| /* |
| * Copyright 2003-2014 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.numeric; |
| |
| 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.PsiUtil; |
| import com.intellij.psi.util.PsiUtilCore; |
| 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.EquivalenceChecker; |
| import com.siyeh.ig.psiutils.ExpressionUtils; |
| import com.siyeh.ig.psiutils.SideEffectChecker; |
| import gnu.trove.THashSet; |
| import org.jetbrains.annotations.NonNls; |
| import org.jetbrains.annotations.NotNull; |
| |
| import javax.swing.*; |
| import java.util.Set; |
| |
| public class PointlessArithmeticExpressionInspection |
| extends BaseInspection { |
| |
| private static final Set<IElementType> arithmeticTokens = |
| new THashSet<IElementType>(9); |
| |
| static { |
| arithmeticTokens.add(JavaTokenType.PLUS); |
| arithmeticTokens.add(JavaTokenType.MINUS); |
| arithmeticTokens.add(JavaTokenType.ASTERISK); |
| arithmeticTokens.add(JavaTokenType.DIV); |
| arithmeticTokens.add(JavaTokenType.PERC); |
| arithmeticTokens.add(JavaTokenType.GT); |
| arithmeticTokens.add(JavaTokenType.LT); |
| arithmeticTokens.add(JavaTokenType.LE); |
| arithmeticTokens.add(JavaTokenType.GE); |
| } |
| |
| /** |
| * @noinspection PublicField |
| */ |
| public boolean m_ignoreExpressionsContainingConstants = true; |
| |
| @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.arithmetic.expression.display.name"); |
| } |
| |
| @Override |
| public boolean isEnabledByDefault() { |
| return true; |
| } |
| |
| @Override |
| @NotNull |
| public String buildErrorString(Object... infos) { |
| return InspectionGadgetsBundle.message( |
| "expression.can.be.replaced.problem.descriptor", |
| calculateReplacementExpression((PsiExpression)infos[0])); |
| } |
| |
| @NonNls |
| String calculateReplacementExpression(PsiExpression expression) { |
| final PsiPolyadicExpression polyadicExpression = (PsiPolyadicExpression)expression; |
| final PsiExpression[] operands = polyadicExpression.getOperands(); |
| final IElementType tokenType = polyadicExpression.getOperationTokenType(); |
| PsiElement fromTarget = null; |
| PsiElement untilTarget = null; |
| PsiExpression previousOperand = null; |
| @NonNls String replacement = ""; |
| for (int i = 0, length = operands.length; i < length; i++) { |
| final PsiExpression operand = operands[i]; |
| if (tokenType.equals(JavaTokenType.PLUS) && isZero(operand) || |
| tokenType.equals(JavaTokenType.MINUS) && isZero(operand) && i > 0 || |
| tokenType.equals(JavaTokenType.ASTERISK) && isOne(operand) || |
| tokenType.equals(JavaTokenType.DIV) && isOne(operand) && i > 0) { |
| fromTarget = (i == length - 1) ? polyadicExpression.getTokenBeforeOperand(operand) : operand; |
| break; |
| } |
| else if ((tokenType.equals(JavaTokenType.MINUS) && i == 1 || tokenType.equals(JavaTokenType.DIV)) && |
| EquivalenceChecker.expressionsAreEquivalent(previousOperand, operand)) { |
| fromTarget = previousOperand; |
| untilTarget = operand; |
| replacement = PsiType.LONG.equals(polyadicExpression.getType()) |
| ? tokenType.equals(JavaTokenType.DIV) ? "1L" : "0L" |
| : tokenType.equals(JavaTokenType.DIV) ? "1" : "0"; |
| break; |
| } |
| else if (tokenType.equals(JavaTokenType.ASTERISK) && isZero(operand) || |
| tokenType.equals(JavaTokenType.PERC) && (isOne(operand) || EquivalenceChecker.expressionsAreEquivalent(previousOperand, operand))) { |
| fromTarget = operands[0]; |
| untilTarget = operands[length - 1]; |
| replacement = PsiType.LONG.equals(polyadicExpression.getType()) ? "0L" : "0"; |
| break; |
| } |
| |
| previousOperand = operand; |
| } |
| return getText(polyadicExpression, fromTarget, untilTarget, replacement).trim(); |
| } |
| |
| public static String getText(PsiPolyadicExpression expression, PsiElement fromTarget, PsiElement untilTarget, |
| @NotNull @NonNls String replacement) { |
| final StringBuilder result = new StringBuilder(); |
| boolean stop = false; |
| for (PsiElement child : expression.getChildren()) { |
| if (child == fromTarget) { |
| stop = true; |
| result.append(replacement); |
| } |
| else if (child == untilTarget) { |
| stop = false; |
| } |
| else if (child instanceof PsiComment || !stop) { |
| result.append(child.getText()); |
| } |
| else if (child instanceof PsiJavaToken && untilTarget == null) { |
| stop = false; |
| } |
| } |
| return result.toString(); |
| } |
| |
| @Override |
| public InspectionGadgetsFix buildFix(Object... infos) { |
| return new PointlessArithmeticFix(); |
| } |
| |
| private class PointlessArithmeticFix 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) { |
