Collect and append SR commit keys.

include/wsrep/sr_key_set.hpp

@@ -0,0 +1,44 @@
+//
+// Copyright (C) 2018 Codership Oy <info@codership.com>
+//
+
+#ifndef WSREP_SR_KEY_SET_HPP
+#define WSREP_SR_KEY_SET_HPP
+
+#include <set>
+#include <map>
+
+namespace wsrep
+{
+    class sr_key_set
+    {
+    public:
+        typedef std::set<std::string> leaf_type;
+        typedef std::map<std::string, leaf_type > branch_type;
+        sr_key_set()
+            : root_()
+        { }
+
+        void insert(const wsrep::key& key)
+        {
+            assert(key.size() == 3);
+            if (key.size() < 3)
+            {
+                throw wsrep::runtime_error("Invalid key size");
+            }
+
+            root_[std::string(
+                    static_cast<const char*>(key.key_parts()[0].data()),
+                    key.key_parts()[0].size())].insert(
+                        std::string(static_cast<const char*>(key.key_parts()[1].data()),
+                                    key.key_parts()[1].size()));
+        }
+
+        const branch_type& root() const { return root_; }
+        void clear() { root_.clear(); }
+    private:
+        branch_type root_;
+    };
+}
+
+#endif // WSREP_KEY_SET_HPP