feat: fs utils

pkg/filesystem/util.go

@@ -0,0 +1,99 @@
+package filesystem
+
+import (
+	"context"
+	"errors"
+	"io/fs"
+	"os"
+	"path"
+	"sort"
+)
+
+var (
+	SkipDir = fs.SkipDir
+	SkipAll = fs.SkipAll
+)
+
+func WalkDir(ctx context.Context, fsys FileSystem, root string, fn func(path string, d fs.DirEntry, err error) error) error {
+	info, err := Stat(ctx, fsys, root)
+	if err != nil {
+		err = fn(root, nil, err)
+	} else {
+		err = walkDir(ctx, fsys, root, &statDirEntry{info}, fn)
+	}
+	if errors.Is(err, SkipDir) || errors.Is(err, SkipAll) {
+		return nil
+	}
+	return err
+}
+
+func Stat(ctx context.Context, fsys FileSystem, name string) (FileInfo, error) {
+	file, err := fsys.OpenFile(ctx, name, os.O_RDONLY, os.ModePerm)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+	return file.Stat()
+}
+
+func ReadDir(ctx context.Context, fsys FileSystem, name string) ([]os.DirEntry, error) {
+	file, err := fsys.OpenFile(ctx, name, os.O_RDONLY, os.ModePerm)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	dir, ok := file.(fs.ReadDirFile)
+	if !ok {
+		return nil, &fs.PathError{Op: "readdir", Path: name, Err: errors.New("not implemented")}
+	}
+
+	list, err := dir.ReadDir(-1)
+	sort.Slice(list, func(i, j int) bool { return list[i].Name() < list[j].Name() })
+	return list, err
+}
+
+func walkDir(ctx context.Context, fsys FileSystem, name string, d fs.DirEntry, walkDirFn fs.WalkDirFunc) error {
+	if err := walkDirFn(name, d, nil); err != nil || !d.IsDir() {
+		if errors.Is(err, SkipDir) && d.IsDir() {
+			// Successfully skipped directory.
+			err = nil
+		}
+		return err
+	}
+
+	dirs, err := ReadDir(ctx, fsys, name)
+	if err != nil {
+		// Second call, to report ReadDir error.
+		err = walkDirFn(name, d, err)
+		if err != nil {
+			if errors.Is(err, SkipDir) && d.IsDir() {
+				err = nil
+			}
+			return err
+		}
+	}
+
+	for _, d1 := range dirs {
+		name1 := path.Join(name, d1.Name())
+		if err := walkDir(ctx, fsys, name1, d1, walkDirFn); err != nil {
+			if errors.Is(err, SkipDir) {
+				break
+			}
+			return err
+		}
+	}
+	return nil
+}
+
+type statDirEntry struct {
+	info FileInfo
+}
+
+func (d *statDirEntry) Name() string            { return d.info.Name() }
+func (d *statDirEntry) IsDir() bool             { return d.info.IsDir() }
+func (d *statDirEntry) Type() fs.FileMode       { return d.info.Mode().Type() }
+func (d *statDirEntry) Info() (FileInfo, error) { return d.info, nil }
+func (d *statDirEntry) String() string {
+	return fs.FormatDirEntry(d)
+}