2 * (C) Copyright 2016 Pantheon Technologies, s.r.o. and others.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
16 package org.opendaylight.yangtools.triemap;
18 import static org.opendaylight.yangtools.triemap.LookupResult.RESTART;
19 import static org.opendaylight.yangtools.triemap.PresencePredicate.ABSENT;
20 import static org.opendaylight.yangtools.triemap.PresencePredicate.PRESENT;
22 import java.util.Optional;
23 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
25 final class INode<K, V> extends BasicNode {
26 @SuppressWarnings("rawtypes")
27 private static final AtomicReferenceFieldUpdater<INode, MainNode> MAINNODE_UPDATER =
28 AtomicReferenceFieldUpdater.newUpdater(INode.class, MainNode.class, "mainnode");
30 private final Gen gen;
32 private volatile MainNode<K, V> mainnode;
34 INode(final Gen gen, final MainNode<K, V> mainnode) {
36 this.mainnode = mainnode;
39 MainNode<K, V> gcasRead(final TrieMap<K, V> ct) {
43 MainNode<K, V> GCAS_READ(final TrieMap<K, V> ct) {
44 MainNode<K, V> m = /* READ */ mainnode;
45 MainNode<K, V> prevval = /* READ */ m.READ_PREV();
46 if (prevval == null) {
50 return GCAS_Complete(m, ct);
53 private MainNode<K, V> GCAS_Complete(MainNode<K, V> m, final TrieMap<K, V> ct) {
60 final MainNode<K, V> prev = /* READ */ m.READ_PREV();
61 final INode<K, V> ctr = ct.readRoot(true);
66 if (prev instanceof FailedNode) {
67 // try to commit to previous value
68 FailedNode<K, V> fn = (FailedNode<K, V>) prev;
69 if (MAINNODE_UPDATER.compareAndSet(this, m, fn.READ_PREV())) {
70 return fn.READ_PREV();
73 // Tail recursion: return GCAS_Complete (/* READ */ mainnode, ct);
74 m = /* READ */ mainnode;
78 // Assume that you've read the root from the generation G.
79 // Assume that the snapshot algorithm is correct.
80 // ==> you can only reach nodes in generations <= G.
82 // We know that `ctr.gen` is >= G.
83 // ==> if `ctr.gen` = `gen` then they are both equal to G.
84 // ==> otherwise, we know that either `ctr.gen` > G, `gen` < G,
86 if (ctr.gen == gen && !ct.isReadOnly()) {
88 if (m.CAS_PREV(prev, null)) {
92 // Tail recursion: return GCAS_Complete (m, ct);
97 m.CAS_PREV(prev, new FailedNode<>(prev));
99 // Tail recursion: return GCAS_Complete(/* READ */ mainnode, ct);
100 m = /* READ */ mainnode;
104 private boolean GCAS(final MainNode<K, V> old, final MainNode<K, V> n, final TrieMap<K, V> ct) {
106 if (MAINNODE_UPDATER.compareAndSet(this, old, n)) {
107 GCAS_Complete(n, ct);
108 return /* READ */ n.READ_PREV() == null;
114 private INode<K, V> inode(final MainNode<K, V> cn) {
115 return new INode<>(gen, cn);
118 INode<K, V> copyToGen(final Gen ngen, final TrieMap<K, V> ct) {
119 return new INode<>(ngen, GCAS_READ(ct));
123 * Inserts a key value pair, overwriting the old pair if the keys match.
125 * @return true if successful, false otherwise
127 boolean rec_insert(final K k, final V v, final int hc, final int lev, final INode<K, V> parent,
128 final TrieMap<K, V> ct) {
129 return rec_insert(k, v, hc, lev, parent, gen, ct);
132 private boolean rec_insert(final K k, final V v, final int hc, final int lev, final INode<K, V> parent,
133 final Gen startgen, final TrieMap<K, V> ct) {
135 final MainNode<K, V> m = GCAS_READ (ct); // use -Yinline!
