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 com.strobel.assembler.metadata.FieldDefinition;
  import com.strobel.assembler.metadata.FieldReference;
  import com.strobel.assembler.metadata.Flags;
  import com.strobel.decompiler.ast.AstCode;
  import com.strobel.decompiler.ast.Expression;
  import com.strobel.decompiler.ast.Loop;
  import com.strobel.decompiler.ast.Node;
  
  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;
  import one.util.huntbugs.warning.Roles;
  
  /**
   * @author Tagir Valeev
   *
   */
  @WarningDefinition(category = "Multithreading", name = "SpinLoopOnField", maxScore = 70)
  public class SpinLoop {
      @AstVisitor
      public void visit(Node node, MethodContext mc) {
          if (!(node instanceof Loop))
              return;
          Loop loop = (Loop) node;
          if (!loop.getBody().getBody().isEmpty())
              return;
          Expression cond = loop.getCondition();
          if (cond == null || !Nodes.isSideEffectFree(cond))
              return;
          checkCondition(cond, mc);
      }
  
      private void checkCondition(Expression cond, MethodContext mc) {
          if (cond.getCode() == AstCode.LogicalAnd || cond.getCode() == AstCode.LogicalOr
              || cond.getCode() == AstCode.LogicalNot) {
              cond.getArguments().forEach(child -> checkCondition(child, mc));
          } else if (cond.getCode().isComparison()) {
              cond.getArguments().forEach(child -> checkFieldRead(child, mc));
          } else
              checkFieldRead(cond, mc);
      }
  
      private void checkFieldRead(Expression expr, MethodContext mc) {
          if (Nodes.isFieldRead(expr)) {
              FieldDefinition fd = ((FieldReference) expr.getOperand()).resolve();
              if (fd != null && !Flags.testAny(fd.getFlags(), Flags.VOLATILE)) {
                  mc.report("SpinLoopOnField", 0, expr, Roles.FIELD.create(fd));
              }
          }
      }
  }
  