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.SupportedFeaturesNamespace;
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 RootStatementContext<?, ?, ?> root = getRoot();
240 return QName.create(StmtContextUtils.getRootModuleQName(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;
303 case REFCOUNT_DEFUNCT:
305 case REFCOUNT_SWEEPING:
310 return String.valueOf(refcount);
315 * Return the context in which this statement was defined.
317 * @return statement definition
319 abstract @NonNull StatementDefinitionContext<A, D, E> definition();
323 // NamespaceStorageSupport/Mutable integration methods. Keep these together.
328 public final <K, V, T extends K, N extends ParserNamespace<K, V>> V namespaceItem(final Class<@NonNull N> type,
330 return getBehaviourRegistry().getNamespaceBehaviour(type).getFrom(this, key);
334 public final <K, V, N extends ParserNamespace<K, V>> Map<K, V> namespace(final Class<@NonNull N> type) {
335 return getNamespace(type);
339 public final <K, V, N extends ParserNamespace<K, V>>
340 Map<K, V> localNamespacePortion(final Class<@NonNull N> type) {
341 return getLocalNamespace(type);
345 protected <K, V, N extends ParserNamespace<K, V>> void onNamespaceElementAdded(final Class<N> type, final K key,
347 // definition().onNamespaceElementAdded(this, type, key, value);
351 * Return the effective statement view of a copy operation. This method may return one of:
353 * <li>{@code this}, when the effective view did not change</li>
354 * <li>an InferredStatementContext, when there is a need for inference-equivalent copy</li>
355 * <li>{@code null}, when the statement failed to materialize</li>
358 * @param parent Proposed new parent
359 * @param type Copy operation type
360 * @param targetModule New target module
361 * @return {@link ReactorStmtCtx} holding effective view
363 abstract @Nullable ReactorStmtCtx<?, ?, ?> asEffectiveChildOf(StatementContextBase<?, ?, ?> parent, CopyType type,
364 QNameModule targetModule);
367 public final ReplicaStatementContext<A, D, E> replicaAsChildOf(final Mutable<?, ?, ?> parent) {
368 checkArgument(parent instanceof StatementContextBase, "Unsupported parent %s", parent);
369 final var ret = replicaAsChildOf((StatementContextBase<?, ?, ?>) parent);
370 definition().onStatementAdded(ret);
374 abstract @NonNull ReplicaStatementContext<A, D, E> replicaAsChildOf(@NonNull StatementContextBase<?, ?, ?> parent);
378 // Statement build entry points -- both public and package-private.
383 public final E buildEffective() {
384 final Object existing;
385 return (existing = effectiveInstance) != null ? EffectiveInstances.local(existing) : loadEffective();
388 private @NonNull E loadEffective() {
389 final E ret = createEffective();
390 effectiveInstance = ret;
391 // we have called createEffective(), substatements are no longer guarded by us. Let's see if we can clear up
393 if (refcount == REFCOUNT_NONE) {
399 abstract @NonNull E createEffective();
402 * Routing of the request to build an effective statement from {@link InferredStatementContext} towards the original
403 * definition site. This is needed to pick the correct instantiation method: for declared statements we will
404 * eventually land in {@link AbstractResumedStatement}, for underclared statements that will be
405 * {@link UndeclaredStmtCtx}.
407 * @param factory Statement factory
408 * @param ctx Inferred statement context, i.e. where the effective statement is instantiated
409 * @return Built effective stateue
411 abstract @NonNull E createInferredEffective(@NonNull StatementFactory<A, D, E> factory,
412 @NonNull InferredStatementContext<A, D, E> ctx, Stream<? extends StmtContext<?, ?, ?>> declared,
413 Stream<? extends StmtContext<?, ?, ?>> effective);
416 * Attach an effective copy of this statement. This essentially acts as a map, where we make a few assumptions:
418 * <li>{@code copy} and {@code this} statement share {@link #getOriginalCtx()} if it exists</li>
419 * <li>{@code copy} did not modify any statements relative to {@code this}</li>
422 * @param state effective statement state, acting as a lookup key
423 * @param stmt New copy to append
424 * @return {@code stmt} or a previously-created instances with the same {@code state}
426 @SuppressWarnings("unchecked")
427 final @NonNull E attachEffectiveCopy(final @NonNull EffectiveStatementState state, final @NonNull E stmt) {
428 final Object local = effectiveInstance;
429 final EffectiveInstances<E> instances;
430 if (local instanceof EffectiveInstances) {
431 instances = (EffectiveInstances<E>) local;
433 effectiveInstance = instances = new EffectiveInstances<>((E) local);
435 return instances.attachCopy(state, stmt);
439 * Walk this statement's copy history and return the statement closest to original which has not had its effective
440 * statements modified. This statement and returned substatement logically have the same set of substatements, hence
441 * share substatement-derived state.
