content: /*
   * Copyright 2016 HuntBugs contributors
   * 
   * 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 one.util.huntbugs.detect;
  
  import java.util.List;
  
  import com.strobel.decompiler.ast.AstCode;
  import com.strobel.decompiler.ast.Block;
  import com.strobel.decompiler.ast.Node;
  import com.strobel.decompiler.ast.TryCatchBlock;
  
  import one.util.huntbugs.registry.MethodContext;
  import one.util.huntbugs.registry.anno.AstVisitor;
  import one.util.huntbugs.registry.anno.WarningDefinition;
  import one.util.huntbugs.util.Nodes;
  
  /**
   * @author Tagir Valeev
   *
   */
  @WarningDefinition(category="Multithreading", name="EmptySynchronizeBlock", maxScore=50)
  public class EmptySync {
      @AstVisitor
      public void visit(Node node, MethodContext mc) {
          if(node instanceof Block) {
              List<Node> body = ((Block) node).getBody();
              for(int i=0; i<body.size()-1; i++) {
                  if(Nodes.isOp(body.get(i), AstCode.MonitorEnter)) {
                      Node next = body.get(i+1);
                      if(Nodes.isOp(next, AstCode.MonitorExit))
                          // ECJ scenario: simply monitorenter/monitorexit
                          mc.report("EmptySynchronizeBlock", 0, body.get(i));
                      else if(next instanceof TryCatchBlock) {
                          TryCatchBlock tryCatch = (TryCatchBlock)next;
                          if(Nodes.isSynchorizedBlock(tryCatch) && tryCatch.getTryBlock().getBody().isEmpty()) {
                              // JAVAC scenario: try-catch added
                              mc.report("EmptySynchronizeBlock", 0, body.get(i));
                          }
                      }
                  }
              }
          }
      }
  }
  