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 org.eclipse.jdt.annotation.NonNull;
21 import org.eclipse.jdt.annotation.Nullable;
22 import org.opendaylight.yangtools.yang.common.QName;
23 import org.opendaylight.yangtools.yang.common.QNameModule;
24 import org.opendaylight.yangtools.yang.common.YangVersion;
25 import org.opendaylight.yangtools.yang.model.api.meta.DeclaredStatement;
26 import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
27 import org.opendaylight.yangtools.yang.model.api.meta.StatementDefinition;
28 import org.opendaylight.yangtools.yang.model.api.stmt.AugmentStatement;
29 import org.opendaylight.yangtools.yang.model.api.stmt.ConfigEffectiveStatement;
30 import org.opendaylight.yangtools.yang.model.api.stmt.DeviationStatement;
31 import org.opendaylight.yangtools.yang.model.api.stmt.RefineStatement;
32 import org.opendaylight.yangtools.yang.model.api.stmt.SchemaNodeIdentifier;
33 import org.opendaylight.yangtools.yang.model.api.stmt.UsesStatement;
34 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
35 import org.opendaylight.yangtools.yang.parser.spi.meta.CopyType;
36 import org.opendaylight.yangtools.yang.parser.spi.meta.EffectiveStmtCtx.Current;
37 import org.opendaylight.yangtools.yang.parser.spi.meta.InferenceException;
38 import org.opendaylight.yangtools.yang.parser.spi.meta.ModelActionBuilder;
39 import org.opendaylight.yangtools.yang.parser.spi.meta.ModelProcessingPhase;
40 import org.opendaylight.yangtools.yang.parser.spi.meta.ModelProcessingPhase.ExecutionOrder;
41 import org.opendaylight.yangtools.yang.parser.spi.meta.NamespaceBehaviour.Registry;
42 import org.opendaylight.yangtools.yang.parser.spi.meta.ParserNamespace;
43 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext;
44 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext.Mutable;
45 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContextUtils;
46 import org.opendaylight.yangtools.yang.parser.spi.source.SourceException;
47 import org.opendaylight.yangtools.yang.parser.spi.source.SupportedFeaturesNamespace;
48 import org.opendaylight.yangtools.yang.parser.spi.source.SupportedFeaturesNamespace.SupportedFeatures;
49 import org.slf4j.Logger;
50 import org.slf4j.LoggerFactory;
53 * Real "core" reactor statement implementation of {@link Mutable}, supporting basic reactor lifecycle.
55 * @param <A> Argument type
56 * @param <D> Declared Statement representation
57 * @param <E> Effective Statement representation
59 abstract class ReactorStmtCtx<A, D extends DeclaredStatement<A>, E extends EffectiveStatement<A, D>>
60 extends NamespaceStorageSupport implements Mutable<A, D, E>, Current<A, D> {
61 private static final Logger LOG = LoggerFactory.getLogger(ReactorStmtCtx.class);
64 * Substatement refcount tracking. This mechanics deals with retaining substatements for the purposes of
65 * instantiating their lazy copies in InferredStatementContext. It works in concert with {@link #buildEffective()}
66 * and {@link #declared()}: declared/effective statement views hold an implicit reference and refcount-based
67 * sweep is not activated until they are done (or this statement is not {@link #isSupportedToBuildEffective}).
70 * Reference count is hierarchical in that parent references also pin down their child statements and do not allow
74 * The counter's positive values are tracking incoming references via {@link #incRef()}/{@link #decRef()} methods.
75 * Once we transition to sweeping, this value becomes negative counting upwards to {@link #REFCOUNT_NONE} based on
76 * {@link #sweepOnChildDone()}. Once we reach that, we transition to {@link #REFCOUNT_SWEPT}.
78 private int refcount = REFCOUNT_NONE;
80 * No outstanding references, this statement is a potential candidate for sweeping, provided it has populated its
81 * declared and effective views and {@link #parentRef} is known to be absent.