443 * @return Closest {@link ReactorStmtCtx} with equivalent effective substatements
445 abstract @NonNull ReactorStmtCtx<A, D, E> unmodifiedEffectiveSource();
448 public final ModelProcessingPhase getCompletedPhase() {
449 return ModelProcessingPhase.ofExecutionOrder(executionOrder());
452 abstract byte executionOrder();
455 * Try to execute current {@link ModelProcessingPhase} of source parsing. If the phase has already been executed,
456 * this method does nothing. This must not be called with {@link ExecutionOrder#NULL}.
458 * @param phase to be executed (completed)
459 * @return true if phase was successfully completed
460 * @throws SourceException when an error occurred in source parsing
462 final boolean tryToCompletePhase(final byte executionOrder) {
463 return executionOrder() >= executionOrder || doTryToCompletePhase(executionOrder);
466 abstract boolean doTryToCompletePhase(byte targetOrder);
470 // Flags-based mechanics. These include public interfaces as well as all the crud we have lurking in our alignment
475 // Non-final form ImplicitStmtCtx
477 public boolean isSupportedToBuildEffective() {
478 return isSupportedToBuildEffective;
482 public final void setUnsupported() {
483 this.isSupportedToBuildEffective = false;
487 public final boolean isSupportedByFeatures() {
488 final int fl = flags & SET_SUPPORTED_BY_FEATURES;
490 return fl == SET_SUPPORTED_BY_FEATURES;
492 if (isIgnoringIfFeatures()) {
493 flags |= SET_SUPPORTED_BY_FEATURES;
498 * If parent is supported, we need to check if-features statements of this context.
500 if (isParentSupportedByFeatures()) {
501 // If the set of supported features has not been provided, all features are supported by default.
502 final Set<QName> supportedFeatures = getFromNamespace(SupportedFeaturesNamespace.class, Empty.value());
503 if (supportedFeatures == null || StmtContextUtils.checkFeatureSupport(this, supportedFeatures)) {
504 flags |= SET_SUPPORTED_BY_FEATURES;
509 // Either parent is not supported or this statement is not supported
510 flags |= HAVE_SUPPORTED_BY_FEATURES;
514 protected abstract boolean isParentSupportedByFeatures();
517 * Config statements are not all that common which means we are performing a recursive search towards the root
518 * every time {@link #effectiveConfig()} is invoked. This is quite expensive because it causes a linear search
519 * for the (usually non-existent) config statement.
522 * This method maintains a resolution cache, so once we have returned a result, we will keep on returning the same
523 * result without performing any lookups, solely to support {@link #effectiveConfig()}.
526 * Note: use of this method implies that {@link #isIgnoringConfig()} is realized with
527 * {@link #isIgnoringConfig(StatementContextBase)}.
529 final @NonNull EffectiveConfig effectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
530 return (flags & HAVE_CONFIG) != 0 ? EFFECTIVE_CONFIGS[flags & MASK_CONFIG] : loadEffectiveConfig(parent);
533 private @NonNull EffectiveConfig loadEffectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
534 final EffectiveConfig parentConfig = parent.effectiveConfig();
536 final EffectiveConfig myConfig;
537 if (parentConfig != EffectiveConfig.IGNORED && !definition().support().isIgnoringConfig()) {
538 final Optional<Boolean> optConfig = findSubstatementArgument(ConfigEffectiveStatement.class);
539 if (optConfig.isPresent()) {
540 if (optConfig.orElseThrow()) {
541 // Validity check: if parent is config=false this cannot be a config=true
542 InferenceException.throwIf(parentConfig == EffectiveConfig.FALSE, this,
543 "Parent node has config=false, this node must not be specifed as config=true");
544 myConfig = EffectiveConfig.TRUE;
546 myConfig = EffectiveConfig.FALSE;
549 // If "config" statement is not specified, the default is the same as the parent's "config" value.
