object: Add interfaces and global parser

2 files changed, 58 insertions, 0 deletions

diff --git a/object/object.go b/object/object.go
new file mode 100644
index 00000000..e4053c93
--- /dev/null
+++ b/object/object.go
@@ -0,0 +1,10 @@
+package object
+
+import "codeberg.org/lindenii/furgit/object/typ"
+
+// Object is a Git object.
+type Object interface {
+	ObjectType() typ.Type
+	AppendWithoutHeader([]byte) ([]byte, error)
+	AppendWithHeader([]byte) ([]byte, error)
+}
diff --git a/object/parse.go b/object/parse.go
new file mode 100644
index 00000000..e1ebb5f8
--- /dev/null
+++ b/object/parse.go
@@ -0,0 +1,48 @@
+package object
+
+import (
+	"fmt"
+
+	"codeberg.org/lindenii/furgit/object/blob"
+	"codeberg.org/lindenii/furgit/object/commit"
+	"codeberg.org/lindenii/furgit/object/header"
+	"codeberg.org/lindenii/furgit/object/id"
+	"codeberg.org/lindenii/furgit/object/tag"
+	"codeberg.org/lindenii/furgit/object/tree"
+	"codeberg.org/lindenii/furgit/object/typ"
+)
+
+// ParseWithHeader parses a loose object in "type size\x00body" format.
+//
+//nolint:ireturn
+func ParseWithHeader(raw []byte, algo id.Algorithm) (Object, error) {
+	ty, size, headerLen, err := header.Parse(raw)
+	if err != nil {
+		return nil, err
+	}
+
+	body := raw[headerLen:]
+	if uint64(len(body)) != size {
+		return nil, fmt.Errorf("object: size mismatch: header says %d bytes, body has %d", size, len(body))
+	}
+
+	return ParseWithoutHeader(ty, body, algo)
+}
+
+// ParseWithoutHeader parses a typed object body.
+//
+//nolint:ireturn
+func ParseWithoutHeader(ty typ.Type, body []byte, algo id.Algorithm) (Object, error) {
+	switch ty {
+	case typ.TypeBlob:
+		return blob.Parse(body)
+	case typ.TypeTree:
+		return tree.Parse(body, algo)
+	case typ.TypeCommit:
+		return commit.Parse(body, algo)
+	case typ.TypeTag:
+		return tag.Parse(body, algo)
+	default:
+		return nil, fmt.Errorf("object: unsupported object type %d", ty)
+	}
+}