83 private static final int REFCOUNT_NONE = 0;
85 * Reference count overflow or some other recoverable logic error. Do not rely on refcounts and do not sweep
89 * Note on value assignment:
90 * This allow our incRef() to naturally progress to being saturated. Others jump there directly.
91 * It also makes it it impossible to observe {@code Interger.MAX_VALUE} children, which we take advantage of for
92 * {@link #REFCOUNT_SWEEPING}.
94 private static final int REFCOUNT_DEFUNCT = Integer.MAX_VALUE;
96 * This statement is being actively swept. This is a transient value set when we are sweeping our children, so that
97 * we prevent re-entering this statement.
100 * Note on value assignment:
101 * The value is lower than any legal child refcount due to {@link #REFCOUNT_DEFUNCT} while still being higher than
102 * {@link #REFCOUNT_SWEPT}.
104 private static final int REFCOUNT_SWEEPING = -Integer.MAX_VALUE;
106 * This statement, along with its entire subtree has been swept and we positively know all our children have reached
107 * this state. We {@link #sweepNamespaces()} upon reaching this state.
110 * Note on value assignment:
111 * This is the lowest value observable, making it easier on checking others on equality.
113 private static final int REFCOUNT_SWEPT = Integer.MIN_VALUE;
116 * Effective instance built from this context. This field as dual types. Under normal circumstances in matches the
117 * {@link #buildEffective()} instance. If this context is reused, it can be inflated to {@link EffectiveInstances}
118 * and also act as a common instance reuse site.
120 private @Nullable E effectiveInstance;
122 // Master flag controlling whether this context can yield an effective statement
123 // FIXME: investigate the mechanics that are being supported by this, as it would be beneficial if we can get rid
124 // of this flag -- eliminating the initial alignment shadow used by below gap-filler fields.
125 private boolean isSupportedToBuildEffective = true;
127 // EffectiveConfig mapping
128 private static final int MASK_CONFIG = 0x03;
129 private static final int HAVE_CONFIG = 0x04;
130 // Effective instantiation mechanics for StatementContextBase: if this flag is set all substatements are known not
131 // change when instantiated. This includes context-independent statements as well as any statements which are
132 // ignored during copy instantiation.
133 private static final int ALL_INDEPENDENT = 0x08;
134 // Flag bit assignments
135 private static final int IS_SUPPORTED_BY_FEATURES = 0x10;
136 private static final int HAVE_SUPPORTED_BY_FEATURES = 0x20;
137 private static final int IS_IGNORE_IF_FEATURE = 0x40;
138 private static final int HAVE_IGNORE_IF_FEATURE = 0x80;
139 // Have-and-set flag constants, also used as masks
140 private static final int SET_SUPPORTED_BY_FEATURES = HAVE_SUPPORTED_BY_FEATURES | IS_SUPPORTED_BY_FEATURES;
141 private static final int SET_IGNORE_IF_FEATURE = HAVE_IGNORE_IF_FEATURE | IS_IGNORE_IF_FEATURE;
143 private static final EffectiveConfig[] EFFECTIVE_CONFIGS;
146 final EffectiveConfig[] values = EffectiveConfig.values();
147 final int length = values.length;
148 verify(length == 4, "Unexpected EffectiveConfig cardinality %s", length);
149 EFFECTIVE_CONFIGS = values;
152 // Flags for use with SubstatementContext. These are hiding in the alignment shadow created by above boolean and
153 // hence improve memory layout.
156 // Flag for use by AbstractResumedStatement, ReplicaStatementContext and InferredStatementContext. Each of them
157 // uses it to indicated a different condition. This is hiding in the alignment shadow created by
158 // 'isSupportedToBuildEffective'.
