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GeezerVison is showing github.com — lmdbjava/src/main/java/org/lmdbjava/Cursor.java at master · lmdbjava/lmdbjava Expand file tree/ Copy pathCursor.javaMore file actions 547 lines (500 loc) · 17.7 KB / Copy pathCursor.javaFile metadata and controls547 lines (500 loc) · 17.7 KB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 /* * Copyright © 2016-2025 The LmdbJava Open Source Project * * 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.util.Objects.requireNonNull; import static org.lmdbjava.Dbi.KeyExistsException.MDB_KEYEXIST; import static org.lmdbjava.Dbi.KeyNotFoundException.MDB_NOTFOUND; import static org.lmdbjava.Env.SHOULD_CHECK; import static org.lmdbjava.Library.LIB; import static org.lmdbjava.PutFlags.MDB_MULTIPLE; import static org.lmdbjava.PutFlags.MDB_NODUPDATA; import static org.lmdbjava.PutFlags.MDB_NOOVERWRITE; import static org.lmdbjava.PutFlags.MDB_RESERVE; import static org.lmdbjava.ResultCodeMapper.checkRc; import static org.lmdbjava.SeekOp.MDB_FIRST; import static org.lmdbjava.SeekOp.MDB_LAST; import static org.lmdbjava.SeekOp.MDB_NEXT; import static org.lmdbjava.SeekOp.MDB_PREV; import jnr.ffi.Pointer; import jnr.ffi.byref.NativeLongByReference; /** * A cursor handle. * * @param <T> buffer type */ public final class Cursor<T> implements AutoCloseable { private boolean closed; private final KeyVal<T> kv; private final Pointer ptrCursor; private Txn<T> txn; private final Env<T> env; Cursor(final Pointer ptr, final Txn<T> txn, final Env<T> env) { requireNonNull(ptr); requireNonNull(txn); this.ptrCursor = ptr; this.txn = txn; this.kv = txn.newKeyVal(); this.env = env; } /** * Close a cursor handle. * * <p>The cursor handle will be freed and must not be used again after this call. Its transaction * must still be live if it is a write-transaction. */ @Override public void close() { if (closed) { return; } kv.close(); if (SHOULD_CHECK) { env.checkNotClosed(); if (!txn.isReadOnly()) { txn.checkReady(); } } LIB.mdb_cursor_close(ptrCursor); closed = true; } /** * Return count of duplicates for current key. * * <p>This call is only valid on databases that support sorted duplicate data items {@link * DbiFlags#MDB_DUPSORT}. * * @return count of duplicates for current key */ public long count() { if (SHOULD_CHECK) { env.checkNotClosed(); checkNotClosed(); txn.checkReady(); } final NativeLongByReference longByReference = new NativeLongByReference(); checkRc(LIB.mdb_cursor_count(ptrCursor, longByReference)); return longByReference.longValue(); } /** * @deprecated Instead use {@link Cursor#delete(PutFlagSet)}. <hr> Delete current key/data pair. * <p>This function deletes the key/data pair to which the cursor refers. * @param flags flags (either null or {@link PutFlags#MDB_NODUPDATA} */ @Deprecated public void delete(final PutFlags... flags) { delete(PutFlagSet.of(flags)); } /** * Delete current key/data pair. * * <p>This function deletes the key/data pair to which the cursor refers. */ public void delete() { delete(PutFlagSet.EMPTY); } /** * Delete current key/data pair. * * <p>This function deletes the key/data pair to which the cursor refers. * * @param flags flags (either null or {@link PutFlags#MDB_NODUPDATA} */ public void delete(final PutFlagSet flags) { if (SHOULD_CHECK) { env.checkNotClosed(); checkNotClosed(); txn.checkReady(); txn.checkWritesAllowed(); } final PutFlagSet putFlagSet = flags != null ? flags : PutFlagSet.EMPTY; checkRc(LIB.mdb_cursor_del(ptrCursor, putFlagSet.getMask())); } /** * Position at first key/data item. * * @return false if requested position not found */ public boolean first() { return seek(MDB_FIRST); } /** * Reposition the key/value buffers based on the passed key and operation. * * @param key to search for * @param data to search for * @param op options for this operation * @return false if key not found */ public boolean get(final T key, final T data, final SeekOp op) { if (SHOULD_CHECK) { requireNonNull(key); requireNonNull(op); env.checkNotClosed(); checkNotClosed(); txn.checkReady(); } final