lmdbjava/src/main/java/org/lmdbjava/Env.java at gh-267 · lmdbjava/lmdbjava · GitHub

History

676 lines (609 loc) · 21 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

408

409

410

411

412

413

414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

435

436

437

438

439

440

441

442

443

444

445

446

447

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

497

498

499

500

501

502

503

504

505

506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

558

559

560

561

562

563

564

565

566

567

568

569

570

571

572

573

574

575

576

577

578

579

580

581

582

583

584

585

586

587

588

589

590

591

592

593

594

595

596

597

598

599

600

601

602

603

604

605

606

607

608

609

610

611

612

613

614

615

616

617

618

619

620

621

622

623

624

625

626

627

628

629

630

631

632

633

634

635

636

637

638

639

640

641

642

643

644

645

646

647

648

649

650

651

652

653

654

655

656

657

658

659

660

661

662

663

664

665

666

667

668

669

670

671

672

673

674

675

676

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

* http://www.apache.org/licenses/LICENSE-2.0

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

package org.lmdbjava;

import static java.lang.Boolean.getBoolean;

import static java.nio.charset.StandardCharsets.UTF_8;

import static java.util.Objects.requireNonNull;

import static org.lmdbjava.ByteBufferProxy.PROXY_OPTIMAL;

import static org.lmdbjava.EnvFlags.MDB_NOSUBDIR;

import static org.lmdbjava.EnvFlags.MDB_RDONLY_ENV;

import static org.lmdbjava.Library.LIB;

import static org.lmdbjava.Library.RUNTIME;

import static org.lmdbjava.MaskedFlag.isSet;

import static org.lmdbjava.MaskedFlag.mask;

import static org.lmdbjava.ResultCodeMapper.checkRc;

import static org.lmdbjava.TxnFlags.MDB_RDONLY_TXN;

import java.io.File;

import java.nio.ByteBuffer;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

import jnr.ffi.Pointer;

import jnr.ffi.byref.IntByReference;

import jnr.ffi.byref.PointerByReference;

import org.lmdbjava.Library.MDB_envinfo;

import org.lmdbjava.Library.MDB_stat;

/**

* LMDB environment.

* @param <T> buffer type

public final class Env<T> implements AutoCloseable {

/** Java system property name that can be set to disable optional checks. */

public static final String DISABLE_CHECKS_PROP = "lmdbjava.disable.checks";

/**

* Indicates whether optional checks should be applied in LmdbJava. Optional checks are only

* disabled in critical paths (see package-level JavaDocs). Non-critical paths have optional

* checks performed at all times, regardless of this property.

public static final boolean SHOULD_CHECK = !getBoolean(DISABLE_CHECKS_PROP);

private boolean closed;

private final int maxKeySize;

private final boolean noSubDir;

private final BufferProxy<T> proxy;

private final Pointer ptr;

private final boolean readOnly;

private Env(

final BufferProxy<T> proxy,

final Pointer ptr,

final boolean readOnly,

final boolean noSubDir) {

this.proxy = proxy;

this.readOnly = readOnly;

this.noSubDir = noSubDir;

this.ptr = ptr;

// cache max key size to avoid further JNI calls

this.maxKeySize = LIB.mdb_env_get_maxkeysize(ptr);

}

/**

* Create an {@link Env} using the {@link ByteBufferProxy#PROXY_OPTIMAL}.

* @return the environment (never null)

public static Builder<ByteBuffer> create() {

return new Builder<>(PROXY_OPTIMAL);

}

/**

* Create an {@link Env} using the passed {@link BufferProxy}.

* @param <T> buffer type

* @param proxy the proxy to use (required)

* @return the environment (never null)

public static <T> Builder<T> create(final BufferProxy<T> proxy) {

return new Builder<>(proxy);

}

/**

* Opens an environment with a single default database in 0664 mode using the {@link

* ByteBufferProxy#PROXY_OPTIMAL}.

