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.Empty;
23 import org.opendaylight.yangtools.yang.common.QName;
24 import org.opendaylight.yangtools.yang.common.QNameModule;
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.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.EffectiveStatementState;
38 import org.opendaylight.yangtools.yang.parser.spi.meta.EffectiveStmtCtx.Current;
39 import org.opendaylight.yangtools.yang.parser.spi.meta.EffectiveStmtCtx.Parent;
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.StmtContext;
47 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext.Mutable;
48 import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContextUtils;
49 import org.opendaylight.yangtools.yang.parser.spi.source.SourceException;
50 import org.opendaylight.yangtools.yang.parser.spi.source.SupportedFeaturesNamespace;
51 import org.slf4j.Logger;
52 import org.slf4j.LoggerFactory;
55 * Real "core" reactor statement implementation of {@link Mutable}, supporting basic reactor lifecycle.
57 * @param <A> Argument type
58 * @param <D> Declared Statement representation
59 * @param <E> Effective Statement representation
61 abstract class ReactorStmtCtx<A, D extends DeclaredStatement<A>, E extends EffectiveStatement<A, D>>
62 extends NamespaceStorageSupport implements Mutable<A, D, E>, Current<A, D> {
63 private static final Logger LOG = LoggerFactory.getLogger(ReactorStmtCtx.class);
66 * Substatement refcount tracking. This mechanics deals with retaining substatements for the purposes of
67 * instantiating their lazy copies in InferredStatementContext. It works in concert with {@link #buildEffective()}
68 * and {@link #declared()}: declared/effective statement views hold an implicit reference and refcount-based
69 * sweep is not activated until they are done (or this statement is not {@link #isSupportedToBuildEffective}).
72 * Reference count is hierarchical in that parent references also pin down their child statements and do not allow
76 * The counter's positive values are tracking incoming references via {@link #incRef()}/{@link #decRef()} methods.
77 * Once we transition to sweeping, this value becomes negative counting upwards to {@link #REFCOUNT_NONE} based on
78 * {@link #sweepOnChildDone()}. Once we reach that, we transition to {@link #REFCOUNT_SWEPT}.
80 private int refcount = REFCOUNT_NONE;
82 * No outstanding references, this statement is a potential candidate for sweeping, provided it has populated its
83 * declared and effective views and {@link #parentRef} is known to be absent.
85 private static final int REFCOUNT_NONE = 0;
87 * Reference count overflow or some other recoverable logic error. Do not rely on refcounts and do not sweep
91 * Note on value assignment:
92 * This allow our incRef() to naturally progress to being saturated. Others jump there directly.
93 * It also makes it it impossible to observe {@code Interger.MAX_VALUE} children, which we take advantage of for
94 * {@link #REFCOUNT_SWEEPING}.
96 private static final int REFCOUNT_DEFUNCT = Integer.MAX_VALUE;
98 * This statement is being actively swept. This is a transient value set when we are sweeping our children, so that
99 * we prevent re-entering this statement.
102 * Note on value assignment:
103 * The value is lower than any legal child refcount due to {@link #REFCOUNT_DEFUNCT} while still being higher than
104 * {@link #REFCOUNT_SWEPT}.
106 private static final int REFCOUNT_SWEEPING = -Integer.MAX_VALUE;
108 * This statement, along with its entire subtree has been swept and we positively know all our children have reached
109 * this state. We {@link #sweepNamespaces()} upon reaching this state.
112 * Note on value assignment:
113 * This is the lowest value observable, making it easier on checking others on equality.
115 private static final int REFCOUNT_SWEPT = Integer.MIN_VALUE;
118 * Effective instance built from this context. This field as dual types. Under normal circumstances in matches the
119 * {@link #buildEffective()} instance. If this context is reused, it can be inflated to {@link EffectiveInstances}
120 * and also act as a common instance reuse site.
122 private @Nullable Object effectiveInstance;
124 // Master flag controlling whether this context can yield an effective statement
125 // FIXME: investigate the mechanics that are being supported by this, as it would be beneficial if we can get rid
126 // of this flag -- eliminating the initial alignment shadow used by below gap-filler fields.
