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.SchemaNodeIdentifier;
25 import org.opendaylight.yangtools.yang.common.YangVersion;
26 import org.opendaylight.yangtools.yang.model.api.meta.DeclaredStatement;
27 import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
28 import org.opendaylight.yangtools.yang.model.api.meta.StatementDefinition;
29 import org.opendaylight.yangtools.yang.model.api.stmt.AugmentStatement;
30 import org.opendaylight.yangtools.yang.model.api.stmt.ConfigEffectiveStatement;
31 import org.opendaylight.yangtools.yang.model.api.stmt.DeviationStatement;
32 import org.opendaylight.yangtools.yang.model.api.stmt.RefineStatement;
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 @Deprecated(since = "7.0.9", forRemoval = true)
242 public final EffectiveStatement<?, ?> original() {
243 return getOriginalCtx().map(StmtContext::buildEffective).orElse(null);
247 // In the next two methods we are looking for an effective statement. If we already have an effective instance,
248 // defer to it's implementation of the equivalent search. Otherwise we search our substatement contexts.
250 // Note that the search function is split, so as to allow InferredStatementContext to do its own thing first.
254 public final <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgument(
255 final @NonNull Class<Z> type) {
256 final E existing = effectiveInstance;
257 return existing != null ? existing.findFirstEffectiveSubstatementArgument(type)
258 : findSubstatementArgumentImpl(type);
262 public final boolean hasSubstatement(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
263 final E existing = effectiveInstance;
264 return existing != null ? existing.findFirstEffectiveSubstatement(type).isPresent() : hasSubstatementImpl(type);
267 // Visible due to InferredStatementContext's override. At this point we do not have an effective instance available.
268 <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgumentImpl(
269 final @NonNull Class<Z> type) {
270 return allSubstatementsStream()
271 .filter(ctx -> ctx.isSupportedToBuildEffective() && ctx.producesEffective(type))
273 .map(ctx -> (X) ctx.getArgument());
276 // Visible due to InferredStatementContext's override. At this point we do not have an effective instance available.
277 boolean hasSubstatementImpl(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
278 return allSubstatementsStream()
279 .anyMatch(ctx -> ctx.isSupportedToBuildEffective() && ctx.producesEffective(type));
284 @SuppressWarnings("unchecked")
285 public final <Z extends EffectiveStatement<A, D>> StmtContext<A, D, Z> caerbannog() {
286 return (StmtContext<A, D, Z>) this;
290 public final String toString() {
291 return addToStringAttributes(MoreObjects.toStringHelper(this).omitNullValues()).toString();
294 protected ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {
295 return toStringHelper.add("definition", definition()).add("rawArgument", rawArgument())
296 .add("refCount", refString());
299 private String refString() {
300 final int current = refcount;
302 case REFCOUNT_DEFUNCT:
304 case REFCOUNT_SWEEPING:
309 return String.valueOf(refcount);
314 * Return the context in which this statement was defined.
316 * @return statement definition
318 abstract @NonNull StatementDefinitionContext<A, D, E> definition();
322 // NamespaceStorageSupport/Mutable integration methods. Keep these together.
327 public final <K, V, T extends K, N extends ParserNamespace<K, V>> V namespaceItem(final Class<@NonNull N> type,
329 return getBehaviourRegistry().getNamespaceBehaviour(type).getFrom(this, key);
333 public final <K, V, N extends ParserNamespace<K, V>> Map<K, V> namespace(final Class<@NonNull N> type) {
334 return getNamespace(type);
338 public final <K, V, N extends ParserNamespace<K, V>>
339 Map<K, V> localNamespacePortion(final Class<@NonNull N> type) {
340 return getLocalNamespace(type);
344 protected <K, V, N extends ParserNamespace<K, V>> void onNamespaceElementAdded(final Class<N> type, final K key,
346 // definition().onNamespaceElementAdded(this, type, key, value);
350 * Return the effective statement view of a copy operation. This method may return one of:
352 * <li>{@code this}, when the effective view did not change</li>
353 * <li>an InferredStatementContext, when there is a need for inference-equivalent copy</li>
354 * <li>{@code null}, when the statement failed to materialize</li>
357 * @param parent Proposed new parent
358 * @param type Copy operation type
359 * @param targetModule New target module
360 * @return {@link ReactorStmtCtx} holding effective view
362 abstract @Nullable ReactorStmtCtx<?, ?, ?> asEffectiveChildOf(StatementContextBase<?, ?, ?> parent, CopyType type,
363 QNameModule targetModule);
366 public final ReactorStmtCtx<A, D, E> replicaAsChildOf(final Mutable<?, ?, ?> parent) {
367 checkArgument(parent instanceof StatementContextBase, "Unsupported parent %s", parent);
368 return replicaAsChildOf((StatementContextBase<?, ?, ?>) parent);
371 abstract @NonNull ReplicaStatementContext<A, D, E> replicaAsChildOf(@NonNull StatementContextBase<?, ?, ?> parent);
375 // Statement build entry points -- both public and package-private.
