Implemented value events emitter

src/value/valueevents.cpp

 #include "valueevents.h"
 #include "yaml-cpp/value.h"
+#include "yaml-cpp/eventhandler.h"
+#include "yaml-cpp/mark.h"
 
 namespace YAML
 {
+	void ValueEvents::AliasManager::RegisterReference(const detail::node& node)
+	{
+		m_anchorByIdentity.insert(std::make_pair(node.ref(), _CreateNewAnchor()));
+	}
+	
+	anchor_t ValueEvents::AliasManager::LookupAnchor(const detail::node& node) const
+	{
+		AnchorByIdentity::const_iterator it = m_anchorByIdentity.find(node.ref());
+		if(it == m_anchorByIdentity.end())
+			return 0;
+		return it->second;
+	}
+
 	ValueEvents::ValueEvents(const Value& value): m_pMemory(value.m_pMemory), m_root(*value.m_pNode)
 	{
-		Visit(m_root);
+		Setup(m_root);
 	}
 
-	void ValueEvents::Visit(const detail::node& node)
+	void ValueEvents::Setup(const detail::node& node)
 	{
 		int& refCount = m_refCount[node.ref()];
 		refCount++;
@@ -17,12 +32,67 @@ namespace YAML
 		
 		if(node.type() == ValueType::Sequence) {
 			for(detail::const_node_iterator it=node.begin();it!=node.end();++it)
-				Visit(**it);
+				Setup(**it);
 		} else if(node.type() == ValueType::Map) {
 			for(detail::const_node_iterator it=node.begin();it!=node.end();++it) {
-				Visit(*it->first);
-				Visit(*it->second);
+				Setup(*it->first);
+				Setup(*it->second);
+			}
 		}
 	}
+
+	void ValueEvents::Emit(EventHandler& handler)
+	{
+		AliasManager am;
+		
+		handler.OnDocumentStart(Mark());
+		Emit(m_root, handler, am);
+		handler.OnDocumentEnd();
+	}
+
+	void ValueEvents::Emit(const detail::node& node, EventHandler& handler, AliasManager& am) const
+	{
+		anchor_t anchor = NullAnchor;
+		if(IsAliased(node)) {
+			anchor = am.LookupAnchor(node);
+			if(anchor) {
+				handler.OnAlias(Mark(), anchor);
+				return;
+			}
+			
+			am.RegisterReference(node);
+			anchor = am.LookupAnchor(node);
+		}
+		
+		switch(node.type()) {
+			case ValueType::Undefined:
+				break;
+			case ValueType::Null:
+				handler.OnNull(Mark(), anchor);
+				break;
+			case ValueType::Scalar:
+				handler.OnScalar(Mark(), "", anchor, node.scalar());
+				break;
+			case ValueType::Sequence:
+				handler.OnSequenceStart(Mark(), "", anchor);
+				for(detail::const_node_iterator it=node.begin();it!=node.end();++it)
+					Emit(**it, handler, am);
+				handler.OnSequenceEnd();
+				break;
+			case ValueType::Map:
+				handler.OnMapStart(Mark(), "", anchor);
+				for(detail::const_node_iterator it=node.begin();it!=node.end();++it) {
+					Emit(*it->first, handler, am);
+					Emit(*it->second, handler, am);
+				}
+				handler.OnMapEnd();
+				break;
+		}
+	}
+
+	bool ValueEvents::IsAliased(const detail::node& node) const
+	{
+		RefCount::const_iterator it = m_refCount.find(node.ref());
+		return it != m_refCount.end() && it->second > 1;
 	}
 }

src/value/valueevents.h

@@ -13,14 +13,36 @@
 namespace YAML
 {
 	class Value;
+	class EventHandler;
 	
 	class ValueEvents
 	{
 	public:
 		ValueEvents(const Value& value);
 		
+		void Emit(EventHandler& handler);
+		
+	private:
+		class AliasManager {
+		public:
+			AliasManager(): m_curAnchor(0) {}
+			
+			void RegisterReference(const detail::node& node);
+			anchor_t LookupAnchor(const detail::node& node) const;
+			
 		private:
-		void Visit(const detail::node& node);
+			anchor_t _CreateNewAnchor() { return ++m_curAnchor; }
+			
+		private:
+			typedef std::map<const detail::node_ref*, anchor_t> AnchorByIdentity;
+			AnchorByIdentity m_anchorByIdentity;
+			
+			anchor_t m_curAnchor;
+		};
+		
+		void Setup(const detail::node& node);
+		void Emit(const detail::node& node, EventHandler& handler, AliasManager& am) const;
+		bool IsAliased(const detail::node& node) const;
 		
 	private:
 		detail::shared_memory_holder m_pMemory;