550 myConfig = parentConfig;
553 myConfig = EffectiveConfig.IGNORED;
556 flags = (byte) (flags & ~MASK_CONFIG | HAVE_CONFIG | myConfig.ordinal());
560 protected abstract boolean isIgnoringConfig();
563 * This method maintains a resolution cache for ignore config, so once we have returned a result, we will
564 * keep on returning the same result without performing any lookups. Exists only to support
565 * {@link SubstatementContext#isIgnoringConfig()}.
568 * Note: use of this method implies that {@link #isConfiguration()} is realized with
569 * {@link #effectiveConfig(StatementContextBase)}.
571 final boolean isIgnoringConfig(final StatementContextBase<?, ?, ?> parent) {
572 return EffectiveConfig.IGNORED == effectiveConfig(parent);
575 protected abstract boolean isIgnoringIfFeatures();
578 * This method maintains a resolution cache for ignore if-feature, so once we have returned a result, we will
579 * keep on returning the same result without performing any lookups. Exists only to support
580 * {@link SubstatementContext#isIgnoringIfFeatures()}.
582 final boolean isIgnoringIfFeatures(final StatementContextBase<?, ?, ?> parent) {
583 final int fl = flags & SET_IGNORE_IF_FEATURE;
585 return fl == SET_IGNORE_IF_FEATURE;
587 if (definition().support().isIgnoringIfFeatures() || parent.isIgnoringIfFeatures()) {
588 flags |= SET_IGNORE_IF_FEATURE;
592 flags |= HAVE_IGNORE_IF_FEATURE;
596 // These two exist only due to memory optimization, should live in AbstractResumedStatement.
597 final boolean fullyDefined() {
601 final void setFullyDefined() {
605 // This exists only due to memory optimization, should live in ReplicaStatementContext. In this context the flag
606 // indicates the need to drop source's reference count when we are being swept.
607 final boolean haveSourceReference() {
611 // These three exist due to memory optimization, should live in InferredStatementContext. In this context the flag
612 // indicates whether or not this statement's substatement file was modified, i.e. it is not quite the same as the
614 final boolean isModified() {
618 final void setModified() {
622 final void setUnmodified() {
626 // These two exist only for StatementContextBase. Since we are squeezed for size, with only a single bit available
627 // in flags, we default to 'false' and only set the flag to true when we are absolutely sure -- and all other cases
628 // err on the side of caution by taking the time to evaluate each substatement separately.
629 final boolean allSubstatementsContextIndependent() {
630 return (flags & ALL_INDEPENDENT) != 0;
633 final void setAllSubstatementsContextIndependent() {
634 flags |= ALL_INDEPENDENT;
639 // Various functionality from AbstractTypeStatementSupport. This used to work on top of SchemaPath, now it still
640 // lives here. Ultimate future is either proper graduation or (more likely) move to AbstractTypeStatementSupport.
645 public final QName argumentAsTypeQName() {
646 // FIXME: This may yield illegal argument exceptions
647 return StmtContextUtils.qnameFromArgument(getOriginalCtx().orElse(this), getRawArgument());
651 public final QNameModule effectiveNamespace() {
652 if (StmtContextUtils.isUnknownStatement(this)) {
653 return publicDefinition().getStatementName().getModule();
655 if (producesDeclared(UsesStatement.class)) {
656 return coerceParent().effectiveNamespace();
659 final Object argument = argument();
660 if (argument instanceof QName) {
661 return ((QName) argument).getModule();
663 if (argument instanceof String) {
664 // FIXME: This may yield illegal argument exceptions
665 return StmtContextUtils.qnameFromArgument(getOriginalCtx().orElse(this), (String) argument).getModule();
667 if (argument instanceof SchemaNodeIdentifier
668 && (producesDeclared(AugmentStatement.class) || producesDeclared(RefineStatement.class)
669 || producesDeclared(DeviationStatement.class))) {
670 return ((SchemaNodeIdentifier) argument).lastNodeIdentifier().getModule();
673 return coerceParent().effectiveNamespace();
676 private ReactorStmtCtx<?, ?, ?> coerceParent() {
677 return (ReactorStmtCtx<?, ?, ?>) coerceParentContext();
682 // Reference counting mechanics start. Please keep these methods in one block for clarity. Note this does not
683 // contribute to state visible outside of this package.