137 if (m instanceof CNode) {
138 // 1) a multiway node
139 final CNode<K, V> cn = (CNode<K, V>) m;
140 final int idx = (hc >>> lev) & 0x1f;
141 final int flag = 1 << idx;
142 final int bmp = cn.bitmap;
143 final int mask = flag - 1;
144 final int pos = Integer.bitCount(bmp & mask);
145 if ((bmp & flag) != 0) {
147 final BasicNode cnAtPos = cn.array[pos];
148 if (cnAtPos instanceof INode) {
149 final INode<K, V> in = (INode<K, V>) cnAtPos;
150 if (startgen == in.gen) {
151 return in.rec_insert(k, v, hc, lev + 5, this, startgen, ct);
153 if (GCAS(cn, cn.renewed(startgen, ct), ct)) {
154 // Tail recursion: return rec_insert (k, v, hc, lev, parent, startgen, ct);
159 } else if (cnAtPos instanceof SNode) {
160 final SNode<K, V> sn = (SNode<K, V>) cnAtPos;
161 if (sn.hc == hc && ct.equal(sn.k, k)) {
162 return GCAS(cn, cn.updatedAt(pos, new SNode<>(k, v, hc), gen), ct);
165 final CNode<K, V> rn = (cn.gen == gen) ? cn : cn.renewed(gen, ct);
166 final MainNode<K, V> nn = rn.updatedAt(pos, inode(CNode.dual(sn, sn.hc, new SNode<>(k, v, hc),
167 hc, lev + 5, gen)), gen);
168 return GCAS (cn, nn, ct);
171 CNode<K, V> rn = (cn.gen == gen) ? cn : cn.renewed(gen, ct);
172 MainNode<K, V> ncnode = rn.insertedAt(pos, flag, new SNode<> (k, v, hc), gen);
173 return GCAS (cn, ncnode, ct);
175 } else if (m instanceof TNode) {
176 clean(parent, ct, lev - 5);
178 } else if (m instanceof LNode) {
179 return insertln((LNode<K, V>) m, k, v, ct);
181 throw new IllegalStateException("Unhandled node " + m);
184 throw new RuntimeException ("Should not happen");
189 * Inserts a new key value pair, given that a specific condition is met.
192 * null - don't care if the key was there
193 * KEY_ABSENT - key wasn't there
194 * KEY_PRESENT - key was there
195 * other value `v` - key must be bound to `v`
196 * @return null if unsuccessful, Option[V] otherwise (indicating
197 * previous value bound to the key)
199 Optional<V> rec_insertif(final K k, final V v, final int hc, final Object cond, final int lev,
200 final INode<K, V> parent, final TrieMap<K, V> ct) {
201 return rec_insertif(k, v, hc, cond, lev, parent, gen, ct);
204 private Optional<V> rec_insertif(final K k, final V v, final int hc, final Object cond, final int lev,
205 final INode<K, V> parent, final Gen startgen, final TrieMap<K, V> ct) {
207 final MainNode<K, V> m = GCAS_READ(ct); // use -Yinline!
209 if (m instanceof CNode) {
210 // 1) a multiway node
211 final CNode<K, V> cn = (CNode<K, V>) m;
212 final int idx = (hc >>> lev) & 0x1f;
213 final int flag = 1 << idx;
214 final int bmp = cn.bitmap;
215 final int mask = flag - 1;
216 final int pos = Integer.bitCount(bmp & mask);
218 if ((bmp & flag) != 0) {
220 final BasicNode cnAtPos = cn.array[pos];
221 if (cnAtPos instanceof INode) {
222 final INode<K, V> in = (INode<K, V>) cnAtPos;
223 if (startgen == in.gen) {
224 return in.rec_insertif(k, v, hc, cond, lev + 5, this, startgen, ct);
227 if (GCAS(cn, cn.renewed(startgen, ct), ct)) {
228 // Tail recursion: return rec_insertif (k, v, hc, cond, lev, parent, startgen, ct);
233 } else if (cnAtPos instanceof SNode) {
234 final SNode<K, V> sn = (SNode<K, V>) cnAtPos;
236 if (sn.hc == hc && ct.equal(sn.k, k)) {
237 if (GCAS(cn, cn.updatedAt(pos, new SNode<>(k, v, hc), gen), ct)) {
238 return Optional.of(sn.v);
244 final CNode<K, V> rn = (cn.gen == gen) ? cn : cn.renewed(gen, ct);
245 final MainNode<K, V> nn = rn.updatedAt(pos, inode (CNode.dual(sn, sn.hc,
246 new SNode<>(k, v, hc), hc, lev + 5, gen)), gen);
247 if (GCAS(cn, nn, ct)) {
248 return Optional.empty();
252 } else if (cond == ABSENT) {
253 if (sn.hc == hc && ct.equal(sn.k, k)) {
254 return Optional.of(sn.v);
257 final CNode<K, V> rn = (cn.gen == gen) ? cn : cn.renewed(gen, ct);
258 final MainNode<K, V> nn = rn.updatedAt(pos, inode (CNode.dual(sn, sn.hc,
259 new SNode<>(k, v, hc), hc, lev + 5, gen)), gen);
260 if (GCAS(cn, nn, ct)) {
261 return Optional.empty();
265 } else if (cond == PRESENT) {
266 if (sn.hc == hc && ct.equal(sn.k, k)) {
267 if (GCAS(cn, cn.updatedAt(pos, new SNode<>(k, v, hc), gen), ct)) {
268 return Optional.of(sn.v);
273 return Optional.empty();
