slinkydeveloper commented on a change in pull request #18524: URL: https://github.com/apache/flink/pull/18524#discussion_r793370325
########## File path: flink-table/flink-table-planner/src/main/java/org/apache/calcite/sql/fun/SqlCastFunction.java ########## @@ -0,0 +1,213 @@ +/* + * 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.calcite.sql.fun; + +import org.apache.flink.table.planner.calcite.FlinkTypeFactory; +import org.apache.flink.table.types.logical.LogicalType; +import org.apache.flink.table.types.logical.LogicalTypeFamily; +import org.apache.flink.table.types.logical.LogicalTypeRoot; +import org.apache.flink.table.types.logical.utils.LogicalTypeCasts; + +import com.google.common.collect.ImmutableSetMultimap; +import com.google.common.collect.SetMultimap; +import org.apache.calcite.rel.type.RelDataType; +import org.apache.calcite.rel.type.RelDataTypeFamily; +import org.apache.calcite.sql.SqlCall; +import org.apache.calcite.sql.SqlCallBinding; +import org.apache.calcite.sql.SqlDynamicParam; +import org.apache.calcite.sql.SqlFunction; +import org.apache.calcite.sql.SqlFunctionCategory; +import org.apache.calcite.sql.SqlIntervalQualifier; +import org.apache.calcite.sql.SqlKind; +import org.apache.calcite.sql.SqlLiteral; +import org.apache.calcite.sql.SqlNode; +import org.apache.calcite.sql.SqlOperandCountRange; +import org.apache.calcite.sql.SqlOperatorBinding; +import org.apache.calcite.sql.SqlSyntax; +import org.apache.calcite.sql.SqlUtil; +import org.apache.calcite.sql.SqlWriter; +import org.apache.calcite.sql.type.InferTypes; +import org.apache.calcite.sql.type.SqlOperandCountRanges; +import org.apache.calcite.sql.type.SqlTypeFamily; +import org.apache.calcite.sql.type.SqlTypeUtil; +import org.apache.calcite.sql.validate.SqlMonotonicity; +import org.apache.calcite.sql.validate.SqlValidatorImpl; + +import java.text.Collator; +import java.util.Objects; + +import static org.apache.calcite.util.Static.RESOURCE; + +/** + * SqlCastFunction. Note that the std functions are really singleton objects, because they always + * get fetched via the StdOperatorTable. So you can't store any local info in the class and hence + * the return type data is maintained in operand[1] through the validation phase. + * + * <p>Can be used for both {@link SqlCall} and {@link org.apache.calcite.rex.RexCall}. Note that the + * {@code SqlCall} has two operands (expression and type), while the {@code RexCall} has one operand + * (expression) and the type is obtained from {@link org.apache.calcite.rex.RexNode#getType()}. + * + * <p>The class was copied over because of CALCITE-XXXX, in order to workaround the method {@link + * SqlTypeUtil#canCastFrom(RelDataType, RelDataType, boolean)}. Line 141 in {@link + * #checkOperandTypes(SqlCallBinding, boolean)} and new method {@link #canCastFrom(RelDataType, + * RelDataType)}. + * + * @see SqlCastOperator + */ +public class SqlCastFunction extends SqlFunction { + // ~ Instance fields -------------------------------------------------------- + + /** Map of all casts that do not preserve monotonicity. */ + private final SetMultimap<SqlTypeFamily, SqlTypeFamily> nonMonotonicCasts = + ImmutableSetMultimap.