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.SchemaPath;
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.SchemaNodeIdentifier;
34 import org.opendaylight.yangtools.yang.model.api.stmt.UsesStatement;
35 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
36 import org.opendaylight.yangtools.yang.parser.spi.meta.CopyType;
37 import org.opendaylight.yangtools.yang.parser.spi.meta.EffectiveStmtCtx.Current;
38 import org.opendaylight.yangtools.yang.parser.spi.meta.InferenceException;
39 import org.opendaylight.yangtools.yang.parser.spi.meta.ModelActionBuilder;
40 import org.opendaylight.yangtools.yang.parser.spi.meta.ModelProcessingPhase;
41 import org.opendaylight.yangtools.yang.parser.spi.meta.ModelProcessingPhase.ExecutionOrder;
42 import org.opendaylight.yangtools.yang.parser.spi.meta.NamespaceBehaviour.Registry;
43 import org.opendaylight.yangtools.yang.parser.spi.meta.ParserNamespace;
44 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext;
45 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext.Mutable;
46 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContextUtils;
47 import org.opendaylight.yangtools.yang.parser.spi.source.SourceException;
48 import org.opendaylight.yangtools.yang.parser.spi.source.SupportedFeaturesNamespace;
49 import org.opendaylight.yangtools.yang.parser.spi.source.SupportedFeaturesNamespace.SupportedFeatures;
50 import org.slf4j.Logger;
51 import org.slf4j.LoggerFactory;
54 * Real "core" reactor statement implementation of {@link Mutable}, supporting basic reactor lifecycle.
56 * @param <A> Argument type
57 * @param <D> Declared Statement representation
58 * @param <E> Effective Statement representation
60 abstract class ReactorStmtCtx<A, D extends DeclaredStatement<A>, E extends EffectiveStatement<A, D>>
61 extends NamespaceStorageSupport implements Mutable<A, D, E>, Current<A, D> {
62 private static final Logger LOG = LoggerFactory.getLogger(ReactorStmtCtx.class);
65 * Substatement refcount tracking. This mechanics deals with retaining substatements for the purposes of
66 * instantiating their lazy copies in InferredStatementContext. It works in concert with {@link #buildEffective()}
67 * and {@link #declared()}: declared/effective statement views hold an implicit reference and refcount-based
68 * sweep is not activated until they are done (or this statement is not {@link #isSupportedToBuildEffective}).
71 * Reference count is hierarchical in that parent references also pin down their child statements and do not allow
75 * The counter's positive values are tracking incoming references via {@link #incRef()}/{@link #decRef()} methods.
76 * Once we transition to sweeping, this value becomes negative counting upwards to {@link #REFCOUNT_NONE} based on
77 * {@link #sweepOnChildDone()}. Once we reach that, we transition to {@link #REFCOUNT_SWEPT}.
79 private int refcount = REFCOUNT_NONE;
81 * No outstanding references, this statement is a potential candidate for sweeping, provided it has populated its
82 * declared and effective views and {@link #parentRef} is known to be absent.
84 private static final int REFCOUNT_NONE = 0;
86 * Reference count overflow or some other recoverable logic error. Do not rely on refcounts and do not sweep
90 * Note on value assignment:
91 * This allow our incRef() to naturally progress to being saturated. Others jump there directly.
92 * It also makes it it impossible to observe {@code Interger.MAX_VALUE} children, which we take advantage of for
93 * {@link #REFCOUNT_SWEEPING}.
95 private static final int REFCOUNT_DEFUNCT = Integer.MAX_VALUE;
97 * This statement is being actively swept. This is a transient value set when we are sweeping our children, so that
98 * we prevent re-entering this statement.
101 * Note on value assignment:
102 * The value is lower than any legal child refcount due to {@link #REFCOUNT_DEFUNCT} while still being higher than
103 * {@link #REFCOUNT_SWEPT}.
