| /* |
| * Copyright 2003-2013 Dave Griffith, Bas Leijdekkers |
| * |
| * 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 com.siyeh.ig.controlflow; |
| |
| import com.intellij.codeInspection.ProblemDescriptor; |
| import com.intellij.codeInspection.ui.SingleCheckboxOptionsPanel; |
| import com.intellij.openapi.project.Project; |
| import com.intellij.psi.*; |
| import com.intellij.psi.tree.IElementType; |
| import com.intellij.psi.util.ConstantExpressionUtil; |
| import com.intellij.util.IncorrectOperationException; |
| import com.siyeh.InspectionGadgetsBundle; |
| import com.siyeh.ig.BaseInspection; |
| import com.siyeh.ig.BaseInspectionVisitor; |
| import com.siyeh.ig.InspectionGadgetsFix; |
| import com.siyeh.ig.PsiReplacementUtil; |
| import com.siyeh.ig.psiutils.ComparisonUtils; |
| import com.siyeh.ig.psiutils.ExpressionUtils; |
| import com.siyeh.ig.psiutils.ParenthesesUtils; |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| import javax.swing.*; |
| import java.util.ArrayList; |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Set; |
| |
| public class PointlessBooleanExpressionInspection extends BaseInspection { |
| |
| private static final Set<IElementType> booleanTokens = new HashSet<IElementType>(); |
| static { |
| booleanTokens.add(JavaTokenType.ANDAND); |
| booleanTokens.add(JavaTokenType.AND); |
| booleanTokens.add(JavaTokenType.OROR); |
| booleanTokens.add(JavaTokenType.OR); |
| booleanTokens.add(JavaTokenType.XOR); |
| booleanTokens.add(JavaTokenType.EQEQ); |
| booleanTokens.add(JavaTokenType.NE); |
| } |
| |
| @SuppressWarnings("PublicField") |
| public boolean m_ignoreExpressionsContainingConstants = false; |
| |
| @Override |
| public JComponent createOptionsPanel() { |
| return new SingleCheckboxOptionsPanel( |
| InspectionGadgetsBundle.message("pointless.boolean.expression.ignore.option"), this, "m_ignoreExpressionsContainingConstants" |
| ); |
| } |
| |
| @Override |
| @NotNull |
| public String getDisplayName() { |
| return InspectionGadgetsBundle.message("pointless.boolean.expression.display.name"); |
| } |
| |
| @Override |
| public boolean isEnabledByDefault() { |
| return true; |
| } |
| |
| @Override |
| @NotNull |
| public String buildErrorString(Object... infos) { |
| final PsiExpression expression = (PsiExpression)infos[0]; |
| return InspectionGadgetsBundle.message("boolean.expression.can.be.simplified.problem.descriptor", |
| buildSimplifiedExpression(expression, new StringBuilder()).toString()); |
| } |
| |
| private StringBuilder buildSimplifiedExpression(@Nullable PsiExpression expression, StringBuilder out) { |
| if (expression instanceof PsiPolyadicExpression) { |
| buildSimplifiedPolyadicExpression((PsiPolyadicExpression)expression, out); |
| } |
| else if (expression instanceof PsiPrefixExpression) { |
| buildSimplifiedPrefixExpression((PsiPrefixExpression)expression, out); |
| } |
| else if (expression instanceof PsiParenthesizedExpression) { |
| final PsiParenthesizedExpression parenthesizedExpression = (PsiParenthesizedExpression)expression; |
| final PsiExpression expression1 = parenthesizedExpression.getExpression(); |
| out.append('('); |
| buildSimplifiedExpression(expression1, out); |
| out.append(')'); |
| } |
| else if (expression != null) { |
| out.append(expression.getText()); |
| } |
| return out; |
| } |
| |
| private void buildSimplifiedPolyadicExpression(PsiPolyadicExpression expression, StringBuilder out) { |
| final IElementType tokenType = expression.getOperationTokenType(); |