275 if (sn.hc == hc && ct.equal(sn.k, k) && cond.equals(sn.v)) {
276 if (GCAS(cn, cn.updatedAt(pos, new SNode<>(k, v, hc), gen), ct)) {
277 return Optional.of(sn.v);
283 return Optional.empty();
286 } else if (cond == null || cond == ABSENT) {
287 final CNode<K, V> rn = (cn.gen == gen) ? cn : cn.renewed(gen, ct);
288 final CNode<K, V> ncnode = rn.insertedAt (pos, flag, new SNode<>(k, v, hc), gen);
289 if (GCAS(cn, ncnode, ct)) {
290 return Optional.empty();
295 return Optional.empty();
297 } else if (m instanceof TNode) {
298 clean(parent, ct, lev - 5);
300 } else if (m instanceof LNode) {
302 final LNode<K, V> ln = (LNode<K, V>) m;
304 final Optional<V> optv = ln.get(k);
305 if (insertln(ln, k, v, ct)) {
309 } else if (cond == ABSENT) {
310 final Optional<V> t = ln.get(k);
314 if (insertln(ln, k, v, ct)) {
315 return Optional.empty();
318 } else if (cond == PRESENT) {
319 final Optional<V> t = ln.get(k);
320 if (!t.isPresent()) {
323 if (insertln(ln, k, v, ct)) {
328 final Optional<V> t = ln.get(k);
330 if (cond.equals(t.get())) {
331 if (insertln(ln, k, v, ct)) {
332 // Difference from Scala: we choose to reuse the object returned from LNode,
333 // as the identity of the value does not matter in this call graph.
341 return Optional.empty();
344 throw new IllegalStateException("Unhandled node " + m);
347 throw new RuntimeException("Should never happen");
351 private boolean insertln(final LNode<K, V> ln, final K k, final V v, final TrieMap<K, V> ct) {
352 return GCAS(ln, ln.addChild(k, v), ct);
356 * Looks up the value associated with the key.
358 * @return null if no value has been found, RESTART if the operation
359 * wasn't successful, or any other value otherwise
361 Object rec_lookup(final K k, final int hc, final int lev, final INode<K, V> parent, final TrieMap<K, V> ct) {
362 return rec_lookup(k, hc, lev, parent, gen, ct);
365 private Object rec_lookup(final K k, final int hc, final int lev, final INode<K, V> parent, final Gen startgen,
366 final TrieMap<K, V> ct) {
368 final MainNode<K, V> m = GCAS_READ(ct); // use -Yinline!
370 if (m instanceof CNode) {
372 final CNode<K, V> cn = (CNode<K, V>) m;
373 final int idx = (hc >>> lev) & 0x1f;
374 final int flag = 1 << idx;
375 final int bmp = cn.bitmap;
376 if ((bmp & flag) == 0) {
377 // 1a) bitmap shows no binding
381 // 1b) bitmap contains a value - descend
382 final int pos = (bmp == 0xffffffff) ? idx : Integer.bitCount(bmp & (flag - 1));
383 final BasicNode sub = cn.array[pos];
384 if (sub instanceof INode) {
385 final INode<K, V> in = (INode<K, V>) sub;
386 if (ct.isReadOnly() || (startgen == in.gen)) {
387 return in.rec_lookup(k, hc, lev + 5, this, startgen, ct);
390 if (GCAS(cn, cn.renewed(startgen, ct), ct)) {
391 // Tail recursion: return rec_lookup(k, hc, lev, parent, startgen, ct);
396 } else if (sub instanceof SNode) {
398 final SNode<K, V> sn = (SNode<K, V>) sub;
399 if (sn.hc == hc && ct.equal(sn.k, k)) {
405 } else if (m instanceof TNode) {
407 return cleanReadOnly((TNode<K, V>) m, lev, parent, ct, k, hc);
408 } else if (m instanceof LNode) {
410 return ((LNode<K, V>) m).get(k).orElse(null);
412 throw new IllegalStateException("Unhandled node " + m);
415 throw new RuntimeException ("Should not happen");
419 private Object cleanReadOnly(final TNode<K, V> tn, final int lev, final INode<K, V> parent,
420 final TrieMap<K, V> ct, final K k, final int hc) {
421 if (ct.isReadOnly()) {
422 if (tn.hc == hc && ct.equal(tn.k, k)) {
429 clean(parent, ct, lev - 5);
434 * Removes the key associated with the given value.
437 * if null, will remove the key regardless of the value;
438 * otherwise removes only if binding contains that exact key
440 * @return null if not successful, an Option[V] indicating the previous
443 Optional<V> rec_remove(final K k, final V v, final int hc, final int lev, final INode<K, V> parent,
444 final TrieMap<K, V> ct) {
445 return rec_remove(k, v, hc, lev, parent, gen, ct);
448 private Optional<V> rec_remove(final K k, final V v, final int hc, final int lev, final INode<K, V> parent,
449 final Gen startgen, final TrieMap<K, V> ct) {
450 final MainNode<K, V> m = GCAS_READ(ct); // use -Yinline!