* @param path file system destination

* @param size size in megabytes

* @param flags the flags for this new environment

* @return env the environment (never null)

public static Env<ByteBuffer> open(final File path, final int size, final EnvFlags... flags) {

return new Builder<>(PROXY_OPTIMAL).setMapSize(size * 1_024L * 1_024L).open(path, flags);

}

/**

* Close the handle.

* Will silently return if already closed or never opened.

@Override

public void close() {

if (closed) {

return;

}

closed = true;

LIB.mdb_env_close(ptr);

}

/**

* Copies an LMDB environment to the specified destination path.

* This function may be used to make a backup of an existing environment. No lockfile is

* created, since it gets recreated at need.

* If this environment was created using {@link EnvFlags#MDB_NOSUBDIR}, the destination path

* must be a directory that exists but contains no files. If {@link EnvFlags#MDB_NOSUBDIR} was

* used, the destination path must not exist, but it must be possible to create a file at the

* provided path.

* Note: This call can trigger significant file size growth if run in parallel with write

* transactions, because it employs a read-only transaction. See long-lived transactions under

* "Caveats" in the LMDB native documentation.

* @param path writable destination path as described above

* @param flags special options for this copy

public void copy(final File path, final CopyFlags... flags) {

requireNonNull(path);

validatePath(path);

final int flagsMask = mask(true, flags);

checkRc(LIB.mdb_env_copy2(ptr, path.getAbsolutePath(), flagsMask));

}

/**

* Obtain the DBI names.

* This method is only compatible with {@link Env}s that use named databases. If an unnamed

* {@link Dbi} is being used to store data, this method will attempt to return all such keys from

* the unnamed database.

* This method must not be called from concurrent threads.

* @return a list of DBI names (never null)

public List<byte[]> getDbiNames() {

final List<byte[]> result = new ArrayList<>();

final Dbi<T> names = openDbi((byte[]) null);

try (Txn<T> txn = txnRead();

Cursor<T> cursor = names.openCursor(txn)) {

if (!cursor.first()) {

return Collections.emptyList();

}

do {

final byte[] name = proxy.getBytes(cursor.key());

result.add(name);

} while (cursor.next());

}

return result;

}

/**

* Set the size of the data memory map.

* @param mapSize the new size, in bytes

public void setMapSize(final long mapSize) {

checkRc(LIB.mdb_env_set_mapsize(ptr, mapSize));

}

/**

* Get the maximum size of keys and MDB_DUPSORT data we can write.

* @return the maximum size of keys.

public int getMaxKeySize() {

return maxKeySize;

}

/**

* Return information about this environment.

* @return an immutable information object.

public EnvInfo info() {

if (closed) {

throw new AlreadyClosedException();

}

final MDB_envinfo info = new MDB_envinfo(RUNTIME);

checkRc(LIB.mdb_env_info(ptr, info));

final long mapAddress;

if (info.f0_me_mapaddr.get() == null) {

mapAddress = 0;

} else {

mapAddress = info.f0_me_mapaddr.get().address();

}

return new EnvInfo(

mapAddress,

info.f1_me_mapsize.longValue(),

info.f2_me_last_pgno.longValue(),

info.f3_me_last_txnid.longValue(),

info.f4_me_maxreaders.intValue(),

info.f5_me_numreaders.intValue());

}

/**

* Indicates whether this environment has been closed.

* @return true if closed

public boolean isClosed() {

return closed;

}

/**

* Indicates if this environment was opened with {@link EnvFlags#MDB_RDONLY_ENV}.

* @return true if read-only

public boolean isReadOnly() {

return readOnly;

}

/**

* Convenience method that opens a {@link Dbi} with a UTF-8 database name and default {@link

* Comparator} that is not invoked from native code.

* @param name name of the database (or null if no name is required)

* @param flags to open the database with

* @return a database that is ready to use

public Dbi<T> openDbi(final String name, final DbiFlags... flags) {

final byte[] nameBytes = name == null ? null : name.getBytes(UTF_8);

return openDbi(nameBytes, null, false, flags);

}

/**

* Convenience method that opens a {@link Dbi} with a UTF-8 database name and associated {@link

* Comparator} that is not invoked from native code.

