data: performance optimization NameHierarchy

* For performance reasons nodes now store a serialized version of their name hierarchy directly. Removed NameHierarchy table from database.

src/lib/data/name/NameHierarchy.cpp

@@ -1,5 +1,40 @@
 #include "data/name/NameHierarchy.h"
 
+#include "utility/logging/logging.h"
+#include "utility/utilityString.h"
+
+std::string NameHierarchy::serialize(NameHierarchy nameHierarchy)
+{
+	std::string serializedName = "";
+	for (size_t i = 0; i < nameHierarchy.size(); i++)
+	{
+		serializedName += nameHierarchy[i]->getFullName() + "\t";
+		serializedName += nameHierarchy[i]->getFullSignature();
+		if (i + 1 < nameHierarchy.size())
+			serializedName += "\n";
+	}
+	return serializedName;
+}
+
+NameHierarchy NameHierarchy::deserialize(const std::string& serializedName)
+{
+	NameHierarchy nameHierarchy;
+	
+	std::vector<std::string> serializedNameElements = utility::splitToVector(serializedName, "\n");
+	for (size_t i = 0; i < serializedNameElements.size(); i++)
+	{
+		std::vector<std::string> nameParts = utility::splitToVector(serializedNameElements[i], "\t");
+		if (nameParts.size() != 2)
+		{
+			LOG_ERROR("unable to deserialize name hierarchy: " + serializedName); // todo: obfuscate serializedName!
+			return NameHierarchy();
+		}
+		nameHierarchy.push(std::make_shared<NameElement>(nameParts[0], nameParts[1]));
+	}
+
+	return nameHierarchy;
+}
+
 NameHierarchy::NameHierarchy()
 {
 }
@@ -25,7 +60,11 @@ void NameHierarchy::pop()
 
 std::shared_ptr<NameElement> NameHierarchy::back() const
 {
-	return m_elements.back();
+	if (m_elements.size() > 0)
+	{
+		return m_elements.back();
+	}
+	return std::shared_ptr<NameElement>();
 }
 
 std::shared_ptr<NameElement> NameHierarchy::operator[](size_t pos) const

src/lib/data/name/NameHierarchy.h

@@ -10,6 +10,9 @@
 class NameHierarchy
 {
 public:
+	static std::string serialize(NameHierarchy nameHierarchy);
+	static NameHierarchy deserialize(const std::string& serializedName);
+
 	NameHierarchy();
 	NameHierarchy(const std::string& name);
 	~NameHierarchy();