88 lines
2.7 KiB
Java
88 lines
2.7 KiB
Java
package it.cavallium.dbengine.database.disk;
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import it.cavallium.dbengine.database.LLSingleton;
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import it.cavallium.dbengine.database.LLSnapshot;
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import java.io.IOException;
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import java.util.Arrays;
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import java.util.function.Function;
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import org.jetbrains.annotations.Nullable;
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import org.rocksdb.ColumnFamilyHandle;
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import org.rocksdb.ReadOptions;
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import org.rocksdb.RocksDB;
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import org.rocksdb.RocksDBException;
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import org.rocksdb.Snapshot;
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import reactor.core.publisher.Mono;
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import reactor.core.scheduler.Scheduler;
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import reactor.core.scheduler.Schedulers;
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public class LLLocalSingleton implements LLSingleton {
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private static final ReadOptions EMPTY_READ_OPTIONS = new ReadOptions();
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private final RocksDB db;
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private final ColumnFamilyHandle cfh;
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private final Function<LLSnapshot, Snapshot> snapshotResolver;
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private final byte[] name;
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private final String databaseName;
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private final Scheduler dbScheduler;
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public LLLocalSingleton(RocksDB db, ColumnFamilyHandle singletonListColumn,
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Function<LLSnapshot, Snapshot> snapshotResolver,
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String databaseName,
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byte[] name,
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Scheduler dbScheduler,
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byte[] defaultValue) throws RocksDBException {
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this.db = db;
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this.cfh = singletonListColumn;
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this.databaseName = databaseName;
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this.snapshotResolver = snapshotResolver;
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this.name = name;
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this.dbScheduler = dbScheduler;
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if (Schedulers.isInNonBlockingThread()) {
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throw new UnsupportedOperationException("Initialized in a nonblocking thread");
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}
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if (db.get(cfh, this.name) == null) {
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db.put(cfh, this.name, defaultValue);
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}
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}
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private ReadOptions resolveSnapshot(LLSnapshot snapshot) {
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if (snapshot != null) {
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return new ReadOptions().setSnapshot(snapshotResolver.apply(snapshot));
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} else {
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return EMPTY_READ_OPTIONS;
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}
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}
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@Override
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public Mono<byte[]> get(@Nullable LLSnapshot snapshot) {
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return Mono
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.fromCallable(() -> {
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if (Schedulers.isInNonBlockingThread()) {
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throw new UnsupportedOperationException("Called get in a nonblocking thread");
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}
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return db.get(cfh, resolveSnapshot(snapshot), name);
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})
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.onErrorMap(cause -> new IOException("Failed to read " + Arrays.toString(name), cause))
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.subscribeOn(dbScheduler);
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}
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@Override
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public Mono<Void> set(byte[] value) {
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return Mono
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.<Void>fromCallable(() -> {
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if (Schedulers.isInNonBlockingThread()) {
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throw new UnsupportedOperationException("Called set in a nonblocking thread");
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}
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db.put(cfh, name, value);
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return null;
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})
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.onErrorMap(cause -> new IOException("Failed to write " + Arrays.toString(name), cause))
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.subscribeOn(dbScheduler);
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}
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@Override
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public String getDatabaseName() {
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return databaseName;
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}
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}
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