2 * Copyright (c) 2020 PANTHEON.tech, s.r.o. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.yangtools.yang.parser.stmt.reactor;
10 import static com.google.common.base.Preconditions.checkArgument;
11 import static com.google.common.base.Verify.verify;
13 import com.google.common.base.MoreObjects;
14 import com.google.common.base.MoreObjects.ToStringHelper;
15 import com.google.common.base.VerifyException;
16 import java.util.Collection;
18 import java.util.Optional;
20 import java.util.stream.Stream;
21 import org.eclipse.jdt.annotation.NonNull;
22 import org.eclipse.jdt.annotation.Nullable;
23 import org.opendaylight.yangtools.yang.common.Empty;
24 import org.opendaylight.yangtools.yang.common.QName;
25 import org.opendaylight.yangtools.yang.common.QNameModule;
26 import org.opendaylight.yangtools.yang.common.YangVersion;
27 import org.opendaylight.yangtools.yang.model.api.meta.DeclaredStatement;
28 import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
29 import org.opendaylight.yangtools.yang.model.api.meta.StatementDefinition;
30 import org.opendaylight.yangtools.yang.model.api.stmt.AugmentStatement;
31 import org.opendaylight.yangtools.yang.model.api.stmt.ConfigEffectiveStatement;
32 import org.opendaylight.yangtools.yang.model.api.stmt.DeviationStatement;
33 import org.opendaylight.yangtools.yang.model.api.stmt.RefineStatement;
34 import org.opendaylight.yangtools.yang.model.api.stmt.SchemaNodeIdentifier;
35 import org.opendaylight.yangtools.yang.model.api.stmt.UsesStatement;
36 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
37 import org.opendaylight.yangtools.yang.parser.spi.meta.CopyType;
38 import org.opendaylight.yangtools.yang.parser.spi.meta.EffectiveStatementState;
39 import org.opendaylight.yangtools.yang.parser.spi.meta.EffectiveStmtCtx.Current;
40 import org.opendaylight.yangtools.yang.parser.spi.meta.InferenceException;
41 import org.opendaylight.yangtools.yang.parser.spi.meta.ModelActionBuilder;
42 import org.opendaylight.yangtools.yang.parser.spi.meta.ModelProcessingPhase;
43 import org.opendaylight.yangtools.yang.parser.spi.meta.ModelProcessingPhase.ExecutionOrder;
44 import org.opendaylight.yangtools.yang.parser.spi.meta.NamespaceBehaviour.Registry;
45 import org.opendaylight.yangtools.yang.parser.spi.meta.ParserNamespace;
46 import org.opendaylight.yangtools.yang.parser.spi.meta.StatementFactory;
47 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext;
48 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext.Mutable;
49 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContextUtils;
50 import org.opendaylight.yangtools.yang.parser.spi.source.SourceException;
51 import org.opendaylight.yangtools.yang.parser.spi.source.SourceParserNamespaces;
52 import org.slf4j.Logger;
53 import org.slf4j.LoggerFactory;
56 * Real "core" reactor statement implementation of {@link Mutable}, supporting basic reactor lifecycle.
58 * @param <A> Argument type
59 * @param <D> Declared Statement representation
60 * @param <E> Effective Statement representation
62 abstract class ReactorStmtCtx<A, D extends DeclaredStatement<A>, E extends EffectiveStatement<A, D>>
63 extends NamespaceStorageSupport implements Mutable<A, D, E>, Current<A, D> {
64 private static final Logger LOG = LoggerFactory.getLogger(ReactorStmtCtx.class);
67 * Substatement refcount tracking. This mechanics deals with retaining substatements for the purposes of
68 * instantiating their lazy copies in InferredStatementContext. It works in concert with {@link #buildEffective()}
69 * and {@link #declared()}: declared/effective statement views hold an implicit reference and refcount-based
70 * sweep is not activated until they are done (or this statement is not {@link #isSupportedToBuildEffective}).
73 * Reference count is hierarchical in that parent references also pin down their child statements and do not allow
77 * The counter's positive values are tracking incoming references via {@link #incRef()}/{@link #decRef()} methods.
