[EGD-5027] Services synchronization introduced

Dependencies between services are now supported.

module-sys/SystemManager/DependencyGraph.cpp

@@ -0,0 +1,32 @@
+// Copyright (c) 2017-2021, Mudita Sp. z.o.o. All rights reserved.
+// For licensing, see https://github.com/mudita/MuditaOS/LICENSE.md
+
+#include "DependencyGraph.hpp"
+
+#include <algorithm>
+#include <cassert>
+
+namespace sys
+{
+    namespace graph
+    {
+        Nodes nodesFrom(const std::vector<std::unique_ptr<BaseServiceCreator>> &services)
+        {
+            Nodes nodes;
+            nodes.reserve(services.size());
+            std::transform(services.begin(), services.end(), std::back_inserter(nodes), [](const auto &service) {
+                return std::ref(*service);
+            });
+            return nodes;
+        }
+    } // namespace graph
+
+    DependencyGraph::DependencyGraph(graph::Nodes nodes, std::unique_ptr<DependencySortingStrategy> &&strategy)
+        : nodes{std::move(nodes)}, strategy{std::move(strategy)}
+    {}
+
+    auto DependencyGraph::sort() const -> graph::Nodes
+    {
+        return strategy->sort(nodes);
+    }
+} // namespace sys