159 // FIXME: move this out once we have JDK15+
160 private boolean boolFlag;
166 ReactorStmtCtx(final ReactorStmtCtx<A, D, E> original) {
167 isSupportedToBuildEffective = original.isSupportedToBuildEffective;
168 boolFlag = original.boolFlag;
169 flags = original.flags;
172 // Used by ReplicaStatementContext only
173 ReactorStmtCtx(final ReactorStmtCtx<A, D, E> original, final Void dummy) {
174 boolFlag = isSupportedToBuildEffective = original.isSupportedToBuildEffective;
175 flags = original.flags;
180 // Common public interface contracts with simple mechanics. Please keep this in one logical block, so we do not end
181 // up mixing concerns and simple details with more complex logic.
186 public abstract StatementContextBase<?, ?, ?> getParentContext();
189 public abstract RootStatementContext<?, ?, ?> getRoot();
192 public abstract Collection<? extends StatementContextBase<?, ?, ?>> mutableDeclaredSubstatements();
195 public final @NonNull Registry getBehaviourRegistry() {
196 return getRoot().getBehaviourRegistryImpl();
200 public final YangVersion yangVersion() {
201 return getRoot().getRootVersionImpl();
205 public final void setRootVersion(final YangVersion version) {
206 getRoot().setRootVersionImpl(version);
210 public final void addRequiredSource(final SourceIdentifier dependency) {
211 getRoot().addRequiredSourceImpl(dependency);
215 public final void setRootIdentifier(final SourceIdentifier identifier) {
216 getRoot().setRootIdentifierImpl(identifier);
220 public final ModelActionBuilder newInferenceAction(final ModelProcessingPhase phase) {
221 return getRoot().getSourceContext().newInferenceAction(phase);
225 public final StatementDefinition publicDefinition() {
226 return definition().getPublicView();
230 public final Parent effectiveParent() {
231 return getParentContext();
235 public final QName moduleName() {
236 final RootStatementContext<?, ?, ?> root = getRoot();
237 return QName.create(StmtContextUtils.getRootModuleQName(root), root.getRawArgument());
241 public final EffectiveStatement<?, ?> original() {
242 return getOriginalCtx().map(StmtContext::buildEffective).orElse(null);
246 // In the next two methods we are looking for an effective statement. If we already have an effective instance,
247 // defer to it's implementation of the equivalent search. Otherwise we search our substatement contexts.
249 // Note that the search function is split, so as to allow InferredStatementContext to do its own thing first.
253 public final <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgument(
254 final @NonNull Class<Z> type) {
255 final E existing = effectiveInstance;
256 return existing != null ? existing.findFirstEffectiveSubstatementArgument(type)
257 : findSubstatementArgumentImpl(type);
261 public final boolean hasSubstatement(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
262 final E existing = effectiveInstance;
263 return existing != null ? existing.findFirstEffectiveSubstatement(type).isPresent() : hasSubstatementImpl(type);
266 // Visible due to InferredStatementContext's override. At this point we do not have an effective instance available.
267 <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgumentImpl(
268 final @NonNull Class<Z> type) {
269 return allSubstatementsStream()
270 .filter(ctx -> ctx.isSupportedToBuildEffective() && ctx.producesEffective(type))
272 .map(ctx -> (X) ctx.getArgument());
275 // Visible due to InferredStatementContext's override. At this point we do not have an effective instance available.
276 boolean hasSubstatementImpl(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
277 return allSubstatementsStream()
278 .anyMatch(ctx -> ctx.isSupportedToBuildEffective() && ctx.producesEffective(type));
283 @SuppressWarnings("unchecked")
284 public final <Z extends EffectiveStatement<A, D>> StmtContext<A, D, Z> caerbannog() {
285 return (StmtContext<A, D, Z>) this;
289 public final String toString() {
290 return addToStringAttributes(MoreObjects.toStringHelper(this).omitNullValues()).toString();
293 protected ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {
294 return toStringHelper.add("definition", definition()).add("rawArgument", rawArgument())
295 .add("refCount", refString());
298 private String refString() {
299 final int current = refcount;
301 case REFCOUNT_DEFUNCT:
303 case REFCOUNT_SWEEPING:
308 return String.valueOf(refcount);
313 * Return the context in which this statement was defined.
