public void Initialize(Logger log, string password)
{
// get log instance to disk
_log = log;
// if stream are empty, create header page and save to stream
if (_stream.Length == 0)
{
_log.Write(Logger.DISK, "initialize new datafile");
// create datafile
UltraLiteEngine.CreateDatabase(_stream, password);
}
}
private static Dictionary <uint, string> RecoveryCollectionPages(UltraLiteEngine engine, HeaderPage header, StringBuilder log)
{
var result = new Dictionary <uint, string>();
// get collection page
foreach (var col in header.CollectionPages)
{
CollectionPage colPage = null;
try
{
// read collection page
var buffer = engine._disk.ReadPage(col.Value);
var page = BasePage.ReadPage(buffer);
if (page.PageType != PageType.Collection)
{
continue;
}
colPage = page as CollectionPage;
}
catch (Exception ex)
{
log.AppendLine($"Page {col.Value} (Collection) Error: {ex.Message}");
continue;
}
// get all pageID from all valid indexes
var pagesID = new HashSet <uint>(colPage.Indexes.Where(x => x.IsEmpty == false && x.HeadNode.PageID != uint.MaxValue).Select(x => x.HeadNode.PageID));
// load all dataPages from this initial index pageIDs
var dataPages = RecoveryDetectCollectionByIndexPages(engine, pagesID, log);
// populate resultset with this collection name/data page
foreach (var page in dataPages)
{
result[page] = col.Key;
}
}
return(result);
}
public void Initialize(Logger log, string password)
{
// get log instance to disk
_log = log;
_log.Write(Logger.DISK, "open datafile '{0}'", Path.GetFileName(_filename));
// open/create file using read only/exclusive options
_stream = this.CreateFileStream(_filename,
System.IO.FileMode.OpenOrCreate,
FileAccess.ReadWrite,
FileShare.None);
// if file is new, initialize
if (_stream.Length == 0)
{
_log.Write(Logger.DISK, "initialize new datafile");
// create datafile
UltraLiteEngine.CreateDatabase(_stream, password, _options.InitialSize);
}
}
private static HashSet <uint> RecoveryDetectCollectionByIndexPages(UltraLiteEngine engine, HashSet <uint> initialPagesID, StringBuilder log)
{
var indexPages = new Dictionary <uint, bool>();
var dataPages = new HashSet <uint>();
foreach (var pageID in initialPagesID)
{
indexPages.Add(pageID, false);
}
// discover all indexes pages related with this current indexPage (all of them are in same collection)
while (indexPages.Count(x => x.Value == false) > 0)
{
var item = indexPages.First(x => x.Value == false);
// mark page as readed
indexPages[item.Key] = true;
IndexPage indexPage = null;
try
{
// try read page from disk and deserialize as IndexPage
var buffer = engine._disk.ReadPage(item.Key);
var page = BasePage.ReadPage(buffer);
if (page.PageType != PageType.Index)
{
continue;
}
indexPage = page as IndexPage;
}
catch (Exception ex)
{
log.AppendLine($"Page {item.Key} (Collection) Error: {ex.Message}");
continue;
}
// now, check for all nodes to get dataPages
foreach (var node in indexPage.Nodes.Values)
{
if (node.DataBlock.PageID != uint.MaxValue)
{
dataPages.Add(node.DataBlock.PageID);
}
// add into indexPages all possible indexPages
if (!indexPages.ContainsKey(node.PrevNode.PageID) && node.PrevNode.PageID != uint.MaxValue)
{
indexPages.Add(node.PrevNode.PageID, false);
}
if (!indexPages.ContainsKey(node.NextNode.PageID) && node.NextNode.PageID != uint.MaxValue)
{
indexPages.Add(node.NextNode.PageID, false);
}
foreach (var pos in node.Prev.Where(x => !x.IsEmpty && x.PageID != uint.MaxValue))
{
if (!indexPages.ContainsKey(pos.PageID))
{
indexPages.Add(pos.PageID, false);
}
}
foreach (var pos in node.Next.Where(x => !x.IsEmpty && x.PageID != uint.MaxValue))
{
if (!indexPages.ContainsKey(pos.PageID))
{
indexPages.Add(pos.PageID, false);
}
}
}
}
return(dataPages);
}
/// <summary>
/// Try recovery data from current datafile into a new datafile.
