// returns list of resolved files if updated successfully, or null if write action or dumb mode
  // started
  private int[] processFile(
      @NotNull final VirtualFile file, int fileId, @NotNull final ProgressIndicator indicator) {
    final TIntHashSet forward;
    try {
      forward = calcForwardRefs(file, indicator);
    } catch (IndexNotReadyException e) {
      return null;
    } catch (ApplicationUtil.CannotRunReadActionException e) {
      return null;
    } catch (ProcessCanceledException e) {
      throw e;
    } catch (Exception e) {
      log(ExceptionUtil.getThrowableText(e));
      flushLog();
      return null;
    }

    int[] forwardIds = forward.toArray();
    fileIsResolved.set(fileId);
    logf(
        "  ---- " + file.getPresentableUrl() + " processed. forwardIds: " + toVfString(forwardIds));
    for (Listener listener : myListeners) {
      listener.fileResolved(file);
    }
    return forwardIds;
  }
  private void processBatch(
      @NotNull final ProgressIndicator indicator, @NotNull Set<VirtualFile> files) {
    assert !myApplication.isDispatchThread();
    final int resolvedInPreviousBatch = this.resolvedInPreviousBatch;
    final int totalSize = files.size() + resolvedInPreviousBatch;
    final ConcurrentIntObjectMap<int[]> fileToForwardIds =
        ContainerUtil.createConcurrentIntObjectMap();
    final Set<VirtualFile> toProcess = Collections.synchronizedSet(files);
    indicator.setIndeterminate(false);
    ProgressIndicatorUtils.forceWriteActionPriority(indicator, (Disposable) indicator);
    long start = System.currentTimeMillis();
    Processor<VirtualFile> processor =
        file -> {
          double fraction = 1 - toProcess.size() * 1.0 / totalSize;
          indicator.setFraction(fraction);
          try {
            if (!file.isDirectory() && toResolve(file, myProject)) {
              int fileId = getAbsId(file);
              int i = totalSize - toProcess.size();
              indicator.setText(i + "/" + totalSize + ": Resolving " + file.getPresentableUrl());
              int[] forwardIds = processFile(file, fileId, indicator);
              if (forwardIds == null) {
                // queueUpdate(file);
                return false;
              }
              fileToForwardIds.put(fileId, forwardIds);
            }
            toProcess.remove(file);
            return true;
          } catch (RuntimeException e) {
            indicator.checkCanceled();
          }
          return true;
        };
    boolean success = true;
    try {
      success = processFilesConcurrently(files, indicator, processor);
    } finally {
      this.resolvedInPreviousBatch = toProcess.isEmpty() ? 0 : totalSize - toProcess.size();
      queue(toProcess, "re-added after fail. success=" + success);
      storeIds(fileToForwardIds);

      long end = System.currentTimeMillis();
      log(
          "Resolved batch of "
              + (totalSize - toProcess.size())
              + " from "
              + totalSize
              + " files in "
              + ((end - start) / 1000)
              + "sec. (Gap: "
              + storage.gap
              + ")");
      synchronized (filesToResolve) {
        upToDate = filesToResolve.isEmpty();
        log("upToDate = " + upToDate);
        if (upToDate) {
          for (Listener listener : myListeners) {
            listener.allFilesResolved();
          }
        }
      }
    }
  }