105 private static final int REFCOUNT_SWEEPING = -Integer.MAX_VALUE;
107 * This statement, along with its entire subtree has been swept and we positively know all our children have reached
108 * this state. We {@link #sweepNamespaces()} upon reaching this state.
111 * Note on value assignment:
112 * This is the lowest value observable, making it easier on checking others on equality.
114 private static final int REFCOUNT_SWEPT = Integer.MIN_VALUE;
117 * Effective instance built from this context. This field as dual types. Under normal circumstances in matches the
118 * {@link #buildEffective()} instance. If this context is reused, it can be inflated to {@link EffectiveInstances}
119 * and also act as a common instance reuse site.
121 private @Nullable E effectiveInstance;
123 // Master flag controlling whether this context can yield an effective statement
124 // FIXME: investigate the mechanics that are being supported by this, as it would be beneficial if we can get rid
125 // of this flag -- eliminating the initial alignment shadow used by below gap-filler fields.
126 private boolean isSupportedToBuildEffective = true;
128 // EffectiveConfig mapping
129 private static final int MASK_CONFIG = 0x03;
130 private static final int HAVE_CONFIG = 0x04;
131 // Effective instantiation mechanics for StatementContextBase: if this flag is set all substatements are known not
132 // change when instantiated. This includes context-independent statements as well as any statements which are
133 // ignored during copy instantiation.
134 private static final int ALL_INDEPENDENT = 0x08;
135 // Flag bit assignments
136 private static final int IS_SUPPORTED_BY_FEATURES = 0x10;
137 private static final int HAVE_SUPPORTED_BY_FEATURES = 0x20;
138 private static final int IS_IGNORE_IF_FEATURE = 0x40;
139 private static final int HAVE_IGNORE_IF_FEATURE = 0x80;
140 // Have-and-set flag constants, also used as masks
141 private static final int SET_SUPPORTED_BY_FEATURES = HAVE_SUPPORTED_BY_FEATURES | IS_SUPPORTED_BY_FEATURES;
142 private static final int SET_IGNORE_IF_FEATURE = HAVE_IGNORE_IF_FEATURE | IS_IGNORE_IF_FEATURE;
144 private static final EffectiveConfig[] EFFECTIVE_CONFIGS;
147 final EffectiveConfig[] values = EffectiveConfig.values();
148 final int length = values.length;
149 verify(length == 4, "Unexpected EffectiveConfig cardinality %s", length);
150 EFFECTIVE_CONFIGS = values;
153 // Flags for use with SubstatementContext. These are hiding in the alignment shadow created by above boolean and
154 // hence improve memory layout.
157 // Flag for use by AbstractResumedStatement, ReplicaStatementContext and InferredStatementContext. Each of them
158 // uses it to indicated a different condition. This is hiding in the alignment shadow created by
159 // 'isSupportedToBuildEffective'.
160 // FIXME: move this out once we have JDK15+
161 private boolean boolFlag;
163 // SchemaPath cache for use with SubstatementContext and InferredStatementContext. This hurts RootStatementContext
164 // a bit in terms of size -- but those are only a few and SchemaPath is on its way out anyway.
165 // FIXME: this should become 'QName'
166 private SchemaPath schemaPath;
172 ReactorStmtCtx(final ReactorStmtCtx<A, D, E> original) {
173 isSupportedToBuildEffective = original.isSupportedToBuildEffective;
174 boolFlag = original.boolFlag;
175 flags = original.flags;
178 // Used by ReplicaStatementContext only
179 ReactorStmtCtx(final ReactorStmtCtx<A, D, E> original, final Void dummy) {
180 boolFlag = isSupportedToBuildEffective = original.isSupportedToBuildEffective;
181 flags = original.flags;
186 // Common public interface contracts with simple mechanics. Please keep this in one logical block, so we do not end
187 // up mixing concerns and simple details with more complex logic.
