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.Condition;
  import com.strobel.decompiler.ast.Expression;
  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;
  import one.util.huntbugs.warning.Role.LocationRole;
  
  /**
   * @author Tagir Valeev
   *
   */
  @WarningDefinition(category = "RedundantCode", name = "SameConditions", maxScore = 50)
  @WarningDefinition(category = "RedundantCode", name = "SameConditionsExcluding", maxScore = 75)
  public class ConditionChain {
      private static final LocationRole SAME_CONDITION = LocationRole.forName("SAME_CONDITION");
  
      @AstVisitor
      public void visit(Node node, MethodContext mc, MethodDefinition md) {
          if (node instanceof Condition) {
              Condition cond = (Condition) node;
              Expression expr = cond.getCondition();
              check(expr, cond.getTrueBlock(), mc, false);
              check(expr, cond.getFalseBlock(), mc, true);
          }
          if (node instanceof Expression) {
              Expression expr = (Expression) node;
              if (expr.getCode() == AstCode.LogicalAnd || expr.getCode() == AstCode.LogicalOr) {
                  check(expr.getArguments().get(0), expr.getArguments().get(1), expr.getCode(), mc);
              }
          }
      }
  
      private void check(Expression left, Expression right, AstCode condCode, MethodContext mc) {
          if (Nodes.isEquivalent(left, right)) {
              mc.report("SameConditions", 0, left, SAME_CONDITION.create(mc, right), Roles.EXPRESSION.create(left));
          } else if (left.getCode() == condCode && Nodes.isSideEffectFree(right)) {
              if (Nodes.isSideEffectFree(left))
                  check(left.getArguments().get(0), right, condCode, mc);
              check(left.getArguments().get(1), right, condCode, mc);
          }
      }
  
      private void check(Expression expr, Block block, MethodContext mc, boolean excluding) {
          List<Node> body = block.getBody();
          if (body.isEmpty())
              return;
          Node node = body.get(0);
          if (node instanceof Condition) {
              Condition condNode = (Condition) node;
              Expression condition = condNode.getCondition();
              if (Nodes.isEquivalent(expr, condition)) {
                  int priority = 0;
                  if (Nodes.isEmptyOrBreak(condNode.getTrueBlock())) {
                      excluding = !excluding;
                      priority = 10;
                  }
                  mc.report(excluding ? "SameConditionsExcluding" : "SameConditions", priority, expr, Roles.EXPRESSION
                          .create(condition), SAME_CONDITION.create(mc, condition));
                  return;
              }
              if (expr.getCode() == AstCode.LogicalAnd && !excluding && Nodes.isSideEffectFree(expr)) {
                  check(expr.getArguments().get(0), block, mc, excluding);
                  check(expr.getArguments().get(1), block, mc, excluding);
              }
              if (expr.getCode() == AstCode.LogicalOr && excluding && Nodes.isSideEffectFree(expr)) {
                  check(expr.getArguments().get(0), block, mc, excluding);
                  check(expr.getArguments().get(1), block, mc, excluding);
              }
              if (Nodes.isSideEffectFree(condition)) {
                  check(expr, condNode.getTrueBlock(), mc, excluding);
                  check(expr, condNode.getFalseBlock(), mc, excluding);
              }
          }
      }
  }
  