private OwnersMap fetchOwners()

in owners-common/src/main/java/com/googlesource/gerrit/owners/common/PathOwners.java [111:178]
57 lines of code
7 McCabe index (conditional complexity)

  private OwnersMap fetchOwners(String branch) {
    OwnersMap ownersMap = new OwnersMap();
    try {
      String rootPath = "OWNERS";

      PathOwnersEntry projectEntry =
          getOwnersConfig(rootPath, RefNames.REFS_CONFIG)
              .map(
                  conf ->
                      new PathOwnersEntry(
                          rootPath,
                          conf,
                          accounts,
                          Collections.emptySet(),
                          Collections.emptySet(),
                          Collections.emptySet()))
              .orElse(new PathOwnersEntry());

      PathOwnersEntry rootEntry =
          getOwnersConfig(rootPath, branch)
              .map(
                  conf ->
                      new PathOwnersEntry(
                          rootPath,
                          conf,
                          accounts,
                          Collections.emptySet(),
                          Collections.emptySet(),
                          Collections.emptySet()))
              .orElse(new PathOwnersEntry());

      Set<String> modifiedPaths = getModifiedPaths();
      Map<String, PathOwnersEntry> entries = new HashMap<>();
      PathOwnersEntry currentEntry = null;
      for (String path : modifiedPaths) {
        currentEntry = resolvePathEntry(path, branch, projectEntry, rootEntry, entries);

        // add owners and reviewers to file for matcher predicates
        ownersMap.addFileOwners(path, currentEntry.getOwners());
        ownersMap.addFileReviewers(path, currentEntry.getReviewers());

        // Only add the path to the OWNERS file to reduce the number of
        // entries in the result
        if (currentEntry.getOwnersPath() != null) {
          ownersMap.addPathOwners(currentEntry.getOwnersPath(), currentEntry.getOwners());
          ownersMap.addPathReviewers(currentEntry.getOwnersPath(), currentEntry.getReviewers());
        }
        ownersMap.addMatchers(currentEntry.getMatchers());
      }

      // We need to only keep matchers that match files in the patchset
      Map<String, Matcher> matchers = ownersMap.getMatchers();
      if (matchers.size() > 0) {
        HashMap<String, Matcher> newMatchers = Maps.newHashMap();
        // extra loop
        for (String path : modifiedPaths) {
          processMatcherPerPath(matchers, newMatchers, path, ownersMap);
        }
        if (matchers.size() != newMatchers.size()) {
          ownersMap.setMatchers(newMatchers);
        }
      }
      return ownersMap;
    } catch (IOException e) {
      log.warn("Invalid OWNERS file", e);
      return ownersMap;
    }
  }