FileRegion Classe
Definição
Representa uma região de um arquivo a ser arquivada.Represents a region of a file to be archived. Essa classe não pode ser herdada.This class cannot be inherited.
public ref class FileRegion sealed
public sealed class FileRegion
type FileRegion = class
Public NotInheritable Class FileRegion
- Herança
-
FileRegion
Exemplos
O exemplo a seguir demonstra como arquivar um repositório de logs em XML usando as LogStore FileRegion classes e.The following example demonstrates how to archive a log store to XML using the LogStore and FileRegion classes.
class LogBackup
{
static void ArchiveToXML(LogStore logStore, string fileName)
{
LogArchiveSnapshot snapshot = logStore.CreateLogArchiveSnapshot();
{
XmlTextWriter writer = new XmlTextWriter(fileName, System.Text.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", System.Convert.ToBase64String(data));
}
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;
long length;
long offset;
path = reader.ReadElementString("path");
length = System.Int64.Parse(reader.ReadElementString("length"));
offset = System.Int64.Parse(reader.ReadElementString("offset"));
string dataString = reader.ReadElementString("data");
byte[] data = System.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();
}
}
}
Friend Class LogBackup
Private Shared Sub ArchiveToXML(ByVal logStore As LogStore, ByVal fileName As String)
Dim snapshot As LogArchiveSnapshot = logStore.CreateLogArchiveSnapshot()
Dim writer As New XmlTextWriter(fileName, System.Text.Encoding.ASCII)
writer.WriteStartElement("logArchive")
For Each region As FileRegion In snapshot.ArchiveRegions
With writer
.WriteStartElement("fileRegion")
.WriteElementString("path", region.Path)
.WriteElementString("length", region.FileLength.ToString())
.WriteElementString("offset", region.Offset.ToString())
End With
Using dataStream As Stream = region.GetStream()
Dim data(dataStream.Length - 1) As Byte
dataStream.Read(data, 0, data.Length)
writer.WriteElementString("data", System.Convert.ToBase64String(data))
End Using
writer.WriteEndElement()
Next region
writer.Close()
logStore.SetArchiveTail(snapshot.LastSequenceNumber)
End Sub
Private Shared Sub RestoreFromXML(ByVal fileName As String)
Using reader As New XmlTextReader(fileName)
reader.ReadStartElement("logArchive")
Do While reader.IsStartElement()
Dim path As String
Dim length As Long
Dim offset As Long
path = reader.ReadElementString("path")
length = System.Int64.Parse(reader.ReadElementString("length"))
offset = System.Int64.Parse(reader.ReadElementString("offset"))
Dim dataString = reader.ReadElementString("data")
Dim data() = System.Convert.FromBase64String(dataString)
Dim fileStream As FileStream
fileStream = New FileStream(path, FileMode.OpenOrCreate, FileAccess.Write)
Using fileStream
fileStream.SetLength(length)
fileStream.Position = offset
fileStream.Write(data, 0, data.Length)
End Using
Loop
reader.ReadEndElement()
End Using
End Sub
End Class
Comentários
Um LogArchiveSnapshot objeto contém as informações necessárias para gerar um backup consistente dos dados em um LogStore .A LogArchiveSnapshot object contains the information necessary to generate a consistent backup of the data in a LogStore. Os dados reais estão contidos na coleção enumerável de FileRegion objetos retornados pela ArchiveRegions propriedade.The actual data is contained in the enumerable collection of FileRegion objects returned by the ArchiveRegions property. Cada FileRegion instância representa uma sequência de bytes em um arquivo que deve ser arquivado.Each FileRegion instance represents a sequence of bytes in a file that must be archived.
Propriedades
| FileLength |
Obtém tamanho do arquivo em bytes.Gets the length of the file in bytes. |
| Offset |
Obtém o deslocamento no arquivo em que os dados começam.Gets the offset into the file where the data begins. |
| Path |
Obtém o local totalmente qualificado do arquivo que contém essa região.Gets the fully qualified location of the file containing this region. |
Métodos
| Equals(Object) |
Determina se o objeto especificado é igual ao objeto atual.Determines whether the specified object is equal to the current object. (Herdado de Object) |
| GetHashCode() |
Serve como a função de hash padrão.Serves as the default hash function. (Herdado de Object) |
| GetStream() |
Retorna um fluxo que pode ser usado para ler os dados a serem arquivados.Returns a stream that can be used to read the data to be archived. |
| GetType() |
Obtém o Type da instância atual.Gets the Type of the current instance. (Herdado de Object) |
| MemberwiseClone() |
Cria uma cópia superficial do Object atual.Creates a shallow copy of the current Object. (Herdado de Object) |
| ToString() |
Retorna uma cadeia de caracteres que representa o objeto atual.Returns a string that represents the current object. (Herdado de Object) |