/**
* Remove all the local of a context (but keep global).
*
* @param context a counter context
* @return a version of {@code context} where no shards are local.
*/
public ByteBuffer clearAllLocal(ByteBuffer context) {
int count = Math.abs(context.getShort(context.position()));
if (count == 0) return context; // no local or global shards present.
List<Short> globalShardIndexes = new ArrayList<>(count);
for (int i = 0; i < count; i++) {
short elt = context.getShort(context.position() + HEADER_SIZE_LENGTH + i * HEADER_ELT_LENGTH);
if (elt < 0) globalShardIndexes.add(elt);
}
if (count == globalShardIndexes.size()) return context; // no local shards detected.
// allocate a smaller BB for the cleared context - with no local header elts.
ByteBuffer cleared =
ByteBuffer.allocate(
context.remaining() - (count - globalShardIndexes.size()) * HEADER_ELT_LENGTH);
cleared.putShort(cleared.position(), (short) globalShardIndexes.size());
for (int i = 0; i < globalShardIndexes.size(); i++)
cleared.putShort(
cleared.position() + HEADER_SIZE_LENGTH + i * HEADER_ELT_LENGTH,
globalShardIndexes.get(i));
int origHeaderLength = headerLength(context);
ByteBufferUtil.arrayCopy(
context,
context.position() + origHeaderLength,
cleared,
cleared.position() + headerLength(cleared),
context.remaining() - origHeaderLength);
return cleared;
}
public Validator(TreeRequest request) {
this(
request,
// TODO: memory usage (maxsize) should either be tunable per
// CF, globally, or as shared for all CFs in a cluster
new MerkleTree(
DatabaseDescriptor.getPartitioner(),
request.range,
MerkleTree.RECOMMENDED_DEPTH,
(int) Math.pow(2, 15)));
}
/** Detects whether or not the context has any legacy (local or remote) shards in it. */
public boolean hasLegacyShards(ByteBuffer context) {
int totalCount = (context.remaining() - headerLength(context)) / STEP_LENGTH;
int localAndGlobalCount = Math.abs(context.getShort(context.position()));
if (localAndGlobalCount < totalCount) return true; // remote shard(s) present
for (int i = 0; i < localAndGlobalCount; i++)
if (context.getShort(context.position() + HEADER_SIZE_LENGTH + i * HEADER_ELT_LENGTH) >= 0)
return true; // found a local shard
return false;
}
private static int headerLength(ByteBuffer context) {
return HEADER_SIZE_LENGTH + Math.abs(context.getShort(context.position())) * HEADER_ELT_LENGTH;
}
