feat: support explicit instance data deletion

internal/platform/files/instance_data_remover.go

@@ -0,0 +1,77 @@
+package files
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+var (
+	ErrUnsafeInstanceDataDirectory = errors.New("unsafe instance data directory")
+	ErrInstanceDataNotDirectory    = errors.New("instance data path is not a directory")
+)
+
+// InstanceDataRemover deletes one explicitly authorized browser User Data Dir.
+// Callers must check browser occupancy before invoking it.
+type InstanceDataRemover interface {
+	RemoveInstanceData(context.Context, string) error
+}
+
+type instanceDataRemover struct {
+	lstat     func(string) (os.FileInfo, error)
+	removeAll func(string) error
+}
+
+func NewInstanceDataRemover() InstanceDataRemover {
+	return newInstanceDataRemover(os.Lstat, os.RemoveAll)
+}
+
+func newInstanceDataRemover(lstat func(string) (os.FileInfo, error), removeAll func(string) error) instanceDataRemover {
+	return instanceDataRemover{lstat: lstat, removeAll: removeAll}
+}
+
+func (r instanceDataRemover) RemoveInstanceData(ctx context.Context, userDataDir string) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	path, err := normalizeRemovableInstanceDataDir(userDataDir)
+	if err != nil {
+		return err
+	}
+	info, err := r.lstat(path)
+	if errors.Is(err, os.ErrNotExist) {
+		return nil
+	}
+	if err != nil {
+		return fmt.Errorf("inspect instance data directory: %w", err)
+	}
+	if info.Mode()&(os.ModeSymlink|os.ModeIrregular) != 0 || isReparsePoint(info) {
+		return fmt.Errorf("%w: links and reparse points are not removable", ErrUnsafeInstanceDataDirectory)
+	}
+	if !info.IsDir() {
+		return ErrInstanceDataNotDirectory
+	}
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	if err := r.removeAll(path); err != nil {
+		return fmt.Errorf("remove instance data directory: %w", err)
+	}
+	return nil
+}
+
+func normalizeRemovableInstanceDataDir(value string) (string, error) {
+	value = strings.TrimSpace(value)
+	if value == "" || !filepath.IsAbs(value) {
+		return "", fmt.Errorf("%w: path must be absolute", ErrUnsafeInstanceDataDirectory)
+	}
+	path := filepath.Clean(value)
+	volumeRoot := filepath.Clean(filepath.VolumeName(path) + string(filepath.Separator))
+	if strings.EqualFold(path, volumeRoot) {
+		return "", fmt.Errorf("%w: volume root is not removable", ErrUnsafeInstanceDataDirectory)
+	}
+	return path, nil
+}