nullaway/src/main/java/com/uber/nullaway/fixserialization/out/ClassAndMethodInfo.java

/*
 * Copyright (c) 2022 Uber Technologies, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package com.uber.nullaway.fixserialization.out;

import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.ClassTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.util.TreePath;
import com.sun.tools.javac.code.Symbol;
import javax.annotation.Nullable;

/** Class and method corresponding to a program point at which an error was reported. */
public class ClassAndMethodInfo {
  /** Path to the program point of the reported error */
  public final TreePath path;

  /**
   * Finding values for these properties is costly and are not needed by default, hence, they are
   * not {@code final} and are only initialized at request.
   */
  @Nullable private MethodTree method;

  @Nullable private ClassTree clazz;

  public ClassAndMethodInfo(TreePath path) {
    this.path = path;
  }

  /** Finds the class and method where the error is reported according to {@code path}. */
  public void findValues() {
    // If the error is reported on a method, that method itself is the relevant program point.
    // Otherwise, use the enclosing method (if present).
    method =
        path.getLeaf() instanceof MethodTree
            ? (MethodTree) path.getLeaf()
            : ASTHelpers.findEnclosingNode(path, MethodTree.class);
    // If the error is reported on a class, that class itself is the relevant program point.
    // Otherwise, use the enclosing class.
    clazz =
        path.getLeaf() instanceof ClassTree
            ? (ClassTree) path.getLeaf()
            : ASTHelpers.findEnclosingNode(path, ClassTree.class);
    if (clazz != null && method != null) {
      // It is possible that the computed method is not enclosed by the computed class, e.g., for
      // the following case:
      //  class C {
      //    void foo() {
      //      class Local {
      //        Object f = null; // error
      //      }
      //    }
      //  }
      // Here the above code will compute clazz to be Local and method as foo().  In such cases, set
      // method to null, we always want the corresponding method to be nested in the corresponding
      // class.
      Symbol.ClassSymbol classSymbol = ASTHelpers.getSymbol(clazz);
      Symbol.MethodSymbol methodSymbol = ASTHelpers.getSymbol(method);
      if (!methodSymbol.isEnclosedBy(classSymbol)) {
        method = null;
      }
    }
  }

  @Nullable
  public MethodTree getMethod() {
    return method;
  }

  @Nullable
  public ClassTree getClazz() {
    return clazz;
  }
}