From 90021e1d335efac1017562c1d5dee43e99580319 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Roman=20Smr=C5=BE?= <roman.smrz@seznam.cz>
Date: Wed, 22 Jul 2020 22:13:33 +0200
Subject: Local and shared state

---
 include/erebos/state.h | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 include/erebos/state.h

(limited to 'include/erebos/state.h')

diff --git a/include/erebos/state.h b/include/erebos/state.h
new file mode 100644
index 0000000..543e03c
--- /dev/null
+++ b/include/erebos/state.h
@@ -0,0 +1,55 @@
+#pragma once
+
+#include <erebos/identity.h>
+#include <erebos/uuid.h>
+
+#include <optional>
+
+namespace erebos {
+
+using std::optional;
+using std::vector;
+
+class LocalState
+{
+public:
+	LocalState();
+	explicit LocalState(const Ref &);
+	static LocalState load(const Ref & ref) { return LocalState(ref); }
+	Ref store(const Storage &) const;
+
+	static const UUID headTypeId;
+
+	const optional<Identity> & identity() const;
+	LocalState identity(const Identity &) const;
+
+	template<class T> optional<T> shared() const;
+	template<class T> LocalState shared(const vector<Stored<T>> &) const;
+	template<class T> LocalState shared(const Stored<T> & x) const { return shared({ x }); };
+	template<class T> LocalState shared(const Storage & st, const T & x)
+	{ return updateShared(T::sharedTypeId, x.store(st)); }
+
+private:
+	vector<Ref> lookupShared(UUID) const;
+	LocalState updateShared(UUID, const vector<Ref> &) const;
+
+	struct Priv;
+	std::shared_ptr<Priv> p;
+};
+
+template<class T>
+optional<T> LocalState::shared() const
+{
+	return T::load(lookupShared(T::sharedTypeId));
+}
+
+template<class T>
+LocalState LocalState::shared(const vector<Stored<T>> & v) const
+{
+	vector<Ref> refs;
+	for (const auto x : v)
+		refs.push_back(x.ref());
+	return updateShared(T::sharedTypeId, refs);
+}
+
+}
-- 
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