| final PsiExpression[] operands = expression.getOperands(); |
| final List<PsiExpression> expressions = new ArrayList(); |
| if (tokenType.equals(JavaTokenType.ANDAND) || tokenType.equals(JavaTokenType.AND)) { |
| for (PsiExpression operand : operands) { |
| if (evaluate(operand) == Boolean.TRUE) { |
| continue; |
| } |
| else if (evaluate(operand) == Boolean.FALSE) { |
| out.append(PsiKeyword.FALSE); |
| return; |
| } |
| expressions.add(operand); |
| } |
| if (expressions.isEmpty()) { |
| out.append(PsiKeyword.TRUE); |
| return; |
| } |
| buildSimplifiedExpression(expressions, tokenType.equals(JavaTokenType.ANDAND) ? "&&" : "&", false, out); |
| } else if (tokenType.equals(JavaTokenType.OROR) || tokenType.equals(JavaTokenType.OR)) { |
| for (PsiExpression operand : operands) { |
| if (evaluate(operand) == Boolean.FALSE) { |
| continue; |
| } |
| else if (evaluate(operand) == Boolean.TRUE) { |
| out.append(PsiKeyword.TRUE); |
| return; |
| } |
| expressions.add(operand); |
| } |
| if (expressions.isEmpty()) { |
| out.append(PsiKeyword.FALSE); |
| return; |
| } |
| buildSimplifiedExpression(expressions, tokenType.equals(JavaTokenType.OROR) ? "||" : "|", false, out); |
| } |
| else if (tokenType.equals(JavaTokenType.XOR) || tokenType.equals(JavaTokenType.NE)) { |
| boolean negate = false; |
| for (PsiExpression operand : operands) { |
| if (evaluate(operand) == Boolean.FALSE) { |
| continue; |
| } |
| else if (evaluate(operand) == Boolean.TRUE) { |
| negate = !negate; |
| continue; |
| } |
| expressions.add(operand); |
| } |
| if (expressions.isEmpty()) { |
| if (negate) { |
| out.append(PsiKeyword.TRUE); |
| } |
| else { |
| out.append(PsiKeyword.FALSE); |
| } |
| return; |
| } |
| buildSimplifiedExpression(expressions, tokenType.equals(JavaTokenType.XOR) ? "^" : "!=", negate, out); |
| } |
| else if (tokenType.equals(JavaTokenType.EQEQ)) { |
| boolean negate = false; |
| for (PsiExpression operand : operands) { |
| if (evaluate(operand) == Boolean.TRUE) { |
| continue; |
| } |
| else if (evaluate(operand) == Boolean.FALSE) { |
| negate = !negate; |
| continue; |
| } |
| expressions.add(operand); |
| } |
| if (expressions.isEmpty()) { |
| if (negate) { |
| out.append(PsiKeyword.FALSE); |
| } |
| else { |
| out.append(PsiKeyword.TRUE); |
| } |
| return; |
| } |
| buildSimplifiedExpression(expressions, "==", negate, out); |
| } |
| else { |
| out.append(expression.getText()); |
| } |
| } |
| |
| private void buildSimplifiedExpression(List<PsiExpression> expressions, String token, boolean negate, StringBuilder out) { |
| if (expressions.size() == 1) { |
| final PsiExpression expression = expressions.get(0); |
| if (!negate) { |
| out.append(expression.getText()); |
| return; |
| } |
| if (ComparisonUtils.isComparison(expression)) { |
| final PsiBinaryExpression binaryExpression = (PsiBinaryExpression)expression; |
| final String negatedComparison = ComparisonUtils.getNegatedComparison(binaryExpression.getOperationTokenType()); |
| final PsiExpression lhs = binaryExpression.getLOperand(); |
| final PsiExpression rhs = binaryExpression.getROperand(); |
| assert rhs != null; |
| out.append(lhs.getText()).append(negatedComparison).append(rhs.getText()); |
| } |
| else { |
| if (ParenthesesUtils.getPrecedence(expression) > ParenthesesUtils.PREFIX_PRECEDENCE) { |
| out.append("!(").append(expression.getText()).append(')'); |
| } |
| else { |
| out.append('!').append(expression.getText()); |
| } |
| } |
| } |
| else { |