78 * Once we transition to sweeping, this value becomes negative counting upwards to {@link #REFCOUNT_NONE} based on
79 * {@link #sweepOnChildDone()}. Once we reach that, we transition to {@link #REFCOUNT_SWEPT}.
81 private int refcount = REFCOUNT_NONE;
83 * No outstanding references, this statement is a potential candidate for sweeping, provided it has populated its
84 * declared and effective views and {@link #parentRef} is known to be absent.
86 private static final int REFCOUNT_NONE = 0;
88 * Reference count overflow or some other recoverable logic error. Do not rely on refcounts and do not sweep
92 * Note on value assignment:
93 * This allow our incRef() to naturally progress to being saturated. Others jump there directly.
94 * It also makes it it impossible to observe {@code Interger.MAX_VALUE} children, which we take advantage of for
95 * {@link #REFCOUNT_SWEEPING}.
97 private static final int REFCOUNT_DEFUNCT = Integer.MAX_VALUE;
99 * This statement is being actively swept. This is a transient value set when we are sweeping our children, so that
100 * we prevent re-entering this statement.
103 * Note on value assignment:
104 * The value is lower than any legal child refcount due to {@link #REFCOUNT_DEFUNCT} while still being higher than
105 * {@link #REFCOUNT_SWEPT}.
107 private static final int REFCOUNT_SWEEPING = -Integer.MAX_VALUE;
109 * This statement, along with its entire subtree has been swept and we positively know all our children have reached
110 * this state. We {@link #sweepNamespaces()} upon reaching this state.
113 * Note on value assignment:
114 * This is the lowest value observable, making it easier on checking others on equality.
116 private static final int REFCOUNT_SWEPT = Integer.MIN_VALUE;
119 * Effective instance built from this context. This field as dual types. Under normal circumstances in matches the
120 * {@link #buildEffective()} instance. If this context is reused, it can be inflated to {@link EffectiveInstances}
121 * and also act as a common instance reuse site.
123 private @Nullable Object effectiveInstance;
125 // Master flag controlling whether this context can yield an effective statement
126 // FIXME: investigate the mechanics that are being supported by this, as it would be beneficial if we can get rid
127 // of this flag -- eliminating the initial alignment shadow used by below gap-filler fields.
128 private boolean isSupportedToBuildEffective = true;
130 // EffectiveConfig mapping
131 private static final int MASK_CONFIG = 0x03;
132 private static final int HAVE_CONFIG = 0x04;
133 // Effective instantiation mechanics for StatementContextBase: if this flag is set all substatements are known not
134 // change when instantiated. This includes context-independent statements as well as any statements which are
135 // ignored during copy instantiation.
136 private static final int ALL_INDEPENDENT = 0x08;
137 // Flag bit assignments
138 private static final int IS_SUPPORTED_BY_FEATURES = 0x10;
139 private static final int HAVE_SUPPORTED_BY_FEATURES = 0x20;
140 private static final int IS_IGNORE_IF_FEATURE = 0x40;
141 private static final int HAVE_IGNORE_IF_FEATURE = 0x80;
142 // Have-and-set flag constants, also used as masks
143 private static final int SET_SUPPORTED_BY_FEATURES = HAVE_SUPPORTED_BY_FEATURES | IS_SUPPORTED_BY_FEATURES;
144 private static final int SET_IGNORE_IF_FEATURE = HAVE_IGNORE_IF_FEATURE | IS_IGNORE_IF_FEATURE;
146 private static final EffectiveConfig[] EFFECTIVE_CONFIGS;
149 final EffectiveConfig[] values = EffectiveConfig.values();
150 final int length = values.length;
151 verify(length == 4, "Unexpected EffectiveConfig cardinality %s", length);
152 EFFECTIVE_CONFIGS = values;
155 // Flags for use with SubstatementContext. These are hiding in the alignment shadow created by above boolean and
156 // hence improve memory layout.
159 // Flag for use by AbstractResumedStatement, ReplicaStatementContext and InferredStatementContext. Each of them
160 // uses it to indicated a different condition. This is hiding in the alignment shadow created by
161 // 'isSupportedToBuildEffective'.