688 * Local knowledge of {@link #refcount} values up to statement root. We use this field to prevent recursive lookups
689 * in {@link #noParentRefs(StatementContextBase)} -- once we discover a parent reference once, we keep that
690 * knowledge and update it when {@link #sweep()} is invoked.
692 private byte parentRef = PARENTREF_UNKNOWN;
693 private static final byte PARENTREF_UNKNOWN = -1;
694 private static final byte PARENTREF_ABSENT = 0;
695 private static final byte PARENTREF_PRESENT = 1;
698 * Acquire a reference on this context. As long as there is at least one reference outstanding,
699 * {@link #buildEffective()} will not result in {@link #effectiveSubstatements()} being discarded.
701 * @throws VerifyException if {@link #effectiveSubstatements()} has already been discarded
703 final void incRef() {
704 final int current = refcount;
705 verify(current >= REFCOUNT_NONE, "Attempted to access reference count of %s", this);
706 if (current != REFCOUNT_DEFUNCT) {
707 // Note: can end up becoming REFCOUNT_DEFUNCT on overflow
708 refcount = current + 1;
710 LOG.debug("Disabled refcount increment of {}", this);
715 * Release a reference on this context. This call may result in {@link #effectiveSubstatements()} becoming
718 final void decRef() {
719 final int current = refcount;
720 if (current == REFCOUNT_DEFUNCT) {
722 LOG.debug("Disabled refcount decrement of {}", this);
725 if (current <= REFCOUNT_NONE) {
726 // Underflow, become defunct
727 // FIXME: add a global 'warn once' flag
728 LOG.warn("Statement refcount underflow, reference counting disabled for {}", this, new Throwable());
729 refcount = REFCOUNT_DEFUNCT;
733 refcount = current - 1;
734 LOG.trace("Refcount {} on {}", refcount, this);
736 if (refcount == REFCOUNT_NONE) {
742 * Return {@code true} if this context has no outstanding references.
744 * @return True if this context has no outstanding references.
746 final boolean noRefs() {
747 final int local = refcount;
748 return local < REFCOUNT_NONE || local == REFCOUNT_NONE && noParentRef();
751 private void lastDecRef() {
752 if (noImplictRef()) {
753 // We are no longer guarded by effective instance
758 final byte prevRefs = parentRef;
759 if (prevRefs == PARENTREF_ABSENT) {
760 // We are the last reference towards root, any children who observed PARENTREF_PRESENT from us need to be
763 } else if (prevRefs == PARENTREF_UNKNOWN) {
764 // Noone observed our parentRef, just update it
765 loadParentRefcount();
769 static final void markNoParentRef(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
770 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
771 final byte prevRef = stmt.parentRef;
772 stmt.parentRef = PARENTREF_ABSENT;
773 if (prevRef == PARENTREF_PRESENT && stmt.refcount == REFCOUNT_NONE) {
774 // Child thinks it is pinned down, update its perspective
775 stmt.markNoParentRef();
780 abstract void markNoParentRef();
782 static final void sweep(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
783 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
789 * Sweep this statement context as a result of {@link #sweepSubstatements()}, i.e. when parent is also being swept.
791 private void sweep() {
792 parentRef = PARENTREF_ABSENT;
793 if (refcount == REFCOUNT_NONE && noImplictRef()) {
794 LOG.trace("Releasing {}", this);
799 static final int countUnswept(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
801 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
802 if (stmt.refcount > REFCOUNT_NONE || !stmt.noImplictRef()) {
810 * Implementation-specific sweep action. This is expected to perform a recursive {@link #sweep(Collection)} on all
811 * {@link #declaredSubstatements()} and {@link #effectiveSubstatements()} and report the result of the sweep
815 * {@link #effectiveSubstatements()} as well as namespaces may become inoperable as a result of this operation.
