/// <summary>
/// Directly enumerates the contents of BPlusTree from disk in read-only mode.
/// </summary>
/// <param name="options"> The options normally used to create the <see cref="BPlusTree{TKey, TValue}"/> instance </param>
/// <returns> Yields the Key/Value pairs found in the file </returns>
public static IEnumerable <KeyValuePair <TKey, TValue> > EnumerateFile(BPlusTreeOptions <TKey, TValue> options)
{
options = options.Clone();
options.CreateFile = CreatePolicy.Never;
options.ReadOnly = true;
using (INodeStorage store = options.CreateStorage())
{
bool isnew;
Node root;
IStorageHandle hroot = store.OpenRoot(out isnew);
if (isnew)
{
yield break;
}
NodeSerializer nodeReader = new NodeSerializer(options, new NodeHandleSerializer(store));
if (isnew || !store.TryGetNode(hroot, out root, nodeReader))
{
throw new InvalidDataException();
}
Stack <KeyValuePair <Node, int> > todo = new Stack <KeyValuePair <Node, int> >();
todo.Push(new KeyValuePair <Node, int>(root, 0));
while (todo.Count > 0)
{
KeyValuePair <Node, int> cur = todo.Pop();
if (cur.Value == cur.Key.Count)
{
continue;
}
todo.Push(new KeyValuePair <Node, int>(cur.Key, cur.Value + 1));
Node child;
if (!store.TryGetNode(cur.Key[cur.Value].ChildNode.StoreHandle, out child, nodeReader))
{
throw new InvalidDataException();
}
if (child.IsLeaf)
{
for (int ix = 0; ix < child.Count; ix++)
{
var set = child[ix].ToKeyValuePair();
var enumerator = set.Value.GetEnumerator();
while (enumerator.MoveNext())
{
yield return(new KeyValuePair <TKey, TValue>(set.Key, enumerator.Current.Key));
}
}
}
else
{
todo.Push(new KeyValuePair <Node, int>(child, 0));
}
}
}
}
public NodeCacheBase(BPlusTreeOptions <TKey, TValue> options)
{
Options = options;
LockFactory = Options.LockingFactory;
Storage = Options.CreateStorage();
if (Options.UseStorageCache)
{
Storage = new StorageCache(Storage, Options.CacheKeepAliveMaximumHistory);
}
NodeSerializer = new NodeSerializer(Options, new NodeHandleSerializer(Storage));
_version = new NodeVersion();
}