192 public abstract StatementContextBase<?, ?, ?> getParentContext();
195 public abstract RootStatementContext<?, ?, ?> getRoot();
198 public abstract Collection<? extends StatementContextBase<?, ?, ?>> mutableDeclaredSubstatements();
201 public final @NonNull Registry getBehaviourRegistry() {
202 return getRoot().getBehaviourRegistryImpl();
206 public final YangVersion yangVersion() {
207 return getRoot().getRootVersionImpl();
211 public final void setRootVersion(final YangVersion version) {
212 getRoot().setRootVersionImpl(version);
216 public final void addRequiredSource(final SourceIdentifier dependency) {
217 getRoot().addRequiredSourceImpl(dependency);
221 public final void setRootIdentifier(final SourceIdentifier identifier) {
222 getRoot().setRootIdentifierImpl(identifier);
226 public final ModelActionBuilder newInferenceAction(final ModelProcessingPhase phase) {
227 return getRoot().getSourceContext().newInferenceAction(phase);
231 public final StatementDefinition publicDefinition() {
232 return definition().getPublicView();
236 public final Parent effectiveParent() {
237 return getParentContext();
241 public final QName moduleName() {
242 final RootStatementContext<?, ?, ?> root = getRoot();
243 return QName.create(StmtContextUtils.getRootModuleQName(root), root.getRawArgument());
247 public final EffectiveStatement<?, ?> original() {
248 return getOriginalCtx().map(StmtContext::buildEffective).orElse(null);
252 // In the next two methods we are looking for an effective statement. If we already have an effective instance,
253 // defer to it's implementation of the equivalent search. Otherwise we search our substatement contexts.
255 // Note that the search function is split, so as to allow InferredStatementContext to do its own thing first.
259 public final <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgument(
260 final @NonNull Class<Z> type) {
261 final E existing = effectiveInstance;
262 return existing != null ? existing.findFirstEffectiveSubstatementArgument(type)
263 : findSubstatementArgumentImpl(type);
267 public final boolean hasSubstatement(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
268 final E existing = effectiveInstance;
269 return existing != null ? existing.findFirstEffectiveSubstatement(type).isPresent() : hasSubstatementImpl(type);
272 // Visible due to InferredStatementContext's override. At this point we do not have an effective instance available.
273 <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgumentImpl(
274 final @NonNull Class<Z> type) {
275 return allSubstatementsStream()
276 .filter(ctx -> ctx.isSupportedToBuildEffective() && ctx.producesEffective(type))
278 .map(ctx -> (X) ctx.getArgument());
281 // Visible due to InferredStatementContext's override. At this point we do not have an effective instance available.
282 boolean hasSubstatementImpl(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
283 return allSubstatementsStream()
284 .anyMatch(ctx -> ctx.isSupportedToBuildEffective() && ctx.producesEffective(type));
289 @SuppressWarnings("unchecked")
290 public final <Z extends EffectiveStatement<A, D>> StmtContext<A, D, Z> caerbannog() {
291 return (StmtContext<A, D, Z>) this;
295 public final String toString() {
296 return addToStringAttributes(MoreObjects.toStringHelper(this).omitNullValues()).toString();
299 protected ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {
300 return toStringHelper.add("definition", definition()).add("rawArgument", rawArgument())
301 .add("refCount", refString());
304 private String refString() {
305 final int current = refcount;
307 case REFCOUNT_DEFUNCT:
309 case REFCOUNT_SWEEPING:
314 return String.valueOf(refcount);
319 * Return the context in which this statement was defined.
321 * @return statement definition
323 abstract @NonNull StatementDefinitionContext<A, D, E> definition();
327 // NamespaceStorageSupport/Mutable integration methods. Keep these together.
