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 final class INode<K, V> extends INodeBase<K, V> {
19 static final Object KEY_PRESENT = new Object ();
20 static final Object KEY_ABSENT = new Object ();
23 * Virtual result for lookup methods indicating that the lookup needs to be restarted. This is a faster version
24 * of throwing a checked exception to control the restart.
26 static final Object RESTART = new Object();
28 INode(final Gen gen, final MainNode<K, V> bn) {
32 MainNode<K, V> gcasRead(final TrieMap<K, V> ct) {
36 MainNode<K, V> GCAS_READ(final TrieMap<K, V> ct) {
37 MainNode<K, V> m = /* READ */ READ();
38 MainNode<K, V> prevval = /* READ */ m.READ_PREV();
39 if (prevval == null) {
43 return GCAS_Complete(m, ct);
46 private MainNode<K, V> GCAS_Complete(MainNode<K, V> m, final TrieMap<K, V> ct) {
53 final MainNode<K, V> prev = /* READ */ m.READ_PREV();
54 final INode<K, V> ctr = ct.readRoot(true);
59 if (prev instanceof FailedNode) {
60 // try to commit to previous value
61 FailedNode<K, V> fn = (FailedNode<K, V>) prev;
62 if (CAS(m, fn.READ_PREV())) {
63 return fn.READ_PREV();
66 // Tail recursion: return GCAS_Complete (/* READ */ READ(), ct);
67 m = /* READ */ READ();
71 // Assume that you've read the root from the generation G.
72 // Assume that the snapshot algorithm is correct.
73 // ==> you can only reach nodes in generations <= G.
75 // We know that `ctr.gen` is >= G.
76 // ==> if `ctr.gen` = `gen` then they are both equal to G.
77 // ==> otherwise, we know that either `ctr.gen` > G, `gen` < G,
79 if ((ctr.gen == gen) && ct.nonReadOnly()) {
81 if (m.CAS_PREV(prev, null)) {
85 // Tail recursion: return GCAS_Complete (m, ct);
90 m.CAS_PREV(prev, new FailedNode<>(prev));
92 // Tail recursion: return GCAS_Complete(/* READ */ READ(), ct);
93 m = /* READ */ READ();
97 private boolean GCAS(final MainNode<K, V> old, final MainNode<K, V> n, final TrieMap<K, V> ct) {
100 GCAS_Complete(n, ct);
101 return /* READ */ n.READ_PREV() == null;
107 private static <K, V> boolean equal(final K k1, final K k2, final TrieMap<K, V> ct) {
108 return ct.equality().equiv(k1, k2);
111 private INode<K, V> inode(final MainNode<K, V> cn) {
112 return new INode<>(gen, cn);
115 INode<K, V> copyToGen(final Gen ngen, final TrieMap<K, V> ct) {
116 return new INode<>(ngen, GCAS_READ(ct));
120 * Inserts a key value pair, overwriting the old pair if the keys match.
122 * @return true if successful, false otherwise
124 boolean rec_insert(final K k, final V v, final int hc, final int lev, final INode<K, V> parent, final Gen startgen,
125 final TrieMap<K, V> ct) {
127 final MainNode<K, V> m = GCAS_READ (ct); // use -Yinline!
129 if (m instanceof CNode) {
130 // 1) a multiway node
131 final CNode<K, V> cn = (CNode<K, V>) m;
132 final int idx = (hc >>> lev) & 0x1f;
133 final int flag = 1 << idx;
134 final int bmp = cn.bitmap;
135 final int mask = flag - 1;
136 final int pos = Integer.bitCount(bmp & mask);
137 if ((bmp & flag) != 0) {
139 final BasicNode cnAtPos = cn.array[pos];
140 if (cnAtPos instanceof INode) {
141 final INode<K, V> in = (INode<K, V>) cnAtPos;
142 if (startgen == in.gen) {
143 return in.rec_insert(k, v, hc, lev + 5, this, startgen, ct);
145 if (GCAS(cn, cn.renewed(startgen, ct), ct)) {
146 // Tail recursion: return rec_insert (k, v, hc, lev, parent, startgen, ct);
151 } else if (cnAtPos instanceof SNode) {
152 final SNode<K, V> sn = (SNode<K, V>) cnAtPos;
153 if (sn.hc == hc && equal(sn.k, k, ct)) {
154 return GCAS(cn, cn.updatedAt(pos, new SNode<>(k, v, hc), gen), ct);
157 final CNode<K, V> rn = (cn.gen == gen) ? cn : cn.renewed(gen, ct);
158 final MainNode<K, V> nn = rn.updatedAt(pos, inode(CNode.dual(sn, sn.hc, new SNode<>(k, v, hc),
159 hc, lev + 5, gen)), gen);
160 return GCAS (cn, nn, ct);
163 CNode<K, V> rn = (cn.gen == gen) ? cn : cn.renewed(gen, ct);
164 MainNode<K, V> ncnode = rn.insertedAt(pos, flag, new SNode<> (k, v, hc), gen);
165 return GCAS (cn, ncnode, ct);
167 } else if (m instanceof TNode) {
168 clean(parent, ct, lev - 5);
170 } else if (m instanceof LNode) {
171 LNode<K, V> ln = (LNode<K, V>) m;
172 MainNode<K, V> nn = ln.inserted(k, v);
173 return GCAS(ln, nn, ct);
176 throw new RuntimeException ("Should not happen");
181 * Inserts a new key value pair, given that a specific condition is met.
