[WIP][SPARK-29848][SQL] PostgreSQL dialect: cast to long

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/PostgreSQLDialect.scala

@@ -19,15 +19,15 @@ package org.apache.spark.sql.catalyst.analysis
 
 import org.apache.spark.internal.Logging
 import org.apache.spark.sql.catalyst.expressions.Cast
-import org.apache.spark.sql.catalyst.expressions.postgreSQL.PostgreCastToBoolean
+import org.apache.spark.sql.catalyst.expressions.postgreSQL.{PostgreCastToBoolean, PostgreCastToLong}
 import org.apache.spark.sql.catalyst.plans.logical.LogicalPlan
 import org.apache.spark.sql.catalyst.rules.Rule
 import org.apache.spark.sql.internal.SQLConf
-import org.apache.spark.sql.types.{BooleanType, StringType}
+import org.apache.spark.sql.types.{BooleanType, LongType, StringType}
 
 object PostgreSQLDialect {
   val postgreSQLDialectRules: List[Rule[LogicalPlan]] =
-    CastToBoolean ::
+    CastToBoolean :: CastToLong ::
       Nil
 
   object CastToBoolean extends Rule[LogicalPlan] with Logging {
@@ -46,4 +46,21 @@ object PostgreSQLDialect {
       }
     }
   }
+
+  object CastToLong extends Rule[LogicalPlan] with Logging {
+    override def apply(plan: LogicalPlan): LogicalPlan = {
+      // The SQL configuration `spark.sql.dialect` can be changed in runtime.
+      // To make sure the configuration is effective, we have to check it during rule execution.
+      val conf = SQLConf.get
+      if (conf.usePostgreSQLDialect) {
+        plan.transformExpressions {
+          case Cast(child, dataType, timeZoneId)
+            if child.dataType != LongType && dataType == LongType =>
+            PostgreCastToLong(child, timeZoneId)
+        }
+      } else {
+        plan
+      }
+    }
+  }
 }

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Cast.scala

@@ -471,7 +471,7 @@ abstract class CastBase extends UnaryExpression with TimeZoneAwareExpression wit
   }
 
   // LongConverter
-  private[this] def castToLong(from: DataType): Any => Any = from match {
+  protected[this] def castToLong(from: DataType): Any => Any = from match {
     case StringType =>
       val result = new LongWrapper()
       buildCast[UTF8String](_, s => if (s.toLong(result)) result.value else null)
@@ -1422,7 +1422,9 @@ abstract class CastBase extends UnaryExpression with TimeZoneAwareExpression wit
       (c, evPrim, evNull) => code"$evPrim = (int) $c;"
   }
 
-  private[this] def castToLongCode(from: DataType, ctx: CodegenContext): CastFunction = from match {
+  protected[this] def castToLongCode(
+      from: DataType,
+      ctx: CodegenContext): CastFunction = from match {
     case StringType =>
       val wrapper = ctx.freshVariable("longWrapper", classOf[UTF8String.LongWrapper])
 

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/postgreSQL/PostgreCastToLong.scala

@@ -0,0 +1,76 @@
+/*
+ * 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.postgreSQL
+
+import org.apache.spark.sql.AnalysisException
+import org.apache.spark.sql.catalyst.analysis.TypeCheckResult
+import org.apache.spark.sql.catalyst.expressions.{CastBase, Expression, TimeZoneAwareExpression}
+import org.apache.spark.sql.catalyst.expressions.codegen.Block._
+import org.apache.spark.sql.catalyst.expressions.codegen.CodegenContext
+import org.apache.spark.sql.types._
+import org.apache.spark.unsafe.types.UTF8String
+import org.apache.spark.unsafe.types.UTF8String.LongWrapper
+
+case class PostgreCastToLong(child: Expression, timeZoneId: Option[String])
+  extends CastBase {
+  override def dataType: DataType = LongType
+
+  override protected def ansiEnabled: Boolean =
+    throw new AnalysisException("")
+
+  override def checkInputDataTypes(): TypeCheckResult = child.dataType match {
+    case DateType | TimestampType | NullType =>
+      TypeCheckResult.TypeCheckFailure(s"cannot cast type ${child.dataType} to long")
+    case _ =>
+      TypeCheckResult.TypeCheckSuccess
+  }
+  /** Returns a copy of this expression with the specified timeZoneId. */
+  override def withTimeZone(timeZoneId: String): TimeZoneAwareExpression =
+    copy(timeZoneId = Option(timeZoneId))
+
+  override def castToLong(from: DataType): Any => Any = from match {
+    case StringType =>
+      val result = new LongWrapper()
+      buildCast[UTF8String](_, s => if (s.toLong(result)) result.value
+      else throw new AnalysisException(s"invalid input syntax for type long: $s"))
+    case BooleanType =>
+      buildCast[Boolean](_, b => if (b) 1L else 0L)
+    case x: NumericType =>
+      b => x.numeric.asInstanceOf[Numeric[Any]].toLong(b)
+  }
+
+  override def castToLongCode(from: DataType, ctx: CodegenContext): CastFunction = from match {
+      case StringType =>
+        val wrapper = ctx.freshVariable("longWrapper", classOf[UTF8String.LongWrapper])
+        (c, evPrim, _) =>
+          code"""
+          UTF8String.LongWrapper $wrapper = new UTF8String.LongWrapper();
+          if ($c.toLong($wrapper)) {
+            $evPrim = $wrapper.value;
+          } else {
+            throw new AnalysisException(s"invalid input syntax for type long: $c");
+          }
+          $wrapper = null;
+        """
+      case BooleanType =>
+        (c, evPrim, _) => code"$evPrim = $c ? 1L : 0L;"
+      case DecimalType() =>
+        (c, evPrim, _) => code"$evPrim = $c.to${"long".capitalize}();"
+      case NumericType() =>
+        (c, evPrim, _) => code"$evPrim = (long) $c;"
+    }
+}

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/postgreSQL/CastSuite.scala

@@ -70,4 +70,8 @@ class CastSuite extends SparkFunSuite with ExpressionEvalHelper {
     assert(PostgreCastToBoolean(Literal(1.toDouble), None).checkInputDataTypes().isFailure)
     assert(PostgreCastToBoolean(Literal(1.toFloat), None).checkInputDataTypes().isFailure)
   }
+
+  test("unsupported data types to cast to long") {
+    // TODO: Test cases to be added
+  }
 }

sql/core/src/test/scala/org/apache/spark/sql/PostgreSQLDialectQuerySuite.scala

@@ -19,6 +19,7 @@ package org.apache.spark.sql
 import org.apache.spark.SparkConf
 import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.test.SharedSparkSession
+import org.apache.spark.sql.types.DateType
 
 class PostgreSQLDialectQuerySuite extends QueryTest with SharedSparkSession {
 
@@ -39,4 +40,8 @@ class PostgreSQLDialectQuerySuite extends QueryTest with SharedSparkSession {
       intercept[IllegalArgumentException](sql(s"select cast('$input' as boolean)").collect())
     }
   }
+
+  test("cast to long") {
+    // TODO: Add test cases
+  }
 }