332 public final <K, V, T extends K, N extends ParserNamespace<K, V>> V namespaceItem(final Class<@NonNull N> type,
334 return getBehaviourRegistry().getNamespaceBehaviour(type).getFrom(this, key);
338 public final <K, V, N extends ParserNamespace<K, V>> Map<K, V> namespace(final Class<@NonNull N> type) {
339 return getNamespace(type);
343 public final <K, V, N extends ParserNamespace<K, V>>
344 Map<K, V> localNamespacePortion(final Class<@NonNull N> type) {
345 return getLocalNamespace(type);
349 protected <K, V, N extends ParserNamespace<K, V>> void onNamespaceElementAdded(final Class<N> type, final K key,
351 // definition().onNamespaceElementAdded(this, type, key, value);
355 * Return the effective statement view of a copy operation. This method may return one of:
357 * <li>{@code this}, when the effective view did not change</li>
358 * <li>an InferredStatementContext, when there is a need for inference-equivalent copy</li>
359 * <li>{@code null}, when the statement failed to materialize</li>
362 * @param parent Proposed new parent
363 * @param type Copy operation type
364 * @param targetModule New target module
365 * @return {@link ReactorStmtCtx} holding effective view
367 abstract @Nullable ReactorStmtCtx<?, ?, ?> asEffectiveChildOf(StatementContextBase<?, ?, ?> parent, CopyType type,
368 QNameModule targetModule);
371 public final ReactorStmtCtx<A, D, E> replicaAsChildOf(final Mutable<?, ?, ?> parent) {
372 checkArgument(parent instanceof StatementContextBase, "Unsupported parent %s", parent);
373 return replicaAsChildOf((StatementContextBase<?, ?, ?>) parent);
376 abstract @NonNull ReplicaStatementContext<A, D, E> replicaAsChildOf(@NonNull StatementContextBase<?, ?, ?> parent);
380 // Statement build entry points -- both public and package-private.
385 public final E buildEffective() {
387 return (existing = effectiveInstance) != null ? existing : loadEffective();
390 private @NonNull E loadEffective() {
391 // Creating an effective statement does not strictly require a declared instance -- there are statements like
392 // 'input', which are implicitly defined.
393 // Our implementation design makes an invariant assumption that buildDeclared() has been called by the time
394 // we attempt to create effective statement:
397 final E ret = createEffective();
398 effectiveInstance = ret;
399 // we have called createEffective(), substatements are no longer guarded by us. Let's see if we can clear up
401 if (refcount == REFCOUNT_NONE) {
407 abstract @NonNull E createEffective();
410 * Walk this statement's copy history and return the statement closest to original which has not had its effective
411 * statements modified. This statement and returned substatement logically have the same set of substatements, hence
412 * share substatement-derived state.
414 * @return Closest {@link ReactorStmtCtx} with equivalent effective substatements
416 abstract @NonNull ReactorStmtCtx<A, D, E> unmodifiedEffectiveSource();
419 public final ModelProcessingPhase getCompletedPhase() {
420 return ModelProcessingPhase.ofExecutionOrder(executionOrder());
423 abstract byte executionOrder();
426 * Try to execute current {@link ModelProcessingPhase} of source parsing. If the phase has already been executed,
427 * this method does nothing. This must not be called with {@link ExecutionOrder#NULL}.
429 * @param phase to be executed (completed)
430 * @return true if phase was successfully completed
431 * @throws SourceException when an error occurred in source parsing
433 final boolean tryToCompletePhase(final byte executionOrder) {
434 return executionOrder() >= executionOrder || doTryToCompletePhase(executionOrder);
437 abstract boolean doTryToCompletePhase(byte targetOrder);
441 // Flags-based mechanics. These include public interfaces as well as all the crud we have lurking in our alignment
447 public final boolean isSupportedToBuildEffective() {
448 return isSupportedToBuildEffective;
452 public final void setIsSupportedToBuildEffective(final boolean isSupportedToBuildEffective) {
453 this.isSupportedToBuildEffective = isSupportedToBuildEffective;
457 public final boolean isSupportedByFeatures() {
458 final int fl = flags & SET_SUPPORTED_BY_FEATURES;
460 return fl == SET_SUPPORTED_BY_FEATURES;
462 if (isIgnoringIfFeatures()) {
463 flags |= SET_SUPPORTED_BY_FEATURES;
468 * If parent is supported, we need to check if-features statements of this context.