Pointer transientKey = kv.keyIn(key); final Pointer transientVal = kv.valIn(data); final int rc = LIB.mdb_cursor_get(ptrCursor, kv.pointerKey(), kv.pointerVal(), op.getCode()); if (rc == MDB_NOTFOUND) { return false; } checkRc(rc); kv.keyOut(); kv.valOut(); ReferenceUtil.reachabilityFence0(transientKey); ReferenceUtil.reachabilityFence0(transientVal); ReferenceUtil.reachabilityFence0(kv.key()); ReferenceUtil.reachabilityFence0(kv.val()); ReferenceUtil.reachabilityFence0(key); return true; } /** * Reposition the key/value buffers based on the passed key and operation. * * @param key to search for * @param op options for this operation * @return false if key not found */ public boolean get(final T key, final GetOp op) { if (SHOULD_CHECK) { requireNonNull(key); requireNonNull(op); env.checkNotClosed(); checkNotClosed(); txn.checkReady(); } final Pointer transientKey = kv.keyIn(key); final int rc = LIB.mdb_cursor_get(ptrCursor, kv.pointerKey(), kv.pointerVal(), op.getCode()); if (rc == MDB_NOTFOUND) { return false; } checkRc(rc); kv.keyOut(); kv.valOut(); ReferenceUtil.reachabilityFence0(transientKey); ReferenceUtil.reachabilityFence0(kv.key()); ReferenceUtil.reachabilityFence0(kv.val()); ReferenceUtil.reachabilityFence0(key); return true; } /** * Obtain the key. * * @return the key that the cursor is located at. */ public T key() { return kv.key(); } KeyVal<T> keyVal() { return kv; } /** * Position at last key/data item. * * @return false if requested position not found */ public boolean last() { return seek(MDB_LAST); } /** * Position at next data item. * * @return false if requested position not found */ public boolean next() { return seek(MDB_NEXT); } /** * Position at previous data item. * * @return false if requested position not found */ public boolean prev() { return seek(MDB_PREV); } /** * @deprecated Use {@link Cursor#put(Object, Object, PutFlagSet)} instead. <hr> Store by cursor. * <p>This function stores key/data pairs into the database. * @param key key to store * @param val data to store * @param flags options for this operation * @return true if the value was put, false if MDB_NOOVERWRITE or MDB_NODUPDATA were set and the * key/value existed already. */ @Deprecated public boolean put(final T key, final T val, final PutFlags... flags) { return put(key, val, PutFlagSet.of(flags)); } /** * Store by cursor. * * <p>This function stores key/data pairs into the database. * * @param key key to store * @param val data to store * @return true if the value was put, false if MDB_NOOVERWRITE or MDB_NODUPDATA were set and the * key/value existed already. */ public boolean put(final T key, final T val) { return put(key, val, PutFlagSet.EMPTY); } /** * Store by cursor. * * <p>This function stores key/data pairs into the database. * * @param key key to store * @param val data to store * @param flags options for this operation * @return true if the value was put, false if MDB_NOOVERWRITE or MDB_NODUPDATA were set and the * key/value existed already. */ public boolean put(final T key, final T val, final PutFlagSet flags) { if (SHOULD_CHECK) { requireNonNull(key); requireNonNull(val); requireNonNull(flags); env.checkNotClosed(); checkNotClosed(); txn.checkReady(); txn.checkWritesAllowed(); } final Pointer transientKey = kv.keyIn(key); final Pointer transientVal = kv.valIn(val); final int rc = LIB.mdb_cursor_put(ptrCursor, kv.pointerKey(), kv.pointerVal(), flags.getMask()); if (rc == MDB_KEYEXIST) { if (flags.isSet(MDB_NOOVERWRITE)) { kv.valOut(); // marked as in,out in LMDB C docs } else if (!flags.isSet(MDB_NODUPDATA)) { checkRc(rc); } return false; } checkRc(rc); ReferenceUtil.reachabilityFence0(transientKey); ReferenceUtil.reachabilityFence0(transientVal); ReferenceUtil.reachabilityFence0(key); ReferenceUtil.reachabilityFence0(val); return true; } /** * @deprecated Use {@link Cursor#put(Object, Object, PutFlagSet)} instead. <hr> Put multiple * values into the database in one <code>MDB_MULTIPLE</code> operation. * <p>The database must have been opened with {@link