* @param name name of the database (or null if no name is required)

* @param comparator custom comparator callback (or null to use default)

* @param flags to open the database with

* @return a database that is ready to use

public Dbi<T> openDbi(

final String name, final Comparator<T> comparator, final DbiFlags... flags) {

final byte[] nameBytes = name == null ? null : name.getBytes(UTF_8);

return openDbi(nameBytes, comparator, false, flags);

}

/**

* Convenience method that opens a {@link Dbi} with a UTF-8 database name and associated {@link

* Comparator} that may be invoked from native code if specified.

* @param name name of the database (or null if no name is required)

* @param comparator custom comparator callback (or null to use default)

* @param nativeCb whether native code calls back to the Java comparator

* @param flags to open the database with

* @return a database that is ready to use

public Dbi<T> openDbi(

final String name,

final Comparator<T> comparator,

final boolean nativeCb,

final DbiFlags... flags) {

final byte[] nameBytes = name == null ? null : name.getBytes(UTF_8);

return openDbi(nameBytes, comparator, nativeCb, flags);

}

/**

* Convenience method that opens a {@link Dbi} with a default {@link Comparator} that is not

* invoked from native code.

* @param name name of the database (or null if no name is required)

* @param flags to open the database with

* @return a database that is ready to use

public Dbi<T> openDbi(final byte[] name, final DbiFlags... flags) {

return openDbi(name, null, false, flags);

}

/**

* Convenience method that opens a {@link Dbi} with an associated {@link Comparator} that is not

* invoked from native code.

* @param name name of the database (or null if no name is required)

* @param comparator custom comparator callback (or null to use LMDB default)

* @param flags to open the database with

* @return a database that is ready to use

public Dbi<T> openDbi(

final byte[] name, final Comparator<T> comparator, final DbiFlags... flags) {

return openDbi(name, comparator, false, flags);

}

/**

* Convenience method that opens a {@link Dbi} with an associated {@link Comparator} that may be

* invoked from native code if specified.

* This method will automatically commit the private transaction before returning. This ensures

* the <code>Dbi</code> is available in the <code>Env</code>.

* @param name name of the database (or null if no name is required)

* @param comparator custom comparator callback (or null to use LMDB default)

* @param nativeCb whether native code calls back to the Java comparator

* @param flags to open the database with

* @return a database that is ready to use

public Dbi<T> openDbi(

final byte[] name,

final Comparator<T> comparator,

final boolean nativeCb,

final DbiFlags... flags) {

try (Txn<T> txn = readOnly ? txnRead() : txnWrite()) {

final Dbi<T> dbi = openDbi(txn, name, comparator, nativeCb, flags);

txn.commit(); // even RO Txns require a commit to retain Dbi in Env

return dbi;

}

/**

* Open the {@link Dbi} using the passed {@link Txn}.

* The caller must commit the transaction after this method returns in order to retain the

* <code>Dbi</code> in the <code>Env</code>.

* A {@link Comparator} may be provided when calling this method. Such comparator is primarily

* used by {@link CursorIterable} instances. A secondary (but uncommon) use of the comparator is

* to act as a callback from the native library if <code>nativeCb</code> is <code>true</code>.

* This is usually avoided due to the overhead of native code calling back into Java. It is

* instead highly recommended to set the correct {@link DbiFlags} to allow the native library to

* correctly order the intended keys.

* A default comparator will be provided if <code>null</code> is passed as the comparator. If a

* custom comparator is provided, it must strictly match the lexicographical order of keys in the

* native LMDB database.

* This method (and its overloaded convenience variants) must not be called from concurrent

* threads.

* @param txn transaction to use (required; not closed)

* @param name name of the database (or null if no name is required)

* @param comparator custom comparator callback (or null to use LMDB default)

* @param nativeCb whether native code should call back to the comparator

* @param flags to open the database with

* @return a database that is ready to use

public Dbi<T> openDbi(

final Txn<T> txn,

final byte[] name,

final Comparator<T> comparator,

final boolean nativeCb,

final DbiFlags... flags) {

return new Dbi<>(this, txn, name, comparator, nativeCb, proxy, flags);

}

/**

* Return statistics about this environment.

