/**
* Finds range of server deltas needed to transform against, then transforms all client ops
* against the server ops.
*/
private VersionedWaveletDelta transformSubmittedDelta(
WaveletDelta submittedDelta, HashedVersion appliedVersion)
throws OperationException, InvalidHashException {
NavigableSet<VersionedWaveletDelta> serverDeltas =
deserializedTransformedDeltas.tailSet(
deserializedTransformedDeltas.floor(
emptyDeserializedDeltaAtVersion(appliedVersion.getVersion())),
true);
if (serverDeltas.size() == 0) {
LOG.warning("Got empty server set, but not sumbitting to head! " + submittedDelta);
// Not strictly an invalid hash, but it's a related issue
throw new InvalidHashException("Cannot submit to head");
}
// Confirm that the target version/hash of this delta is valid.
if (!serverDeltas.first().version.equals(appliedVersion)) {
LOG.warning(
"Mismatched hashes: expected: "
+ serverDeltas.first().version
+ " got: "
+ appliedVersion);
// Don't leak the hash to the client in the error message.
throw new InvalidHashException("Mismatched hashes at version " + appliedVersion.getVersion());
}
ParticipantId clientAuthor = submittedDelta.getAuthor();
List<WaveletOperation> clientOps = submittedDelta.getOperations();
for (VersionedWaveletDelta d : serverDeltas) {
// If the client delta transforms to nothing before we've traversed all the server
// deltas, return the version at which the delta was obliterated (rather than the
// current version) to ensure that delta submission is idempotent.
if (clientOps.isEmpty()) {
return new VersionedWaveletDelta(new WaveletDelta(clientAuthor, clientOps), d.version);
}
ParticipantId serverAuthor = d.delta.getAuthor();
List<WaveletOperation> serverOps = d.delta.getOperations();
if (clientAuthor.equals(serverAuthor) && clientOps.equals(serverOps)) {
return d;
}
clientOps = transformOps(clientOps, clientAuthor, serverOps, serverAuthor);
}
return new VersionedWaveletDelta(new WaveletDelta(clientAuthor, clientOps), currentVersion);
}
/**
* Transform a wavelet delta if it has been submitted against a different head (currentVersion).
* Must be called with write lock held.
*
* @param delta to possibly transform
* @param appliedVersion that the delta is applied to
* @return the transformed delta and the version it was applied at (the version is the current
* version of the wavelet, unless the delta is a duplicate in which case it is the version at
* which it was originally applied)
* @throws InvalidHashException if submitting against same version but different hash
* @throws OperationException if transformation fails
*/
protected VersionedWaveletDelta maybeTransformSubmittedDelta(
WaveletDelta delta, HashedVersion appliedVersion)
throws InvalidHashException, OperationException {
if (appliedVersion.equals(currentVersion)) {
// Applied version is the same, we're submitting against head, don't need to do OT
return new VersionedWaveletDelta(delta, appliedVersion);
} else {
// Not submitting against head, we need to do OT, but check the versions really are different
if (appliedVersion.getVersion() == currentVersion.getVersion()) {
LOG.warning(
"Same version ("
+ currentVersion.getVersion()
+ ") but different hashes ("
+ appliedVersion
+ "/"
+ currentVersion
+ ")");
throw new InvalidHashException(
"Different hash, same version: " + currentVersion.getVersion());
} else {
return transformSubmittedDelta(delta, appliedVersion);
}
}
}
/**
* Returns the applied delta that was applied at a given hashed version.
*
* @param version the version to look up
* @return the applied delta applied at the specified hashed version
*/
protected ByteStringMessage<ProtocolAppliedWaveletDelta> lookupAppliedDelta(
HashedVersion version) {
return appliedDeltas.floor(emptyAppliedDeltaAtVersion(version.getVersion()));
}
/**
* Return a dummy VersionedWaveletDelta instance used as a range boundary for use in searches
* within a NavigableSet of deltas.
*
* @param version the version with which to return the versioned delta
* @return a dummy versioned delta with a null delta
*/
private static VersionedWaveletDelta emptyDeserializedDeltaAtVersion(final long version) {
return new VersionedWaveletDelta(null, HashedVersion.unsigned(version));
}
/**
* Return a dummy ProtocolWaveletDelta instance used as a range boundary for use in searches
* within a NavigableSet of deltas.
*
* @param version the version to return the delta applied at
* @return the generated dummy delta
*/
private static ProtocolWaveletDelta emptyDeltaAtVersion(final long version) {
return ProtocolWaveletDelta.newBuilder()
.setAuthor("dummy")
.setHashedVersion(WaveletOperationSerializer.serialize(HashedVersion.unsigned(version)))
.build();
}