380 public final E buildEffective() {
382 return (existing = effectiveInstance) != null ? existing : loadEffective();
385 private @NonNull E loadEffective() {
386 // Creating an effective statement does not strictly require a declared instance -- there are statements like
387 // 'input', which are implicitly defined.
388 // Our implementation design makes an invariant assumption that buildDeclared() has been called by the time
389 // we attempt to create effective statement:
392 final E ret = createEffective();
393 effectiveInstance = ret;
394 // we have called createEffective(), substatements are no longer guarded by us. Let's see if we can clear up
396 if (refcount == REFCOUNT_NONE) {
402 abstract @NonNull E createEffective();
405 * Walk this statement's copy history and return the statement closest to original which has not had its effective
406 * statements modified. This statement and returned substatement logically have the same set of substatements, hence
407 * share substatement-derived state.
409 * @return Closest {@link ReactorStmtCtx} with equivalent effective substatements
411 abstract @NonNull ReactorStmtCtx<A, D, E> unmodifiedEffectiveSource();
414 public final ModelProcessingPhase getCompletedPhase() {
415 return ModelProcessingPhase.ofExecutionOrder(executionOrder());
418 abstract byte executionOrder();
421 * Try to execute current {@link ModelProcessingPhase} of source parsing. If the phase has already been executed,
422 * this method does nothing. This must not be called with {@link ExecutionOrder#NULL}.
424 * @param phase to be executed (completed)
425 * @return true if phase was successfully completed
426 * @throws SourceException when an error occurred in source parsing
428 final boolean tryToCompletePhase(final byte executionOrder) {
429 return executionOrder() >= executionOrder || doTryToCompletePhase(executionOrder);
432 abstract boolean doTryToCompletePhase(byte targetOrder);
436 // Flags-based mechanics. These include public interfaces as well as all the crud we have lurking in our alignment
442 public final boolean isSupportedToBuildEffective() {
443 return isSupportedToBuildEffective;
447 public final void setIsSupportedToBuildEffective(final boolean isSupportedToBuildEffective) {
448 this.isSupportedToBuildEffective = isSupportedToBuildEffective;
452 public final boolean isSupportedByFeatures() {
453 final int fl = flags & SET_SUPPORTED_BY_FEATURES;
455 return fl == SET_SUPPORTED_BY_FEATURES;
457 if (isIgnoringIfFeatures()) {
458 flags |= SET_SUPPORTED_BY_FEATURES;
463 * If parent is supported, we need to check if-features statements of this context.
465 if (isParentSupportedByFeatures()) {
466 // If the set of supported features has not been provided, all features are supported by default.
467 final Set<QName> supportedFeatures = getFromNamespace(SupportedFeaturesNamespace.class,
468 SupportedFeatures.SUPPORTED_FEATURES);
469 if (supportedFeatures == null || StmtContextUtils.checkFeatureSupport(this, supportedFeatures)) {
470 flags |= SET_SUPPORTED_BY_FEATURES;
475 // Either parent is not supported or this statement is not supported
476 flags |= HAVE_SUPPORTED_BY_FEATURES;
480 protected abstract boolean isParentSupportedByFeatures();
483 * Config statements are not all that common which means we are performing a recursive search towards the root
484 * every time {@link #effectiveConfig()} is invoked. This is quite expensive because it causes a linear search
485 * for the (usually non-existent) config statement.
488 * This method maintains a resolution cache, so once we have returned a result, we will keep on returning the same
489 * result without performing any lookups, solely to support {@link #effectiveConfig()}.
492 * Note: use of this method implies that {@link #isIgnoringConfig()} is realized with
493 * {@link #isIgnoringConfig(StatementContextBase)}.
