/// <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 BPlusTree(BPlusTreeOptions <TKey, TValue> ioptions)
{
bool fileExists =
ioptions.StorageType == StorageType.Disk &&
ioptions.CreateFile != CreatePolicy.Always &&
File.Exists(ioptions.FileName) &&
new FileInfo(ioptions.FileName).Length > 0;
_options = ioptions.Clone();
_selfLock = _options.CallLevelLock;
_keyComparer = _options.KeyComparer;
_itemComparer = new ElementComparer(_keyComparer);
switch (_options.CachePolicy)
{
case CachePolicy.All: _storage = new NodeCacheFull(_options); break;
case CachePolicy.Recent: _storage = new NodeCacheNormal(_options); break;
case CachePolicy.None: _storage = new NodeCacheNone(_options); break;
default: throw new InvalidConfigurationValueException("CachePolicy");
}
try
{
_storage.Load();
}
catch
{
_storage.Dispose();
throw;
}
if (_options.LogFile != null && !_options.ReadOnly)
{
if (_options.ExistingLogAction == ExistingLogAction.Truncate ||
_options.ExistingLogAction == ExistingLogAction.Default && !fileExists)
{
_options.LogFile.TruncateLog();
}
else if (_options.LogFile.Size > 0 && (
_options.ExistingLogAction == ExistingLogAction.Replay ||
_options.ExistingLogAction == ExistingLogAction.ReplayAndCommit ||
(_options.ExistingLogAction == ExistingLogAction.Default && fileExists)
))
{
bool commit = (_options.ExistingLogAction == ExistingLogAction.ReplayAndCommit ||
(_options.ExistingLogAction == ExistingLogAction.Default && fileExists));
bool merge = false;
if (_options.StorageType == StorageType.Disk)
{
merge = new FileInfo(_options.FileName).Length < _options.LogFile.Size;
}
if (merge) // log data is larger than we are...
{
BulkInsertOptions opts = new BulkInsertOptions();
opts.CommitOnCompletion = commit;
opts.DuplicateHandling = DuplicateHandling.LastValueWins;
opts.InputIsSorted = true;
opts.ReplaceContents = true;
BulkInsert(
_options.LogFile.MergeLog(_options.KeyComparer,
File.Exists(ioptions.FileName) ? EnumerateFile(ioptions) : new KeyValuePair <TKey, TValue> [0]),
opts
);
}
else
{
_options.LogFile.ReplayLog(this);
if (commit) //Now commit the recovered changes
{
Commit();
}
}
}
}
var nodeStoreWithCount = _storage.Storage as INodeStoreWithCount;
if (nodeStoreWithCount != null)
{
_count = nodeStoreWithCount.Count;
_hasCount = _count >= 0;
}
}