LogArchiveSnapshot Class
Represents a snapshot of the LogStore instance that can be used to generate an archive.
Assembly: System.IO.Log (in System.IO.Log.dll)
A LogArchiveSnapshot object contains the information necessary to generate a consistent backup of the data in a LogStore. The actual data is contained in the enumerable collection of FileRegion objects returned by the ArchiveRegions property. Each FileRegion instance represents a sequence of bytes in a file that must be archived.
The ArchiveTail, BaseSequenceNumber, and LastSequenceNumber properties are for informational purposes only. They can be recorded along with the archive data to provide optional information, but are not required to restore the data.
The following example shows how to use the LogArchiveSnapshot class to archive a LogStore to an XML document.
class LogBackup { static void ArchiveToXML(LogStore logStore, string fileName) { LogArchiveSnapshot snapshot = logStore.CreateLogArchiveSnapshot(); XmlTextWriter writer = new XmlTextWriter(fileName, Encoding.ASCII); writer.WriteStartElement("logArchive"); foreach(FileRegion region in snapshot.ArchiveRegions) { writer.WriteStartElement("fileRegion"); writer.WriteElementString("path", region.Path); writer.WriteElementString("length", region.FileLength.ToString()); writer.WriteElementString("offset", region.Offset.ToString()); using(Stream dataStream = region.GetStream()) { byte[] data = new byte[dataStream.Length]; dataStream.Read(data, 0, data.Length); writer.WriteElementString("data", Convert.ToBase64String(data)); } writer.WriteEndElement(); } writer.WriteEndElement(); writer.Close(); logStore.SetArchiveTail(snapshot.LastSequenceNumber); } static void RestoreFromXML(string fileName) { using(XmlTextReader reader = new XmlTextReader(fileName)) { reader.ReadStartElement("logArchive"); while(reader.IsStartElement()) { string path = reader.ReadElementString("path"); long length = Int64.Parse(reader.ReadElementString("length")); long offset = Int64.Parse(reader.ReadElementString("offset")); string dataString = reader.ReadElementString("data"); byte[] data = Convert.FromBase64String(dataString); FileStream fileStream; using(fileStream = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write)) { fileStream.SetLength(length); fileStream.Position = offset; fileStream.Write(data, 0, data.Length); } } reader.ReadEndElement(); } } }
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.