315 * @return statement definition
317 abstract @NonNull StatementDefinitionContext<A, D, E> definition();
321 // NamespaceStorageSupport/Mutable integration methods. Keep these together.
326 public final <K, V, T extends K, N extends ParserNamespace<K, V>> V namespaceItem(final Class<@NonNull N> type,
328 return getBehaviourRegistry().getNamespaceBehaviour(type).getFrom(this, key);
332 public final <K, V, N extends ParserNamespace<K, V>> Map<K, V> namespace(final Class<@NonNull N> type) {
333 return getNamespace(type);
337 public final <K, V, N extends ParserNamespace<K, V>>
338 Map<K, V> localNamespacePortion(final Class<@NonNull N> type) {
339 return getLocalNamespace(type);
343 protected <K, V, N extends ParserNamespace<K, V>> void onNamespaceElementAdded(final Class<N> type, final K key,
345 // definition().onNamespaceElementAdded(this, type, key, value);
349 * Return the effective statement view of a copy operation. This method may return one of:
351 * <li>{@code this}, when the effective view did not change</li>
352 * <li>an InferredStatementContext, when there is a need for inference-equivalent copy</li>
353 * <li>{@code null}, when the statement failed to materialize</li>
356 * @param parent Proposed new parent
357 * @param type Copy operation type
358 * @param targetModule New target module
359 * @return {@link ReactorStmtCtx} holding effective view
361 abstract @Nullable ReactorStmtCtx<?, ?, ?> asEffectiveChildOf(StatementContextBase<?, ?, ?> parent, CopyType type,
362 QNameModule targetModule);
365 public final ReactorStmtCtx<A, D, E> replicaAsChildOf(final Mutable<?, ?, ?> parent) {
366 checkArgument(parent instanceof StatementContextBase, "Unsupported parent %s", parent);
367 return replicaAsChildOf((StatementContextBase<?, ?, ?>) parent);
370 abstract @NonNull ReplicaStatementContext<A, D, E> replicaAsChildOf(@NonNull StatementContextBase<?, ?, ?> parent);
374 // Statement build entry points -- both public and package-private.
379 public final E buildEffective() {
381 return (existing = effectiveInstance) != null ? existing : loadEffective();
384 private @NonNull E loadEffective() {
385 // Creating an effective statement does not strictly require a declared instance -- there are statements like
386 // 'input', which are implicitly defined.
387 // Our implementation design makes an invariant assumption that buildDeclared() has been called by the time
388 // we attempt to create effective statement:
391 final E ret = createEffective();
392 effectiveInstance = ret;
393 // we have called createEffective(), substatements are no longer guarded by us. Let's see if we can clear up
395 if (refcount == REFCOUNT_NONE) {
401 abstract @NonNull E createEffective();
404 * Walk this statement's copy history and return the statement closest to original which has not had its effective
405 * statements modified. This statement and returned substatement logically have the same set of substatements, hence
406 * share substatement-derived state.
408 * @return Closest {@link ReactorStmtCtx} with equivalent effective substatements
410 abstract @NonNull ReactorStmtCtx<A, D, E> unmodifiedEffectiveSource();
413 public final ModelProcessingPhase getCompletedPhase() {
414 return ModelProcessingPhase.ofExecutionOrder(executionOrder());
417 abstract byte executionOrder();
420 * Try to execute current {@link ModelProcessingPhase} of source parsing. If the phase has already been executed,
421 * this method does nothing. This must not be called with {@link ExecutionOrder#NULL}.
