ToArrayCallWithZeroLengthArrayArgumentInspection.java

/*
 * Copyright 2007-2015 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.performance;

import com.intellij.codeInspection.ProblemDescriptor;
import com.intellij.openapi.project.Project;
import com.intellij.psi.*;
import com.intellij.psi.util.PsiTreeUtil;
import com.intellij.util.IncorrectOperationException;
import com.siyeh.InspectionGadgetsBundle;
import com.siyeh.ig.InspectionGadgetsFix;
import com.siyeh.ig.PsiReplacementUtil;
import com.siyeh.ig.psiutils.HighlightUtils;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

public class ToArrayCallWithZeroLengthArrayArgumentInspection extends ToArrayCallWithZeroLengthArrayArgumentInspectionBase {

  @Override
  @Nullable
  protected InspectionGadgetsFix buildFix(Object... infos) {
    return new ToArrayCallWithZeroLengthArrayArgumentFix();
  }

  private static class ToArrayCallWithZeroLengthArrayArgumentFix extends InspectionGadgetsFix {

    @Override
    @NotNull
    public String getFamilyName() {
      return InspectionGadgetsBundle.message("to.array.call.with.zero.length.array.argument.quickfix");
    }

    @Override
    protected void doFix(Project project, ProblemDescriptor descriptor) throws IncorrectOperationException {
      final PsiElement element = descriptor.getPsiElement();
      final PsiElement parent = element.getParent();
      final PsiElement grandParent = parent.getParent();
      if (!(grandParent instanceof PsiMethodCallExpression)) {
        return;
      }
      final PsiMethodCallExpression methodCallExpression = (PsiMethodCallExpression)grandParent;
      final PsiReferenceExpression methodExpression = methodCallExpression.getMethodExpression();
      final PsiExpression qualifier = methodExpression.getQualifierExpression();
      final PsiElementFactory factory = JavaPsiFacade.getElementFactory(project);
      final PsiExpressionList argumentList = methodCallExpression.getArgumentList();
      final PsiExpression[] arguments = argumentList.getExpressions();
      if (arguments.length != 1) {
        return;
      }
      final PsiExpression argument = arguments[0];
      if (qualifier == null) {
        return;
      }
      final String collectionText = qualifier.getText();
      final PsiType type = argument.getType();
      if (type == null) {
        return;
      }
      final PsiType componentType = type.getDeepComponentType();
      final String typeText = componentType.getCanonicalText();
      if (!(qualifier instanceof PsiMethodCallExpression)) {
        @NonNls final String replacementText = "new " + typeText + '[' + collectionText + ".size()]";
        final String newExpressionText = PsiReplacementUtil.getElementText(methodCallExpression, argument, replacementText);
        PsiReplacementUtil.replaceExpression(methodCallExpression, newExpressionText);
        return;
      }
      // need to introduce a variable to prevent calling a method twice
      PsiStatement statement = PsiTreeUtil.getParentOfType(methodCallExpression, PsiStatement.class);
      if (statement == null) {
        return;
      }
      final PsiType qualifierType = qualifier.getType();
      if (qualifierType == null) {
        return;
      }
      PsiDeclarationStatement declarationStatement = factory.createVariableDeclarationStatement("var", qualifierType, qualifier);
      PsiElement statementParent = statement.getParent();
      while (statementParent instanceof PsiLoopStatement || statementParent instanceof PsiIfStatement) {
        statement = (PsiStatement) statementParent;
        statementParent = statement.getParent();
      }
      final String toArrayText = "var.toArray(new " + typeText + "[var.size()])";
      PsiMethodCallExpression newMethodCallExpression =
        (PsiMethodCallExpression)factory.createExpressionFromText(toArrayText, methodCallExpression);
      declarationStatement = (PsiDeclarationStatement)statementParent.addBefore(declarationStatement, statement);
      newMethodCallExpression = (PsiMethodCallExpression)methodCallExpression.replace(newMethodCallExpression);
      showRenameTemplate(declarationStatement, newMethodCallExpression, statementParent);
    }

    private void showRenameTemplate(PsiDeclarationStatement declarationStatement, PsiMethodCallExpression methodCallExpression,
                                    PsiElement context) {
      if (!isOnTheFly()) {
        return;
      }
      final PsiVariable variable = (PsiVariable)declarationStatement.getDeclaredElements()[0];
      final PsiReferenceExpression ref1 = (PsiReferenceExpression)methodCallExpression.getMethodExpression().getQualifierExpression();
      final PsiNewExpression argument = (PsiNewExpression)methodCallExpression.getArgumentList().getExpressions()[0];
      final PsiMethodCallExpression sizeExpression = (PsiMethodCallExpression)argument.getArrayDimensions()[0];
      final PsiReferenceExpression ref2 = (PsiReferenceExpression)sizeExpression.getMethodExpression().getQualifierExpression();
      HighlightUtils.showRenameTemplate(context, variable, ref1, ref2);
    }
  }
}