452 if (m instanceof CNode) {
453 final CNode<K, V> cn = (CNode<K, V>) m;
454 final int idx = (hc >>> lev) & 0x1f;
455 final int bmp = cn.bitmap;
456 final int flag = 1 << idx;
457 if ((bmp & flag) == 0) {
458 return Optional.empty();
461 final int pos = Integer.bitCount(bmp & (flag - 1));
462 final BasicNode sub = cn.array[pos];
463 Optional<V> res = null;
464 if (sub instanceof INode) {
465 final INode<K, V> in = (INode<K, V>) sub;
466 if (startgen == in.gen) {
467 res = in.rec_remove(k, v, hc, lev + 5, this, startgen, ct);
469 if (GCAS(cn, cn.renewed (startgen, ct), ct)) {
470 res = rec_remove(k, v, hc, lev, parent, startgen, ct);
476 } else if (sub instanceof SNode) {
477 final SNode<K, V> sn = (SNode<K, V>) sub;
478 if (sn.hc == hc && ct.equal(sn.k, k) && (v == null || v.equals(sn.v))) {
479 final MainNode<K, V> ncn = cn.removedAt(pos, flag, gen).toContracted(lev);
480 if (GCAS(cn, ncn, ct)) {
481 res = Optional.of(sn.v);
486 res = Optional.empty();
490 if (res == null || !res.isPresent()) {
494 if (parent != null) {
495 // never tomb at root
496 final MainNode<K, V> n = GCAS_READ(ct);
497 if (n instanceof TNode) {
498 cleanParent(n, parent, ct, hc, lev, startgen);
503 } else if (m instanceof TNode) {
504 clean(parent, ct, lev - 5);
506 } else if (m instanceof LNode) {
507 final LNode<K, V> ln = (LNode<K, V>) m;
508 final Optional<V> optv = ln.get(k);
510 if (!optv.isPresent()) {
511 // Key was not found, hence no modification is needed
512 return Optional.empty();
515 if (v != null && !v.equals(optv.get())) {
516 // Value does not match
517 return Optional.empty();
520 return GCAS(ln, ln.removeChild(k, hc, ct), ct) ? optv : null;
522 throw new IllegalStateException("Unhandled node " + m);
526 private void cleanParent(final Object nonlive, final INode<K, V> parent, final TrieMap<K, V> ct, final int hc,
527 final int lev, final Gen startgen) {
529 final MainNode<K, V> pm = parent.GCAS_READ(ct);
530 if ((!(pm instanceof CNode))) {
531 // parent is no longer a cnode, we're done
535 final CNode<K, V> cn = (CNode<K, V>) pm;
536 final int idx = (hc >>> (lev - 5)) & 0x1f;
537 final int bmp = cn.bitmap;
538 final int flag = 1 << idx;
539 if ((bmp & flag) == 0) {
540 // somebody already removed this i-node, we're done
544 final int pos = Integer.bitCount(bmp & (flag - 1));
545 final BasicNode sub = cn.array[pos];
547 if (nonlive instanceof TNode) {
548 final TNode<K, V> tn = (TNode<K, V>) nonlive;
549 MainNode<K, V> ncn = cn.updatedAt(pos, tn.copyUntombed(), gen).toContracted(lev - 5);
550 if (!parent.GCAS(cn, ncn, ct)) {
551 if (ct.readRoot().gen == startgen) {
552 // Tail recursion: cleanParent(nonlive, parent, ct, hc, lev, startgen);
562 private void clean(final INode<K, V> nd, final TrieMap<K, V> ct, final int lev) {
563 final MainNode<K, V> m = nd.GCAS_READ(ct);
564 if (m instanceof CNode) {
565 final CNode<K, V> cn = (CNode<K, V>) m;
566 nd.GCAS(cn, cn.toCompressed(ct, lev, gen), ct);
570 int cachedSize(final TrieMap<K, V> ct) {
571 MainNode<K, V> m = GCAS_READ(ct);
572 return m.cachedSize(ct);
575 // /* this is a quiescent method! */
576 // def string(lev: Int) = "%sINode -> %s".format(" " * lev, mainnode
578 // case null => "<null>"
579 // case tn: TNode[_, _] => "TNode(%s, %s, %d, !)".format(tn.k, tn.v,
581 // case cn: CNode[_, _] => cn.string(lev)
582 // case ln: LNode[_, _] => ln.string(lev)
583 // case x => "<elem: %s>".format(x)
587 String string(final int lev) {