feat: add durable client command spool

internal/client/spool/lock_windows.go

@@ -0,0 +1,58 @@
+//go:build windows
+
+package spool
+
+import (
+	"os"
+
+	"golang.org/x/sys/windows"
+)
+
+func acquireInstanceLock(path string) (func() error, error) {
+	if err := ensurePrivateFile(path); err != nil {
+		return nil, err
+	}
+	file, err := os.OpenFile(path, os.O_RDWR, 0)
+	if err != nil {
+		return nil, err
+	}
+	var overlapped windows.Overlapped
+	err = windows.LockFileEx(windows.Handle(file.Fd()), windows.LOCKFILE_EXCLUSIVE_LOCK|windows.LOCKFILE_FAIL_IMMEDIATELY, 0, 1, 0, &overlapped)
+	if err != nil {
+		_ = file.Close()
+		return nil, ErrAlreadyOpen
+	}
+	return func() error {
+		unlockErr := windows.UnlockFileEx(windows.Handle(file.Fd()), 0, 1, 0, &overlapped)
+		closeErr := file.Close()
+		if unlockErr != nil {
+			return unlockErr
+		}
+		return closeErr
+	}, nil
+}
+
+func syncDirectory(path string) error {
+	value, err := windows.UTF16PtrFromString(path)
+	if err != nil {
+		return err
+	}
+	handle, err := windows.CreateFile(value, windows.GENERIC_READ, windows.FILE_SHARE_READ|windows.FILE_SHARE_WRITE|windows.FILE_SHARE_DELETE, nil, windows.OPEN_EXISTING, windows.FILE_FLAG_BACKUP_SEMANTICS, 0)
+	if err != nil {
+		return err
+	}
+	defer windows.CloseHandle(handle)
+	return windows.FlushFileBuffers(handle)
+}
+
+func replaceIdentityFile(temporaryPath, targetPath string) error {
+	from, err := windows.UTF16PtrFromString(temporaryPath)
+	if err != nil {
+		return err
+	}
+	to, err := windows.UTF16PtrFromString(targetPath)
+	if err != nil {
+		return err
+	}
+	return windows.MoveFileEx(from, to, windows.MOVEFILE_REPLACE_EXISTING|windows.MOVEFILE_WRITE_THROUGH)
+}