470 if (isParentSupportedByFeatures()) {
471 // If the set of supported features has not been provided, all features are supported by default.
472 final Set<QName> supportedFeatures = getFromNamespace(SupportedFeaturesNamespace.class,
473 SupportedFeatures.SUPPORTED_FEATURES);
474 if (supportedFeatures == null || StmtContextUtils.checkFeatureSupport(this, supportedFeatures)) {
475 flags |= SET_SUPPORTED_BY_FEATURES;
480 // Either parent is not supported or this statement is not supported
481 flags |= HAVE_SUPPORTED_BY_FEATURES;
485 protected abstract boolean isParentSupportedByFeatures();
488 * Config statements are not all that common which means we are performing a recursive search towards the root
489 * every time {@link #effectiveConfig()} is invoked. This is quite expensive because it causes a linear search
490 * for the (usually non-existent) config statement.
493 * This method maintains a resolution cache, so once we have returned a result, we will keep on returning the same
494 * result without performing any lookups, solely to support {@link #effectiveConfig()}.
497 * Note: use of this method implies that {@link #isIgnoringConfig()} is realized with
498 * {@link #isIgnoringConfig(StatementContextBase)}.
500 final @NonNull EffectiveConfig effectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
501 return (flags & HAVE_CONFIG) != 0 ? EFFECTIVE_CONFIGS[flags & MASK_CONFIG] : loadEffectiveConfig(parent);
504 private @NonNull EffectiveConfig loadEffectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
505 final EffectiveConfig parentConfig = parent.effectiveConfig();
507 final EffectiveConfig myConfig;
508 if (parentConfig != EffectiveConfig.IGNORED && !definition().support().isIgnoringConfig()) {
509 final Optional<Boolean> optConfig = findSubstatementArgument(ConfigEffectiveStatement.class);
510 if (optConfig.isPresent()) {
511 if (optConfig.orElseThrow()) {
512 // Validity check: if parent is config=false this cannot be a config=true
513 InferenceException.throwIf(parentConfig == EffectiveConfig.FALSE, this,
514 "Parent node has config=false, this node must not be specifed as config=true");
515 myConfig = EffectiveConfig.TRUE;
517 myConfig = EffectiveConfig.FALSE;
520 // If "config" statement is not specified, the default is the same as the parent's "config" value.
521 myConfig = parentConfig;
524 myConfig = EffectiveConfig.IGNORED;
527 flags = (byte) (flags & ~MASK_CONFIG | HAVE_CONFIG | myConfig.ordinal());
531 protected abstract boolean isIgnoringConfig();
534 * This method maintains a resolution cache for ignore config, so once we have returned a result, we will
535 * keep on returning the same result without performing any lookups. Exists only to support
536 * {@link SubstatementContext#isIgnoringConfig()}.
539 * Note: use of this method implies that {@link #isConfiguration()} is realized with
540 * {@link #effectiveConfig(StatementContextBase)}.
542 final boolean isIgnoringConfig(final StatementContextBase<?, ?, ?> parent) {
543 return EffectiveConfig.IGNORED == effectiveConfig(parent);
546 protected abstract boolean isIgnoringIfFeatures();
549 * This method maintains a resolution cache for ignore if-feature, so once we have returned a result, we will
550 * keep on returning the same result without performing any lookups. Exists only to support
551 * {@link SubstatementContext#isIgnoringIfFeatures()}.
