CavalliumDBEngine/src/main/java/it/cavallium/dbengine/database/disk/LLLocalGroupedReactiveRocksIterator.java
2021-05-03 21:41:51 +02:00

113 lines
3.2 KiB
Java

package it.cavallium.dbengine.database.disk;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.ByteBufUtil;
import it.cavallium.dbengine.database.LLRange;
import it.cavallium.dbengine.database.LLUtils;
import it.cavallium.dbengine.database.collections.DatabaseMapDictionaryDeep;
import it.unimi.dsi.fastutil.objects.ObjectArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicBoolean;
import org.rocksdb.ColumnFamilyHandle;
import org.rocksdb.ReadOptions;
import org.rocksdb.RocksDB;
import org.rocksdb.RocksMutableObject;
import reactor.core.publisher.Flux;
import static io.netty.buffer.Unpooled.*;
public abstract class LLLocalGroupedReactiveRocksIterator<T> {
private final RocksDB db;
private final ByteBufAllocator alloc;
private final ColumnFamilyHandle cfh;
private final int prefixLength;
private final LLRange range;
private final ReadOptions readOptions;
private final boolean canFillCache;
private final boolean readValues;
public LLLocalGroupedReactiveRocksIterator(RocksDB db, ByteBufAllocator alloc, ColumnFamilyHandle cfh,
int prefixLength,
LLRange range,
ReadOptions readOptions,
boolean canFillCache,
boolean readValues) {
this.db = db;
this.alloc = alloc;
this.cfh = cfh;
this.prefixLength = prefixLength;
this.range = range;
this.readOptions = readOptions;
this.canFillCache = canFillCache;
this.readValues = readValues;
}
public Flux<List<T>> flux() {
return Flux
.generate(() -> {
var readOptions = new ReadOptions(this.readOptions);
readOptions.setFillCache(canFillCache && range.hasMin() && range.hasMax());
return LLLocalDictionary.getRocksIterator(readOptions, range.retain(), db, cfh);
}, (tuple, sink) -> {
range.retain();
try {
var rocksIterator = tuple.getT1();
ObjectArrayList<T> values = new ObjectArrayList<>();
ByteBuf firstGroupKey = null;
try {
while (rocksIterator.isValid()) {
ByteBuf key = LLUtils.readDirectNioBuffer(alloc, rocksIterator::key);
try {
if (firstGroupKey == null) {
firstGroupKey = key.retain();
} else if (!ByteBufUtil.equals(firstGroupKey, firstGroupKey.readerIndex(), key, key.readerIndex(), prefixLength)) {
break;
}
ByteBuf value;
if (readValues) {
value = LLUtils.readDirectNioBuffer(alloc, rocksIterator::value);
} else {
value = alloc.buffer(0);
}
try {
rocksIterator.next();
T entry = getEntry(key.retain(), value.retain());
values.add(entry);
} finally {
value.release();
}
} finally {
key.release();
}
}
} finally {
if (firstGroupKey != null) {
firstGroupKey.release();
}
}
if (!values.isEmpty()) {
sink.next(values);
} else {
sink.complete();
}
return tuple;
} finally {
range.release();
}
}, tuple -> {
var rocksIterator = tuple.getT1();
rocksIterator.close();
tuple.getT2().release();
tuple.getT3().release();
});
}
public abstract T getEntry(ByteBuf key, ByteBuf value);
public void release() {
range.release();
}
}