423 * @param phase to be executed (completed)
424 * @return true if phase was successfully completed
425 * @throws SourceException when an error occurred in source parsing
427 final boolean tryToCompletePhase(final byte executionOrder) {
428 return executionOrder() >= executionOrder || doTryToCompletePhase(executionOrder);
431 abstract boolean doTryToCompletePhase(byte targetOrder);
435 // Flags-based mechanics. These include public interfaces as well as all the crud we have lurking in our alignment
441 public final boolean isSupportedToBuildEffective() {
442 return isSupportedToBuildEffective;
446 public final void setIsSupportedToBuildEffective(final boolean isSupportedToBuildEffective) {
447 this.isSupportedToBuildEffective = isSupportedToBuildEffective;
451 public final boolean isSupportedByFeatures() {
452 final int fl = flags & SET_SUPPORTED_BY_FEATURES;
454 return fl == SET_SUPPORTED_BY_FEATURES;
456 if (isIgnoringIfFeatures()) {
457 flags |= SET_SUPPORTED_BY_FEATURES;
462 * If parent is supported, we need to check if-features statements of this context.
464 if (isParentSupportedByFeatures()) {
465 // If the set of supported features has not been provided, all features are supported by default.
466 final Set<QName> supportedFeatures = getFromNamespace(SupportedFeaturesNamespace.class,
467 SupportedFeatures.SUPPORTED_FEATURES);
468 if (supportedFeatures == null || StmtContextUtils.checkFeatureSupport(this, supportedFeatures)) {
469 flags |= SET_SUPPORTED_BY_FEATURES;
474 // Either parent is not supported or this statement is not supported
475 flags |= HAVE_SUPPORTED_BY_FEATURES;
479 protected abstract boolean isParentSupportedByFeatures();
482 * Config statements are not all that common which means we are performing a recursive search towards the root
483 * every time {@link #effectiveConfig()} is invoked. This is quite expensive because it causes a linear search
484 * for the (usually non-existent) config statement.
487 * This method maintains a resolution cache, so once we have returned a result, we will keep on returning the same
488 * result without performing any lookups, solely to support {@link #effectiveConfig()}.
491 * Note: use of this method implies that {@link #isIgnoringConfig()} is realized with
492 * {@link #isIgnoringConfig(StatementContextBase)}.
494 final @NonNull EffectiveConfig effectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
495 return (flags & HAVE_CONFIG) != 0 ? EFFECTIVE_CONFIGS[flags & MASK_CONFIG] : loadEffectiveConfig(parent);
498 private @NonNull EffectiveConfig loadEffectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
499 final EffectiveConfig parentConfig = parent.effectiveConfig();
501 final EffectiveConfig myConfig;
502 if (parentConfig != EffectiveConfig.IGNORED && !definition().support().isIgnoringConfig()) {
503 final Optional<Boolean> optConfig = findSubstatementArgument(ConfigEffectiveStatement.class);
504 if (optConfig.isPresent()) {
505 if (optConfig.orElseThrow()) {
506 // Validity check: if parent is config=false this cannot be a config=true
507 InferenceException.throwIf(parentConfig == EffectiveConfig.FALSE, this,
508 "Parent node has config=false, this node must not be specifed as config=true");
509 myConfig = EffectiveConfig.TRUE;
511 myConfig = EffectiveConfig.FALSE;
514 // If "config" statement is not specified, the default is the same as the parent's "config" value.
515 myConfig = parentConfig;
518 myConfig = EffectiveConfig.IGNORED;
521 flags = (byte) (flags & ~MASK_CONFIG | HAVE_CONFIG | myConfig.ordinal());
525 protected abstract boolean isIgnoringConfig();
528 * This method maintains a resolution cache for ignore config, so once we have returned a result, we will
529 * keep on returning the same result without performing any lookups. Exists only to support
530 * {@link SubstatementContext#isIgnoringConfig()}.
533 * Note: use of this method implies that {@link #isConfiguration()} is realized with
534 * {@link #effectiveConfig(StatementContextBase)}.
