matriv commented on a change in pull request #18063: URL: https://github.com/apache/flink/pull/18063#discussion_r765794401
########## File path: flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/functions/casting/AnyToCharVarchar.java ########## @@ -0,0 +1,105 @@ +/* + * 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.flink.table.planner.functions.casting; + +import org.apache.flink.table.data.StringData; +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.VarCharType; +import org.apache.flink.table.types.logical.utils.LogicalTypeChecks; + +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.methodCall; +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.shouldPossiblyTrim; +import static org.apache.flink.table.types.logical.utils.LogicalTypeChecks.isStringType; + +/** + * {@link LogicalTypeFamily#CHARACTER_STRING} to {@link LogicalTypeFamily#BINARY_STRING} cast rule. + */ +class AnyToCharVarchar extends AbstractNullAwareCodeGeneratorCastRule<StringData, StringData> { + + static final AnyToCharVarchar INSTANCE = new AnyToCharVarchar(); + + private AnyToCharVarchar() { + super( + CastRulePredicate.builder() + .predicate( + (inputType, targetType) -> + !inputType.is(LogicalTypeRoot.ARRAY) + && targetType.is(LogicalTypeFamily.CHARACTER_STRING) + && !isStringType(targetType)) + .build()); + } + + /* Example generated code for STRING() -> VARCHAR(4) cast + + isNull$0 = _myInputIsNull; + if (!isNull$0) { + if (_myInput.numChars() > 4) { + result$1 = (_myInput).substring(0, 4); + } else { + result$1 = _myInput; + } + isNull$0 = result$1 == null; + } else { + result$1 = org.apache.flink.table.data.binary.BinaryStringData.EMPTY_UTF8; + } + + */ + @Override + protected String generateCodeBlockInternal( + CodeGeneratorCastRule.Context context, + String inputTerm, + String returnVariable, + LogicalType inputLogicalType, + LogicalType targetLogicalType) { + final int precision = LogicalTypeChecks.getLength(targetLogicalType); + CastRule<?, ?> castRule = + CastRuleProvider.resolve(inputLogicalType, VarCharType.STRING_TYPE); + + // Only used for non-Constructed types - for constructed, the trimming/padding is applied + // on each individual rule, i.e.: ArrayToStringCastRule + if (castRule instanceof ExpressionCodeGeneratorCastRule) { + @SuppressWarnings("rawtypes") + final String stringExpr = + ((ExpressionCodeGeneratorCastRule) castRule) + .generateExpression( + context, inputTerm, inputLogicalType, targetLogicalType); + + CastRuleUtils.CodeWriter writer = new CastRuleUtils.CodeWriter(); + if (context.legacyBehaviour() || !shouldPossiblyTrim(precision)) { + return writer.assignStmt(returnVariable, stringExpr).toString(); + } + return writer.ifStmt( + methodCall(stringExpr, "numChars") + " > " + precision, + thenWriter -> + thenWriter.assignStmt( + returnVariable, + methodCall( + "(" + stringExpr + ")", + "substring", + 0, + precision)), + elseWriter -> elseWriter.assignStmt(returnVariable, stringExpr)) + .toString(); + } else { + throw new IllegalStateException("This is a bug. Please file an issue."); Review comment: I don't, because those constructed types have the trimming logic incorporated and shouldn't be "wrapped" by this rule. (break early for example). -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