184 * null - don't care if the key was there
185 * KEY_ABSENT - key wasn't there
186 * KEY_PRESENT - key was there
187 * other value `v` - key must be bound to `v`
188 * @return null if unsuccessful, Option[V] otherwise (indicating
189 * previous value bound to the key)
191 Option<V> rec_insertif(final K k, final V v, final int hc, final Object cond, final int lev,
192 final INode<K, V> parent, final Gen startgen, final TrieMap<K, V> ct) {
194 final MainNode<K, V> m = GCAS_READ(ct); // use -Yinline!
196 if (m instanceof CNode) {
197 // 1) a multiway node
198 final CNode<K, V> cn = (CNode<K, V>) m;
199 final int idx = (hc >>> lev) & 0x1f;
200 final int flag = 1 << idx;
201 final int bmp = cn.bitmap;
202 final int mask = flag - 1;
203 final int pos = Integer.bitCount(bmp & mask);
205 if ((bmp & flag) != 0) {
207 final BasicNode cnAtPos = cn.array[pos];
208 if (cnAtPos instanceof INode) {
209 final INode<K, V> in = (INode<K, V>) cnAtPos;
210 if (startgen == in.gen) {
211 return in.rec_insertif(k, v, hc, cond, lev + 5, this, startgen, ct);
214 if (GCAS(cn, cn.renewed(startgen, ct), ct)) {
215 // Tail recursion: return rec_insertif (k, v, hc, cond, lev, parent, startgen, ct);
220 } else if (cnAtPos instanceof SNode) {
221 final SNode<K, V> sn = (SNode<K, V>) cnAtPos;
223 if (sn.hc == hc && equal(sn.k, k, ct)) {
224 if (GCAS(cn, cn.updatedAt(pos, new SNode<>(k, v, hc), gen), ct)) {
225 return Option.makeOption(sn.v);
231 final CNode<K, V> rn = (cn.gen == gen) ? cn : cn.renewed(gen, ct);
232 final MainNode<K, V> nn = rn.updatedAt(pos, inode (CNode.dual(sn, sn.hc,
233 new SNode<>(k, v, hc), hc, lev + 5, gen)), gen);
234 if (GCAS(cn, nn, ct)) {
235 return Option.makeOption(); // None;
239 } else if (cond == INode.KEY_ABSENT) {
240 if (sn.hc == hc && equal(sn.k, k, ct)) {
241 return Option.makeOption(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 Option.makeOption(); // None
252 } else if (cond == INode.KEY_PRESENT) {
253 if (sn.hc == hc && equal(sn.k, k, ct)) {
254 if (GCAS(cn, cn.updatedAt(pos, new SNode<>(k, v, hc), gen), ct)) {
255 return Option.makeOption(sn.v);
260 return Option.makeOption();// None;
262 if (sn.hc == hc && equal(sn.k, k, ct) && sn.v == cond) {
263 if (GCAS(cn, cn.updatedAt(pos, new SNode<>(k, v, hc), gen), ct)) {
264 return Option.makeOption(sn.v);
270 return Option.makeOption(); // None
273 } else if (cond == null || cond == INode.KEY_ABSENT) {
274 final CNode<K, V> rn = (cn.gen == gen) ? cn : cn.renewed(gen, ct);
275 final CNode<K, V> ncnode = rn.insertedAt (pos, flag, new SNode<>(k, v, hc), gen);
276 if (GCAS(cn, ncnode, ct)) {
277 return Option.makeOption(); // None
281 } else if (cond == INode.KEY_PRESENT) {
282 return Option.makeOption(); // None;
285 return Option.makeOption(); // None
287 } else if (m instanceof TNode) {
288 clean(parent, ct, lev - 5);
290 } else if (m instanceof LNode) {
292 final LNode<K, V> ln = (LNode<K, V>) m;
294 final Option<V> optv = ln.get(k);