| if (negate) { |
| out.append("!("); |
| } |
| boolean useToken = false; |
| for (PsiExpression expression : expressions) { |
| if (useToken) { |
| out.append(token); |
| final PsiElement previousSibling = expression.getPrevSibling(); |
| if (previousSibling instanceof PsiWhiteSpace) { |
| out.append(previousSibling.getText()); |
| } |
| } |
| else { |
| useToken = true; |
| } |
| buildSimplifiedExpression(expression, out); |
| final PsiElement nextSibling = expression.getNextSibling(); |
| if (nextSibling instanceof PsiWhiteSpace) { |
| out.append(nextSibling.getText()); |
| } |
| } |
| if (negate) { |
| out.append(')'); |
| } |
| } |
| } |
| |
| private void buildSimplifiedPrefixExpression(PsiPrefixExpression expression, StringBuilder out) { |
| final PsiJavaToken sign = expression.getOperationSign(); |
| final IElementType tokenType = sign.getTokenType(); |
| final PsiExpression operand = expression.getOperand(); |
| if (JavaTokenType.EXCL.equals(tokenType)) { |
| final Boolean value = evaluate(operand); |
| if (value == Boolean.TRUE) { |
| out.append(PsiKeyword.FALSE); |
| return; |
| } |
| else if (value == Boolean.FALSE) { |
| out.append(PsiKeyword.TRUE); |
| return; |
| } |
| } |
| buildSimplifiedExpression(operand, out.append(sign.getText())); |
| } |
| |
| @Override |
| public InspectionGadgetsFix buildFix(Object... infos) { |
| return new PointlessBooleanExpressionFix(); |
| } |
| |
| private class PointlessBooleanExpressionFix extends InspectionGadgetsFix { |
| @Override |
| @NotNull |
| public String getFamilyName() { |
| return getName(); |
| } |
| |
| @Override |
| @NotNull |
| public String getName() { |
| return InspectionGadgetsBundle.message("constant.conditional.expression.simplify.quickfix"); |
| } |
| |
| @Override |
| public void doFix(Project project, ProblemDescriptor descriptor) throws IncorrectOperationException { |
| final PsiElement element = descriptor.getPsiElement(); |
| if (!(element instanceof PsiExpression)) { |
| return; |
| } |
| final PsiExpression expression = (PsiExpression)element; |
| PsiReplacementUtil.replaceExpression(expression, buildSimplifiedExpression(expression, new StringBuilder()).toString()); |
| } |
| } |
| |
| @Override |
| public BaseInspectionVisitor buildVisitor() { |
| return new PointlessBooleanExpressionVisitor(); |
| } |
| |
| private class PointlessBooleanExpressionVisitor extends BaseInspectionVisitor { |
| |
| @Override |
| public void visitPolyadicExpression(PsiPolyadicExpression expression) { |
| super.visitPolyadicExpression(expression); |
| checkExpression(expression); |
| } |
| |
| @Override |
| public void visitPrefixExpression(PsiPrefixExpression expression) { |
| super.visitPrefixExpression(expression); |
| checkExpression(expression); |
| } |
| |
| private void checkExpression(PsiExpression expression) { |
| if (!isPointlessBooleanExpression(expression)) { |
| return; |
| } |
| final PsiElement parent = ParenthesesUtils.getParentSkipParentheses(expression); |
| if (parent instanceof PsiExpression && isPointlessBooleanExpression((PsiExpression)parent)) { |
| return; |
| } |
| registerError(expression, expression); |
| } |
| |
| private boolean isPointlessBooleanExpression(PsiExpression expression) { |
| if (expression instanceof PsiPrefixExpression) { |
| return evaluate(expression) != null; |
| } |
| else if (expression instanceof PsiPolyadicExpression) { |
| final PsiPolyadicExpression polyadicExpression = (PsiPolyadicExpression)expression; |