495 final @NonNull EffectiveConfig effectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
496 return (flags & HAVE_CONFIG) != 0 ? EFFECTIVE_CONFIGS[flags & MASK_CONFIG] : loadEffectiveConfig(parent);
499 private @NonNull EffectiveConfig loadEffectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
500 final EffectiveConfig parentConfig = parent.effectiveConfig();
502 final EffectiveConfig myConfig;
503 if (parentConfig != EffectiveConfig.IGNORED && !definition().support().isIgnoringConfig()) {
504 final Optional<Boolean> optConfig = findSubstatementArgument(ConfigEffectiveStatement.class);
505 if (optConfig.isPresent()) {
506 if (optConfig.orElseThrow()) {
507 // Validity check: if parent is config=false this cannot be a config=true
508 InferenceException.throwIf(parentConfig == EffectiveConfig.FALSE, this,
509 "Parent node has config=false, this node must not be specifed as config=true");
510 myConfig = EffectiveConfig.TRUE;
512 myConfig = EffectiveConfig.FALSE;
515 // If "config" statement is not specified, the default is the same as the parent's "config" value.
516 myConfig = parentConfig;
519 myConfig = EffectiveConfig.IGNORED;
522 flags = (byte) (flags & ~MASK_CONFIG | HAVE_CONFIG | myConfig.ordinal());
526 protected abstract boolean isIgnoringConfig();
529 * This method maintains a resolution cache for ignore config, so once we have returned a result, we will
530 * keep on returning the same result without performing any lookups. Exists only to support
531 * {@link SubstatementContext#isIgnoringConfig()}.
534 * Note: use of this method implies that {@link #isConfiguration()} is realized with
535 * {@link #effectiveConfig(StatementContextBase)}.
537 final boolean isIgnoringConfig(final StatementContextBase<?, ?, ?> parent) {
538 return EffectiveConfig.IGNORED == effectiveConfig(parent);
541 protected abstract boolean isIgnoringIfFeatures();
544 * This method maintains a resolution cache for ignore if-feature, so once we have returned a result, we will
545 * keep on returning the same result without performing any lookups. Exists only to support
546 * {@link SubstatementContext#isIgnoringIfFeatures()}.
548 final boolean isIgnoringIfFeatures(final StatementContextBase<?, ?, ?> parent) {
549 final int fl = flags & SET_IGNORE_IF_FEATURE;
551 return fl == SET_IGNORE_IF_FEATURE;
553 if (definition().support().isIgnoringIfFeatures() || parent.isIgnoringIfFeatures()) {
554 flags |= SET_IGNORE_IF_FEATURE;
558 flags |= HAVE_IGNORE_IF_FEATURE;
562 // These two exist only due to memory optimization, should live in AbstractResumedStatement.
563 final boolean fullyDefined() {
567 final void setFullyDefined() {
571 // This exists only due to memory optimization, should live in ReplicaStatementContext. In this context the flag
572 // indicates the need to drop source's reference count when we are being swept.
573 final boolean haveSourceReference() {
577 // These three exist due to memory optimization, should live in InferredStatementContext. In this context the flag
578 // indicates whether or not this statement's substatement file was modified, i.e. it is not quite the same as the
580 final boolean isModified() {
584 final void setModified() {
588 final void setUnmodified() {
592 // These two exist only for StatementContextBase. Since we are squeezed for size, with only a single bit available
593 // in flags, we default to 'false' and only set the flag to true when we are absolutely sure -- and all other cases
594 // err on the side of caution by taking the time to evaluate each substatement separately.
595 final boolean allSubstatementsContextIndependent() {
596 return (flags & ALL_INDEPENDENT) != 0;
599 final void setAllSubstatementsContextIndependent() {
600 flags |= ALL_INDEPENDENT;
605 // Various functionality from AbstractTypeStatementSupport. This used to work on top of SchemaPath, now it still
606 // lives here. Ultimate future is either proper graduation or (more likely) move to AbstractTypeStatementSupport.
