plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/style/UnnecessarilyQualifiedStaticUsageInspection.java

/*
 * Copyright 2003-2012 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.style;

import com.intellij.codeInspection.CleanupLocalInspectionTool;
import com.intellij.codeInspection.ProblemDescriptor;
import com.intellij.codeInspection.ProblemHighlightType;
import com.intellij.codeInspection.ui.MultipleCheckboxOptionsPanel;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.util.TextRange;
import com.intellij.psi.*;
import com.intellij.psi.util.PsiTreeUtil;
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.psiutils.ClassUtils;
import org.jetbrains.annotations.NotNull;

import javax.swing.*;

public class UnnecessarilyQualifiedStaticUsageInspection extends BaseInspection implements CleanupLocalInspectionTool{

  /**
   * @noinspection PublicField
   */
  public boolean m_ignoreStaticFieldAccesses = false;

  /**
   * @noinspection PublicField
   */
  public boolean m_ignoreStaticMethodCalls = false;

  /**
   * @noinspection PublicField
   */
  public boolean m_ignoreStaticAccessFromStaticContext = false;

  @Override
  @NotNull
  public String getDisplayName() {
    return InspectionGadgetsBundle.message("unnecessarily.qualified.static.usage.display.name");
  }

  @Override
  @NotNull
  public String buildErrorString(Object... infos) {
    final PsiJavaCodeReferenceElement element = (PsiJavaCodeReferenceElement)infos[0];
    final PsiElement parent = element.getParent();
    if (parent instanceof PsiMethodCallExpression) {
      return InspectionGadgetsBundle.message("unnecessarily.qualified.static.usage.problem.descriptor", element.getText());
    }
    else {
      return InspectionGadgetsBundle.message("unnecessarily.qualified.static.usage.problem.descriptor1", element.getText());
    }
  }

  @Override
  public JComponent createOptionsPanel() {
    final MultipleCheckboxOptionsPanel optionsPanel = new MultipleCheckboxOptionsPanel(this);
    optionsPanel.addCheckbox(InspectionGadgetsBundle.message("unnecessarily.qualified.static.usage.ignore.field.option"),
                             "m_ignoreStaticFieldAccesses");
    optionsPanel.addCheckbox(InspectionGadgetsBundle.message("unnecessarily.qualified.static.usage.ignore.method.option"),
                             "m_ignoreStaticMethodCalls");
    optionsPanel.addCheckbox(InspectionGadgetsBundle.message("only.report.qualified.static.usages.option"),
                             "m_ignoreStaticAccessFromStaticContext");
    return optionsPanel;
  }

  @Override
  public InspectionGadgetsFix buildFix(Object... infos) {
    return new UnnecessarilyQualifiedStaticUsageFix();
  }

  private static class UnnecessarilyQualifiedStaticUsageFix extends InspectionGadgetsFix {

    @Override
    @NotNull
    public String getName() {
      return InspectionGadgetsBundle.message("unnecessary.qualifier.for.this.remove.quickfix");
    }

    @NotNull
    @Override
    public String getFamilyName() {
      return getName();
    }

    @Override
    public void doFix(Project project, ProblemDescriptor descriptor) throws IncorrectOperationException {
      final PsiElement element = descriptor.getPsiElement();
      element.delete();
    }
  }

  @Override
  public BaseInspectionVisitor buildVisitor() {
    return new UnnecessarilyQualifiedStaticUsageVisitor();
  }

  private class UnnecessarilyQualifiedStaticUsageVisitor extends BaseInspectionVisitor {

    @Override
    public void visitReferenceElement(PsiJavaCodeReferenceElement reference) {
      super.visitReferenceElement(reference);
      final PsiElement qualifier = reference.getQualifier();
      if (qualifier == null) {
        return;
      }
      if (!isUnnecessarilyQualifiedAccess(reference)) {
        return;
      }
      registerError(qualifier, ProblemHighlightType.LIKE_UNUSED_SYMBOL, reference);
    }

