[GitHub] [spark] LuciferYang commented on a diff in pull request #38947: [SPARK-41231][SQL] Adds an array_prepend function to catalyst

[GitBox <gi...@apache.org>]

LuciferYang commented on code in PR #38947:
URL: https://github.com/apache/spark/pull/38947#discussion_r1042026795


##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/collectionOperations.scala:
##########
@@ -1399,6 +1399,119 @@ case class ArrayContains(left: Expression, right: Expression)
     copy(left = newLeft, right = newRight)
 }
 
+// scalastyle:off line.size.limit
+@ExpressionDescription(
+  usage =
+    "_FUNC_(array, value) - Returns an array containing value as well as all elements from array. The new element is positioned at the beginning of the array.",
+  examples = """
+    Examples:
+      > SELECT _FUNC_(array(1, 2, 3), 4);
+       [4, 1, 2, 3]
+  """,
+  group = "array_funcs",
+  since = "3.4.0")
+case class ArrayPrepend(left: Expression, right: Expression)
+  extends BinaryExpression
+    with ImplicitCastInputTypes
+    with NullIntolerant
+    with QueryErrorsBase {
+
+  override def nullSafeEval(arr: Any, value: Any): Any = {
+    val numberOfElements = arr.asInstanceOf[ArrayData].numElements()
+    if (numberOfElements + 1 > ByteArrayMethods.MAX_ROUNDED_ARRAY_LENGTH) {
+      throw QueryExecutionErrors.concatArraysWithElementsExceedLimitError(numberOfElements)
+    }
+    val newArray = new Array[Any](numberOfElements + 1)
+    newArray(0) = value
+    var pos = 1
+    arr
+      .asInstanceOf[ArrayData]
+      .foreach(
+        right.dataType,
+        (i, v) => {
+          newArray(pos) = v
+          pos += 1
+        })
+    new GenericArrayData(newArray)
+  }
+  override protected def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
+    nullSafeCodeGen(
+      ctx,
+      ev,
+      (arr, value) => {
+        val newArraySize = ctx.freshName("newArraySize")
+        val newArray = ctx.freshName("newArray")
+        val i = ctx.freshName("i")
+        val pos = ctx.freshName("pos")
+        val allocation = CodeGenerator.createArrayData(
+          newArray,
+          right.dataType,
+          newArraySize,
+          s" $prettyName failed.")
+        val assignment =
+          CodeGenerator.createArrayAssignment(newArray, right.dataType, arr, pos, i, false)
+        val newElemAssignment =
+          CodeGenerator.setArrayElement(newArray, right.dataType, pos, value)
+        s"""
+           |int $pos = 0;
+           |int $newArraySize = $arr.numElements() + 1;
+           |$allocation
+           |$newElemAssignment
+           |$pos = $pos + 1;
+           |for (int $i = 0; $i < $arr.numElements(); $i ++) {
+           |  $assignment
+           |  $pos = $pos + 1;
+           |}
+           |${ev.value} = $newArray;
+           |""".stripMargin
+      })
+  }
+
+  override def prettyName: String = "array_prepend"
+  override protected def withNewChildrenInternal(
+                                                  newLeft: Expression,
+                                                  newRight: Expression): ArrayPrepend =
+    copy(left = newLeft, right = newRight)
+  override def dataType: DataType = left.dataType
+  override def checkInputDataTypes(): TypeCheckResult = {
+    (left.dataType, right.dataType) match {
+      case (_, NullType) | (NullType, _) =>
+        DataTypeMismatch(
+          errorSubClass = "NULL_TYPE",
+          messageParameters = Map("functionName" -> toSQLId(prettyName)))
+      case (l, _) if !ArrayType.acceptsType(l) =>
+        DataTypeMismatch(
+          errorSubClass = "UNEXPECTED_INPUT_TYPE",
+          messageParameters = Map(
+            "paramIndex" -> "1",
+            "requiredType" -> toSQLType(ArrayType),
+            "inputSql" -> toSQLExpr(left),
+            "inputType" -> toSQLType(left.dataType)))
+      case (ArrayType(e1, _), e2) if e1.sameType(e2) =>
+        TypeUtils.checkForOrderingExpr(e2, prettyName)

Review Comment:
   Why need  check `e2` can be ordered ?



-- 
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.

To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org
For additional commands, e-mail: reviews-help@spark.apache.org