plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/j2me/ConnectionResourceInspection.java

/*
 * Copyright 2003-2011 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.j2me;

import com.intellij.psi.*;
import com.intellij.psi.util.PsiTreeUtil;
import com.siyeh.HardcodedMethodConstants;
import com.siyeh.InspectionGadgetsBundle;
import com.siyeh.ig.BaseInspection;
import com.siyeh.ig.BaseInspectionVisitor;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;

public class ConnectionResourceInspection extends BaseInspection {

  @Override
  @NotNull
  public String getID() {
    return "ConnectionOpenedButNotSafelyClosed";
  }

  @Override
  @NotNull
  public String getDisplayName() {
    return InspectionGadgetsBundle.message(
      "connection.opened.not.safely.closed.display.name");
  }

  @Override
  @NotNull
  public String buildErrorString(Object... infos) {
    final PsiType type = (PsiType)infos[0];
    final String text = type.getPresentableText();
    return InspectionGadgetsBundle.message(
      "resource.opened.not.closed.problem.descriptor", text);
  }

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

  private static class RecordStoreResourceVisitor
    extends BaseInspectionVisitor {

    @Override
    public void visitMethodCallExpression(
      @NotNull PsiMethodCallExpression expression) {
      super.visitMethodCallExpression(expression);
      if (!isConnectionFactoryMethod(expression)) {
        return;
      }
      final PsiElement parent = expression.getParent();
      final PsiAssignmentExpression assignment;
      if (!(parent instanceof PsiAssignmentExpression)) {
        if (!(parent instanceof PsiTypeCastExpression)) {
          final PsiType type = expression.getType();
          if (type != null) {
            registerError(expression, type);
          }
          return;
        }
        final PsiElement grandParent = parent.getParent();
        if (!(grandParent instanceof PsiAssignmentExpression)) {
          final PsiType type = expression.getType();
          if (type != null) {
            registerError(expression, type);
          }
          return;
        }
        assignment = (PsiAssignmentExpression)grandParent;
      }
      else {
        assignment = (PsiAssignmentExpression)parent;
      }
      final PsiExpression lhs = assignment.getLExpression();
      if (!(lhs instanceof PsiReferenceExpression)) {
        return;
      }
      final PsiReferenceExpression referenceExpression =
        (PsiReferenceExpression)lhs;
      final PsiElement referent = referenceExpression.resolve();
      if (!(referent instanceof PsiVariable)) {
        return;
      }
      final PsiVariable boundVariable = (PsiVariable)referent;
      PsiElement currentContext = expression;
      while (true) {
        final PsiTryStatement tryStatement =
          PsiTreeUtil.getParentOfType(currentContext,
                                      PsiTryStatement.class);
        if (tryStatement == null) {
          final PsiType type = expression.getType();
          if (type != null) {
            registerError(expression, type);
          }
          return;
        }
        if (resourceIsOpenedInTryAndClosedInFinally(
          tryStatement, expression, boundVariable)) {
          return;
        }
        currentContext = tryStatement;
      }
    }


    private static boolean resourceIsOpenedInTryAndClosedInFinally(
      PsiTryStatement tryStatement, PsiExpression lhs,
      PsiVariable boundVariable) {
      final PsiCodeBlock finallyBlock = tryStatement.getFinallyBlock();
      if (finallyBlock == null) {
        return false;
      }
      final PsiCodeBlock tryBlock = tryStatement.getTryBlock();
      if (tryBlock == null) {
        return false;
      }
      if (!PsiTreeUtil.isAncestor(tryBlock, lhs, true)) {
        return false;
      }
      return containsResourceClose(finallyBlock, boundVariable);
    }

    private static boolean containsResourceClose(
      PsiCodeBlock finallyBlock, PsiVariable boundVariable) {
      final CloseVisitor visitor =
        new CloseVisitor(boundVariable);
      finallyBlock.accept(visitor);
      return visitor.containsStreamClose();
    }

    private static boolean isConnectionFactoryMethod(
      @NotNull PsiMethodCallExpression expression) {
      final PsiReferenceExpression methodExpression =
        expression.getMethodExpression();
      final String methodName = methodExpression.getReferenceName();
      if (!HardcodedMethodConstants.OPEN.equals(methodName)) {
        return false;
      }
      final PsiMethod method = expression.resolveMethod();
      if (method == null) {
        return false;
      }
      final PsiClass containingClass = method.getContainingClass();
      if (containingClass == null) {
        return false;
      }
      final String className = containingClass.getQualifiedName();
      @NonNls final String microeditionConnector =
        "javax.microedition.io.Connector";
      return microeditionConnector.equals(className);
    }
  }

  private static class CloseVisitor extends JavaRecursiveElementVisitor {

    private boolean containsClose = false;
    private final PsiVariable objectToClose;

    private CloseVisitor(PsiVariable objectToClose) {
      super();
      this.objectToClose = objectToClose;
    }

    @Override
    public void visitElement(@NotNull PsiElement element) {
      if (containsClose) {
        return;
      }
      super.visitElement(element);
    }

    @Override
    public void visitMethodCallExpression(
      @NotNull PsiMethodCallExpression call) {
      if (containsClose) {
        return;
      }
      super.visitMethodCallExpression(call);
      final PsiReferenceExpression methodExpression =
        call.getMethodExpression();
      final String methodName = methodExpression.getReferenceName();
      if (!HardcodedMethodConstants.CLOSE.equals(methodName)) {
        return;
      }
      final PsiExpression qualifier =
        methodExpression.getQualifierExpression();
      if (!(qualifier instanceof PsiReferenceExpression)) {
        return;
      }
      final PsiReferenceExpression referenceExpression =
        (PsiReferenceExpression)qualifier;
      final PsiElement referent = referenceExpression.resolve();
      if (referent == null) {
        return;
      }
      if (referent.equals(objectToClose)) {
        containsClose = true;
      }
    }

    public boolean containsStreamClose() {
      return containsClose;
    }
  }
}