536 final boolean isIgnoringConfig(final StatementContextBase<?, ?, ?> parent) {
537 return EffectiveConfig.IGNORED == effectiveConfig(parent);
540 protected abstract boolean isIgnoringIfFeatures();
543 * This method maintains a resolution cache for ignore if-feature, so once we have returned a result, we will
544 * keep on returning the same result without performing any lookups. Exists only to support
545 * {@link SubstatementContext#isIgnoringIfFeatures()}.
547 final boolean isIgnoringIfFeatures(final StatementContextBase<?, ?, ?> parent) {
548 final int fl = flags & SET_IGNORE_IF_FEATURE;
550 return fl == SET_IGNORE_IF_FEATURE;
552 if (definition().support().isIgnoringIfFeatures() || parent.isIgnoringIfFeatures()) {
553 flags |= SET_IGNORE_IF_FEATURE;
557 flags |= HAVE_IGNORE_IF_FEATURE;
561 // These two exist only due to memory optimization, should live in AbstractResumedStatement.
562 final boolean fullyDefined() {
566 final void setFullyDefined() {
570 // This exists only due to memory optimization, should live in ReplicaStatementContext. In this context the flag
571 // indicates the need to drop source's reference count when we are being swept.
572 final boolean haveSourceReference() {
576 // These three exist due to memory optimization, should live in InferredStatementContext. In this context the flag
577 // indicates whether or not this statement's substatement file was modified, i.e. it is not quite the same as the
579 final boolean isModified() {
583 final void setModified() {
587 final void setUnmodified() {
591 // These two exist only for StatementContextBase. Since we are squeezed for size, with only a single bit available
592 // in flags, we default to 'false' and only set the flag to true when we are absolutely sure -- and all other cases
593 // err on the side of caution by taking the time to evaluate each substatement separately.
594 final boolean allSubstatementsContextIndependent() {
595 return (flags & ALL_INDEPENDENT) != 0;
598 final void setAllSubstatementsContextIndependent() {
599 flags |= ALL_INDEPENDENT;
604 // Various functionality from AbstractTypeStatementSupport. This used to work on top of SchemaPath, now it still
605 // lives here. Ultimate future is either proper graduation or (more likely) move to AbstractTypeStatementSupport.
610 public final QName argumentAsTypeQName() {
611 // FIXME: This may yield illegal argument exceptions
612 return StmtContextUtils.qnameFromArgument(getOriginalCtx().orElse(this), getRawArgument());
616 public final QNameModule effectiveNamespace() {
617 if (StmtContextUtils.isUnknownStatement(this)) {
618 return publicDefinition().getStatementName().getModule();
620 if (producesDeclared(UsesStatement.class)) {
621 return coerceParent().effectiveNamespace();
624 final Object argument = argument();
625 if (argument instanceof QName) {
626 return ((QName) argument).getModule();
628 if (argument instanceof String) {
629 // FIXME: This may yield illegal argument exceptions
630 return StmtContextUtils.qnameFromArgument(getOriginalCtx().orElse(this), (String) argument).getModule();
632 if (argument instanceof SchemaNodeIdentifier
633 && (producesDeclared(AugmentStatement.class) || producesDeclared(RefineStatement.class)
634 || producesDeclared(DeviationStatement.class))) {
635 return ((SchemaNodeIdentifier) argument).lastNodeIdentifier().getModule();
638 return coerceParent().effectiveNamespace();
641 private ReactorStmtCtx<?, ?, ?> coerceParent() {
642 return (ReactorStmtCtx<?, ?, ?>) coerceParentContext();
647 // Reference counting mechanics start. Please keep these methods in one block for clarity. Note this does not
648 // contribute to state visible outside of this package.
653 * Local knowledge of {@link #refcount} values up to statement root. We use this field to prevent recursive lookups
654 * in {@link #noParentRefs(StatementContextBase)} -- once we discover a parent reference once, we keep that
655 * knowledge and update it when {@link #sweep()} is invoked.
