com.google.javascript.refactoring.ApplySuggestedFixes Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of closure-compiler-unshaded Show documentation
Closure Compiler is a JavaScript optimizing compiler. It parses your JavaScript, analyzes it, removes dead code and rewrites and minimizes what's left. It also checks syntax, variable references, and types, and warns about common JavaScript pitfalls. It is used in many of Google's JavaScript apps, including Gmail, Google Web Search, Google Maps, and Google Docs.
There is a newer version: v20240317
Show newest version
/*
 * Copyright 2014 The Closure Compiler Authors.
 *
 * 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.javascript.refactoring;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static com.google.common.collect.Streams.stream;
import static java.nio.charset.StandardCharsets.UTF_8;

import com.google.common.base.Joiner;
import com.google.common.base.Preconditions;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSortedSet;
import com.google.common.collect.Iterables;
import com.google.common.collect.Multimaps;
import com.google.common.collect.SetMultimap;
import com.google.common.io.Files;
import java.io.File;
import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.function.Predicate;
import java.util.stream.IntStream;

/**
 * Class that applies suggested fixes to code or files.
 */
public final class ApplySuggestedFixes {

  private static final Joiner DOUBLE_LINE_JOINER = Joiner.on("\n\n");

  /**
   * Applies the provided set of suggested fixes to the files listed in the suggested fixes.
   * The fixes can be provided in any order, but they may not have any overlapping modifications
   * for the same file.
   */
  public static void applySuggestedFixesToFiles(Iterable fixes)
      throws IOException {
    Set filenames = new HashSet<>();
    for (SuggestedFix fix : fixes) {
      filenames.addAll(fix.getReplacements().keySet());
    }

    Map filenameToCodeMap = new HashMap<>();
    for (String filename : filenames) {
      filenameToCodeMap.put(filename, Files.asCharSource(new File(filename), UTF_8).read());
    }

    ImmutableMap newCode = applySuggestedFixesToCode(fixes, filenameToCodeMap);
    for (Map.Entry entry : newCode.entrySet()) {
      Files.asCharSink(new File(entry.getKey()), UTF_8).write(entry.getValue());
    }
  }

  /**
   * Applies all possible options from each {@code SuggestedFixAlternative} to the provided code and
   * returns the new code. This only makes sense if all the SuggestedFixAlternatives come from the
   * same checker, i.e. they offer the same number of choices and the same index corresponds to
   * similar fixes. The {@code filenameToCodeMap} must contain all the files that the provided fixes
   * apply to. The fixes can be provided in any order, but they may not have any overlapping
   * modifications for the same file. This function will return new code only for the files that
   * have been modified.
   */
  public static ImmutableList> applyAllSuggestedFixChoicesToCode(
      Iterable fixChoices, Map fileNameToCodeMap) {
    if (Iterables.isEmpty(fixChoices)) {
      return ImmutableList.of(ImmutableMap.of());
    }
    int alternativeCount = Iterables.getFirst(fixChoices, null).getAlternatives().size();
    Preconditions.checkArgument(
        stream(fixChoices)
            .map(f -> f.getAlternatives().size())
            .allMatch(Predicate.isEqual(alternativeCount)),
        "All SuggestedFixAlternatives must offer an equal number of choices for this "
            + "utility to make sense");
    return IntStream.range(0, alternativeCount)
        .mapToObj(i -> applySuggestedFixChoicesToCode(fixChoices, i, fileNameToCodeMap))
        .collect(toImmutableList());
  }

  private static ImmutableMap applySuggestedFixChoicesToCode(
      Iterable fixChoices,
      final int choiceIndex,
      Map fileNameToCodeMap) {
    ImmutableList chosenFixes =
        stream(fixChoices)
            .map(choices -> choices.getAlternatives().get(choiceIndex))
            .collect(toImmutableList());
    return applySuggestedFixesToCode(chosenFixes, fileNameToCodeMap);
  }

  /**
   * Applies the provided set of suggested fixes to the provided code and returns the new code,
   * ignoring alternative fixes. The {@code filenameToCodeMap} must contain all the files that the
   * provided fixes apply to. The fixes can be provided in any order, but they may not have any
   * overlapping modifications for the same file. This function will return new code only for the
   * files that have been modified.
   */
  public static ImmutableMap applySuggestedFixesToCode(
      Iterable fixes, Map filenameToCodeMap) {
    ReplacementMap map = new ReplacementMap();
    for (SuggestedFix fix : fixes) {
      map.putIfNoOverlap(fix);
    }
    ImmutableMap.Builder newCodeMap = ImmutableMap.builder();
    for (Map.Entry> entry : map.entrySet()) {
      String filename = entry.getKey();
      if (!filenameToCodeMap.containsKey(filename)) {
        throw new IllegalArgumentException("filenameToCodeMap missing code for file: " + filename);
      }
      Set replacements = entry.getValue();
      String newCode = applyCodeReplacements(replacements, filenameToCodeMap.get(filename));
      newCodeMap.put(filename, newCode);
    }
    return newCodeMap.buildOrThrow();
  }

  /**
   * Applies the provided set of code replacements to the code and returns the transformed code. The
   * code replacements may not have any overlap.
   */
  public static String applyCodeReplacements(
      Collection replacements, String code) {
    ImmutableSortedSet sortedReplacements =
        ImmutableSortedSet.copyOf(replacements);
    checkArgument(
        !containsOverlaps(sortedReplacements),
        "Found overlap between code replacements:\n%s",
        DOUBLE_LINE_JOINER.join(sortedReplacements));

    StringBuilder sb = new StringBuilder();
    int lastIndex = 0;
    for (CodeReplacement replacement : sortedReplacements) {
      sb.append(code, lastIndex, replacement.getStartPosition());
      sb.append(replacement.getNewContent());
      lastIndex = replacement.getEndPosition();
    }
    if (lastIndex <= code.length()) {
      sb.append(code, lastIndex, code.length());
    }
    return sb.toString();
  }

  /**
   * Checks whether the `CodeReplacement`s have any overlap.
   *
   * We intentinoally accept a set here beceuse we want to supprt/ignore equivalent
   * `CodeReplacement`s. It's safe if those overlap as long as we only apply one of them.
   */
  private static boolean containsOverlaps(ImmutableSortedSet replacements) {
    int start = -1;
    for (CodeReplacement replacement : replacements) {
      if (replacement.getStartPosition() < start) {
        return true;
      }
      start = replacement.getEndPosition();
    }
    return false;
  }

  private static class ReplacementMap {
    private final SetMultimap map = HashMultimap.create();

    void putIfNoOverlap(SuggestedFix fix) {
      if (canPut(fix)) {
        map.putAll(fix.getReplacements());
      }
    }

    private boolean canPut(SuggestedFix fix) {
      for (String filename : fix.getReplacements().keySet()) {
        ImmutableSortedSet replacements =
            ImmutableSortedSet.naturalOrder()
                .addAll(map.get(filename))
                .addAll(fix.getReplacements().get(filename))
                .build();
        if (containsOverlaps(replacements)) {
          return false;
        }
      }
      return true;
    }

    Set>> entrySet() {
      return Multimaps.asMap(map).entrySet();
    }
  }

  private ApplySuggestedFixes() {}
}