feat: support context cancellation in file store (#803)

Closes #619

---------

Signed-off-by: Lucas Rodriguez <lucas.rodriguez9616@gmail.com>

content/file/file.go

@@ -395,7 +395,7 @@ func (s *Store) Predecessors(ctx context.Context, node ocispec.Descriptor) ([]oc
 }
 
 // Add adds a file into the file store.
-func (s *Store) Add(_ context.Context, name, mediaType, path string) (ocispec.Descriptor, error) {
+func (s *Store) Add(ctx context.Context, name, mediaType, path string) (ocispec.Descriptor, error) {
 	if s.isClosedSet() {
 		return ocispec.Descriptor{}, ErrStoreClosed
 	}
@@ -426,7 +426,7 @@ func (s *Store) Add(_ context.Context, name, mediaType, path string) (ocispec.De
 	// generate descriptor
 	var desc ocispec.Descriptor
 	if fi.IsDir() {
-		desc, err = s.descriptorFromDir(name, mediaType, path)
+		desc, err = s.descriptorFromDir(ctx, name, mediaType, path)
 	} else {
 		desc, err = s.descriptorFromFile(fi, mediaType, path)
 	}
@@ -505,7 +505,7 @@ func (s *Store) pushDir(name, target string, expected ocispec.Descriptor, conten
 }
 
 // descriptorFromDir generates descriptor from the given directory.
-func (s *Store) descriptorFromDir(name, mediaType, dir string) (desc ocispec.Descriptor, err error) {
+func (s *Store) descriptorFromDir(ctx context.Context, name, mediaType, dir string) (desc ocispec.Descriptor, err error) {
 	// make a temp file to store the gzip
 	gz, err := s.tempFile()
 	if err != nil {
@@ -532,7 +532,7 @@ func (s *Store) descriptorFromDir(name, mediaType, dir string) (desc ocispec.Des
 	tw := io.MultiWriter(gzw, tarDigester.Hash())
 	buf := bufPool.Get().(*[]byte)
 	defer bufPool.Put(buf)
-	if err := tarDirectory(dir, name, tw, s.TarReproducible, *buf); err != nil {
+	if err := tarDirectory(ctx, dir, name, tw, s.TarReproducible, *buf); err != nil {
 		return ocispec.Descriptor{}, fmt.Errorf("failed to tar %s: %w", dir, err)
 	}
 

content/file/utils.go

@@ -18,6 +18,7 @@ package file
 import (
 	"archive/tar"
 	"compress/gzip"
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -31,7 +32,7 @@ import (
 
 // tarDirectory walks the directory specified by path, and tar those files with a new
 // path prefix.
-func tarDirectory(root, prefix string, w io.Writer, removeTimes bool, buf []byte) (err error) {
+func tarDirectory(ctx context.Context, root, prefix string, w io.Writer, removeTimes bool, buf []byte) (err error) {
 	tw := tar.NewWriter(w)
 	defer func() {
 		closeErr := tw.Close()
@@ -45,6 +46,12 @@ func tarDirectory(root, prefix string, w io.Writer, removeTimes bool, buf []byte
 			return err
 		}
 
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+		}
+
 		// Rename path
 		name, err := filepath.Rel(root, path)
 		if err != nil {

content/file/utils_test.go

@@ -16,11 +16,89 @@ limitations under the License.
 package file
 
 import (
+	"compress/gzip"
+	"context"
+	"errors"
 	"os"
 	"path/filepath"
 	"testing"
 )
 
+func Test_tarDirectory(t *testing.T) {
+	setup := func(t *testing.T) (tmpdir string, gz *os.File, gw *gzip.Writer) {
+		tmpdir = t.TempDir()
+
+		paths := []string{
+			filepath.Join(tmpdir, "file1.txt"),
+			filepath.Join(tmpdir, "file2.txt"),
+		}
+
+		for _, p := range paths {
+			err := os.WriteFile(p, []byte("test content"), 0644)
+			if err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		gz, err := os.CreateTemp(tmpdir, "tarDirectory-*")
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		return tmpdir, gz, gzip.NewWriter(gz)
+	}
+
+	t.Run("success", func(t *testing.T) {
+		tmpdir, gz, gw := setup(t)
+		defer func() {
+			if err := gw.Close(); err != nil {
+				t.Fatal(err)
+			}
+			if err := gz.Close(); err != nil {
+				t.Fatal(err)
+			}
+		}()
+
+		err := tarDirectory(context.Background(), tmpdir, "prefix", gw, false, nil)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		_, err = gz.Stat()
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+
+	t.Run("context cancellation", func(t *testing.T) {
+		tmpdir, gz, gw := setup(t)
+		defer func() {
+			if err := gw.Close(); err != nil {
+				t.Fatal(err)
+			}
+			if err := gz.Close(); err != nil {
+				t.Fatal(err)
+			}
+		}()
+
+		ctx, cancel := context.WithCancel(context.Background())
+		cancel()
+
+		err := tarDirectory(ctx, tmpdir, "prefix", gw, false, nil)
+		if err == nil {
+			t.Fatal("expected context cancellation error, got nil")
+		}
+		if !errors.Is(err, context.Canceled) {
+			t.Fatalf("expected context.Canceled error, got %v", err)
+		}
+
+		_, err = gz.Stat()
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+}
+
 func Test_ensureBasePath(t *testing.T) {
 	root := t.TempDir()
 	if err := os.MkdirAll(filepath.Join(root, "hello world", "foo", "bar"), 0700); err != nil {