162 // FIXME: move this out once we have JDK15+
163 private boolean boolFlag;
169 ReactorStmtCtx(final ReactorStmtCtx<A, D, E> original) {
170 isSupportedToBuildEffective = original.isSupportedToBuildEffective;
171 boolFlag = original.boolFlag;
172 flags = original.flags;
175 // Used by ReplicaStatementContext only
176 ReactorStmtCtx(final ReactorStmtCtx<A, D, E> original, final Void dummy) {
177 boolFlag = isSupportedToBuildEffective = original.isSupportedToBuildEffective;
178 flags = original.flags;
183 // Common public interface contracts with simple mechanics. Please keep this in one logical block, so we do not end
184 // up mixing concerns and simple details with more complex logic.
189 public abstract StatementContextBase<?, ?, ?> getParentContext();
192 public abstract RootStatementContext<?, ?, ?> getRoot();
195 public abstract Collection<? extends @NonNull StatementContextBase<?, ?, ?>> mutableDeclaredSubstatements();
198 public final Registry getBehaviourRegistry() {
199 return getRoot().getBehaviourRegistryImpl();
203 public final YangVersion yangVersion() {
204 return getRoot().getRootVersionImpl();
208 public final void setRootVersion(final YangVersion version) {
209 getRoot().setRootVersionImpl(version);
213 public final void addRequiredSource(final SourceIdentifier dependency) {
214 getRoot().addRequiredSourceImpl(dependency);
218 public final void setRootIdentifier(final SourceIdentifier identifier) {
219 getRoot().setRootIdentifierImpl(identifier);
223 public final ModelActionBuilder newInferenceAction(final ModelProcessingPhase phase) {
224 return getRoot().getSourceContext().newInferenceAction(phase);
228 public final StatementDefinition publicDefinition() {
229 return definition().getPublicView();
233 public final Parent effectiveParent() {
234 return getParentContext();
238 public final QName moduleName() {
239 final var root = getRoot();
240 return QName.create(StmtContextUtils.getModuleQName(root), root.getRawArgument());
244 // In the next two methods we are looking for an effective statement. If we already have an effective instance,
245 // defer to it's implementation of the equivalent search. Otherwise we search our substatement contexts.
247 // Note that the search function is split, so as to allow InferredStatementContext to do its own thing first.
251 public final <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgument(
252 final @NonNull Class<Z> type) {
253 final E existing = effectiveInstance();
254 return existing != null ? existing.findFirstEffectiveSubstatementArgument(type)
255 : findSubstatementArgumentImpl(type);
259 public final boolean hasSubstatement(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
260 final E existing = effectiveInstance();
261 return existing != null ? existing.findFirstEffectiveSubstatement(type).isPresent() : hasSubstatementImpl(type);
264 private E effectiveInstance() {
265 final Object existing = effectiveInstance;
266 return existing != null ? EffectiveInstances.local(existing) : null;
269 // Visible due to InferredStatementContext's override. At this point we do not have an effective instance available.
270 <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgumentImpl(
271 final @NonNull Class<Z> type) {
272 return allSubstatementsStream()
273 .filter(ctx -> ctx.isSupportedToBuildEffective() && ctx.producesEffective(type))
275 .map(ctx -> (X) ctx.getArgument());
278 // Visible due to InferredStatementContext's override. At this point we do not have an effective instance available.
279 boolean hasSubstatementImpl(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
280 return allSubstatementsStream()
281 .anyMatch(ctx -> ctx.isSupportedToBuildEffective() && ctx.producesEffective(type));
286 @SuppressWarnings("unchecked")
287 public final <Z extends EffectiveStatement<A, D>> StmtContext<A, D, Z> caerbannog() {
288 return (StmtContext<A, D, Z>) this;
292 public final String toString() {
293 return addToStringAttributes(MoreObjects.toStringHelper(this).omitNullValues()).toString();
296 protected ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {
297 return toStringHelper.add("definition", definition()).add("argument", argument()).add("refCount", refString());
300 private String refString() {
301 final int current = refcount;
302 return switch (current) {
303 case REFCOUNT_DEFUNCT -> "DEFUNCT";
304 case REFCOUNT_SWEEPING -> "SWEEPING";
305 case REFCOUNT_SWEPT -> "SWEPT";
306 default -> String.valueOf(refcount);
311 * Return the context in which this statement was defined.
