RemoveInitializerFix.java

/*
 * Copyright 2000-2016 JetBrains s.r.o.
 *
 * 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.intellij.codeInspection;

import com.intellij.codeInsight.FileModificationService;
import com.intellij.codeInsight.daemon.impl.quickfix.RemoveUnusedVariableFix;
import com.intellij.codeInsight.daemon.impl.quickfix.RemoveUnusedVariableUtil;
import com.intellij.openapi.application.WriteAction;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.fileEditor.FileEditorManager;
import com.intellij.openapi.project.Project;
import com.intellij.psi.*;
import com.intellij.psi.util.PsiExpressionTrimRenderer;
import com.intellij.psi.util.PsiUtil;
import org.jetbrains.annotations.NotNull;

import java.util.ArrayList;
import java.util.List;

public class RemoveInitializerFix implements LocalQuickFix {
  private static final Logger LOG = Logger.getInstance(RemoveInitializerFix.class);

  @Override
  @NotNull
  public String getFamilyName() {
    return InspectionsBundle.message("inspection.unused.assignment.remove.quickfix");
  }

  @Override
  public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
    final PsiElement psiInitializer = descriptor.getPsiElement();
    if (!(psiInitializer instanceof PsiExpression)) return;
    if (!(psiInitializer.getParent() instanceof PsiVariable)) return;

    final PsiVariable variable = (PsiVariable)psiInitializer.getParent();
    sideEffectAwareRemove(project, (PsiExpression)psiInitializer, psiInitializer, variable);
  }

  @Override
  public boolean startInWriteAction() {
    return false;
  }

  public static void sideEffectAwareRemove(Project project,
                                           PsiExpression psiInitializer,
                                           PsiElement elementToDelete,
                                           PsiVariable variable) {
    if (!FileModificationService.getInstance().prepareFileForWrite(elementToDelete.getContainingFile())) return;

    final PsiElement declaration = variable.getParent();
    final List<PsiElement> sideEffects = new ArrayList<>();
    boolean hasSideEffects = RemoveUnusedVariableUtil.checkSideEffects(psiInitializer, variable, sideEffects);
    RemoveUnusedVariableUtil.RemoveMode res;
    if (hasSideEffects) {
      hasSideEffects = PsiUtil.isStatement(psiInitializer);
      PsiTypeElement typeElement = variable.getTypeElement();
      res = RemoveUnusedVariableFix.showSideEffectsWarning(sideEffects, variable,
                                                           FileEditorManager.getInstance(project).getSelectedTextEditor(),
                                                           hasSideEffects, sideEffects.get(0).getText(),
                                                           (typeElement != null ? typeElement.getText() + " " + variable.getName() + ";<br>"
                                                                                : "") +
                                                           PsiExpressionTrimRenderer.render(psiInitializer)
      );
    }
    else {
      res = RemoveUnusedVariableUtil.RemoveMode.DELETE_ALL;
    }
    WriteAction.run(() -> {
      if (res == RemoveUnusedVariableUtil.RemoveMode.DELETE_ALL) {
        elementToDelete.delete();
      }
      else if (res == RemoveUnusedVariableUtil.RemoveMode.MAKE_STATEMENT) {
        final PsiElementFactory factory = JavaPsiFacade.getInstance(project).getElementFactory();
        final PsiStatement statementFromText = factory.createStatementFromText(psiInitializer.getText() + ";", null);
        final PsiElement parent = elementToDelete.getParent();
        if (parent instanceof PsiExpressionStatement) {
          parent.replace(statementFromText);
        }
        else {
          declaration.getParent().addBefore(statementFromText, declaration);
          elementToDelete.delete();
        }
      }
    });
  }
}