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.assembler.metadata.MethodDefinition;
  import com.strobel.decompiler.ast.AstCode;
  import com.strobel.decompiler.ast.Block;
  import com.strobel.decompiler.ast.Node;
  
  import one.util.huntbugs.db.MethodStats;
  import one.util.huntbugs.db.MethodStats.MethodData;
  import one.util.huntbugs.registry.MethodContext;
  import one.util.huntbugs.registry.anno.AstNodes;
  import one.util.huntbugs.registry.anno.AstVisitor;
  import one.util.huntbugs.registry.anno.WarningDefinition;
  import one.util.huntbugs.util.Nodes;
  
  /**
   * @author lan
   *
   */
  @WarningDefinition(category="RedundantCode", name="UselessVoidMethod", maxScore=50)
  public class UselessVoidMethod {
      @AstVisitor(nodes=AstNodes.ROOT)
      public void checkMethod(Block root, MethodDefinition md, MethodStats ms, MethodContext mc) {
          if(md.getReturnType().isVoid()) {
              MethodData stats = ms.getStats(md);
              if (stats != null && !stats.mayHaveSideEffect(true) && !stats.testAny(MethodStats.METHOD_MAY_THROW, true)) {
                  List<Node> body = root.getBody();
                  if(body.isEmpty())
                      return;
                  if(md.isConstructor() && body.size() == 1 && Nodes.isOp(body.get(0), AstCode.InvokeSpecial))
                      return;
                  int codeSize = Nodes.estimateCodeSize(root);
                  int priority = codeSize < 10 ? 20 : codeSize < 20 ? 10 : codeSize < 30 ? 5 : 0;
                  mc.report("UselessVoidMethod", priority);
              }
          }
      }
  }
  