// Based on cmd/go's matchPackages function.
	var pkgs []string

	src := filepath.Join(goroot, "src") + string(filepath.Separator)
	walkFn := func(path string, d fs.DirEntry, err error) error {
		if err != nil || !d.IsDir() || path == src {
			return nil
		}

		base := filepath.Base(path)
		if strings.HasPrefix(base, ".") || strings.HasPrefix(base, "_") || base == "testdata" {
			return filepath.SkipDir
		}

	fi, err := os.Stat(s.outdir)
	if err != nil {
		return fmt.Errorf("output directory %q inaccessible (err: %v); no coverage data written", s.outdir, err)
	}
	if !fi.IsDir() {
		return fmt.Errorf("output directory %q not a directory; no coverage data written", s.outdir)
	}

	if (which & metaDataFile) != 0 {
		if err := s.openMetaFile(metaHash, metaLen); err != nil {
			return err

			}
			r.err = err
			return metaCacheEntriesSorted{o: res}, err
		}
		if len(meta.metadata) == 0 {
			metaDataPoolPut(meta.metadata)
			meta.metadata = nil
		}
		if !inclDirs && (meta.isDir() || (!inclVersions && meta.isObjectDir() && meta.isLatestDeletemarker())) {
			continue
		}
		if !inclDeleted && meta.isLatestDeletemarker() && meta.isObject() && !meta.isObjectDir() {
			continue
		}

	// reason.
	rootDir := filepath.Join(gorootTest, "typeparam")
	list, err := os.ReadDir(rootDir)
	if err != nil {
		t.Fatal(err)
	}

	for _, entry := range list {
		if entry.IsDir() || !strings.HasSuffix(entry.Name(), ".go") {
			// For now, only consider standalone go files.
			continue
		}

		t.Run(entry.Name(), func(t *testing.T) {
			filename := filepath.Join(rootDir, entry.Name())

// Stat(), RmDir(), and IsDir() are not needed on Windows CE at this
// time and thus not defined there.
# else
inline int FileNo(FILE* file) { return _fileno(file); }
inline int Stat(const char* path, StatStruct* buf) { return _stat(path, buf); }
inline int RmDir(const char* dir) { return _rmdir(dir); }
inline bool IsDir(const StatStruct& st) {
  return (_S_IFDIR & st.st_mode) != 0;
}

		cmData := map[string][]byte{}
		generatedFiles, err := os.ReadDir(subsetDir)
		if err != nil {
			return err
		}
		for _, file := range generatedFiles {
			if file.IsDir() {
				continue
			}
			cmData[file.Name()], err = os.ReadFile(path.Join(subsetDir, file.Name()))
			if err != nil {
				return err
			}
		}

func (tw *Writer) AddFS(fsys fs.FS) error {
	return fs.WalkDir(fsys, ".", func(name string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() {
			return nil
		}
		info, err := d.Info()
		if err != nil {
			return err
		}
		// TODO(#49580): Handle symlinks when fs.ReadLinkFS is available.
		if !info.Mode().IsRegular() {

					fileCount := 0
					err = filepath.Walk(tmpDir,
						func(path string, info os.FileInfo, err error) error {
							if err != nil {
								return err
							}
							if !info.IsDir() {
								fileCount++
							}
							return nil
						})
					// Check existence of module files. files should be deleted before timing out.
					if err == nil && fileCount == 0 {
						moduleDeleted = true

				globalExpiryState.enqueueByDays(objInfo, evt, lcEventSrc_Rebal)
				return true
			}

			return false
		}

		rebalanceEntry := func(entry metaCacheEntry) {
			defer wk.Give()

			if entry.isDir() {
				return
			}

			// rebalance on poolIdx has reached its goal
			if z.checkIfRebalanceDone(poolIdx) {
				return
			}

			fivs, err := entry.fileInfoVersions(bucket)
			if err != nil {

// network file systems and may not suffice to protect the cache.
func Open(dir string) (*DiskCache, error) {
	info, err := os.Stat(dir)
	if err != nil {
		return nil, err
	}
	if !info.IsDir() {
		return nil, &fs.PathError{Op: "open", Path: dir, Err: fmt.Errorf("not a directory")}
	}
	for i := 0; i < 256; i++ {
		name := filepath.Join(dir, fmt.Sprintf("%02x", i))