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/*
* 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.numeric;
import com.intellij.psi.*;
import com.intellij.psi.tree.IElementType;
import com.intellij.psi.util.ConstantExpressionUtil;
import com.siyeh.InspectionGadgetsBundle;
import com.siyeh.ig.BaseInspection;
import com.siyeh.ig.BaseInspectionVisitor;
import org.jetbrains.annotations.NotNull;
public class DivideByZeroInspection extends BaseInspection {
@NotNull
public String getID() {
return "divzero";
}
@NotNull
public String getDisplayName() {
return InspectionGadgetsBundle.message("divide.by.zero.display.name");
}
@NotNull
protected String buildErrorString(Object... infos) {
return InspectionGadgetsBundle.message(
"divide.by.zero.problem.descriptor");
}
public BaseInspectionVisitor buildVisitor() {
return new DivisionByZeroVisitor();
}
private static class DivisionByZeroVisitor extends BaseInspectionVisitor {
@Override
public void visitPolyadicExpression(PsiPolyadicExpression expression) {
super.visitPolyadicExpression(expression);
final IElementType tokenType = expression.getOperationTokenType();
if (!JavaTokenType.DIV.equals(tokenType) && !JavaTokenType.PERC.equals(tokenType)) {
return;
}
final PsiExpression[] operands = expression.getOperands();
for (int i = 1; i < operands.length; i++) {
final PsiExpression operand = operands[i];
if (isZero(operand)) {
registerError(operand);
return;
}
}
}
@Override
public void visitAssignmentExpression(PsiAssignmentExpression expression) {
super.visitAssignmentExpression(expression);
final PsiExpression rhs = expression.getRExpression();
if (rhs == null) {
return;
}
final IElementType tokenType = expression.getOperationTokenType();
if (!tokenType.equals(JavaTokenType.DIVEQ) && !tokenType.equals(JavaTokenType.PERCEQ) || isZero(rhs)) {
return;
}
registerError(expression);
}
private static boolean isZero(PsiExpression expression) {
final Object value = ConstantExpressionUtil.computeCastTo(expression, PsiType.DOUBLE);
if (!(value instanceof Double)) {
return false;
}
final double constantValue = ((Double)value).doubleValue();
return constantValue == 0.0 || constantValue == -0.0;
}
}
}
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