Update gomod and vendor

vendor/github.com/moby/buildkit/cache/util/fsutil.go

@@ -0,0 +1,139 @@
+package util
+
+import (
+	"context"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"github.com/containerd/continuity/fs"
+	"github.com/moby/buildkit/cache"
+	"github.com/moby/buildkit/snapshot"
+	"github.com/pkg/errors"
+	"github.com/tonistiigi/fsutil"
+	fstypes "github.com/tonistiigi/fsutil/types"
+)
+
+type ReadRequest struct {
+	Filename string
+	Range    *FileRange
+}
+
+type FileRange struct {
+	Offset int
+	Length int
+}
+
+func withMount(ctx context.Context, ref cache.ImmutableRef, cb func(string) error) error {
+	mount, err := ref.Mount(ctx, true)
+	if err != nil {
+		return err
+	}
+
+	lm := snapshot.LocalMounter(mount)
+
+	root, err := lm.Mount()
+	if err != nil {
+		return err
+	}
+
+	defer func() {
+		if lm != nil {
+			lm.Unmount()
+		}
+	}()
+
+	if err := cb(root); err != nil {
+		return err
+	}
+
+	if err := lm.Unmount(); err != nil {
+		return err
+	}
+	lm = nil
+	return nil
+}
+
+func ReadFile(ctx context.Context, ref cache.ImmutableRef, req ReadRequest) ([]byte, error) {
+	var dt []byte
+
+	err := withMount(ctx, ref, func(root string) error {
+		fp, err := fs.RootPath(root, req.Filename)
+		if err != nil {
+			return errors.WithStack(err)
+		}
+
+		if req.Range == nil {
+			dt, err = ioutil.ReadFile(fp)
+			if err != nil {
+				return errors.WithStack(err)
+			}
+		} else {
+			f, err := os.Open(fp)
+			if err != nil {
+				return errors.WithStack(err)
+			}
+			dt, err = ioutil.ReadAll(io.NewSectionReader(f, int64(req.Range.Offset), int64(req.Range.Length)))
+			f.Close()
+			if err != nil {
+				return errors.WithStack(err)
+			}
+		}
+		return nil
+	})
+	return dt, err
+}
+
+type ReadDirRequest struct {
+	Path           string
+	IncludePattern string
+}
+
+func ReadDir(ctx context.Context, ref cache.ImmutableRef, req ReadDirRequest) ([]*fstypes.Stat, error) {
+	var (
+		rd []*fstypes.Stat
+		wo fsutil.WalkOpt
+	)
+	if req.IncludePattern != "" {
+		wo.IncludePatterns = append(wo.IncludePatterns, req.IncludePattern)
+	}
+	err := withMount(ctx, ref, func(root string) error {
+		fp, err := fs.RootPath(root, req.Path)
+		if err != nil {
+			return errors.WithStack(err)
+		}
+		return fsutil.Walk(ctx, fp, &wo, func(path string, info os.FileInfo, err error) error {
+			if err != nil {
+				return errors.Wrapf(err, "walking %q", root)
+			}
+			stat, ok := info.Sys().(*fstypes.Stat)
+			if !ok {
+				// This "can't happen(tm)".
+				return errors.Errorf("expected a *fsutil.Stat but got %T", info.Sys())
+			}
+			rd = append(rd, stat)
+
+			if info.IsDir() {
+				return filepath.SkipDir
+			}
+			return nil
+		})
+	})
+	return rd, err
+}
+
+func StatFile(ctx context.Context, ref cache.ImmutableRef, path string) (*fstypes.Stat, error) {
+	var st *fstypes.Stat
+	err := withMount(ctx, ref, func(root string) error {
+		fp, err := fs.RootPath(root, path)
+		if err != nil {
+			return errors.WithStack(err)
+		}
+		if st, err = fsutil.Stat(fp); err != nil {
+			return errors.WithStack(err)
+		}
+		return nil
+	})
+	return st, err
+}