553 final boolean isIgnoringIfFeatures(final StatementContextBase<?, ?, ?> parent) {
554 final int fl = flags & SET_IGNORE_IF_FEATURE;
556 return fl == SET_IGNORE_IF_FEATURE;
558 if (definition().support().isIgnoringIfFeatures() || parent.isIgnoringIfFeatures()) {
559 flags |= SET_IGNORE_IF_FEATURE;
563 flags |= HAVE_IGNORE_IF_FEATURE;
567 // These two exist only due to memory optimization, should live in AbstractResumedStatement.
568 final boolean fullyDefined() {
572 final void setFullyDefined() {
576 // This exists only due to memory optimization, should live in ReplicaStatementContext. In this context the flag
577 // indicates the need to drop source's reference count when we are being swept.
578 final boolean haveSourceReference() {
582 // These three exist due to memory optimization, should live in InferredStatementContext. In this context the flag
583 // indicates whether or not this statement's substatement file was modified, i.e. it is not quite the same as the
585 final boolean isModified() {
589 final void setModified() {
593 final void setUnmodified() {
597 // These two exist only for StatementContextBase. Since we are squeezed for size, with only a single bit available
598 // in flags, we default to 'false' and only set the flag to true when we are absolutely sure -- and all other cases
599 // err on the side of caution by taking the time to evaluate each substatement separately.
600 final boolean allSubstatementsContextIndependent() {
601 return (flags & ALL_INDEPENDENT) != 0;
604 final void setAllSubstatementsContextIndependent() {
605 flags |= ALL_INDEPENDENT;
610 // Various functionality from AbstractTypeStatementSupport. This used to work on top of SchemaPath, now it still
611 // lives here. Ultimate future is either proper graduation or (more likely) move to AbstractTypeStatementSupport.
616 public final QName argumentAsTypeQName() {
617 return interpretAsQName(getRawArgument());
621 public final QNameModule effectiveNamespace() {
622 // FIXME: there has to be a better way to do this
623 return getSchemaPath().getLastComponent().getModule();
628 // Common SchemaPath cache. All of this is bound to be removed once YANGTOOLS-1066 is done.
632 // Exists only to support {SubstatementContext,InferredStatementContext}.schemaPath()
634 final @Nullable SchemaPath substatementGetSchemaPath() {
635 if (schemaPath == null) {
636 schemaPath = createSchemaPath((StatementContextBase<?, ?, ?>) coerceParentContext());
641 // FIXME: 7.0.0: this method's logic needs to be moved to the respective StatementSupport classes
643 private SchemaPath createSchemaPath(final StatementContextBase<?, ?, ?> parent) {
644 final SchemaPath parentPath = parent.getSchemaPath();
645 if (StmtContextUtils.isUnknownStatement(this)) {
646 return parentPath.createChild(publicDefinition().getStatementName());
648 final Object argument = argument();
649 if (argument instanceof QName) {
650 final QName qname = (QName) argument;
651 if (producesDeclared(UsesStatement.class)) {
655 return parentPath.createChild(qname);
657 if (argument instanceof String) {
658 return parentPath.createChild(interpretAsQName((String) argument));
660 if (argument instanceof SchemaNodeIdentifier
661 && (producesDeclared(AugmentStatement.class) || producesDeclared(RefineStatement.class)
662 || producesDeclared(DeviationStatement.class))) {
664 return parentPath.createChild(((SchemaNodeIdentifier) argument).getNodeIdentifiers());
667 // FIXME: this does not look right, investigate more?
671 private @NonNull QName interpretAsQName(final String argument) {
672 // FIXME: This may yield illegal argument exceptions
673 return StmtContextUtils.qnameFromArgument(getOriginalCtx().orElse(this), argument);
678 // Reference counting mechanics start. Please keep these methods in one block for clarity. Note this does not
679 // contribute to state visible outside of this package.
684 * Local knowledge of {@link #refcount} values up to statement root. We use this field to prevent recursive lookups
685 * in {@link #noParentRefs(StatementContextBase)} -- once we discover a parent reference once, we keep that
686 * knowledge and update it when {@link #sweep()} is invoked.
