chore(tvix): move store golang bindings to tvix/store-go

Similar to the castore-go CL before, this also updates the store-go
bindings to the new layout.

Change-Id: Id73d7ad43f7d70171ab021728e303300c5db71f0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9788
Tested-by: BuildkiteCI
Reviewed-by: Connor Brewster <cbrewster@hey.com>

tvix/store-go/export_test.go

@@ -0,0 +1,134 @@
+package storev1_test
+
+import (
+	"bytes"
+	"io"
+	"os"
+	"testing"
+
+	castorev1pb "code.tvl.fyi/tvix/castore/protos"
+	storev1pb "code.tvl.fyi/tvix/store/protos"
+	"github.com/stretchr/testify/require"
+)
+
+func mustDirectoryDigest(d *castorev1pb.Directory) []byte {
+	dgst, err := d.Digest()
+	if err != nil {
+		panic(err)
+	}
+	return dgst
+}
+
+func TestSymlink(t *testing.T) {
+	node := &castorev1pb.Node{
+		Node: &castorev1pb.Node_Symlink{
+			Symlink: &castorev1pb.SymlinkNode{
+				Name:   []byte("doesntmatter"),
+				Target: []byte("/nix/store/somewhereelse"),
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+
+	err := storev1pb.Export(&buf, node, func([]byte) (*castorev1pb.Directory, error) {
+		panic("no directories expected")
+	}, func([]byte) (io.ReadCloser, error) {
+		panic("no files expected")
+	})
+	require.NoError(t, err, "exporter shouldn't fail")
+
+	f, err := os.Open("testdata/symlink.nar")
+	require.NoError(t, err)
+
+	bytesExpected, err := io.ReadAll(f)
+	if err != nil {
+		panic(err)
+	}
+
+	require.Equal(t, bytesExpected, buf.Bytes(), "expected nar contents to match")
+}
+
+func TestRegular(t *testing.T) {
+	// The blake3 digest of the 0x01 byte.
+	BLAKE3_DIGEST_0X01 := []byte{
+		0x48, 0xfc, 0x72, 0x1f, 0xbb, 0xc1, 0x72, 0xe0, 0x92, 0x5f, 0xa2, 0x7a, 0xf1, 0x67, 0x1d,
+		0xe2, 0x25, 0xba, 0x92, 0x71, 0x34, 0x80, 0x29, 0x98, 0xb1, 0x0a, 0x15, 0x68, 0xa1, 0x88,
+		0x65, 0x2b,
+	}
+
+	node := &castorev1pb.Node{
+		Node: &castorev1pb.Node_File{
+			File: &castorev1pb.FileNode{
+				Name:       []byte("doesntmatter"),
+				Digest:     BLAKE3_DIGEST_0X01,
+				Size:       1,
+				Executable: false,
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+
+	err := storev1pb.Export(&buf, node, func([]byte) (*castorev1pb.Directory, error) {
+		panic("no directories expected")
+	}, func(blobRef []byte) (io.ReadCloser, error) {
+		if !bytes.Equal(blobRef, BLAKE3_DIGEST_0X01) {
+			panic("unexpected blobref")
+		}
+		return io.NopCloser(bytes.NewBuffer([]byte{0x01})), nil
+	})
+	require.NoError(t, err, "exporter shouldn't fail")
+
+	f, err := os.Open("testdata/onebyteregular.nar")
+	require.NoError(t, err)
+
+	bytesExpected, err := io.ReadAll(f)
+	if err != nil {
+		panic(err)
+	}
+
+	require.Equal(t, bytesExpected, buf.Bytes(), "expected nar contents to match")
+}
+
+func TestEmptyDirectory(t *testing.T) {
+	// construct empty directory node this refers to
+	emptyDirectory := &castorev1pb.Directory{
+		Directories: []*castorev1pb.DirectoryNode{},
+		Files:       []*castorev1pb.FileNode{},
+		Symlinks:    []*castorev1pb.SymlinkNode{},
+	}
+	emptyDirectoryDigest := mustDirectoryDigest(emptyDirectory)
+
+	node := &castorev1pb.Node{
+		Node: &castorev1pb.Node_Directory{
+			Directory: &castorev1pb.DirectoryNode{
+				Name:   []byte("doesntmatter"),
+				Digest: emptyDirectoryDigest,
+				Size:   0,
+			},
+		},
+	}
+
+	var buf bytes.Buffer
+
+	err := storev1pb.Export(&buf, node, func(directoryRef []byte) (*castorev1pb.Directory, error) {
+		if !bytes.Equal(directoryRef, emptyDirectoryDigest) {
+			panic("unexpected directoryRef")
+		}
+		return emptyDirectory, nil
+	}, func([]byte) (io.ReadCloser, error) {
+		panic("no files expected")
+	})
+	require.NoError(t, err, "exporter shouldn't fail")
+
+	f, err := os.Open("testdata/emptydirectory.nar")
+	require.NoError(t, err)
+
+	bytesExpected, err := io.ReadAll(f)
+	if err != nil {
+		panic(err)
+	}
+
+	require.Equal(t, bytesExpected, buf.Bytes(), "expected nar contents to match")
+}