object/store/packed: Start the internal/reading split

1 files changed, 52 insertions, 0 deletions

diff --git a/object/store/packed/internal/reading/store.go b/object/store/packed/internal/reading/store.go
new file mode 100644
index 00000000..cb4829ab
--- /dev/null
+++ b/object/store/packed/internal/reading/store.go
@@ -0,0 +1,52 @@
+package reading
+
+import (
+	"os"
+	"sync"
+	"sync/atomic"
+
+	objectid "codeberg.org/lindenii/furgit/object/id"
+	objectstore "codeberg.org/lindenii/furgit/object/store"
+)
+
+// Store reads Git objects from pack/index files under an objects/pack root.
+//
+// Cached pack/index mappings are retained until Close.
+//
+// Labels: Close-Caller.
+type Store struct {
+	// root is the borrowed objects/pack capability used for all file access.
+	root *os.Root
+	// algo is the expected object ID algorithm for lookups.
+	algo objectid.Algorithm
+	// refreshPolicy controls automatic candidate refresh on lookup misses.
+	refreshPolicy RefreshPolicy
+
+	// candidates stores the latest immutable candidate snapshot.
+	candidates atomic.Pointer[candidateSnapshot]
+	// refreshMu serializes candidate refresh.
+	refreshMu sync.Mutex
+	// mruMu guards candidate MRU linked-list state.
+	mruMu sync.RWMutex
+	// mruHead is the first pack in MRU order.
+	mruHead *packCandidateNode
+	// mruTail is the last pack in MRU order.
+	mruTail *packCandidateNode
+	// mruNodeByPack maps pack basename to MRU node.
+	mruNodeByPack map[string]*packCandidateNode
+	// idxByPack caches opened and parsed indexes by pack basename.
+	idxByPack map[string]*idxFile
+
+	// stateMu guards pack cache and close state.
+	stateMu sync.RWMutex
+	// idxMu guards parsed index cache.
+	idxMu sync.RWMutex
+	// cacheMu guards delta cache operations.
+	cacheMu sync.RWMutex
+	// packs caches opened .pack handles by basename.
+	packs map[string]*packFile
+	// deltaCache caches resolved base objects by pack location.
+	deltaCache *deltaCache
+}
+
+var _ objectstore.Reader = (*Store)(nil)