From 0d988526bc99654160487c88834d921e316b9249 Mon Sep 17 00:00:00 2001
From: Ingo Weinhold <ingo_weinhold@gmx.de>
Date: Thu, 7 Jul 2011 11:39:49 +0200
Subject: [PATCH] GenericIndexIterator: Add node change helpers

Add NodeChangeBegin()/NodeChangeEnd() methods that can be used by the
index when the respective node attribute has changed. They make sure
that the iterator doesn't move with the node, should it be inserted into
the index at a different position.
---
 .../kernel/file_systems/packagefs/IndexImpl.h | 44 +++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/src/add-ons/kernel/file_systems/packagefs/IndexImpl.h b/src/add-ons/kernel/file_systems/packagefs/IndexImpl.h
index 7bd84b4fe7..9714c16c2e 100644
--- a/src/add-ons/kernel/file_systems/packagefs/IndexImpl.h
+++ b/src/add-ons/kernel/file_systems/packagefs/IndexImpl.h
@@ -46,6 +46,9 @@ public:
 			bool				SetTo(Index* index, const Value& name,
 									bool ignoreValue = false);
 
+	inline	void				NodeChangeBegin(Node* node);
+	inline	void				NodeChangeEnd(Node* node);
+
 	virtual void				NodeRemoved(Node* node);
 
 protected:
@@ -160,6 +163,47 @@ GenericIndexIterator<Policy>::SetTo(Index* index, const Value& value,
 }
 
 
+/*!	Moves the iterator temporarily off the current node.
+	Called when the node the iterator currently points to has been modified and
+	the index is about to remove it from and reinsert it into the tree. After
+	having done that NodeChangeEnd() must be called.
+*/
+template<typename Policy>
+void
+GenericIndexIterator<Policy>::NodeChangeBegin(Node* node)
+{
+	fNextTreeNode = Policy::GetNodeTree(fIndex)->Previous(fNextTreeNode);
+}
+
+
+/*!	Brackets a NodeChangeBegin() call.
+*/
+template<typename Policy>
+void
+GenericIndexIterator<Policy>::NodeChangeEnd(Node* node)
+{
+	if (fNextTreeNode != NULL) {
+		fNextTreeNode = Policy::GetNodeTree(fIndex)->Next(fNextTreeNode);
+	} else {
+		typename NodeTree::Iterator iterator;
+		Policy::GetNodeTree(fIndex)->GetIterator(&iterator);
+		fNextTreeNode = iterator.CurrentNode();
+	}
+
+	// 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();
+		if (newNode != node) {
+			fIndex->GetVolume()->RemoveNodeListener(this);
+			fIndex->GetVolume()->AddNodeListener(this, newNode);
+		}
+	}
+}
+
+
 template<typename Policy>
 void
 GenericIndexIterator<Policy>::NodeRemoved(Node* node)