nullaway/src/main/java/com/uber/nullaway/fixserialization/out/ErrorInfo.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.common.collect.ImmutableMap;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.util.TreePath;
import com.sun.tools.javac.code.Symbol;
import com.uber.nullaway.ErrorMessage;
import com.uber.nullaway.fixserialization.location.SymbolLocation;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.annotation.Nullable;

/** Stores information regarding an error which will be reported by NullAway. */
public class ErrorInfo {

  private final ErrorMessage errorMessage;
  private final ClassAndMemberInfo classAndMemberInfo;

  /**
   * if non-null, this error involved a pseudo-assignment of a @Nullable expression into a @NonNull
   * target, and this field is the Symbol for that target.
   */
  @Nullable private final Symbol nonnullTarget;
  /**
   * In cases where {@link ErrorInfo#nonnullTarget} is {@code null}, we serialize this value at its
   * placeholder in the output tsv file.
   */
  private static final String EMPTY_NONNULL_TARGET_LOCATION_STRING =
      "null\tnull\tnull\tnull\tnull\tnull";

  /** Special characters that need to be escaped in TSV files. */
  private static final ImmutableMap<Character, Character> escapes =
      ImmutableMap.of(
          '\n', 'n',
          '\t', 't',
          '\f', 'f',
          '\b', 'b',
          '\r', 'r');

  public ErrorInfo(TreePath path, ErrorMessage errorMessage, @Nullable Symbol nonnullTarget) {
    this.classAndMemberInfo = new ClassAndMemberInfo(path);
    this.errorMessage = errorMessage;
    this.nonnullTarget = nonnullTarget;
  }

  /**
   * Escapes special characters in string to conform with TSV file formats. The most common
   * convention for lossless conversion is to escape special characters with a backslash according
   * to <a
   * href="https://en.wikipedia.org/wiki/Tab-separated_values#Conventions_for_lossless_conversion_to_TSV">
   * Conventions for lossless conversion to TSV</a>
   *
   * @param str String to process.
   * @return returns modified str which its special characters are escaped.
   */
  private static String escapeSpecialCharacters(String str) {
    // regex needs "\\" to match character '\', each must also be escaped in string to create "\\",
    // therefore we need four "\".
    // escape existing backslashes
    str = str.replaceAll(Pattern.quote("\\"), Matcher.quoteReplacement("\\\\"));
    // escape special characters
    for (Character key : escapes.keySet()) {
      str = str.replaceAll(String.valueOf(key), Matcher.quoteReplacement("\\" + escapes.get(key)));
    }
    return str;
  }

  /**
   * returns string representation of content of an object.
   *
   * @return string representation of contents of an object in a line seperated by tabs.
   */
  public String tabSeparatedToString() {
    return String.join(
        "\t",
        errorMessage.getMessageType().toString(),
        escapeSpecialCharacters(errorMessage.getMessage()),
        (classAndMemberInfo.getClazz() != null
            ? ASTHelpers.getSymbol(classAndMemberInfo.getClazz()).flatName()
            : "null"),
        (classAndMemberInfo.getMember() != null
            ? classAndMemberInfo.getMember().toString()
            : "null"),
        (nonnullTarget != null
            ? SymbolLocation.createLocationFromSymbol(nonnullTarget).tabSeparatedToString()
            : EMPTY_NONNULL_TARGET_LOCATION_STRING));
  }

  /** Finds the class and member of program point where the error is reported. */
  public void initEnclosing() {
    classAndMemberInfo.findValues();
  }

  /**
   * Creates header of an output file containing all {@link ErrorInfo} written in string which
   * values are separated tabs.
   *
   * @return string representation of the header separated by tabs.
   */
  public static String header() {
    return String.join(
        "\t",
        "message_type",
        "message",
        "enc_class",
        "enc_member",
        "target_kind",
        "target_class",
        "target_method",
        "param",
        "index",
        "uri");
  }
}