657 private byte parentRef = PARENTREF_UNKNOWN;
658 private static final byte PARENTREF_UNKNOWN = -1;
659 private static final byte PARENTREF_ABSENT = 0;
660 private static final byte PARENTREF_PRESENT = 1;
663 * Acquire a reference on this context. As long as there is at least one reference outstanding,
664 * {@link #buildEffective()} will not result in {@link #effectiveSubstatements()} being discarded.
666 * @throws VerifyException if {@link #effectiveSubstatements()} has already been discarded
668 final void incRef() {
669 final int current = refcount;
670 verify(current >= REFCOUNT_NONE, "Attempted to access reference count of %s", this);
671 if (current != REFCOUNT_DEFUNCT) {
672 // Note: can end up becoming REFCOUNT_DEFUNCT on overflow
673 refcount = current + 1;
675 LOG.debug("Disabled refcount increment of {}", this);
680 * Release a reference on this context. This call may result in {@link #effectiveSubstatements()} becoming
683 final void decRef() {
684 final int current = refcount;
685 if (current == REFCOUNT_DEFUNCT) {
687 LOG.debug("Disabled refcount decrement of {}", this);
690 if (current <= REFCOUNT_NONE) {
691 // Underflow, become defunct
692 // FIXME: add a global 'warn once' flag
693 LOG.warn("Statement refcount underflow, reference counting disabled for {}", this, new Throwable());
694 refcount = REFCOUNT_DEFUNCT;
698 refcount = current - 1;
699 LOG.trace("Refcount {} on {}", refcount, this);
701 if (refcount == REFCOUNT_NONE) {
707 * Return {@code true} if this context has no outstanding references.
709 * @return True if this context has no outstanding references.
711 final boolean noRefs() {
712 final int local = refcount;
713 return local < REFCOUNT_NONE || local == REFCOUNT_NONE && noParentRef();
716 private void lastDecRef() {
717 if (noImplictRef()) {
718 // We are no longer guarded by effective instance
723 final byte prevRefs = parentRef;
724 if (prevRefs == PARENTREF_ABSENT) {
725 // We are the last reference towards root, any children who observed PARENTREF_PRESENT from us need to be
728 } else if (prevRefs == PARENTREF_UNKNOWN) {
729 // Noone observed our parentRef, just update it
730 loadParentRefcount();
734 static final void markNoParentRef(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
735 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
736 final byte prevRef = stmt.parentRef;
737 stmt.parentRef = PARENTREF_ABSENT;
738 if (prevRef == PARENTREF_PRESENT && stmt.refcount == REFCOUNT_NONE) {
739 // Child thinks it is pinned down, update its perspective
740 stmt.markNoParentRef();
745 abstract void markNoParentRef();
747 static final void sweep(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
748 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
754 * Sweep this statement context as a result of {@link #sweepSubstatements()}, i.e. when parent is also being swept.
756 private void sweep() {
757 parentRef = PARENTREF_ABSENT;
758 if (refcount == REFCOUNT_NONE && noImplictRef()) {
759 LOG.trace("Releasing {}", this);
764 static final int countUnswept(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
766 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
767 if (stmt.refcount > REFCOUNT_NONE || !stmt.noImplictRef()) {
775 * Implementation-specific sweep action. This is expected to perform a recursive {@link #sweep(Collection)} on all
776 * {@link #declaredSubstatements()} and {@link #effectiveSubstatements()} and report the result of the sweep
780 * {@link #effectiveSubstatements()} as well as namespaces may become inoperable as a result of this operation.
782 * @return True if the entire tree has been completely swept, false otherwise.
784 abstract int sweepSubstatements();
786 // Called when this statement does not have an implicit reference and have reached REFCOUNT_NONE
787 private void sweepOnDecrement() {
788 LOG.trace("Sweeping on decrement {}", this);
790 // No further parent references, sweep our state.