688 private byte parentRef = PARENTREF_UNKNOWN;
689 private static final byte PARENTREF_UNKNOWN = -1;
690 private static final byte PARENTREF_ABSENT = 0;
691 private static final byte PARENTREF_PRESENT = 1;
694 * Acquire a reference on this context. As long as there is at least one reference outstanding,
695 * {@link #buildEffective()} will not result in {@link #effectiveSubstatements()} being discarded.
697 * @throws VerifyException if {@link #effectiveSubstatements()} has already been discarded
699 final void incRef() {
700 final int current = refcount;
701 verify(current >= REFCOUNT_NONE, "Attempted to access reference count of %s", this);
702 if (current != REFCOUNT_DEFUNCT) {
703 // Note: can end up becoming REFCOUNT_DEFUNCT on overflow
704 refcount = current + 1;
706 LOG.debug("Disabled refcount increment of {}", this);
711 * Release a reference on this context. This call may result in {@link #effectiveSubstatements()} becoming
714 final void decRef() {
715 final int current = refcount;
716 if (current == REFCOUNT_DEFUNCT) {
718 LOG.debug("Disabled refcount decrement of {}", this);
721 if (current <= REFCOUNT_NONE) {
722 // Underflow, become defunct
723 // FIXME: add a global 'warn once' flag
724 LOG.warn("Statement refcount underflow, reference counting disabled for {}", this, new Throwable());
725 refcount = REFCOUNT_DEFUNCT;
729 refcount = current - 1;
730 LOG.trace("Refcount {} on {}", refcount, this);
732 if (refcount == REFCOUNT_NONE) {
738 * Return {@code true} if this context has no outstanding references.
740 * @return True if this context has no outstanding references.
742 final boolean noRefs() {
743 final int local = refcount;
744 return local < REFCOUNT_NONE || local == REFCOUNT_NONE && noParentRef();
747 private void lastDecRef() {
748 if (noImplictRef()) {
749 // We are no longer guarded by effective instance
754 final byte prevRefs = parentRef;
755 if (prevRefs == PARENTREF_ABSENT) {
756 // We are the last reference towards root, any children who observed PARENTREF_PRESENT from us need to be
759 } else if (prevRefs == PARENTREF_UNKNOWN) {
760 // Noone observed our parentRef, just update it
761 loadParentRefcount();
765 static final void markNoParentRef(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
766 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
767 final byte prevRef = stmt.parentRef;
768 stmt.parentRef = PARENTREF_ABSENT;
769 if (prevRef == PARENTREF_PRESENT && stmt.refcount == REFCOUNT_NONE) {
770 // Child thinks it is pinned down, update its perspective
771 stmt.markNoParentRef();
776 abstract void markNoParentRef();
778 static final void sweep(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
779 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
785 * Sweep this statement context as a result of {@link #sweepSubstatements()}, i.e. when parent is also being swept.
787 private void sweep() {
788 parentRef = PARENTREF_ABSENT;
789 if (refcount == REFCOUNT_NONE && noImplictRef()) {
790 LOG.trace("Releasing {}", this);
795 static final int countUnswept(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
797 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
798 if (stmt.refcount > REFCOUNT_NONE || !stmt.noImplictRef()) {
806 * Implementation-specific sweep action. This is expected to perform a recursive {@link #sweep(Collection)} on all
807 * {@link #declaredSubstatements()} and {@link #effectiveSubstatements()} and report the result of the sweep
811 * {@link #effectiveSubstatements()} as well as namespaces may become inoperable as a result of this operation.
813 * @return True if the entire tree has been completely swept, false otherwise.
815 abstract int sweepSubstatements();
817 // Called when this statement does not have an implicit reference and have reached REFCOUNT_NONE
818 private void sweepOnDecrement() {
819 LOG.trace("Sweeping on decrement {}", this);
821 // No further parent references, sweep our state.