* @return an immutable statistics object.

public Stat stat() {

if (closed) {

throw new AlreadyClosedException();

}

final MDB_stat stat = new MDB_stat(RUNTIME);

checkRc(LIB.mdb_env_stat(ptr, stat));

return new Stat(

stat.f0_ms_psize.intValue(),

stat.f1_ms_depth.intValue(),

stat.f2_ms_branch_pages.longValue(),

stat.f3_ms_leaf_pages.longValue(),

stat.f4_ms_overflow_pages.longValue(),

stat.f5_ms_entries.longValue());

}

/**

* Flushes the data buffers to disk.

* @param force force a synchronous flush (otherwise if the environment has the MDB_NOSYNC flag

* set the flushes will be omitted, and with MDB_MAPASYNC they will be asynchronous)

public void sync(final boolean force) {

if (closed) {

throw new AlreadyClosedException();

}

final int f = force ? 1 : 0;

checkRc(LIB.mdb_env_sync(ptr, f));

}

/**

* Obtain a transaction with the requested parent and flags.

* @param parent parent transaction (may be null if no parent)

* @param flags applicable flags (eg for a reusable, read-only transaction)

* @return a transaction (never null)

public Txn<T> txn(final Txn<T> parent, final TxnFlags... flags) {

if (closed) {

throw new AlreadyClosedException();

}

return new Txn<>(this, parent, proxy, flags);

}

/**

* Obtain a read-only transaction.

* @return a read-only transaction

public Txn<T> txnRead() {

return txn(null, MDB_RDONLY_TXN);

}

/**

* Obtain a read-write transaction.

* @return a read-write transaction

public Txn<T> txnWrite() {

return txn(null);

}

Pointer pointer() {

return ptr;

}

void checkNotClosed() {

if (closed) {

throw new AlreadyClosedException();

}

private void validateDirectoryEmpty(final File path) {

if (!path.exists()) {

throw new InvalidCopyDestination("Path does not exist");

}

if (!path.isDirectory()) {

throw new InvalidCopyDestination("Path must be a directory");

}

final String[] files = path.list();

if (files != null && files.length > 0) {

throw new InvalidCopyDestination("Path must contain no files");

}

private void validatePath(final File path) {

if (noSubDir) {

if (path.exists()) {

throw new InvalidCopyDestination("Path must not exist for MDB_NOSUBDIR");

}

return;

}

validateDirectoryEmpty(path);

}

/**

* Check for stale entries in the reader lock table.

* @return 0 on success, non-zero on failure

public int readerCheck() {

final IntByReference resultPtr = new IntByReference();

checkRc(LIB.mdb_reader_check(ptr, resultPtr));

return resultPtr.intValue();

}

/** Object has already been closed and the operation is therefore prohibited. */

public static final class AlreadyClosedException extends LmdbException {

private static final long serialVersionUID = 1L;

/** Creates a new instance. */

public AlreadyClosedException() {

super("Environment has already been closed");

}

/** Object has already been opened and the operation is therefore prohibited. */

public static final class AlreadyOpenException extends LmdbException {

private static final long serialVersionUID = 1L;

/** Creates a new instance. */

public AlreadyOpenException() {

super("Environment has already been opened");

}

/**

* Builder for configuring and opening Env.

* @param <T> buffer type

public static final class Builder<T> {

static final int MAX_READERS_DEFAULT = 126;

private long mapSize = 1_024 * 1_024;

private int maxDbs = 1;

private int maxReaders = MAX_READERS_DEFAULT;

private boolean opened;

private final BufferProxy<T> proxy;

Builder(final BufferProxy<T> proxy) {

requireNonNull(proxy);

this.proxy = proxy;

}

/**

* Opens the environment.