611 public final QName argumentAsTypeQName() {
612 // FIXME: This may yield illegal argument exceptions
613 return StmtContextUtils.qnameFromArgument(getOriginalCtx().orElse(this), getRawArgument());
617 public final QNameModule effectiveNamespace() {
618 if (StmtContextUtils.isUnknownStatement(this)) {
619 return publicDefinition().getStatementName().getModule();
621 if (producesDeclared(UsesStatement.class)) {
622 return coerceParent().effectiveNamespace();
625 final Object argument = argument();
626 if (argument instanceof QName) {
627 return ((QName) argument).getModule();
629 if (argument instanceof String) {
630 // FIXME: This may yield illegal argument exceptions
631 return StmtContextUtils.qnameFromArgument(getOriginalCtx().orElse(this), (String) argument).getModule();
633 if (argument instanceof SchemaNodeIdentifier
634 && (producesDeclared(AugmentStatement.class) || producesDeclared(RefineStatement.class)
635 || producesDeclared(DeviationStatement.class))) {
636 return ((SchemaNodeIdentifier) argument).lastNodeIdentifier().getModule();
639 return coerceParent().effectiveNamespace();
642 private ReactorStmtCtx<?, ?, ?> coerceParent() {
643 return (ReactorStmtCtx<?, ?, ?>) coerceParentContext();
648 // Reference counting mechanics start. Please keep these methods in one block for clarity. Note this does not
649 // contribute to state visible outside of this package.
654 * Local knowledge of {@link #refcount} values up to statement root. We use this field to prevent recursive lookups
655 * in {@link #noParentRefs(StatementContextBase)} -- once we discover a parent reference once, we keep that
656 * knowledge and update it when {@link #sweep()} is invoked.
658 private byte parentRef = PARENTREF_UNKNOWN;
659 private static final byte PARENTREF_UNKNOWN = -1;
660 private static final byte PARENTREF_ABSENT = 0;
661 private static final byte PARENTREF_PRESENT = 1;
664 * Acquire a reference on this context. As long as there is at least one reference outstanding,
665 * {@link #buildEffective()} will not result in {@link #effectiveSubstatements()} being discarded.
667 * @throws VerifyException if {@link #effectiveSubstatements()} has already been discarded
669 final void incRef() {
670 final int current = refcount;
671 verify(current >= REFCOUNT_NONE, "Attempted to access reference count of %s", this);
672 if (current != REFCOUNT_DEFUNCT) {
673 // Note: can end up becoming REFCOUNT_DEFUNCT on overflow
674 refcount = current + 1;
676 LOG.debug("Disabled refcount increment of {}", this);
681 * Release a reference on this context. This call may result in {@link #effectiveSubstatements()} becoming
684 final void decRef() {
685 final int current = refcount;
686 if (current == REFCOUNT_DEFUNCT) {
688 LOG.debug("Disabled refcount decrement of {}", this);
691 if (current <= REFCOUNT_NONE) {
692 // Underflow, become defunct
693 // FIXME: add a global 'warn once' flag
694 LOG.warn("Statement refcount underflow, reference counting disabled for {}", this, new Throwable());
695 refcount = REFCOUNT_DEFUNCT;
699 refcount = current - 1;
700 LOG.trace("Refcount {} on {}", refcount, this);
702 if (refcount == REFCOUNT_NONE) {
708 * Return {@code true} if this context has no outstanding references.
710 * @return True if this context has no outstanding references.
712 final boolean noRefs() {
713 final int local = refcount;
714 return local < REFCOUNT_NONE || local == REFCOUNT_NONE && noParentRef();
717 private void lastDecRef() {
718 if (noImplictRef()) {
719 // We are no longer guarded by effective instance
724 final byte prevRefs = parentRef;
725 if (prevRefs == PARENTREF_ABSENT) {
726 // We are the last reference towards root, any children who observed PARENTREF_PRESENT from us need to be
729 } else if (prevRefs == PARENTREF_UNKNOWN) {
730 // Noone observed our parentRef, just update it
731 loadParentRefcount();
735 static final void markNoParentRef(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
736 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
737 final byte prevRef = stmt.parentRef;
738 stmt.parentRef = PARENTREF_ABSENT;
739 if (prevRef == PARENTREF_PRESENT && stmt.refcount == REFCOUNT_NONE) {
740 // Child thinks it is pinned down, update its perspective
741 stmt.markNoParentRef();
746 abstract void markNoParentRef();
748 static final void sweep(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
749 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
755 * Sweep this statement context as a result of {@link #sweepSubstatements()}, i.e. when parent is also being swept.
757 private void sweep() {
758 parentRef = PARENTREF_ABSENT;
759 if (refcount == REFCOUNT_NONE && noImplictRef()) {
760 LOG.trace("Releasing {}", this);
765 static final int countUnswept(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
767 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
768 if (stmt.refcount > REFCOUNT_NONE || !stmt.noImplictRef()) {
776 * Implementation-specific sweep action. This is expected to perform a recursive {@link #sweep(Collection)} on all
777 * {@link #declaredSubstatements()} and {@link #effectiveSubstatements()} and report the result of the sweep
781 * {@link #effectiveSubstatements()} as well as namespaces may become inoperable as a result of this operation.