817 * @return True if the entire tree has been completely swept, false otherwise.
819 abstract int sweepSubstatements();
821 // Called when this statement does not have an implicit reference and have reached REFCOUNT_NONE
822 private void sweepOnDecrement() {
823 LOG.trace("Sweeping on decrement {}", this);
825 // No further parent references, sweep our state.
829 // Propagate towards parent if there is one
833 private void sweepParent() {
834 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
835 if (parent != null) {
836 parent.sweepOnChildDecrement();
840 // Called from child when it has lost its final reference
841 private void sweepOnChildDecrement() {
842 if (isAwaitingChildren()) {
843 // We are a child for which our parent is waiting. Notify it and we are done.
848 // Check parent reference count
849 final int refs = refcount;
850 if (refs > REFCOUNT_NONE || refs <= REFCOUNT_SWEEPING || !noImplictRef()) {
855 // parent is potentially reclaimable
857 LOG.trace("Cleanup {} of parent {}", refs, this);
864 private boolean noImplictRef() {
865 return effectiveInstance != null || !isSupportedToBuildEffective();
868 private boolean noParentRef() {
869 return parentRefcount() == PARENTREF_ABSENT;
872 private byte parentRefcount() {
874 return (refs = parentRef) != PARENTREF_UNKNOWN ? refs : loadParentRefcount();
877 private byte loadParentRefcount() {
878 return parentRef = calculateParentRefcount();
881 private byte calculateParentRefcount() {
882 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
883 if (parent == null) {
884 return PARENTREF_ABSENT;
887 // A slight wrinkle here is that our machinery handles only PRESENT -> ABSENT invalidation and we can reach here
888 // while inference is still ongoing and hence we may not have a complete picture about existing references. We
889 // could therefore end up caching an ABSENT result and then that information becoming stale as a new reference
891 if (parent.executionOrder() < ExecutionOrder.EFFECTIVE_MODEL) {
892 return PARENTREF_UNKNOWN;
895 // There are three possibilities:
896 // - REFCOUNT_NONE, in which case we need to search next parent
897 // - negative (< REFCOUNT_NONE), meaning parent is in some stage of sweeping, hence it does not have
899 // - positive (> REFCOUNT_NONE), meaning parent has an explicit refcount which is holding us down
900 final int refs = parent.refcount;
901 if (refs == REFCOUNT_NONE) {
902 return parent.parentRefcount();
904 return refs < REFCOUNT_NONE ? PARENTREF_ABSENT : PARENTREF_PRESENT;
907 private boolean isAwaitingChildren() {
908 return refcount > REFCOUNT_SWEEPING && refcount < REFCOUNT_NONE;
911 private void sweepOnChildDone() {
912 LOG.trace("Sweeping on child done {}", this);
913 final int current = refcount;
914 if (current >= REFCOUNT_NONE) {
915 // no-op, perhaps we want to handle some cases differently?
916 LOG.trace("Ignoring child sweep of {} for {}", this, current);
919 verify(current != REFCOUNT_SWEPT, "Attempt to sweep a child of swept %s", this);
921 refcount = current + 1;
922 LOG.trace("Child refcount {}", refcount);
923 if (refcount == REFCOUNT_NONE) {
925 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
926 LOG.trace("Propagating to parent {}", parent);
927 if (parent != null && parent.isAwaitingChildren()) {
928 parent.sweepOnChildDone();
933 private void sweepDone() {
934 LOG.trace("Sweep done for {}", this);
935 refcount = REFCOUNT_SWEPT;
939 private boolean sweepState() {
940 refcount = REFCOUNT_SWEEPING;
941 final int childRefs = sweepSubstatements();
942 if (childRefs == 0) {
946 if (childRefs < 0 || childRefs >= REFCOUNT_DEFUNCT) {
947 // FIXME: add a global 'warn once' flag
948 LOG.warn("Negative child refcount {} cannot be stored, reference counting disabled for {}", childRefs, this,
950 refcount = REFCOUNT_DEFUNCT;
952 LOG.trace("Still {} outstanding children of {}", childRefs, this);
953 refcount = -childRefs;