsFirst => "1"
case NullsLast => "-1"
}};
} else {
int comp = ${ctx.genComp(order.child.dataType, primitiveA, primitiveB)};
if (comp != 0) {
return ${if (asc) "comp" else "-comp"};
}
}
"""
}.mkString("\n")
comparisons
}
protected def create(ordering: Seq[SortOrder]): BaseOrdering = {
val ctx = newCodeGenContext()
val comparisons = genComparisons(ctx, ordering)
val codeBody = s"""
public SpecificOrdering generate(Object[] references) {
return new SpecificOrdering(references);
}
class SpecificOrdering extends ${classOf[BaseOrdering].getName} {
private Object[] references;
${ctx.declareMutableStates()}
public SpecificOrdering(Object[] references) {
this.references = references;
${ctx.initMutableStates()}
}
${ctx.declareAddedFunctions()}
public int compare(InternalRow a, InternalRow b) {
InternalRow ${ctx.INPUT_ROW} = null; // Holds current row being evaluated.
$comparisons
return 0;
}
}"""
val code = CodeFormatter.stripOverlappingComments(
new CodeAndComment(codeBody, ctx.getPlaceHolderToComments()))
logDebug(s"Generated Ordering by ${ordering.mkString(",")}:\n${CodeFormatter.format(code)}")
CodeGenerator.compile(code).generate(ctx.references.toArray).asInstanceOf[BaseOrdering]
}
}
/**
* A lazily generated row ordering comparator.
*/
class LazilyGeneratedOrdering(val ordering: Seq[SortOrder])
extends Ordering[InternalRow] with KryoSerializable {
def this(ordering: Seq[SortOrder], inputSchema: Seq[Attribute]) =
this(ordering.map(BindReferences.bindReference(_, inputSchema)))
@transient
private[this] var generatedOrdering = GenerateOrdering.generate(ordering)
def compare(a: InternalRow, b: InternalRow): Int = {
generatedOrdering.compare(a, b)
}
private def readObject(in: ObjectInputStream): Unit = Utils.tryOrIOException {
in.defaultReadObject()
generatedOrdering = GenerateOrdering.generate(ordering)
}
override def write(kryo: Kryo, out: Output): Unit = Utils.tryOrIOException {
kryo.writeObject(out, ordering.toArray)
}
override def read(kryo: Kryo, in: Input): Unit = Utils.tryOrIOException {
generatedOrdering = GenerateOrdering.generate(kryo.readObject(in, classOf[Array[SortOrder]]))
}
}
object LazilyGeneratedOrdering {
/**
* Creates a [[LazilyGeneratedOrdering]] for the given schema, in natural ascending order.
*/
def forSchema(schema: StructType): LazilyGeneratedOrdering = {
new LazilyGeneratedOrdering(schema.zipWithIndex.map {
case (field, ordinal) =>
SortOrder(BoundReference(ordinal, field.dataType, nullable = true), Ascending)
})
}
}
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