/// <summary>
/// Load page content based on page buffer
/// </summary>
public void LoadPage()
{
// check database file format
var info = _buffer.ReadString(P_HEADER_INFO, HEADER_INFO.Length);
var ver = _buffer[P_FILE_VERSION];
if (string.CompareOrdinal(info, HEADER_INFO) != 0 || ver != FILE_VERSION)
{
throw LiteException.InvalidDatabase();
}
// CreateTime is readonly
this.FreeEmptyPageList = _buffer.ReadUInt32(P_FREE_EMPTY_PAGE_ID);
this.LastPageID = _buffer.ReadUInt32(P_LAST_PAGE_ID);
// initialize engine pragmas
this.Pragmas = new EnginePragmas(_buffer, this);
// create new buffer area to store BsonDocument collections
var area = _buffer.Slice(P_COLLECTIONS, COLLECTIONS_SIZE);
using (var r = new BufferReader(new[] { area }, false))
{
_collections = r.ReadDocument();
}
_isCollectionsChanged = false;
}
protected override void ReadContent(ByteReader reader)
{
var info = reader.ReadString(HEADER_INFO.Length);
var ver = reader.ReadByte();
if (info != HEADER_INFO)
{
throw LiteException.InvalidDatabase();
}
if (ver != FILE_VERSION)
{
throw LiteException.InvalidDatabaseVersion(ver);
}
this.ChangeID = reader.ReadUInt16();
this.FreeEmptyPageID = reader.ReadUInt32();
this.LastPageID = reader.ReadUInt32();
this.DbVersion = reader.ReadUInt16();
this.Password = reader.ReadBytes(this.Password.Length);
// read page collections references (position on end of page)
var cols = reader.ReadByte();
for (var i = 0; i < cols; i++)
{
this.CollectionPages.Add(reader.ReadString(), reader.ReadUInt32());
}
}
/// <summary>
/// Read a page with correct instance page object. Checks for pageType
/// </summary>
public static BasePage ReadPage(byte[] buffer)
{
var reader = new ByteReader(buffer);
var pageID = reader.ReadUInt32();
var pageType = (PageType)reader.ReadByte();
if (pageID == 0 && (byte)pageType > 5)
{
throw LiteException.InvalidDatabase();
}
var page = CreateInstance(pageID, pageType);
page.ReadHeader(reader);
page.ReadContent(reader);
page.DiskData = buffer;
return(page);
}
/// <summary>
/// Read all database pages from v7 structure into a flexible BsonDocument - only read what really needs
/// </summary>
private BsonDocument ReadPage(uint pageID)
{
if (pageID * V7_PAGE_SIZE > _stream.Length)
{
return(null);
}
_stream.Position = pageID * V7_PAGE_SIZE; // v7 uses 4k page size
_stream.Read(_buffer, 0, V7_PAGE_SIZE);
// decrypt encrypted page (except header page - header are plain data)
if (_aes != null && pageID > 0)
{
_buffer = _aes.Decrypt(_buffer);
}
var reader = new ByteReader(_buffer);
// reading page header
var page = new BsonDocument
{
["pageID"] = (int)reader.ReadUInt32(),
["pageType"] = (int)reader.ReadByte(),
["prevPageID"] = (int)reader.ReadUInt32(),
["nextPageID"] = (int)reader.ReadUInt32(),
["itemCount"] = (int)reader.ReadUInt16()
};
// skip freeByte + reserved
reader.ReadBytes(2 + 8);
#region Header (1)
// read header
if (page["pageType"] == 1)
{
var info = reader.ReadString(27);
var ver = reader.ReadByte();
if (string.CompareOrdinal(info, HeaderPage.HEADER_INFO) != 0 || ver != 7)
{
throw LiteException.InvalidDatabase();
}
// skip ChangeID + FreeEmptyPageID + LastPageID
reader.ReadBytes(2 + 4 + 4);
page["userVersion"] = (int)reader.ReadUInt16();
page["password"] = reader.ReadBytes(20);
page["salt"] = reader.ReadBytes(16);
page["collections"] = new BsonDocument();
var cols = reader.ReadByte();
for (var i = 0; i < cols; i++)
{
var name = reader.ReadString();
var colPageID = reader.ReadUInt32();
page["collections"][name] = (int)colPageID;
}
}
#endregion
#region Collection (2)
// collection page
else if (page["pageType"] == 2)
{
page["collectionName"] = reader.ReadString();
page["indexes"] = new BsonArray();
reader.ReadBytes(12);
for (var i = 0; i < 16; i++)
{
var index = new BsonDocument();
var field = reader.ReadString();
var eq = field.IndexOf('=');
if (eq > 0)
{
index["name"] = field.Substring(0, eq);
index["expression"] = field.Substring(eq + 1);
}
else
{
index["name"] = field;
index["expression"] = "$." + field;
}
index["unique"] = reader.ReadBoolean();
index["headPageID"] = (int)reader.ReadUInt32();
// skip HeadNode (index) + TailNode + FreeIndexPageID
reader.ReadBytes(2 + 6 + 4);
if (field.Length > 0)
{
page["indexes"].AsArray.Add(index);
}
}
}
#endregion
#region Index (3)
else if (page["pageType"] == 3)
{
page["nodes"] = new BsonArray();
for (var i = 0; i < page["itemCount"].AsInt32; i++)
{
var node = new BsonDocument
{
["index"] = (int)reader.ReadUInt16()
};
var levels = reader.ReadByte();
// skip Slot + PrevNode + NextNode
reader.ReadBytes(1 + 6 + 6);
var length = reader.ReadUInt16();
// skip DataType + KeyValue
reader.ReadBytes(1 + length);
node["dataBlock"] = new BsonDocument
{
["pageID"] = (int)reader.ReadUInt32(),
["index"] = (int)reader.ReadUInt16()
};
// reading Prev[0]
node["prev"] = new BsonDocument
{
["pageID"] = (int)reader.ReadUInt32(),
["index"] = (int)reader.ReadUInt16()
};
// reading Next[0]
node["next"] = new BsonDocument
{
["pageID"] = (int)reader.ReadUInt32(),
["index"] = (int)reader.ReadUInt16()
};
// skip Prev/Next[1..N]
reader.ReadBytes((levels - 1) * (6 + 6));
page["nodes"].AsArray.Add(node);
}
}
#endregion
#region Data (4)
else if (page["pageType"] == 4)
{
page["blocks"] = new BsonArray();
for (var i = 0; i < page["itemCount"].AsInt32; i++)
{
var block = new BsonDocument
{
["index"] = (int)reader.ReadUInt16(),
["extendPageID"] = (int)reader.ReadUInt32()
};
var length = reader.ReadUInt16();
block["data"] = reader.ReadBytes(length);
page["blocks"].AsArray.Add(block);
}
}
#endregion
#region Extend (5)
else if (page["pageType"] == 5)
{
page["data"] = reader.ReadBytes(page["itemCount"].AsInt32);
}
#endregion
return(page);
}