1 files changed, 121 insertions, 0 deletions
diff --git a/lib/base/registry.hpp b/lib/base/registry.hpp
new file mode 100644
index 0000000..c13f7e1
--- /dev/null
+++ b/lib/base/registry.hpp
@@ -0,0 +1,121 @@
+/* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
+
+#ifndef REGISTRY_H
+#define REGISTRY_H
+
+#include "base/i2-base.hpp"
+#include "base/string.hpp"
+#include <boost/signals2.hpp>
+#include <map>
+#include <mutex>
+
+namespace icinga
+{
+
+/**
+ * A registry.
+ *
+ * @ingroup base
+ */
+template<typename U, typename T>
+class Registry
+{
+public:
+	typedef std::map<String, T> ItemMap;
+
+	void RegisterIfNew(const String& name, const T& item)
+	{
+		std::unique_lock<std::mutex> lock(m_Mutex);
+
+		if (m_Items.find(name) != m_Items.end())
+			return;
+
+		RegisterInternal(name, item, lock);
+	}
+
+	void Register(const String& name, const T& item)
+	{
+		std::unique_lock<std::mutex> lock(m_Mutex);
+
+		RegisterInternal(name, item, lock);
+	}
+
+	void Unregister(const String& name)
+	{
+		size_t erased;
+
+		{
+			std::unique_lock<std::mutex> lock(m_Mutex);
+			erased = m_Items.erase(name);
+		}
+
+		if (erased > 0)
+			OnUnregistered(name);
+	}
+
+	void Clear()
+	{
+		typename Registry<U, T>::ItemMap items;
+
+		{
+			std::unique_lock<std::mutex> lock(m_Mutex);
+			items = m_Items;
+		}
+
+		for (const auto& kv : items) {
+			OnUnregistered(kv.first);
+		}
+
+		{
+			std::unique_lock<std::mutex> lock(m_Mutex);
+			m_Items.clear();
+		}
+	}
+
+	T GetItem(const String& name) const
+	{
+		std::unique_lock<std::mutex> lock(m_Mutex);
+
+		auto it = m_Items.find(name);
+
+		if (it == m_Items.end())
+			return T();
+
+		return it->second;
+	}
+
+	ItemMap GetItems() const
+	{
+		std::unique_lock<std::mutex> lock(m_Mutex);
+
+		return m_Items; /* Makes a copy of the map. */
+	}
+
+	boost::signals2::signal<void (const String&, const T&)> OnRegistered;
+	boost::signals2::signal<void (const String&)> OnUnregistered;
+
+private:
+	mutable std::mutex m_Mutex;
+	typename Registry<U, T>::ItemMap m_Items;
+
+	void RegisterInternal(const String& name, const T& item, std::unique_lock<std::mutex>& lock)
+	{
+		bool old_item = false;
+
+		if (m_Items.erase(name) > 0)
+			old_item = true;
+
+		m_Items[name] = item;
+
+		lock.unlock();
+
+		if (old_item)
+			OnUnregistered(name);
+
+		OnRegistered(name, item);
+	}
+};
+
+}
+
+#endif /* REGISTRY_H */