<SqlTypeFamily, SqlTypeFamily>builder() + .put(SqlTypeFamily.EXACT_NUMERIC, SqlTypeFamily.CHARACTER) + .put(SqlTypeFamily.NUMERIC, SqlTypeFamily.CHARACTER) + .put(SqlTypeFamily.APPROXIMATE_NUMERIC, SqlTypeFamily.CHARACTER) + .put(SqlTypeFamily.DATETIME_INTERVAL, SqlTypeFamily.CHARACTER) + .put(SqlTypeFamily.CHARACTER, SqlTypeFamily.EXACT_NUMERIC) + .put(SqlTypeFamily.CHARACTER, SqlTypeFamily.NUMERIC) + .put(SqlTypeFamily.CHARACTER, SqlTypeFamily.APPROXIMATE_NUMERIC) + .put(SqlTypeFamily.CHARACTER, SqlTypeFamily.DATETIME_INTERVAL) + .put(SqlTypeFamily.DATETIME, SqlTypeFamily.TIME) + .put(SqlTypeFamily.TIMESTAMP, SqlTypeFamily.TIME) + .put(SqlTypeFamily.TIME, SqlTypeFamily.DATETIME) + .put(SqlTypeFamily.TIME, SqlTypeFamily.TIMESTAMP) + .build(); + + // ~ Constructors ----------------------------------------------------------- + + public SqlCastFunction() { + super("CAST", SqlKind.CAST, null, InferTypes.FIRST_KNOWN, null, SqlFunctionCategory.SYSTEM); + } + + // ~ Methods ---------------------------------------------------------------- + + public RelDataType inferReturnType(SqlOperatorBinding opBinding) { + assert opBinding.getOperandCount() == 2; + RelDataType ret = opBinding.getOperandType(1); + RelDataType firstType = opBinding.getOperandType(0); + ret = opBinding.getTypeFactory().createTypeWithNullability(ret, firstType.isNullable()); + if (opBinding instanceof SqlCallBinding) { + SqlCallBinding callBinding = (SqlCallBinding) opBinding; + SqlNode operand0 = callBinding.operand(0); + + // dynamic parameters and null constants need their types assigned + // to them using the type they are casted to. + if (((operand0 instanceof SqlLiteral) && (((SqlLiteral) operand0).getValue() == null)) + || (operand0 instanceof SqlDynamicParam)) { + final SqlValidatorImpl validator = (SqlValidatorImpl) callBinding.getValidator(); + validator.setValidatedNodeType(operand0, ret); + } + } + return ret; + } + + public String getSignatureTemplate(final int operandsCount) { + assert operandsCount == 2; + return "{0}({1} AS {2})"; + } + + public SqlOperandCountRange getOperandCountRange() { + return SqlOperandCountRanges.of(2); + } + + /** + * Makes sure that the number and types of arguments are allowable. Operators (such as "ROW" and + * "AS") which do not check their arguments can override this method. + */ + public boolean checkOperandTypes(SqlCallBinding callBinding, boolean throwOnFailure) { + final SqlNode left = callBinding.operand(0); + final SqlNode right = callBinding.operand(1); + if (SqlUtil.isNullLiteral(left, false) || left instanceof SqlDynamicParam) { + return true; + } + RelDataType validatedNodeType = callBinding.getValidator().getValidatedNodeType(left); + RelDataType returnType = SqlTypeUtil.deriveType(callBinding, right); + if (!canCastFrom(returnType, validatedNodeType)) { + if (throwOnFailure) { + throw callBinding.newError( + RESOURCE.cannotCastValue( + validatedNodeType.toString(), returnType.toString())); + } + return false; + } + if (SqlTypeUtil.areCharacterSetsMismatched(validatedNodeType, returnType)) { + if (throwOnFailure) { + // Include full type string to indicate character + // set mismatch. + throw callBinding.newError( + RESOURCE.cannotCastValue( + validatedNodeType.getFullTypeString(), + returnType.getFullTypeString())); + } + return false; + } + return true; + } + + private boolean canCastFrom(RelDataType toType, RelDataType fromType) { + LogicalType from = FlinkTypeFactory.toLogicalType(fromType); + if (from.is(LogicalTypeFamily.CONSTRUCTED) + || from.is(LogicalTypeRoot.RAW) + || from.is(LogicalTypeRoot.STRUCTURED_TYPE)) { + return LogicalTypeCasts.supportsExplicitCast( + from, FlinkTypeFactory.toLogicalType(toType)); + } Review comment: Add comment and check without doing the conversion of `from`, as it's expensive -- This is an automated message from the Apache Git Service. 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