313 * @return statement definition
315 abstract @NonNull StatementDefinitionContext<A, D, E> definition();
319 // NamespaceStorageSupport/Mutable integration methods. Keep these together.
324 public final <K, V, T extends K> V namespaceItem(final ParserNamespace<K, V> type, final T key) {
325 return getBehaviourRegistry().getNamespaceBehaviour(type).getFrom(this, key);
329 public final <K, V> Map<K, V> namespace(final ParserNamespace<K, V> type) {
330 return getNamespace(type);
334 public final <K, V> Map<K, V> localNamespacePortion(final ParserNamespace<K, V> type) {
335 return getLocalNamespace(type);
339 protected <K, V> void onNamespaceElementAdded(final ParserNamespace<K, V> type, final K key, final V value) {
340 // definition().onNamespaceElementAdded(this, type, key, value);
344 * Return the effective statement view of a copy operation. This method may return one of:
346 * <li>{@code this}, when the effective view did not change</li>
347 * <li>an InferredStatementContext, when there is a need for inference-equivalent copy</li>
348 * <li>{@code null}, when the statement failed to materialize</li>
351 * @param parent Proposed new parent
352 * @param type Copy operation type
353 * @param targetModule New target module
354 * @return {@link ReactorStmtCtx} holding effective view
356 abstract @Nullable ReactorStmtCtx<?, ?, ?> asEffectiveChildOf(StatementContextBase<?, ?, ?> parent, CopyType type,
357 QNameModule targetModule);
360 public final ReplicaStatementContext<A, D, E> replicaAsChildOf(final Mutable<?, ?, ?> parent) {
361 checkArgument(parent instanceof StatementContextBase, "Unsupported parent %s", parent);
362 final var ret = replicaAsChildOf((StatementContextBase<?, ?, ?>) parent);
363 definition().onStatementAdded(ret);
367 abstract @NonNull ReplicaStatementContext<A, D, E> replicaAsChildOf(@NonNull StatementContextBase<?, ?, ?> parent);
371 // Statement build entry points -- both public and package-private.
376 public final E buildEffective() {
377 final Object existing;
378 return (existing = effectiveInstance) != null ? EffectiveInstances.local(existing) : loadEffective();
381 private @NonNull E loadEffective() {
382 final E ret = createEffective();
383 effectiveInstance = ret;
384 // we have called createEffective(), substatements are no longer guarded by us. Let's see if we can clear up
386 if (refcount == REFCOUNT_NONE) {
392 abstract @NonNull E createEffective();
395 * Routing of the request to build an effective statement from {@link InferredStatementContext} towards the original
396 * definition site. This is needed to pick the correct instantiation method: for declared statements we will
397 * eventually land in {@link AbstractResumedStatement}, for underclared statements that will be
398 * {@link UndeclaredStmtCtx}.
400 * @param factory Statement factory
401 * @param ctx Inferred statement context, i.e. where the effective statement is instantiated
402 * @return Built effective stateue
404 abstract @NonNull E createInferredEffective(@NonNull StatementFactory<A, D, E> factory,
405 @NonNull InferredStatementContext<A, D, E> ctx, Stream<? extends StmtContext<?, ?, ?>> declared,
406 Stream<? extends StmtContext<?, ?, ?>> effective);
409 * Attach an effective copy of this statement. This essentially acts as a map, where we make a few assumptions:
411 * <li>{@code copy} and {@code this} statement share {@link #getOriginalCtx()} if it exists</li>
412 * <li>{@code copy} did not modify any statements relative to {@code this}</li>
415 * @param state effective statement state, acting as a lookup key
416 * @param stmt New copy to append
417 * @return {@code stmt} or a previously-created instances with the same {@code state}
419 @SuppressWarnings("unchecked")
420 final @NonNull E attachEffectiveCopy(final @NonNull EffectiveStatementState state, final @NonNull E stmt) {
421 final Object local = effectiveInstance;
422 final EffectiveInstances<E> instances;
423 if (local instanceof EffectiveInstances) {
424 instances = (EffectiveInstances<E>) local;
426 effectiveInstance = instances = new EffectiveInstances<>((E) local);
428 return instances.attachCopy(state, stmt);
432 * Walk this statement's copy history and return the statement closest to original which has not had its effective
433 * statements modified. This statement and returned substatement logically have the same set of substatements, hence
434 * share substatement-derived state.
