// Methods
public (Byte[] Result, DeltaFileTransaction Transaction) Restore(FileNode node, LogEntry entry)
{
Byte[] result = null;
Byte[] lastRead = null;
var logEntries = node.LogEntries.Where(x => x.CreatedAt <= entry.CreatedAt);
var strategy = _fileHandlingStrategySelector.Select(node);
foreach (var current in logEntries)
{
switch (current.Type)
{
case LogEntryTypes.Genesis:
result = _archiveManager.Read(node.FileName, node);
break;
case LogEntryTypes.Normal:
var delta = _archiveManager.Read(current.DiffName, node);
lastRead = result;
result = _deltaPatcher.Patch(result, delta);
break;
default:
break;
}
}
var newSignature = _signatureCreator.CreateSignature(result);
var newDelta = _deltaCreator.BuildDelta(newSignature, lastRead);
var transaction = new DeltaFileTransaction(node,
new Signature($"{Guid.NewGuid().ToString()}.signature", newSignature),
new Delta($"{Guid.NewGuid().ToString()}.delta", newDelta));
return(result, transaction);
}
public DeltaFileTransaction CreateDelta(FileNode node)
{
var logEntry = node.LogEntries.First(x => x.Type == LogEntryTypes.Genesis);
var original = _archiveManager.Read(node.FileName, node);
var firstDelta = node.LogEntries.First(x => x.Type == LogEntryTypes.Normal);
var delta = _archiveManager.Read(firstDelta.DiffName, node);
var patched = _deltaPatcher.Patch(original, delta);
foreach (var current in node.LogEntries.Where(x => x.Type == LogEntryTypes.Normal).Skip(1))
{
var rollingDelta = _archiveManager.Read(current.DiffName, node);
patched = _deltaPatcher.Patch(patched, rollingDelta);
}
var deltaName = $"{Guid.NewGuid().ToString()}.delta";
var mostRecentLogEntry = node.LogEntries.OrderBy(x => x.CreatedAt).Last();
var signature = _archiveManager.Read(logEntry.SignatureEntry, node);
var newDelta = _deltaCreator.BuildDelta(signature, node);
String newSignatureName = $"{Guid.NewGuid().ToString()}.signature";
Byte[] newSignature = _signatureCreator.CreateSignature(node);
var newLogEntry = new LogEntry
{
CreatedAt = DateTime.Now,
Type = LogEntryTypes.Normal,
DiffName = deltaName,
SignatureEntry = newSignatureName
};
node.LogEntries.Add(newLogEntry);
var transaction = new DeltaFileTransaction(node,
new Signature(newSignatureName, newSignature),
new Delta(deltaName, newDelta));
return(transaction);
}