/// </summary>
public static string Recovery(string filename)
{
// if not exists, just exit
if (!File.Exists(filename))
{
return("");
}
var log = new StringBuilder();
var newfilename = FileHelper.GetTempFile(filename, "-recovery", true);
var count = 0;
using (var olddb = new UltraLiteEngine(filename))
using (var newdb = new UltraLiteEngine(newfilename, false))
{
// get header from old database (this must must be possible to read)
var header = olddb._pager.GetPage <HeaderPage>(0);
var collections = RecoveryCollectionPages(olddb, header, log);
// try recovery all data pages
for (uint i = 1; i < header.LastPageID; i++)
{
DataPage dataPage = null;
try
{
var buffer = olddb._disk.ReadPage(i);
// searching only for DataPage (PageType == 4)
if (buffer[4] != 4)
{
continue;
}
dataPage = BasePage.ReadPage(buffer) as DataPage;
}
catch (Exception ex)
{
log.AppendLine($"Page {i} (DataPage) Error: {ex.Message}");
continue;
}
// try find collectionName using pageID map (use fixed name if not found)
if (collections.TryGetValue(i, out var colname) == false)
{
colname = "_recovery";
}
foreach (var block in dataPage.DataBlocks)
{
try
{
// read bytes
var bson = olddb._data.Read(block.Value.Position);
// deserialize as document
var doc = BsonSerializer.Deserialize(bson);
// and insert into new database
newdb.Insert(colname, doc);
count++;
}
catch (Exception ex)
{
log.AppendLine($"Document {block.Value.Position} Error: {ex.Message}");
continue;
}
}
}
}
log.Insert(0, $"Document recovery count: {count}\n");
return(log.ToString());
}
/// <summary>
/// Reduce disk size re-arranging unused spaces. Can change password. If temporary disk was not provided, use MemoryStream temp disk
/// </summary>
public long Shrink(string password = null, IDiskService tempDisk = null)
{
var originalSize = _disk.FileLength;
// if temp disk are not passed, use memory stream disk
using (var temp = tempDisk ?? new StreamDiskService(new MemoryStream()))
using (var engine = new UltraLiteEngine(temp, password))
{
// read all collection
foreach (var collectionName in this.GetCollectionNames())
{
// first create all user indexes (exclude _id index)
foreach (var index in this.GetIndexes(collectionName).Where(x => x.Field != "_id"))
{
engine.EnsureIndex(collectionName, index.Field, index.Unique);
}
// now copy documents
var docs = this.Find(collectionName, Query.All());
engine.InsertBulk(collectionName, docs);
// fix collection sequence number
var seq = _collections.Get(collectionName).Sequence;
engine.Transaction(collectionName, true, (col) =>
{
col.Sequence = seq;
engine._pager.SetDirty(col);
return(true);
});
}
// copy user version
engine.UserVersion = this.UserVersion;
// set current disk size to exact new disk usage
_disk.SetLength(temp.FileLength);
// read new header page to start copy
var header = BasePage.ReadPage(temp.ReadPage(0)) as HeaderPage;
// copy (as is) all pages from temp disk to original disk
for (uint i = 0; i <= header.LastPageID; i++)
{
// skip lock page
if (i == 1)
{
continue;
}
var page = temp.ReadPage(i);
_disk.WritePage(i, page);
}
// create/destroy crypto class
if (_crypto != null)
{
_crypto.Dispose();
}
_crypto = password == null ? null : new AesEncryption(password, header.Salt);
// initialize all services again (crypto can be changed)
this.InitializeServices();
// return how many bytes are reduced
return(originalSize - temp.FileLength);
}
}