295 if (insertln(ln, k, v, ct)) {
299 } else if (cond == INode.KEY_ABSENT) {
300 final Option<V> t = ln.get(k);
304 if (insertln(ln, k, v, ct)) {
305 return Option.makeOption();// None
308 } else if (cond == INode.KEY_PRESENT) {
309 final Option<V> t = ln.get(k);
313 if (insertln(ln, k, v, ct)) {
318 final Option<V> t = ln.get(k);
320 if (((Some<V>) t).get() == cond) {
321 if (insertln(ln, k, v, ct)) {
322 return new Some<>((V) cond);
327 return Option.makeOption();
332 // throw new RuntimeException ("Should not happen");
336 boolean insertln(final LNode<K, V> ln, final K k, final V v, final TrieMap<K, V> ct) {
337 final LNode<K, V> nn = ln.inserted (k, v);
338 return GCAS(ln, nn, ct);
342 * Looks up the value associated with the key.
344 * @return null if no value has been found, RESTART if the operation
345 * wasn't successful, or any other value otherwise
347 Object rec_lookup(final K k, final int hc, final int lev, final INode<K, V> parent, final Gen startgen,
348 final TrieMap<K, V> ct) {
350 final MainNode<K, V> m = GCAS_READ(ct); // use -Yinline!
352 if (m instanceof CNode) {
354 final CNode<K, V> cn = (CNode<K, V>) m;
355 final int idx = (hc >>> lev) & 0x1f;
356 final int flag = 1 << idx;
357 final int bmp = cn.bitmap;
358 if ((bmp & flag) == 0) {
359 // 1a) bitmap shows no binding
363 // 1b) bitmap contains a value - descend
364 final int pos = (bmp == 0xffffffff) ? idx : Integer.bitCount(bmp & (flag - 1));
365 final BasicNode sub = cn.array[pos];
366 if (sub instanceof INode) {
367 final INode<K, V> in = (INode<K, V>) sub;
368 if (ct.isReadOnly() || (startgen == in.gen)) {
369 return in.rec_lookup(k, hc, lev + 5, this, startgen, ct);
372 if (GCAS(cn, cn.renewed(startgen, ct), ct)) {
373 // Tail recursion: return rec_lookup(k, hc, lev, parent, startgen, ct);
377 // used to be throw RestartException
379 } else if (sub instanceof SNode) {
381 final SNode<K, V> sn = (SNode<K, V>) sub;
382 if (sn.hc == hc && equal(sn.k, k, ct)) {
388 } else if (m instanceof TNode) {
390 return cleanReadOnly((TNode<K, V>) m, lev, parent, ct, k, hc);
391 } else if (m instanceof LNode) {
393 return ((LNode<K, V>) m).get(k);
396 throw new RuntimeException ("Should not happen");
400 private Object cleanReadOnly(final TNode<K, V> tn, final int lev, final INode<K, V> parent,
401 final TrieMap<K, V> ct, final K k, final int hc) {
402 if (ct.nonReadOnly()) {
403 // used to be throw RestartException
404 clean(parent, ct, lev - 5);
408 if (tn.hc == hc && equal(tn.k, k, ct)) {
416 * Removes the key associated with the given value.
419 * if null, will remove the key regardless of the value;
420 * otherwise removes only if binding contains that exact key
422 * @return null if not successful, an Option[V] indicating the previous
425 Option<V> rec_remove(final K k, final V v, final int hc, final int lev, final INode<K, V> parent,
426 final Gen startgen, final TrieMap<K, V> ct) {
427 final MainNode<K, V> m = GCAS_READ(ct); // use -Yinline!
