More abstraction in GenericIndexIterator

* Move tree node operations to a subpolicy TreePolicy.
* Add a GenericIndexIteratorTreePolicy templatized over the policy,
  implementing the tree policy for the standard indices.

src/add-ons/kernel/file_systems/packagefs/IndexImpl.h

@@ -31,6 +31,7 @@ public:
 			typedef typename Policy::Index		Index;
 			typedef typename Policy::Value		Value;
 			typedef typename Policy::NodeTree	NodeTree;
+			typedef typename Policy::TreePolicy	TreePolicy;
 			typedef typename NodeTree::Node		TreeNode;
 
 public:
@@ -51,9 +52,6 @@ public:
 
 	virtual void				NodeRemoved(Node* node);
 
-protected:
-	inline	Node*				_ToNode() const;
-
 protected:
 			Index*				fIndex;
 			TreeNode*			fNextTreeNode;
@@ -75,7 +73,7 @@ GenericIndexIterator<Policy>::GenericIndexIterator()
 template<typename Policy>
 GenericIndexIterator<Policy>::~GenericIndexIterator()
 {
-	SetTo(NULL, NULL);
+	SetTo(NULL, Value());
 }
 
 
@@ -94,15 +92,14 @@ GenericIndexIterator<Policy>::Next(void* buffer, size_t* _keyLength)
 	if (fSuspended || fNextTreeNode == NULL)
 		return NULL;
 
-	Node* node = _ToNode();
-	if (node != NULL) {
+
 	if (buffer != NULL)
-			Policy::GetNodeValue(node, buffer, _keyLength);
+		TreePolicy::GetTreeNodeValue(fNextTreeNode, buffer, _keyLength);
 
+	TreeNode* treeNode = fNextTreeNode;
 	fNextTreeNode = Policy::GetNodeTree(fIndex)->Next(fNextTreeNode);
-	}
 
-	return node;
+	return TreePolicy::GetNode(treeNode);
 }
 
 
@@ -113,8 +110,10 @@ GenericIndexIterator<Policy>::Suspend()
 	if (fSuspended)
 		return B_BAD_VALUE;
 
-	if (fNextTreeNode != NULL)
-		fIndex->GetVolume()->AddNodeListener(this, _ToNode());
+	if (fNextTreeNode != NULL) {
+		fIndex->GetVolume()->AddNodeListener(this,
+			TreePolicy::GetNode(fNextTreeNode));
+	}
 
 	fSuspended = true;
 	return B_OK;
@@ -150,15 +149,11 @@ GenericIndexIterator<Policy>::SetTo(Index* index, const Value& value,
 	if (fIndex == NULL)
 		return false;
 
-	typename NodeTree::Iterator iterator;
-	if (ignoreValue) {
-		Policy::GetNodeTree(fIndex)->GetIterator(&iterator);
-	} else if (Policy::GetNodeTree(fIndex)->FindFirstClosest(value, false,
-			&iterator) == NULL) {
-		return false;
-	}
+	if (ignoreValue)
+		fNextTreeNode = TreePolicy::GetFirstTreeNode(fIndex);
+	else
+		fNextTreeNode = TreePolicy::FindClosestTreeNode(fIndex, value);
 
-	fNextTreeNode = iterator.CurrentNode();
 	return fNextTreeNode != NULL;
 }
 
@@ -182,20 +177,17 @@ template<typename Policy>
 void
 GenericIndexIterator<Policy>::NodeChangeEnd(Node* node)
 {
-	if (fNextTreeNode != NULL) {
+	if (fNextTreeNode != NULL)
 		fNextTreeNode = Policy::GetNodeTree(fIndex)->Next(fNextTreeNode);
-	} else {
-		typename NodeTree::Iterator iterator;
-		Policy::GetNodeTree(fIndex)->GetIterator(&iterator);
-		fNextTreeNode = iterator.CurrentNode();
-	}
+	else
+		fNextTreeNode = TreePolicy::GetFirstTreeNode(fIndex);
 
 	// If the node is no longer the one we originally pointed to, re-register
 	// the node listener.
 	if (fNextTreeNode == NULL) {
 		fIndex->GetVolume()->RemoveNodeListener(this);
 	} else {
-		Node* newNode = _ToNode();
+		Node* newNode = TreePolicy::GetNode(fNextTreeNode);
 		if (newNode != node) {
 			fIndex->GetVolume()->RemoveNodeListener(this);
 			fIndex->GetVolume()->AddNodeListener(this, newNode);
@@ -215,13 +207,42 @@ GenericIndexIterator<Policy>::NodeRemoved(Node* node)
 
 
 template<typename Policy>
-Node*
-GenericIndexIterator<Policy>::_ToNode() const
+struct GenericIndexIteratorTreePolicy {
+	typedef typename Policy::Index		Index;
+	typedef typename Policy::Value		Value;
+	typedef typename Policy::NodeTree	NodeTree;
+	typedef typename NodeTree::Node		TreeNode;
+
+	static Node* GetNode(TreeNode* treeNode)
 	{
-//	return NodeTree::NodeStrategy().GetValue(fNextTreeNode);
-	typename NodeTree::NodeStrategy strategy;
-	return strategy.GetValue(fNextTreeNode);
+		typename Policy::NodeTree::NodeStrategy strategy;
+		return strategy.GetValue(treeNode);
 	}
 
+	static TreeNode* GetFirstTreeNode(Index* index)
+	{
+		typename NodeTree::Iterator iterator;
+		Policy::GetNodeTree(index)->GetIterator(&iterator);
+		return iterator.CurrentNode();
+	}
+
+	static TreeNode* FindClosestTreeNode(Index* index, const Value& value)
+	{
+		typename NodeTree::Iterator iterator;
+		if (Policy::GetNodeTree(index)->FindFirstClosest(value, false,
+				&iterator) == NULL) {
+			return NULL;
+		}
+
+		return iterator.CurrentNode();
+	}
+
+	static void GetTreeNodeValue(TreeNode* treeNode, void* buffer,
+		size_t* _keyLength)
+	{
+		Policy::GetNodeValue(GetNode(treeNode), buffer, _keyLength);
+	}
+};
+
 
 #endif	// INDEX_IMPL_H

src/add-ons/kernel/file_systems/packagefs/LastModifiedIndex.cpp

@@ -108,6 +108,7 @@ struct LastModifiedIndex::IteratorPolicy {
 	typedef LastModifiedIndex								Index;
 	typedef time_t											Value;
 	typedef LastModifiedIndex::NodeTree						NodeTree;
+	typedef GenericIndexIteratorTreePolicy<IteratorPolicy>	TreePolicy;
 
 	static NodeTree* GetNodeTree(Index* index)
 	{

src/add-ons/kernel/file_systems/packagefs/NameIndex.cpp

@@ -88,6 +88,7 @@ struct NameIndex::IteratorPolicy {
 	typedef NameIndex										Index;
 	typedef const char*										Value;
 	typedef NameIndex::EntryTree							NodeTree;
+	typedef GenericIndexIteratorTreePolicy<IteratorPolicy>	TreePolicy;
 
 	static NodeTree* GetNodeTree(Index* index)
 	{

src/add-ons/kernel/file_systems/packagefs/SizeIndex.cpp

@@ -107,6 +107,7 @@ struct SizeIndex::IteratorPolicy {
 	typedef SizeIndex										Index;
 	typedef off_t											Value;
 	typedef SizeIndex::NodeTree								NodeTree;
+	typedef GenericIndexIteratorTreePolicy<IteratorPolicy>	TreePolicy;
 
 	static NodeTree* GetNodeTree(Index* index)
 	{