436 * @return Closest {@link ReactorStmtCtx} with equivalent effective substatements
438 abstract @NonNull ReactorStmtCtx<A, D, E> unmodifiedEffectiveSource();
441 public final ModelProcessingPhase getCompletedPhase() {
442 return ModelProcessingPhase.ofExecutionOrder(executionOrder());
445 abstract byte executionOrder();
448 * Try to execute current {@link ModelProcessingPhase} of source parsing. If the phase has already been executed,
449 * this method does nothing. This must not be called with {@link ExecutionOrder#NULL}.
451 * @param phase to be executed (completed)
452 * @return true if phase was successfully completed
453 * @throws SourceException when an error occurred in source parsing
455 final boolean tryToCompletePhase(final byte executionOrder) {
456 return executionOrder() >= executionOrder || doTryToCompletePhase(executionOrder);
459 abstract boolean doTryToCompletePhase(byte targetOrder);
463 // Flags-based mechanics. These include public interfaces as well as all the crud we have lurking in our alignment
468 // Non-final form ImplicitStmtCtx
470 public boolean isSupportedToBuildEffective() {
471 return isSupportedToBuildEffective;
475 public final void setUnsupported() {
476 this.isSupportedToBuildEffective = false;
480 public final boolean isSupportedByFeatures() {
481 final int fl = flags & SET_SUPPORTED_BY_FEATURES;
483 return fl == SET_SUPPORTED_BY_FEATURES;
485 if (isIgnoringIfFeatures()) {
486 flags |= SET_SUPPORTED_BY_FEATURES;
491 * If parent is supported, we need to check if-features statements of this context.
493 if (isParentSupportedByFeatures()) {
494 // If the set of supported features has not been provided, all features are supported by default.
495 final Set<QName> supportedFeatures = getFromNamespace(SourceParserNamespaces.SUPPORTED_FEATURES,
497 if (supportedFeatures == null || StmtContextUtils.checkFeatureSupport(this, supportedFeatures)) {
498 flags |= SET_SUPPORTED_BY_FEATURES;
503 // Either parent is not supported or this statement is not supported
504 flags |= HAVE_SUPPORTED_BY_FEATURES;
508 protected abstract boolean isParentSupportedByFeatures();
511 * Config statements are not all that common which means we are performing a recursive search towards the root
512 * every time {@link #effectiveConfig()} is invoked. This is quite expensive because it causes a linear search
513 * for the (usually non-existent) config statement.
516 * This method maintains a resolution cache, so once we have returned a result, we will keep on returning the same
517 * result without performing any lookups, solely to support {@link #effectiveConfig()}.
520 * Note: use of this method implies that {@link #isIgnoringConfig()} is realized with
521 * {@link #isIgnoringConfig(StatementContextBase)}.
523 final @NonNull EffectiveConfig effectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
524 return (flags & HAVE_CONFIG) != 0 ? EFFECTIVE_CONFIGS[flags & MASK_CONFIG] : loadEffectiveConfig(parent);
527 private @NonNull EffectiveConfig loadEffectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
528 final EffectiveConfig parentConfig = parent.effectiveConfig();
530 final EffectiveConfig myConfig;
531 if (parentConfig != EffectiveConfig.IGNORED && !definition().support().isIgnoringConfig()) {
532 final Optional<Boolean> optConfig = findSubstatementArgument(ConfigEffectiveStatement.class);
533 if (optConfig.isPresent()) {
534 if (optConfig.orElseThrow()) {
535 // Validity check: if parent is config=false this cannot be a config=true
536 InferenceException.throwIf(parentConfig == EffectiveConfig.FALSE, this,
537 "Parent node has config=false, this node must not be specifed as config=true");
538 myConfig = EffectiveConfig.TRUE;
540 myConfig = EffectiveConfig.FALSE;
543 // If "config" statement is not specified, the default is the same as the parent's "config" value.
