From 4e3357b476690e02945316519c7804e7f07ccb1b Mon Sep 17 00:00:00 2001
From: Runxi Yu
Date: Wed, 4 Mar 2026 14:36:33 +0800
Subject: objectstore/chain: Add an actual chain object store

---
 objectstore/chain/reader.go | 55 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 objectstore/chain/reader.go

(limited to 'objectstore/chain/reader.go')

diff --git a/objectstore/chain/reader.go b/objectstore/chain/reader.go
new file mode 100644
index 00000000..e005d929
--- /dev/null
+++ b/objectstore/chain/reader.go
@@ -0,0 +1,55 @@
+package chain
+
+import (
+	"errors"
+	"fmt"
+	"io"
+
+	"codeberg.org/lindenii/furgit/objectid"
+	"codeberg.org/lindenii/furgit/objectstore"
+	"codeberg.org/lindenii/furgit/objecttype"
+)
+
+// ReadReaderFull reads a full serialized object stream from the first backend that has it.
+func (chain *Chain) ReadReaderFull(id objectid.ObjectID) (io.ReadCloser, error) {
+	for i, backend := range chain.backends {
+		if backend == nil {
+			continue
+		}
+
+		reader, err := backend.ReadReaderFull(id)
+		if err == nil {
+			return reader, nil
+		}
+
+		if errors.Is(err, objectstore.ErrObjectNotFound) {
+			continue
+		}
+
+		return nil, fmt.Errorf("objectstore: backend %d read reader full: %w", i, err)
+	}
+
+	return nil, objectstore.ErrObjectNotFound
+}
+
+// ReadReaderContent reads an object's type, declared content length, and content stream from the first backend that has it.
+func (chain *Chain) ReadReaderContent(id objectid.ObjectID) (objecttype.Type, int64, io.ReadCloser, error) {
+	for i, backend := range chain.backends {
+		if backend == nil {
+			continue
+		}
+
+		ty, size, reader, err := backend.ReadReaderContent(id)
+		if err == nil {
+			return ty, size, reader, nil
+		}
+
+		if errors.Is(err, objectstore.ErrObjectNotFound) {
+			continue
+		}
+
+		return objecttype.TypeInvalid, 0, nil, fmt.Errorf("objectstore: backend %d read reader content: %w", i, err)
+	}
+
+	return objecttype.TypeInvalid, 0, nil, objectstore.ErrObjectNotFound
+}
-- 
cgit v1.3.1-10-gc9f91