org.codenarc.rule.convention.TrailingCommaRule.groovy Maven / Gradle / Ivy

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The CodeNarc project provides a static analysis tool for Groovy code.
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/*
 * Copyright 2015 the original author or authors.
 *
 * Licensed 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.codenarc.rule.convention

import org.codehaus.groovy.ast.expr.Expression
import org.codehaus.groovy.ast.expr.ListExpression
import org.codehaus.groovy.ast.expr.MapExpression
import org.codehaus.groovy.ast.expr.NamedArgumentListExpression
import org.codenarc.rule.AbstractAstVisitor
import org.codenarc.rule.AbstractAstVisitorRule
import org.codenarc.util.AstUtil
import org.codenarc.util.SourceCodeUtil

/**
 * Check whether list and map literals contain optional trailing comma.
 * 
 * By default, trailing comma is required.
 * Set the checkList and checkMap properties to false if needed.
 *
 * @author Yuriy Chulovskyy
 * @author Chris Mair
 */
class TrailingCommaRule extends AbstractAstVisitorRule {

    String name = 'TrailingComma'
    int priority = 3
    Class astVisitorClass = TrailingCommaAstVisitor
    boolean checkList = true
    boolean checkMap = true
    boolean ignoreSingleElementList = true
    boolean ignoreSingleElementMap = true
}

class TrailingCommaAstVisitor extends AbstractAstVisitor {

    @Override
    void visitMapExpression(MapExpression expression) {
        if (isOneLiner(expression) || isMethodArgument(expression) || expression.mapEntryExpressions.isEmpty()) {
            return
        }

        Expression lastExpression = expression.mapEntryExpressions[-1]
        if (rule.checkMap &&
                !isIgnoredOneElementMap(expression) &&
                !hasTrailingComma(lastExpression, expression) &&
                !expressionFollowedByBracketOrBrace(lastExpression)) {
            addViolation(expression, 'Map should contain trailing comma.')
        }
    }

    @Override
    void visitListExpression(ListExpression expression) {
        if (isOneLiner(expression) || expression.expressions.isEmpty()) {
            return
        }
        Expression lastExpression = expression.expressions[-1]
        if (rule.checkList &&
                !isIgnoredOneElementList(expression) &&
                !hasTrailingComma(lastExpression, expression) &&
                !lastExpressionIsOnTheLastLine(lastExpression, expression)
        ) {
            addViolation(expression, 'List should contain trailing comma.')
        }
    }

    private static boolean isOneLiner(Expression expression) {
        expression.lineNumber == expression.lastLineNumber
    }

    private static boolean isMethodArgument(Expression expression) {
        expression instanceof NamedArgumentListExpression
    }

    private boolean isIgnoredOneElementList(ListExpression expression) {
        return rule.ignoreSingleElementList && expression.getExpressions()?.size() == 1
    }

    private boolean isIgnoredOneElementMap(MapExpression expression) {
        return rule.ignoreSingleElementMap && expression.getMapEntryExpressions()?.size() == 1
    }

    private boolean hasTrailingComma(Expression lastExpression, Expression outerExpression) {
        List sourceLinesBetween = SourceCodeUtil.sourceLinesBetween(sourceCode,
                lastExpression.lastLineNumber,
                lastExpression.lastColumnNumber,
                outerExpression.lastLineNumber,
                outerExpression.lastColumnNumber
        )
        // Also check the full last line of the outer (containing) expression, since the comma might be right after it
        sourceLinesBetween.any { it.contains(',') } || lastSourceLine(outerExpression).contains(',')
    }

    private boolean expressionFollowedByBracketOrBrace(Expression expression) {
        String lastSourceLine = AstUtil.lastSourceLine(expression, sourceCode)
        String restOfLine = lastSourceLine.substring(expression.lastColumnNumber - 1)
        return restOfLine.matches(/\s*]/)
    }

    private static boolean lastExpressionIsOnTheLastLine(Expression lastExpression, Expression expression) {
        return lastExpression.lineNumber == expression.lastLineNumber
    }
}