825 // Propagate towards parent if there is one
826 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
827 if (parent != null) {
828 parent.sweepOnChildDecrement();
832 // Called from child when it has lost its final reference
833 private void sweepOnChildDecrement() {
834 if (isAwaitingChildren()) {
835 // We are a child for which our parent is waiting. Notify it and we are done.
840 // Check parent reference count
841 final int refs = refcount;
842 if (refs > REFCOUNT_NONE || refs <= REFCOUNT_SWEEPING || !noImplictRef()) {
847 // parent is potentially reclaimable
849 LOG.trace("Cleanup {} of parent {}", refcount, this);
851 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
852 if (parent != null) {
853 parent.sweepOnChildDecrement();
859 private boolean noImplictRef() {
860 return effectiveInstance != null || !isSupportedToBuildEffective();
863 private boolean noParentRef() {
864 return parentRefcount() == PARENTREF_ABSENT;
867 private byte parentRefcount() {
869 return (refs = parentRef) != PARENTREF_UNKNOWN ? refs : loadParentRefcount();
872 private byte loadParentRefcount() {
873 return parentRef = calculateParentRefcount();
876 private byte calculateParentRefcount() {
877 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
878 if (parent == null) {
879 return PARENTREF_ABSENT;
882 // A slight wrinkle here is that our machinery handles only PRESENT -> ABSENT invalidation and we can reach here
883 // while inference is still ongoing and hence we may not have a complete picture about existing references. We
884 // could therefore end up caching an ABSENT result and then that information becoming stale as a new reference
886 if (parent.executionOrder() < ExecutionOrder.EFFECTIVE_MODEL) {
887 return PARENTREF_UNKNOWN;
890 // There are three possibilities:
891 // - REFCOUNT_NONE, in which case we need to search next parent
892 // - negative (< REFCOUNT_NONE), meaning parent is in some stage of sweeping, hence it does not have
894 // - positive (> REFCOUNT_NONE), meaning parent has an explicit refcount which is holding us down
895 final int refs = parent.refcount;
896 if (refs == REFCOUNT_NONE) {
897 return parent.parentRefcount();
899 return refs < REFCOUNT_NONE ? PARENTREF_ABSENT : PARENTREF_PRESENT;
902 private boolean isAwaitingChildren() {
903 return refcount > REFCOUNT_SWEEPING && refcount < REFCOUNT_NONE;
906 private void sweepOnChildDone() {
907 LOG.trace("Sweeping on child done {}", this);
908 final int current = refcount;
909 if (current >= REFCOUNT_NONE) {
910 // no-op, perhaps we want to handle some cases differently?
911 LOG.trace("Ignoring child sweep of {} for {}", this, current);
914 verify(current != REFCOUNT_SWEPT, "Attempt to sweep a child of swept %s", this);
916 refcount = current + 1;
917 LOG.trace("Child refcount {}", refcount);
918 if (refcount == REFCOUNT_NONE) {
920 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
921 LOG.trace("Propagating to parent {}", parent);
922 if (parent != null && parent.isAwaitingChildren()) {
923 parent.sweepOnChildDone();
928 private void sweepDone() {
929 LOG.trace("Sweep done for {}", this);
930 refcount = REFCOUNT_SWEPT;
934 private boolean sweepState() {
935 refcount = REFCOUNT_SWEEPING;
936 final int childRefs = sweepSubstatements();
937 if (childRefs == 0) {
941 if (childRefs < 0 || childRefs >= REFCOUNT_DEFUNCT) {
942 // FIXME: add a global 'warn once' flag
943 LOG.warn("Negative child refcount {} cannot be stored, reference counting disabled for {}", childRefs, this,
945 refcount = REFCOUNT_DEFUNCT;
947 LOG.trace("Still {} outstanding children of {}", childRefs, this);
948 refcount = -childRefs;