public override int CompareTo(RevisionID other)
{
var otherCast = other as TreeRevisionID;
if (otherCast == null)
{
Log.To.Database.E(Tag, "Cannot compare to {0}, throwing...", other.GetType().Name);
throw new ArgumentException(String.Format("Cannot compare TreeRevisionID to {0}", other.GetType().Name));
}
return(CBLCollateRevIDs(_data, otherCast._data));
}
public static RevisionID RevIDForJSON(IEnumerable <byte> json, bool deleted, RevisionID prevRevID)
{
// Revision IDs have a generation count, a hyphen, and a hex digest
var generation = 0;
if (prevRevID != null)
{
generation = prevRevID.Generation;
if (generation == 0)
{
return(null);
}
}
// Generate a digest for this revision based on the previous revision ID, document JSON,
// and attachment digests. This doesn't need to be secure; we just need to ensure that this
// code consistently generates the same ID given equivalent revisions.
MessageDigest md5Digest;
try {
md5Digest = MessageDigest.GetInstance("MD5");
} catch (NotSupportedException) {
throw Misc.CreateExceptionAndLog(Log.To.Database, Tag, "Failed to acquire a class to create MD5");
}
if (prevRevID != null)
{
var prevIDData = prevRevID.AsData();
var length = prevIDData.Length;
var lengthByte = unchecked ((byte)(length & unchecked ((0xFF))));
md5Digest.Update(lengthByte);
if (lengthByte > 0)
{
md5Digest.Update(prevIDData);
}
}
var isDeleted = deleted ? 1 : 0;
md5Digest.Update((byte)isDeleted);
if (json != null)
{
md5Digest.Update(json.ToArray());
}
var md5DigestResult = md5Digest.Digest();
var digestAsHex = BitConverter.ToString(md5DigestResult).Replace("-", String.Empty);
int generationIncremented = generation + 1;
return(RevisionIDFactory.FromString(String.Format("{0}-{1}", generationIncremented, digestAsHex).ToLower()));
}
internal static int CBLCollateRevIDs(string revId1, string revId2)
{
var parsed1 = RevisionID.ParseRevId(revId1);
var parsed2 = RevisionID.ParseRevId(revId2);
// improper rev IDs; just compare as plain text:
if (parsed1.Item1 == -1 || parsed2.Item1 == -1)
{
var gen1 = RevisionID.GetGeneration(revId1);
var gen2 = RevisionID.GetGeneration(revId2);
if (gen1 != 0 && gen2 != 0)
{
return(gen1 - gen2);
}
// improper rev IDs; just compare as plain text:
return(String.Compare(revId1, revId2, true, CultureInfo.InvariantCulture));
}
// Compare generation numbers; if they match, compare suffixes:
if (parsed1.Item1 != parsed2.Item1)
{
return(parsed1.Item1 - parsed2.Item1);
}
else
{
if (parsed1.Item2 != null && parsed2.Item2 != null)
{
// compare suffixes if possible
return(String.CompareOrdinal(parsed1.Item2, parsed2.Item2));
}
else
{
// just compare as plain text:
return(String.Compare(revId1, revId2, true, CultureInfo.InvariantCulture));
}
}
}
public int Compare(RevisionID x, RevisionID y)
{
return(x.CompareTo(y));
}
