private bool FileHasChanged(FileSystemObject newFile, out int existingVersion)
{
existingVersion = -1;
var oldFile = FindPath(_oldObjects, newFile.MappedPath);
if (oldFile == null)
{
newFile.ComputeHash(HashAlgorithm);
return true;
}
var crit = GetChangeCriterium(newFile);
bool ret;
switch (crit)
{
case ChangeCriterium.ArchiveFlag:
ret = newFile.ArchiveFlag;
break;
case ChangeCriterium.Size:
ret = newFile.Size != oldFile.Size;
break;
case ChangeCriterium.Date:
ret = newFile.ModificationTime != oldFile.ModificationTime;
break;
case ChangeCriterium.Hash:
ret = CompareHashes(newFile, oldFile);
break;
case ChangeCriterium.Custom:
ret = FileHasChanged(newFile, oldFile);
break;
default:
throw new ArgumentOutOfRangeException();
}
if (!ret)
{
oldFile.Hashes.ForEach(x => newFile.Hashes[x.Key] = x.Value);
newFile.LatestVersion = oldFile.LatestVersion;
existingVersion = oldFile.LatestVersion;
}
return ret;
}
private bool CompareHashes(FileSystemObject newFile, FileSystemObject oldFile)
{
if (oldFile.Hashes.Count == 0)
return true;
var kv = oldFile.Hashes.First();
var newHash = newFile.ComputeHash(kv.Key);
return !newHash.SequenceEqual(kv.Value);
}