DbiFlags#MDB_DUPFIXED}. The buffer must * contain fixed-sized values to be inserted. The size of each element is calculated from the * buffer's size divided by the given element count. For example, to populate 10 X 4 byte * integers at once, present a buffer of 40 bytes and specify the element as 10. * @param key key to store in the database (not null) * @param val value to store in the database (not null) * @param elements number of elements contained in the passed value buffer * @param flags options for operation (must set <code>MDB_MULTIPLE</code>) */ @Deprecated public void putMultiple(final T key, final T val, final int elements, final PutFlags... flags) { putMultiple(key, val, elements, PutFlagSet.of(flags)); } /** * Put multiple values into the database in one <code>MDB_MULTIPLE</code> operation. * * <p>The database must have been opened with {@link DbiFlags#MDB_DUPFIXED}. The buffer must * contain fixed-sized values to be inserted. The size of each element is calculated from the * buffer's size divided by the given element count. For example, to populate 10 X 4 byte integers * at once, present a buffer of 40 bytes and specify the element as 10. * * @param key key to store in the database (not null) * @param val value to store in the database (not null) * @param elements number of elements contained in the passed value buffer */ public void putMultiple(final T key, final T val, final int elements) { putMultiple(key, val, elements, PutFlagSet.EMPTY); } /** * Put multiple values into the database in one <code>MDB_MULTIPLE</code> operation. * * <p>The database must have been opened with {@link DbiFlags#MDB_DUPFIXED}. The buffer must * contain fixed-sized values to be inserted. The size of each element is calculated from the * buffer's size divided by the given element count. For example, to populate 10 X 4 byte integers * at once, present a buffer of 40 bytes and specify the element as 10. * * @param key key to store in the database (not null) * @param val value to store in the database (not null) * @param elements number of elements contained in the passed value buffer * @param flags options for operation (must set <code>MDB_MULTIPLE</code>) Either a {@link * PutFlagSet} or a single {@link PutFlags}. */ public void putMultiple(final T key, final T val, final int elements, final PutFlagSet flags) { if (SHOULD_CHECK) { requireNonNull(txn); requireNonNull(key); requireNonNull(val); env.checkNotClosed(); txn.checkReady(); txn.checkWritesAllowed(); if (!flags.isSet(MDB_MULTIPLE)) { throw new IllegalArgumentException("Must set " + MDB_MULTIPLE + " flag"); } } final Pointer transientKey = txn.kv().keyIn(key); final Pointer dataPtr = txn.kv().valInMulti(val, elements); final int rc = LIB.mdb_cursor_put(ptrCursor, txn.kv().pointerKey(), dataPtr, flags.getMask()); checkRc(rc); ReferenceUtil.reachabilityFence0(transientKey); ReferenceUtil.reachabilityFence0(dataPtr); ReferenceUtil.reachabilityFence0(key); ReferenceUtil.reachabilityFence0(val); } /** * Renew a cursor handle. * * <p>A cursor is associated with a specific transaction and database. Cursors that are only used * in read-only transactions may be re-used, to avoid unnecessary malloc/free overhead. The cursor * may be associated with a new read-only transaction, and referencing the same database handle as * it was created with. This may be done whether the previous transaction is live or dead. * * @param newTxn transaction handle */ public void renew(final Txn<T> newTxn) { if (SHOULD_CHECK) { requireNonNull(newTxn); env.checkNotClosed(); checkNotClosed(); this.txn.checkReadOnly(); // existing newTxn.checkReadOnly(); newTxn.checkReady(); } checkRc(LIB.mdb_cursor_renew(newTxn.pointer(), ptrCursor)); this.txn = newTxn; } /** * @deprecated Use {@link Cursor#reserve(Object, int, PutFlagSet)} instead. <hr> Reserve space for * data of the given size, but don't copy the given val. Instead, return a pointer to the * reserved space, which the caller can fill in later - before the next update operation or * the transaction ends. This saves an extra memcpy