544 myConfig = parentConfig;
547 myConfig = EffectiveConfig.IGNORED;
550 flags = (byte) (flags & ~MASK_CONFIG | HAVE_CONFIG | myConfig.ordinal());
554 protected abstract boolean isIgnoringConfig();
557 * This method maintains a resolution cache for ignore config, so once we have returned a result, we will
558 * keep on returning the same result without performing any lookups. Exists only to support
559 * {@link SubstatementContext#isIgnoringConfig()}.
562 * Note: use of this method implies that {@link #isConfiguration()} is realized with
563 * {@link #effectiveConfig(StatementContextBase)}.
565 final boolean isIgnoringConfig(final StatementContextBase<?, ?, ?> parent) {
566 return EffectiveConfig.IGNORED == effectiveConfig(parent);
569 protected abstract boolean isIgnoringIfFeatures();
572 * This method maintains a resolution cache for ignore if-feature, so once we have returned a result, we will
573 * keep on returning the same result without performing any lookups. Exists only to support
574 * {@link SubstatementContext#isIgnoringIfFeatures()}.
576 final boolean isIgnoringIfFeatures(final StatementContextBase<?, ?, ?> parent) {
577 final int fl = flags & SET_IGNORE_IF_FEATURE;
579 return fl == SET_IGNORE_IF_FEATURE;
581 if (definition().support().isIgnoringIfFeatures() || parent.isIgnoringIfFeatures()) {
582 flags |= SET_IGNORE_IF_FEATURE;
586 flags |= HAVE_IGNORE_IF_FEATURE;
590 // These two exist only due to memory optimization, should live in AbstractResumedStatement.
591 final boolean fullyDefined() {
595 final void setFullyDefined() {
599 // This exists only due to memory optimization, should live in ReplicaStatementContext. In this context the flag
600 // indicates the need to drop source's reference count when we are being swept.
601 final boolean haveSourceReference() {
605 // These three exist due to memory optimization, should live in InferredStatementContext. In this context the flag
606 // indicates whether or not this statement's substatement file was modified, i.e. it is not quite the same as the
608 final boolean isModified() {
612 final void setModified() {
616 final void setUnmodified() {
620 // These two exist only for StatementContextBase. Since we are squeezed for size, with only a single bit available
621 // in flags, we default to 'false' and only set the flag to true when we are absolutely sure -- and all other cases
622 // err on the side of caution by taking the time to evaluate each substatement separately.
623 final boolean allSubstatementsContextIndependent() {
624 return (flags & ALL_INDEPENDENT) != 0;
627 final void setAllSubstatementsContextIndependent() {
628 flags |= ALL_INDEPENDENT;
633 // Various functionality from AbstractTypeStatementSupport. This used to work on top of SchemaPath, now it still
634 // lives here. Ultimate future is either proper graduation or (more likely) move to AbstractTypeStatementSupport.
639 public final QName argumentAsTypeQName() {
640 // FIXME: This may yield illegal argument exceptions
641 return StmtContextUtils.qnameFromArgument(getOriginalCtx().orElse(this), getRawArgument());
645 public final QNameModule effectiveNamespace() {
646 if (StmtContextUtils.isUnknownStatement(this)) {
647 return publicDefinition().getStatementName().getModule();
649 if (producesDeclared(UsesStatement.class)) {
650 return coerceParent().effectiveNamespace();
653 final Object argument = argument();
654 if (argument instanceof QName qname) {
655 return qname.getModule();
657 if (argument instanceof String str) {
658 // FIXME: This may yield illegal argument exceptions
659 return StmtContextUtils.qnameFromArgument(getOriginalCtx().orElse(this), str).getModule();
661 if (argument instanceof SchemaNodeIdentifier sni
662 && (producesDeclared(AugmentStatement.class) || producesDeclared(RefineStatement.class)
663 || producesDeclared(DeviationStatement.class))) {
664 return sni.lastNodeIdentifier().getModule();
667 return coerceParent().effectiveNamespace();
670 private ReactorStmtCtx<?, ?, ?> coerceParent() {
671 return (ReactorStmtCtx<?, ?, ?>) coerceParentContext();
676 // Reference counting mechanics start. Please keep these methods in one block for clarity. Note this does not
677 // contribute to state visible outside of this package.