| final IElementType sign = polyadicExpression.getOperationTokenType(); |
| if (!booleanTokens.contains(sign)) { |
| return false; |
| } |
| final PsiExpression[] operands = polyadicExpression.getOperands(); |
| boolean containsConstant = false; |
| for (PsiExpression operand : operands) { |
| if (operand == null) { |
| return false; |
| } |
| final PsiType type = operand.getType(); |
| if (type == null || !type.equals(PsiType.BOOLEAN) && !type.equalsToText(CommonClassNames.JAVA_LANG_BOOLEAN)) { |
| return false; |
| } |
| containsConstant |= (evaluate(operand) != null); |
| } |
| if (!containsConstant) { |
| return false; |
| } |
| return true; |
| } |
| return false; |
| } |
| } |
| |
| @Nullable |
| private Boolean evaluate(@Nullable PsiExpression expression) { |
| if (expression == null || m_ignoreExpressionsContainingConstants && containsReference(expression)) { |
| return null; |
| } |
| if (expression instanceof PsiParenthesizedExpression) { |
| final PsiParenthesizedExpression parenthesizedExpression = (PsiParenthesizedExpression)expression; |
| return evaluate(parenthesizedExpression.getExpression()); |
| } |
| else if (expression instanceof PsiPolyadicExpression) { |
| final PsiPolyadicExpression polyadicExpression = (PsiPolyadicExpression)expression; |
| final IElementType tokenType = polyadicExpression.getOperationTokenType(); |
| if (tokenType.equals(JavaTokenType.OROR)) { |
| final PsiExpression[] operands = polyadicExpression.getOperands(); |
| for (PsiExpression operand : operands) { |
| if (evaluate(operand) == Boolean.TRUE) { |
| return Boolean.TRUE; |
| } |
| } |
| } |
| else if (tokenType.equals(JavaTokenType.ANDAND)) { |
| final PsiExpression[] operands = polyadicExpression.getOperands(); |
| for (PsiExpression operand : operands) { |
| if (evaluate(operand) == Boolean.FALSE) { |
| return Boolean.FALSE; |
| } |
| } |
| } |
| } |
| else if (expression instanceof PsiPrefixExpression) { |
| final PsiPrefixExpression prefixExpression = (PsiPrefixExpression)expression; |
| final IElementType tokenType = prefixExpression.getOperationTokenType(); |
| if (JavaTokenType.EXCL.equals(tokenType)) { |
| final PsiExpression operand = prefixExpression.getOperand(); |
| final Boolean b = evaluate(operand); |
| if (b == Boolean.FALSE) { |
| return Boolean.TRUE; |
| } else if (b == Boolean.TRUE) { |
| return Boolean.FALSE; |
| } |
| } |
| } |
| final Boolean value = (Boolean)ConstantExpressionUtil.computeCastTo(expression, PsiType.BOOLEAN); |
| return value != null ? value : null; |
| } |
| |
| private static boolean containsReference(@Nullable PsiExpression expression) { |
| if (expression == null) { |
| return false; |
| } |
| final ReferenceVisitor visitor = new ReferenceVisitor(); |
| expression.accept(visitor); |
| return visitor.containsReference(); |
| } |
| |
| private static class ReferenceVisitor extends JavaRecursiveElementVisitor { |
| |
| private boolean referenceFound = false; |
| |
| @Override |
| public void visitElement(PsiElement element) { |
| if (referenceFound) { |
| return; |
| } |
| super.visitElement(element); |
| } |
| |
| @Override |
| public void visitReferenceExpression(PsiReferenceExpression expression) { |
| final PsiElement target = expression.resolve(); |
| if (target instanceof PsiField && ExpressionUtils.isConstant((PsiField)target)) { |
| referenceFound = true; |
| } |
| else { |
| super.visitReferenceExpression(expression); |
| } |
| } |
| |
| public boolean containsReference() { |
| return referenceFound; |
| } |
| } |
| } |