783 * @return True if the entire tree has been completely swept, false otherwise.
785 abstract int sweepSubstatements();
787 // Called when this statement does not have an implicit reference and have reached REFCOUNT_NONE
788 private void sweepOnDecrement() {
789 LOG.trace("Sweeping on decrement {}", this);
791 // No further parent references, sweep our state.
795 // Propagate towards parent if there is one
799 private void sweepParent() {
800 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
801 if (parent != null) {
802 parent.sweepOnChildDecrement();
806 // Called from child when it has lost its final reference
807 private void sweepOnChildDecrement() {
808 if (isAwaitingChildren()) {
809 // We are a child for which our parent is waiting. Notify it and we are done.
814 // Check parent reference count
815 final int refs = refcount;
816 if (refs > REFCOUNT_NONE || refs <= REFCOUNT_SWEEPING || !noImplictRef()) {
821 // parent is potentially reclaimable
823 LOG.trace("Cleanup {} of parent {}", refs, this);
830 private boolean noImplictRef() {
831 return effectiveInstance != null || !isSupportedToBuildEffective();
834 private boolean noParentRef() {
835 return parentRefcount() == PARENTREF_ABSENT;
838 private byte parentRefcount() {
840 return (refs = parentRef) != PARENTREF_UNKNOWN ? refs : loadParentRefcount();
843 private byte loadParentRefcount() {
844 return parentRef = calculateParentRefcount();
847 private byte calculateParentRefcount() {
848 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
849 if (parent == null) {
850 return PARENTREF_ABSENT;
853 // A slight wrinkle here is that our machinery handles only PRESENT -> ABSENT invalidation and we can reach here
854 // while inference is still ongoing and hence we may not have a complete picture about existing references. We
855 // could therefore end up caching an ABSENT result and then that information becoming stale as a new reference
857 if (parent.executionOrder() < ExecutionOrder.EFFECTIVE_MODEL) {
858 return PARENTREF_UNKNOWN;
861 // There are three possibilities:
862 // - REFCOUNT_NONE, in which case we need to search next parent
863 // - negative (< REFCOUNT_NONE), meaning parent is in some stage of sweeping, hence it does not have
865 // - positive (> REFCOUNT_NONE), meaning parent has an explicit refcount which is holding us down
866 final int refs = parent.refcount;
867 if (refs == REFCOUNT_NONE) {
868 return parent.parentRefcount();
870 return refs < REFCOUNT_NONE ? PARENTREF_ABSENT : PARENTREF_PRESENT;
873 private boolean isAwaitingChildren() {
874 return refcount > REFCOUNT_SWEEPING && refcount < REFCOUNT_NONE;
877 private void sweepOnChildDone() {
878 LOG.trace("Sweeping on child done {}", this);
879 final int current = refcount;
880 if (current >= REFCOUNT_NONE) {
881 // no-op, perhaps we want to handle some cases differently?
882 LOG.trace("Ignoring child sweep of {} for {}", this, current);
885 verify(current != REFCOUNT_SWEPT, "Attempt to sweep a child of swept %s", this);
887 refcount = current + 1;
888 LOG.trace("Child refcount {}", refcount);
889 if (refcount == REFCOUNT_NONE) {
891 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
892 LOG.trace("Propagating to parent {}", parent);
893 if (parent != null && parent.isAwaitingChildren()) {
894 parent.sweepOnChildDone();
899 private void sweepDone() {
900 LOG.trace("Sweep done for {}", this);
901 refcount = REFCOUNT_SWEPT;
905 private boolean sweepState() {
906 refcount = REFCOUNT_SWEEPING;
907 final int childRefs = sweepSubstatements();
908 if (childRefs == 0) {
912 if (childRefs < 0 || childRefs >= REFCOUNT_DEFUNCT) {
913 // FIXME: add a global 'warn once' flag
914 LOG.warn("Negative child refcount {} cannot be stored, reference counting disabled for {}", childRefs, this,
916 refcount = REFCOUNT_DEFUNCT;
918 LOG.trace("Still {} outstanding children of {}", childRefs, this);
919 refcount = -childRefs;