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GenericIndexIterator: Add node change helpers

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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.
This commit is contained in:
Ingo Weinhold 2011-07-07 11:39:49 +02:00
parent 0209c404dc
commit d56e19fb9e
1 changed files with 44 additions and 0 deletions
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44
src/add-ons/kernel/file_systems/packagefs/IndexImpl.h
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@ -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)