/*
 * Copyright 2017 Google Inc. All Rights Reserved.
 *
 * 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.google.errorprone.bugpatterns;

import static com.google.errorprone.BugPattern.Category.JDK;
import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;

import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.ClassTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.tree.Tree;
import com.sun.source.util.TreeScanner;
import com.sun.tools.javac.code.Symbol.ClassSymbol;
import com.sun.tools.javac.code.Symbol.MethodSymbol;
import javax.lang.model.element.Modifier;

/**
 * Looks for invocations of overridable methods from constructors and similar scopes (instance
 * initializers and variables).
 */
@BugPattern(
  name = "ConstructorInvokesOverridable",
  summary = "Constructors should not invoke overridable methods.",
  category = JDK,
  severity = WARNING
)
public class ConstructorInvokesOverridable extends ConstructorLeakChecker {

  @Override
  protected void traverse(Tree tree, VisitorState state) {
    // If class is final, no method is overridable.
    ClassTree classTree = state.findEnclosing(ClassTree.class);
    if (classTree.getModifiers().getFlags().contains(Modifier.FINAL)) {
      return;
    }
    ClassSymbol classSym = ASTHelpers.getSymbol(classTree);

    tree.accept(
        new TreeScanner<Void, Void>() {
          @Override
          public Void visitMethodInvocation(MethodInvocationTree node, Void data) {
            MethodSymbol method = ASTHelpers.getSymbol(node);
            if (method != null
                && !method.isConstructor()
                && !method.isStatic()
                && !method.isPrivate()
                && !method.getModifiers().contains(Modifier.FINAL)
                && method.isMemberOf(classSym, state.getTypes())) {
              state.reportMatch(describeMatch(node));
            }
            return super.visitMethodInvocation(node, data);
          }
        },
        null);
  }
}