| final PsiExpression expression = |
| (PsiExpression)descriptor.getPsiElement(); |
| final String newExpression = |
| calculateReplacementExpression(expression); |
| PsiReplacementUtil.replaceExpression(expression, newExpression); |
| } |
| } |
| |
| @Override |
| public BaseInspectionVisitor buildVisitor() { |
| return new PointlessArithmeticVisitor(); |
| } |
| |
| private class PointlessArithmeticVisitor extends BaseInspectionVisitor { |
| |
| @Override |
| public void visitPolyadicExpression(@NotNull PsiPolyadicExpression expression) { |
| super.visitPolyadicExpression(expression); |
| final PsiType expressionType = expression.getType(); |
| if (expressionType == null || |
| PsiType.DOUBLE.equals(expressionType) || |
| PsiType.FLOAT.equals(expressionType)) { |
| return; |
| } |
| if (!arithmeticTokens.contains(expression.getOperationTokenType())) { |
| return; |
| } |
| if (ExpressionUtils.hasStringType(expression) || PsiUtilCore.hasErrorElementChild(expression)) { |
| return; |
| } |
| final PsiExpression[] operands = expression.getOperands(); |
| final IElementType tokenType = expression.getOperationTokenType(); |
| final boolean isPointless; |
| if (tokenType.equals(JavaTokenType.PLUS)) { |
| isPointless = additionExpressionIsPointless(operands); |
| } |
| else if (tokenType.equals(JavaTokenType.MINUS)) { |
| isPointless = subtractionExpressionIsPointless(operands); |
| } |
| else if (tokenType.equals(JavaTokenType.ASTERISK)) { |
| isPointless = multiplyExpressionIsPointless(operands); |
| } |
| else if (tokenType.equals(JavaTokenType.DIV)) { |
| isPointless = divideExpressionIsPointless(operands); |
| } |
| else if (tokenType.equals(JavaTokenType.PERC)) { |
| isPointless = modExpressionIsPointless(operands); |
| } |
| else { |
| isPointless = false; |
| } |
| if (!isPointless) { |
| return; |
| } |
| registerError(expression, expression); |
| } |
| |
| private boolean subtractionExpressionIsPointless(PsiExpression[] expressions) { |
| PsiExpression previousExpression = null; |
| for (int i = 0; i < expressions.length; i++) { |
| PsiExpression expression = expressions[i]; |
| if (previousExpression != null && |
| (isZero(expression) || areExpressionsIdenticalWithoutSideEffects(previousExpression, expression, i))) { |
| return true; |
| } |
| previousExpression = expression; |
| } |
| return false; |
| } |
| |
| private boolean additionExpressionIsPointless(PsiExpression[] expressions) { |
| for (PsiExpression expression : expressions) { |
| if (isZero(expression)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| private boolean multiplyExpressionIsPointless(PsiExpression[] expressions) { |
| for (PsiExpression expression : expressions) { |
| if (isZero(expression) || isOne(expression)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| private boolean divideExpressionIsPointless(PsiExpression[] expressions) { |
| PsiExpression previousExpression = null; |
| for (int i = 0; i < expressions.length; i++) { |
| final PsiExpression expression = expressions[i]; |
| if (previousExpression != null && |
| (isOne(expression) || areExpressionsIdenticalWithoutSideEffects(previousExpression, expression, i))) { |
| return true; |
| } |
| previousExpression = expression; |
| } |
| return false; |
| } |
| |
| private boolean modExpressionIsPointless(PsiExpression[] expressions) { |
| PsiExpression previousExpression = null; |
| for (int i = 0; i < expressions.length; i++) { |
| final PsiExpression expression = expressions[i]; |
| if (previousExpression != null && |
| (isOne(expression) || areExpressionsIdenticalWithoutSideEffects(previousExpression, expression, i))) { |
| return true; |
| } |
| previousExpression = expression; |
| } |
| return false; |
| } |
| |
| private boolean areExpressionsIdenticalWithoutSideEffects(PsiExpression expression1, PsiExpression expression2, int index) { |
| return index == 1 && EquivalenceChecker.expressionsAreEquivalent(expression1, expression2) && |
| !SideEffectChecker.mayHaveSideEffects(expression1); |
| } |
| } |
| |
| boolean isZero(PsiExpression expression) { |
| if (m_ignoreExpressionsContainingConstants && PsiUtil.deparenthesizeExpression(expression) instanceof PsiReferenceExpression) { |
| return false; |
| } |
| return ExpressionUtils.isZero(expression); |
| } |
| |
| boolean isOne(PsiExpression expression) { |
| if (m_ignoreExpressionsContainingConstants && PsiUtil.deparenthesizeExpression(expression) instanceof PsiReferenceExpression) { |
| return false; |
| } |
| return ExpressionUtils.isOne(expression); |
| } |
| } |
