*: objectstore -> object/store

1 files changed, 37 insertions, 0 deletions

diff --git a/object/store/loose/read_header.go b/object/store/loose/read_header.go
new file mode 100644
index 00000000..37bf40de
--- /dev/null
+++ b/object/store/loose/read_header.go
@@ -0,0 +1,37 @@
+package loose
+
+import (
+	"bufio"
+
+	"codeberg.org/lindenii/furgit/internal/compress/zlib"
+	objectid "codeberg.org/lindenii/furgit/object/id"
+	objecttype "codeberg.org/lindenii/furgit/object/type"
+)
+
+// ReadHeader reads an object's type and declared content length.
+//
+// It parses only enough of the zlib-decoded object to recover the object
+// header. It does not verify that the remaining object content is readable and
+// does not verify the zlib Adler-32 trailer.
+func (store *Store) ReadHeader(id objectid.ObjectID) (objecttype.Type, int64, error) {
+	file, err := store.openObject(id)
+	if err != nil {
+		return objecttype.TypeInvalid, 0, err
+	}
+
+	defer func() { _ = file.Close() }()
+
+	zr, err := zlib.NewReader(file)
+	if err != nil {
+		return objecttype.TypeInvalid, 0, err
+	}
+
+	defer func() { _ = zr.Close() }()
+
+	_, ty, size, err := readHeader(bufio.NewReader(zr))
+	if err != nil {
+		return objecttype.TypeInvalid, 0, err
+	}
+
+	return ty, size, nil
+}