682 * Local knowledge of {@link #refcount} values up to statement root. We use this field to prevent recursive lookups
683 * in {@link #noParentRefs(StatementContextBase)} -- once we discover a parent reference once, we keep that
684 * knowledge and update it when {@link #sweep()} is invoked.
686 private byte parentRef = PARENTREF_UNKNOWN;
687 private static final byte PARENTREF_UNKNOWN = -1;
688 private static final byte PARENTREF_ABSENT = 0;
689 private static final byte PARENTREF_PRESENT = 1;
692 * Acquire a reference on this context. As long as there is at least one reference outstanding,
693 * {@link #buildEffective()} will not result in {@link #effectiveSubstatements()} being discarded.
695 * @throws VerifyException if {@link #effectiveSubstatements()} has already been discarded
697 final void incRef() {
698 final int current = refcount;
699 verify(current >= REFCOUNT_NONE, "Attempted to access reference count of %s", this);
700 if (current != REFCOUNT_DEFUNCT) {
701 // Note: can end up becoming REFCOUNT_DEFUNCT on overflow
702 refcount = current + 1;
704 LOG.debug("Disabled refcount increment of {}", this);
709 * Release a reference on this context. This call may result in {@link #effectiveSubstatements()} becoming
712 final void decRef() {
713 final int current = refcount;
714 if (current == REFCOUNT_DEFUNCT) {
716 LOG.debug("Disabled refcount decrement of {}", this);
719 if (current <= REFCOUNT_NONE) {
720 // Underflow, become defunct
721 // FIXME: add a global 'warn once' flag
722 LOG.warn("Statement refcount underflow, reference counting disabled for {}", this, new Throwable());
723 refcount = REFCOUNT_DEFUNCT;
727 refcount = current - 1;
728 LOG.trace("Refcount {} on {}", refcount, this);
730 if (refcount == REFCOUNT_NONE) {
736 * Return {@code true} if this context has no outstanding references.
738 * @return True if this context has no outstanding references.
740 final boolean noRefs() {
741 final int local = refcount;
742 return local < REFCOUNT_NONE || local == REFCOUNT_NONE && noParentRef();
745 private void lastDecRef() {
746 if (noImplictRef()) {
747 // We are no longer guarded by effective instance
752 final byte prevRefs = parentRef;
753 if (prevRefs == PARENTREF_ABSENT) {
754 // We are the last reference towards root, any children who observed PARENTREF_PRESENT from us need to be
757 } else if (prevRefs == PARENTREF_UNKNOWN) {
758 // Noone observed our parentRef, just update it
759 loadParentRefcount();
763 static final void markNoParentRef(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
764 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
765 final byte prevRef = stmt.parentRef;
766 stmt.parentRef = PARENTREF_ABSENT;
767 if (prevRef == PARENTREF_PRESENT && stmt.refcount == REFCOUNT_NONE) {
768 // Child thinks it is pinned down, update its perspective
769 stmt.markNoParentRef();
774 abstract void markNoParentRef();
776 static final void sweep(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
777 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
783 * Sweep this statement context as a result of {@link #sweepSubstatements()}, i.e. when parent is also being swept.
785 private void sweep() {
786 parentRef = PARENTREF_ABSENT;
787 if (refcount == REFCOUNT_NONE && noImplictRef()) {
788 LOG.trace("Releasing {}", this);
793 static final int countUnswept(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
795 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
796 if (stmt.refcount > REFCOUNT_NONE || !stmt.noImplictRef()) {
804 * Implementation-specific sweep action. This is expected to perform a recursive {@link #sweep(Collection)} on all
805 * {@link #declaredSubstatements()} and {@link #effectiveSubstatements()} and report the result of the sweep
809 * {@link #effectiveSubstatements()} as well as namespaces may become inoperable as a result of this operation.