429 if (m instanceof CNode) {
430 final CNode<K, V> cn = (CNode<K, V>) m;
431 final int idx = (hc >>> lev) & 0x1f;
432 final int bmp = cn.bitmap;
433 final int flag = 1 << idx;
434 if ((bmp & flag) == 0) {
435 return Option.makeOption();
438 final int pos = Integer.bitCount(bmp & (flag - 1));
439 final BasicNode sub = cn.array[pos];
440 Option<V> res = null;
441 if (sub instanceof INode) {
442 final INode<K, V> in = (INode<K, V>) sub;
443 if (startgen == in.gen) {
444 res = in.rec_remove(k, v, hc, lev + 5, this, startgen, ct);
446 if (GCAS(cn, cn.renewed (startgen, ct), ct)) {
447 res = rec_remove(k, v, hc, lev, parent, startgen, ct);
453 } else if (sub instanceof SNode) {
454 final SNode<K, V> sn = (SNode<K, V>) sub;
455 if (sn.hc == hc && equal(sn.k, k, ct) && (v == null || v.equals(sn.v))) {
456 final MainNode<K, V> ncn = cn.removedAt(pos, flag, gen).toContracted(lev);
457 if (GCAS(cn, ncn, ct)) {
458 res = Option.makeOption(sn.v);
463 res = Option.makeOption ();
467 if (res instanceof None || (res == null)) {
471 if (parent != null) {
472 // never tomb at root
473 final MainNode<K, V> n = GCAS_READ(ct);
474 if (n instanceof TNode) {
475 cleanParent(n, parent, ct, hc, lev, startgen);
480 } else if (m instanceof TNode) {
481 clean(parent, ct, lev - 5);
483 } else if (m instanceof LNode) {
484 final LNode<K, V> ln = (LNode<K, V>) m;
486 final Option<V> optv = ln.get(k);
487 final MainNode<K, V> nn = ln.removed(k, ct);
488 if (GCAS(ln, nn, ct)) {
495 final Option<V> tmp = ln.get(k);
496 if (tmp instanceof Some) {
497 final Some<V> tmp1 = (Some<V>) tmp;
498 if (tmp1.get() == v) {
499 final MainNode<K, V> nn = ln.removed(k, ct);
500 if (GCAS(ln, nn, ct)) {
508 throw new RuntimeException ("Should not happen");
511 private void cleanParent(final Object nonlive, final INode<K, V> parent, final TrieMap<K, V> ct, final int hc,
512 final int lev, final Gen startgen) {
514 final MainNode<K, V> pm = parent.GCAS_READ(ct);
515 if ((!(pm instanceof CNode))) {
516 // parent is no longer a cnode, we're done
520 final CNode<K, V> cn = (CNode<K, V>) pm;
521 final int idx = (hc >>> (lev - 5)) & 0x1f;
522 final int bmp = cn.bitmap;
523 final int flag = 1 << idx;
524 if ((bmp & flag) == 0) {
525 // somebody already removed this i-node, we're done
529 final int pos = Integer.bitCount(bmp & (flag - 1));
530 final BasicNode sub = cn.array[pos];
532 if (nonlive instanceof TNode) {
533 final TNode<K, V> tn = (TNode<K, V>) nonlive;
534 MainNode<K, V> ncn = cn.updatedAt(pos, tn.copyUntombed(), gen).toContracted(lev - 5);
535 if (!parent.GCAS(cn, ncn, ct)) {
536 if (ct.readRoot().gen == startgen) {
537 // Tail recursion: cleanParent(nonlive, parent, ct, hc, lev, startgen);
547 private void clean(final INode<K, V> nd, final TrieMap<K, V> ct, final int lev) {
548 final MainNode<K, V> m = nd.GCAS_READ(ct);
549 if (m instanceof CNode) {
550 final CNode<K, V> cn = (CNode<K, V>) m;
551 nd.GCAS(cn, cn.toCompressed(ct, lev, gen), ct);
555 int cachedSize(final TrieMap<K, V> ct) {
556 MainNode<K, V> m = GCAS_READ(ct);
557 return m.cachedSize(ct);
560 // /* this is a quiescent method! */
561 // def string(lev: Int) = "%sINode -> %s".format(" " * lev, mainnode
563 // case null => "<null>"
564 // case tn: TNode[_, _] => "TNode(%s, %s, %d, !)".format(tn.k, tn.v,
566 // case cn: CNode[_, _] => cn.string(lev)
567 // case ln: LNode[_, _] => ln.string(lev)
568 // case x => "<elem: %s>".format(x)
572 String string(final int lev) {