* @param path file system destination

* @param mode Unix permissions to set on created files and semaphores

* @param flags the flags for this new environment

* @return an environment ready for use

public Env<T> open(final File path, final int mode, final EnvFlags... flags) {

requireNonNull(path);

if (opened) {

throw new AlreadyOpenException();

}

opened = true;

final PointerByReference envPtr = new PointerByReference();

checkRc(LIB.mdb_env_create(envPtr));

final Pointer ptr = envPtr.getValue();

try {

checkRc(LIB.mdb_env_set_mapsize(ptr, mapSize));

checkRc(LIB.mdb_env_set_maxdbs(ptr, maxDbs));

checkRc(LIB.mdb_env_set_maxreaders(ptr, maxReaders));

final int flagsMask = mask(true, flags);

final boolean readOnly = isSet(flagsMask, MDB_RDONLY_ENV);

final boolean noSubDir = isSet(flagsMask, MDB_NOSUBDIR);

checkRc(LIB.mdb_env_open(ptr, path.getAbsolutePath(), flagsMask, mode));

return new Env<>(proxy, ptr, readOnly, noSubDir);

} catch (final LmdbNativeException e) {

LIB.mdb_env_close(ptr);

throw e;

}

/**

* Opens the environment with 0664 mode.

* @param path file system destination

* @param flags the flags for this new environment

* @return an environment ready for use

public Env<T> open(final File path, final EnvFlags... flags) {

return open(path, 0664, flags);

}

/**

* Sets the map size.

* @param mapSize new limit in bytes

* @return the builder

public Builder<T> setMapSize(final long mapSize) {

if (opened) {

throw new AlreadyOpenException();

}

if (mapSize < 0) {

throw new IllegalArgumentException("Negative value; overflow?");

}

this.mapSize = mapSize;

return this;

}

/**

* Sets the maximum number of databases (ie {@link Dbi}s permitted.

* @param dbs new limit

* @return the builder

public Builder<T> setMaxDbs(final int dbs) {

if (opened) {

throw new AlreadyOpenException();

}

this.maxDbs = dbs;

return this;

}

/**

* Sets the maximum number of databases permitted.

* @param readers new limit

* @return the builder

public Builder<T> setMaxReaders(final int readers) {

if (opened) {

throw new AlreadyOpenException();

}

this.maxReaders = readers;

return this;

}

/** File is not a valid LMDB file. */

public static final class FileInvalidException extends LmdbNativeException {

static final int MDB_INVALID = -30_793;

private static final long serialVersionUID = 1L;

FileInvalidException() {

super(MDB_INVALID, "File is not a valid LMDB file");

}

/** The specified copy destination is invalid. */

public static final class InvalidCopyDestination extends LmdbException {

private static final long serialVersionUID = 1L;

/**

* Creates a new instance.

* @param message the reason

public InvalidCopyDestination(final String message) {

super(message);

}

/** Environment mapsize reached. */

public static final class MapFullException extends LmdbNativeException {

static final int MDB_MAP_FULL = -30_792;

private static final long serialVersionUID = 1L;

MapFullException() {

super(MDB_MAP_FULL, "Environment mapsize reached");

}

/** Environment maxreaders reached. */

public static final class ReadersFullException extends LmdbNativeException {

static final int MDB_READERS_FULL = -30_790;

private static final long serialVersionUID = 1L;

ReadersFullException() {

super(MDB_READERS_FULL, "Environment maxreaders reached");

}

/** Environment version mismatch. */

public static final class VersionMismatchException extends LmdbNativeException {

static final int MDB_VERSION_MISMATCH = -30_794;

private static final long serialVersionUID = 1L;

VersionMismatchException() {

super(MDB_VERSION_MISMATCH, "Environment version mismatch");

}

lmdbjava/src/main/java/org/lmdbjava/Env.java at gh-267 · lmdbjava/lmdbjava · GitHub

Uh oh!

Expand file tree

Breadcrumbs

Env.java

Latest commit

History

Breadcrumbs

Env.java

File metadata and controls