if the data is being generated later. LMDB * does nothing else with this memory, the caller is expected to modify all of the space * requested. * <p>This flag must not be specified if the database was opened with MDB_DUPSORT * @param key key to store in the database (not null) * @param size size of the value to be stored in the database (not null) * @param flags options for this operation * @return a buffer that can be used to modify the value */ @Deprecated public T reserve(final T key, final int size, final PutFlags... flags) { return reserve(key, size, PutFlagSet.of(flags)); } /** * Reserve space for data of the given size, but don't copy the given val. Instead, return a * pointer to the reserved space, which the caller can fill in later - before the next update * operation or the transaction ends. This saves an extra {@code memcpy} if the data is being * generated later. LMDB does nothing else with this memory, the caller is expected to modify all * the space requested. * * <p>This flag must not be specified if the database was opened with MDB_DUPSORT * * @param key key to store in the database (not null) * @param size size of the value to be stored in the database (not null) * @return a buffer that can be used to modify the value */ public T reserve(final T key, final int size) { return reserve(key, size, PutFlagSet.EMPTY); } /** * Reserve space for data of the given size, but don't copy the given val. Instead, return a * pointer to the reserved space, which the caller can fill in later - before the next update * operation or the transaction ends. This saves an extra memcpy if the data is being generated * later. LMDB does nothing else with this memory, the caller is expected to modify all the space * requested. * * <p>This flag must not be specified if the database was opened with MDB_DUPSORT * * @param key key to store in the database (not null) * @param size size of the value to be stored in the database (not null) * @param flags options for this operation * @return a buffer that can be used to modify the value */ public T reserve(final T key, final int size, final PutFlagSet flags) { if (SHOULD_CHECK) { requireNonNull(key); requireNonNull(flags); env.checkNotClosed(); checkNotClosed(); txn.checkReady(); txn.checkWritesAllowed(); } final Pointer transientKey = kv.keyIn(key); final Pointer transientVal = kv.valIn(size); // This is inconsistent with putMultiple which require MDB_MULTIPLE to be in the set. final int flagsMask = flags.getMaskWith(MDB_RESERVE); checkRc(LIB.mdb_cursor_put(ptrCursor, kv.pointerKey(), kv.pointerVal(), flagsMask)); kv.valOut(); ReferenceUtil.reachabilityFence0(transientKey); ReferenceUtil.reachabilityFence0(transientVal); ReferenceUtil.reachabilityFence0(key); return val(); } /** * Reposition the key/value buffers based on the passed operation. * * @param op options for this operation * @return false if requested position not found */ public boolean seek(final SeekOp op) { if (SHOULD_CHECK) { requireNonNull(op); env.checkNotClosed(); checkNotClosed(); txn.checkReady(); } final int rc = LIB.mdb_cursor_get(ptrCursor, kv.pointerKey(), kv.pointerVal(), op.getCode()); if (rc == MDB_NOTFOUND) { return false; } checkRc(rc); kv.keyOut(); kv.valOut(); return true; } /** * Obtain the value. * * @return the value that the cursor is located at. */ public T val() { return kv.val(); } private void checkNotClosed() { if (closed) { throw new ClosedException(); } } /** Cursor has already been closed. */ public static final class ClosedException extends LmdbException { private static final long serialVersionUID = 1L; /** Creates a new instance. */ public ClosedException() { super("Cursor has already been closed"); } } /** Cursor stack too deep - internal error. */ public static final class FullException extends LmdbNativeException { static final int MDB_CURSOR_FULL = -30_787; private static final long serialVersionUID = 1L; FullException() { super(MDB_CURSOR_FULL, "Cursor stack too deep - internal error"); } } } |
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