811 * @return True if the entire tree has been completely swept, false otherwise.
813 abstract int sweepSubstatements();
815 // Called when this statement does not have an implicit reference and have reached REFCOUNT_NONE
816 private void sweepOnDecrement() {
817 LOG.trace("Sweeping on decrement {}", this);
819 // No further parent references, sweep our state.
823 // Propagate towards parent if there is one
827 private void sweepParent() {
828 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
829 if (parent != null) {
830 parent.sweepOnChildDecrement();
834 // Called from child when it has lost its final reference
835 private void sweepOnChildDecrement() {
836 if (isAwaitingChildren()) {
837 // We are a child for which our parent is waiting. Notify it and we are done.
842 // Check parent reference count
843 final int refs = refcount;
844 if (refs > REFCOUNT_NONE || refs <= REFCOUNT_SWEEPING || !noImplictRef()) {
849 // parent is potentially reclaimable
851 LOG.trace("Cleanup {} of parent {}", refs, this);
858 private boolean noImplictRef() {
859 return effectiveInstance != null || !isSupportedToBuildEffective();
862 private boolean noParentRef() {
863 return parentRefcount() == PARENTREF_ABSENT;
866 private byte parentRefcount() {
868 return (refs = parentRef) != PARENTREF_UNKNOWN ? refs : loadParentRefcount();
871 private byte loadParentRefcount() {
872 return parentRef = calculateParentRefcount();
875 private byte calculateParentRefcount() {
876 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
877 if (parent == null) {
878 return PARENTREF_ABSENT;
881 // A slight wrinkle here is that our machinery handles only PRESENT -> ABSENT invalidation and we can reach here
882 // while inference is still ongoing and hence we may not have a complete picture about existing references. We
883 // could therefore end up caching an ABSENT result and then that information becoming stale as a new reference
885 if (parent.executionOrder() < ExecutionOrder.EFFECTIVE_MODEL) {
886 return PARENTREF_UNKNOWN;
889 // There are three possibilities:
890 // - REFCOUNT_NONE, in which case we need to search next parent
891 // - negative (< REFCOUNT_NONE), meaning parent is in some stage of sweeping, hence it does not have
893 // - positive (> REFCOUNT_NONE), meaning parent has an explicit refcount which is holding us down
894 final int refs = parent.refcount;
895 if (refs == REFCOUNT_NONE) {
896 return parent.parentRefcount();
898 return refs < REFCOUNT_NONE ? PARENTREF_ABSENT : PARENTREF_PRESENT;
901 private boolean isAwaitingChildren() {
902 return refcount > REFCOUNT_SWEEPING && refcount < REFCOUNT_NONE;
905 private void sweepOnChildDone() {
906 LOG.trace("Sweeping on child done {}", this);
907 final int current = refcount;
908 if (current >= REFCOUNT_NONE) {
909 // no-op, perhaps we want to handle some cases differently?
910 LOG.trace("Ignoring child sweep of {} for {}", this, current);
913 verify(current != REFCOUNT_SWEPT, "Attempt to sweep a child of swept %s", this);
915 refcount = current + 1;
916 LOG.trace("Child refcount {}", refcount);
917 if (refcount == REFCOUNT_NONE) {
919 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
920 LOG.trace("Propagating to parent {}", parent);
921 if (parent != null && parent.isAwaitingChildren()) {
922 parent.sweepOnChildDone();
927 private void sweepDone() {
928 LOG.trace("Sweep done for {}", this);
929 refcount = REFCOUNT_SWEPT;
933 private boolean sweepState() {
934 refcount = REFCOUNT_SWEEPING;
935 final int childRefs = sweepSubstatements();
936 if (childRefs == 0) {
940 if (childRefs < 0 || childRefs >= REFCOUNT_DEFUNCT) {
941 // FIXME: add a global 'warn once' flag
942 LOG.warn("Negative child refcount {} cannot be stored, reference counting disabled for {}", childRefs, this,
944 refcount = REFCOUNT_DEFUNCT;
946 LOG.trace("Still {} outstanding children of {}", childRefs, this);
947 refcount = -childRefs;