794 // Propagate towards parent if there is one
795 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
796 if (parent != null) {
797 parent.sweepOnChildDecrement();
801 // Called from child when it has lost its final reference
802 private void sweepOnChildDecrement() {
803 if (isAwaitingChildren()) {
804 // We are a child for which our parent is waiting. Notify it and we are done.
809 // Check parent reference count
810 final int refs = refcount;
811 if (refs > REFCOUNT_NONE || refs <= REFCOUNT_SWEEPING || !noImplictRef()) {
816 // parent is potentially reclaimable
818 LOG.trace("Cleanup {} of parent {}", refcount, this);
820 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
821 if (parent != null) {
822 parent.sweepOnChildDecrement();
828 private boolean noImplictRef() {
829 return effectiveInstance != null || !isSupportedToBuildEffective();
832 private boolean noParentRef() {
833 return parentRefcount() == PARENTREF_ABSENT;
836 private byte parentRefcount() {
838 return (refs = parentRef) != PARENTREF_UNKNOWN ? refs : loadParentRefcount();
841 private byte loadParentRefcount() {
842 return parentRef = calculateParentRefcount();
845 private byte calculateParentRefcount() {
846 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
847 if (parent == null) {
848 return PARENTREF_ABSENT;
851 // A slight wrinkle here is that our machinery handles only PRESENT -> ABSENT invalidation and we can reach here
852 // while inference is still ongoing and hence we may not have a complete picture about existing references. We
853 // could therefore end up caching an ABSENT result and then that information becoming stale as a new reference
855 if (parent.executionOrder() < ExecutionOrder.EFFECTIVE_MODEL) {
856 return PARENTREF_UNKNOWN;
859 // There are three possibilities:
860 // - REFCOUNT_NONE, in which case we need to search next parent
861 // - negative (< REFCOUNT_NONE), meaning parent is in some stage of sweeping, hence it does not have
863 // - positive (> REFCOUNT_NONE), meaning parent has an explicit refcount which is holding us down
864 final int refs = parent.refcount;
865 if (refs == REFCOUNT_NONE) {
866 return parent.parentRefcount();
868 return refs < REFCOUNT_NONE ? PARENTREF_ABSENT : PARENTREF_PRESENT;
871 private boolean isAwaitingChildren() {
872 return refcount > REFCOUNT_SWEEPING && refcount < REFCOUNT_NONE;
875 private void sweepOnChildDone() {
876 LOG.trace("Sweeping on child done {}", this);
877 final int current = refcount;
878 if (current >= REFCOUNT_NONE) {
879 // no-op, perhaps we want to handle some cases differently?
880 LOG.trace("Ignoring child sweep of {} for {}", this, current);
883 verify(current != REFCOUNT_SWEPT, "Attempt to sweep a child of swept %s", this);
885 refcount = current + 1;
886 LOG.trace("Child refcount {}", refcount);
887 if (refcount == REFCOUNT_NONE) {
889 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
890 LOG.trace("Propagating to parent {}", parent);
891 if (parent != null && parent.isAwaitingChildren()) {
892 parent.sweepOnChildDone();
897 private void sweepDone() {
898 LOG.trace("Sweep done for {}", this);
899 refcount = REFCOUNT_SWEPT;
903 private boolean sweepState() {
904 refcount = REFCOUNT_SWEEPING;
905 final int childRefs = sweepSubstatements();
906 if (childRefs == 0) {
910 if (childRefs < 0 || childRefs >= REFCOUNT_DEFUNCT) {
911 // FIXME: add a global 'warn once' flag
912 LOG.warn("Negative child refcount {} cannot be stored, reference counting disabled for {}", childRefs, this,
914 refcount = REFCOUNT_DEFUNCT;
916 LOG.trace("Still {} outstanding children of {}", childRefs, this);
917 refcount = -childRefs;