From ae879b8cf5a87199802a33d6b15c76afafa8002b Mon Sep 17 00:00:00 2001
From: Runxi Yu
Date: Sat, 21 Feb 2026 05:35:12 +0800
Subject: objectstore/packed: Add initial pack reading support

---
 objectstore/packed/read_reader.go | 93 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100644 objectstore/packed/read_reader.go

(limited to 'objectstore/packed/read_reader.go')

diff --git a/objectstore/packed/read_reader.go b/objectstore/packed/read_reader.go
new file mode 100644
index 00000000..4f40792d
--- /dev/null
+++ b/objectstore/packed/read_reader.go
@@ -0,0 +1,93 @@
+package packed
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+
+	"codeberg.org/lindenii/furgit/objectheader"
+	"codeberg.org/lindenii/furgit/objectid"
+	"codeberg.org/lindenii/furgit/objecttype"
+)
+
+// readCloser proxies reads and closes one underlying closer.
+type readCloser struct {
+	reader io.Reader
+	closer io.Closer
+}
+
+// Read proxies reads to the underlying reader.
+func (reader *readCloser) Read(dst []byte) (int, error) {
+	return reader.reader.Read(dst)
+}
+
+// Close closes the underlying closer.
+func (reader *readCloser) Close() error {
+	return reader.closer.Close()
+}
+
+// ReadReaderContent reads an object's type, declared content size, and content stream.
+//
+// The caller must close the returned reader.
+func (store *Store) ReadReaderContent(id objectid.ObjectID) (objecttype.Type, int64, io.ReadCloser, error) {
+	loc, err := store.lookup(id)
+	if err != nil {
+		return objecttype.TypeInvalid, 0, nil, err
+	}
+
+	pack, meta, err := store.entryMetaAt(loc)
+	if err != nil {
+		return objecttype.TypeInvalid, 0, nil, err
+	}
+	if isBaseObjectType(meta.ty) {
+		zr, err := zlibReaderAt(pack, meta.dataOffset)
+		if err != nil {
+			return objecttype.TypeInvalid, 0, nil, err
+		}
+		return meta.ty, meta.size, &readCloser{
+			reader: io.LimitReader(zr, meta.size),
+			closer: zr,
+		}, nil
+	}
+
+	ty, content, err := store.deltaResolveContent(loc)
+	if err != nil {
+		return objecttype.TypeInvalid, 0, nil, err
+	}
+	return ty, int64(len(content)), io.NopCloser(bytes.NewReader(content)), nil
+}
+
+// ReadReaderFull reads a full serialized object stream as "type size\0content".
+//
+// The caller must close the returned reader.
+func (store *Store) ReadReaderFull(id objectid.ObjectID) (io.ReadCloser, error) {
+	loc, err := store.lookup(id)
+	if err != nil {
+		return nil, err
+	}
+
+	pack, meta, err := store.entryMetaAt(loc)
+	if err != nil {
+		return nil, err
+	}
+	if isBaseObjectType(meta.ty) {
+		header, ok := objectheader.Encode(meta.ty, meta.size)
+		if !ok {
+			return nil, fmt.Errorf("objectstore/packed: failed to encode object header for type %d", meta.ty)
+		}
+		zr, err := zlibReaderAt(pack, meta.dataOffset)
+		if err != nil {
+			return nil, err
+		}
+		return &readCloser{
+			reader: io.MultiReader(bytes.NewReader(header), io.LimitReader(zr, meta.size)),
+			closer: zr,
+		}, nil
+	}
+
+	raw, err := store.ReadBytesFull(id)
+	if err != nil {
+		return nil, err
+	}
+	return io.NopCloser(bytes.NewReader(raw)), nil
+}
-- 
cgit v1.3.1-10-gc9f91