From 4a796e64ac576d6a3e3f2fe6174c4aa476ea0c5c Mon Sep 17 00:00:00 2001
From: Runxi Yu
Date: Mon, 23 Mar 2026 03:25:44 +0000
Subject: refstore: Improve interfaces, errors, and make batch work

---
 refstore/files/update_lock_packed.go | 44 ++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 refstore/files/update_lock_packed.go

(limited to 'refstore/files/update_lock_packed.go')

diff --git a/refstore/files/update_lock_packed.go b/refstore/files/update_lock_packed.go
new file mode 100644
index 00000000..f74a4f5e
--- /dev/null
+++ b/refstore/files/update_lock_packed.go
@@ -0,0 +1,44 @@
+package files
+
+import (
+	"errors"
+	"os"
+	"time"
+)
+
+func (executor *refUpdateExecutor) createPackedRefsLock(timeout time.Duration) error {
+	const (
+		initialBackoffMs     = 1
+		backoffMaxMultiplier = 1000
+	)
+
+	deadline := time.Now().Add(timeout)
+	multiplier := 1
+	n := 1
+
+	for {
+		file, err := executor.store.commonRoot.OpenFile("packed-refs.lock", os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o644)
+		if err == nil {
+			return file.Close()
+		}
+
+		if !errors.Is(err, os.ErrExist) {
+			return err
+		}
+
+		if timeout == 0 || (timeout > 0 && time.Now().After(deadline)) {
+			return err
+		}
+
+		backoffMs := multiplier * initialBackoffMs
+		waitMs := (750 + executor.store.lockRand.Intn(500)) * backoffMs / 1000
+		time.Sleep(time.Duration(waitMs) * time.Millisecond)
+
+		multiplier += 2*n + 1
+		if multiplier > backoffMaxMultiplier {
+			multiplier = backoffMaxMultiplier
+		} else {
+			n++
+		}
+	}
+}
-- 
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