objectstore/packed: Add initial pack reading support

1 files changed, 96 insertions, 0 deletions

diff --git a/objectstore/packed/helpers_test.go b/objectstore/packed/helpers_test.go
new file mode 100644
index 00000000..5af44f66
--- /dev/null
+++ b/objectstore/packed/helpers_test.go
@@ -0,0 +1,96 @@
+package packed_test
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"testing"
+
+	"codeberg.org/lindenii/furgit/internal/testgit"
+	"codeberg.org/lindenii/furgit/objectheader"
+	"codeberg.org/lindenii/furgit/objectid"
+	"codeberg.org/lindenii/furgit/objectstore/packed"
+	"codeberg.org/lindenii/furgit/objecttype"
+)
+
+func openPackedStore(t *testing.T, repoPath string, algo objectid.Algorithm) *packed.Store {
+	t.Helper()
+	packPath := filepath.Join(repoPath, "objects", "pack")
+	root, err := os.OpenRoot(packPath)
+	if err != nil {
+		t.Fatalf("OpenRoot(%q): %v", packPath, err)
+	}
+	t.Cleanup(func() { _ = root.Close() })
+
+	store, err := packed.New(root, algo)
+	if err != nil {
+		t.Fatalf("packed.New: %v", err)
+	}
+	return store
+}
+
+func mustReadAllAndClose(t *testing.T, reader io.ReadCloser) []byte {
+	t.Helper()
+	data, err := io.ReadAll(reader)
+	if err != nil {
+		_ = reader.Close()
+		t.Fatalf("ReadAll: %v", err)
+	}
+	if err := reader.Close(); err != nil {
+		t.Fatalf("Close: %v", err)
+	}
+	return data
+}
+
+func expectedRawObject(t *testing.T, testRepo *testgit.TestRepo, id objectid.ObjectID) (objecttype.Type, []byte, []byte) {
+	t.Helper()
+
+	typeName := testRepo.Run(t, "cat-file", "-t", id.String())
+	ty, ok := objecttype.ParseName(typeName)
+	if !ok {
+		t.Fatalf("ParseName(%q) failed", typeName)
+	}
+	body := testRepo.CatFile(t, typeName, id)
+	header, ok := objectheader.Encode(ty, int64(len(body)))
+	if !ok {
+		t.Fatalf("objectheader.Encode failed")
+	}
+
+	raw := make([]byte, len(header)+len(body))
+	copy(raw, header)
+	copy(raw[len(header):], body)
+	return ty, body, raw
+}
+
+func createPackedFixtureRepo(t *testing.T, algo objectid.Algorithm) (*testgit.TestRepo, []objectid.ObjectID) {
+	t.Helper()
+
+	testRepo := testgit.NewBareRepo(t, algo)
+	blobID, treeID, commitID := testRepo.MakeCommit(t, "packed store base commit")
+	testRepo.Run(t, "update-ref", "refs/heads/main", commitID.String())
+	tagID := testRepo.TagAnnotated(t, "v1.0.0", commitID, "packed-store-tag")
+
+	parent := commitID
+	for i := range 24 {
+		content := "common-prefix\n" + strings.Repeat("line-"+strconv.Itoa(i%3)+"\n", 256) + fmt.Sprintf("tail-%d\n", i)
+		nextBlob, nextTree := testRepo.MakeSingleFileTree(t, fmt.Sprintf("file-%02d.txt", i), []byte(content))
+		nextCommit := testRepo.CommitTree(t, nextTree, fmt.Sprintf("commit-%02d", i), parent)
+		testRepo.Run(t, "update-ref", "refs/heads/main", nextCommit.String())
+		parent = nextCommit
+
+		_ = nextBlob
+		_ = nextTree
+	}
+
+	testRepo.Repack(t, "-a", "-d", "-f", "--window=64", "--depth=64")
+	return testRepo, []objectid.ObjectID{
+		blobID,
+		treeID,
+		commitID,
+		tagID,
+		parent,
+	}
+}