    @Override
    public void visitReferenceExpression(PsiReferenceExpression expression) {
      visitReferenceElement(expression);
    }

    private boolean isUnnecessarilyQualifiedAccess(@NotNull PsiJavaCodeReferenceElement referenceElement) {
      if (referenceElement instanceof PsiMethodReferenceExpression) {
        return false;
      }
      final PsiElement parent = referenceElement.getParent();
      if (parent instanceof PsiImportStatementBase) {
        return false;
      }
      final PsiElement qualifierElement = referenceElement.getQualifier();
      if (!(qualifierElement instanceof PsiJavaCodeReferenceElement)) {
        return false;
      }
      final PsiJavaCodeReferenceElement qualifier = (PsiJavaCodeReferenceElement)qualifierElement;
      if (isGenericReference(referenceElement, qualifier)) {
        return false;
      }
      final PsiElement target = referenceElement.resolve();
      if ((!(target instanceof PsiField) || m_ignoreStaticFieldAccesses) && (!(target instanceof PsiMethod) || m_ignoreStaticMethodCalls)) {
        return false;
      }
      if (m_ignoreStaticAccessFromStaticContext) {
        final PsiMember containingMember = PsiTreeUtil.getParentOfType(referenceElement, PsiMember.class);
        if (containingMember != null && !containingMember.hasModifierProperty(PsiModifier.STATIC)) {
          return false;
        }
      }
      final String referenceName = referenceElement.getReferenceName();
      if (referenceName == null) {
        return false;
      }
      final PsiElement resolvedQualifier = qualifier.resolve();
      if (!(resolvedQualifier instanceof PsiClass)) {
        return false;
      }
      final PsiClass containingClass = PsiTreeUtil.getParentOfType(referenceElement, PsiClass.class);
      final PsiClass qualifyingClass = (PsiClass)resolvedQualifier;
      if (containingClass == null || !PsiTreeUtil.isAncestor(qualifyingClass, containingClass, false)) {
        return false;
      }
      final Project project = referenceElement.getProject();
      final JavaPsiFacade manager = JavaPsiFacade.getInstance(project);
      final PsiResolveHelper resolveHelper = manager.getResolveHelper();
      final PsiMember member = (PsiMember)target;
      final PsiClass memberClass;
      if (target instanceof PsiField) {
        final PsiVariable variable = resolveHelper.resolveReferencedVariable(referenceName, referenceElement);
        if (variable == null || !variable.equals(member)) {
          return false;
        }
        final TextRange referenceElementTextRange = referenceElement.getTextRange();
        if (referenceElementTextRange == null) {
          return false;
        }
        final TextRange variableTextRange = variable.getTextRange();
        if (variableTextRange == null) {
          return false;
        }
        //illegal forward ref
        if (referenceElementTextRange.getStartOffset() < variableTextRange.getEndOffset()) {
          return false;
        }
        final PsiMember memberVariable = (PsiMember)variable;
        memberClass = memberVariable.getContainingClass();
      }
      else if (target instanceof PsiClass) {
        final PsiClass aClass = resolveHelper.resolveReferencedClass(referenceName, referenceElement);
        if (aClass == null || !aClass.equals(member)) {
          return false;
        }
        memberClass = aClass.getContainingClass();
      }
      else {
        return isMethodAccessibleWithoutQualifier(referenceElement, qualifyingClass);
      }
      return resolvedQualifier.equals(memberClass);
    }

    private boolean isMethodAccessibleWithoutQualifier(PsiJavaCodeReferenceElement referenceElement, PsiClass qualifyingClass) {
      final String referenceName = referenceElement.getReferenceName();
      if (referenceName == null) {
        return false;
      }
      PsiClass containingClass = ClassUtils.getContainingClass(referenceElement);
      while (containingClass != null) {
        final PsiMethod[] methods = containingClass.findMethodsByName(referenceName, true);
        for (final PsiMethod method : methods) {
          final String name = method.getName();
          if (referenceName.equals(name)) {
            return containingClass.equals(qualifyingClass);
          }
        }
        containingClass = ClassUtils.getContainingClass(containingClass);
      }
      return false;
    }
  }

  static boolean isGenericReference(PsiJavaCodeReferenceElement referenceElement, PsiJavaCodeReferenceElement qualifierElement) {
    final PsiReferenceParameterList qualifierParameterList = qualifierElement.getParameterList();
    if (qualifierParameterList != null) {
      final PsiTypeElement[] typeParameterElements = qualifierParameterList.getTypeParameterElements();
      if (typeParameterElements.length > 0) {
        return true;
      }
    }
    final PsiReferenceParameterList parameterList = referenceElement.getParameterList();
    if (parameterList != null) {
      final PsiTypeElement[] typeParameterElements = parameterList.getTypeParameterElements();
      if (typeParameterElements.length > 0) {
        return true;
      }
    }
    return false;
  }
}