127 private boolean isSupportedToBuildEffective = true;
129 // EffectiveConfig mapping
130 private static final int MASK_CONFIG = 0x03;
131 private static final int HAVE_CONFIG = 0x04;
132 // Effective instantiation mechanics for StatementContextBase: if this flag is set all substatements are known not
133 // change when instantiated. This includes context-independent statements as well as any statements which are
134 // ignored during copy instantiation.
135 private static final int ALL_INDEPENDENT = 0x08;
136 // Flag bit assignments
137 private static final int IS_SUPPORTED_BY_FEATURES = 0x10;
138 private static final int HAVE_SUPPORTED_BY_FEATURES = 0x20;
139 private static final int IS_IGNORE_IF_FEATURE = 0x40;
140 private static final int HAVE_IGNORE_IF_FEATURE = 0x80;
141 // Have-and-set flag constants, also used as masks
142 private static final int SET_SUPPORTED_BY_FEATURES = HAVE_SUPPORTED_BY_FEATURES | IS_SUPPORTED_BY_FEATURES;
143 private static final int SET_IGNORE_IF_FEATURE = HAVE_IGNORE_IF_FEATURE | IS_IGNORE_IF_FEATURE;
145 private static final EffectiveConfig[] EFFECTIVE_CONFIGS;
148 final EffectiveConfig[] values = EffectiveConfig.values();
149 final int length = values.length;
150 verify(length == 4, "Unexpected EffectiveConfig cardinality %s", length);
151 EFFECTIVE_CONFIGS = values;
154 // Flags for use with SubstatementContext. These are hiding in the alignment shadow created by above boolean and
155 // hence improve memory layout.
158 // Flag for use by AbstractResumedStatement, ReplicaStatementContext and InferredStatementContext. Each of them
159 // uses it to indicated a different condition. This is hiding in the alignment shadow created by
160 // 'isSupportedToBuildEffective'.
161 // FIXME: move this out once we have JDK15+
162 private boolean boolFlag;
168 ReactorStmtCtx(final ReactorStmtCtx<A, D, E> original) {
169 isSupportedToBuildEffective = original.isSupportedToBuildEffective;
170 boolFlag = original.boolFlag;
171 flags = original.flags;
174 // Used by ReplicaStatementContext only
175 ReactorStmtCtx(final ReactorStmtCtx<A, D, E> original, final Void dummy) {
176 boolFlag = isSupportedToBuildEffective = original.isSupportedToBuildEffective;
177 flags = original.flags;
182 // Common public interface contracts with simple mechanics. Please keep this in one logical block, so we do not end
183 // up mixing concerns and simple details with more complex logic.
188 public abstract StatementContextBase<?, ?, ?> getParentContext();
191 public abstract RootStatementContext<?, ?, ?> getRoot();
194 public abstract Collection<? extends StatementContextBase<?, ?, ?>> mutableDeclaredSubstatements();
197 public final @NonNull Registry getBehaviourRegistry() {
198 return getRoot().getBehaviourRegistryImpl();
202 public final YangVersion yangVersion() {
203 return getRoot().getRootVersionImpl();
207 public final void setRootVersion(final YangVersion version) {
208 getRoot().setRootVersionImpl(version);
212 public final void addRequiredSource(final SourceIdentifier dependency) {
213 getRoot().addRequiredSourceImpl(dependency);
217 public final void setRootIdentifier(final SourceIdentifier identifier) {
218 getRoot().setRootIdentifierImpl(identifier);
222 public final ModelActionBuilder newInferenceAction(final ModelProcessingPhase phase) {
223 return getRoot().getSourceContext().newInferenceAction(phase);
227 public final StatementDefinition publicDefinition() {
228 return definition().getPublicView();
232 public final Parent effectiveParent() {
233 return getParentContext();
237 public final QName moduleName() {
238 final RootStatementContext<?, ?, ?> root = getRoot();
239 return QName.create(StmtContextUtils.getRootModuleQName(root), root.getRawArgument());
243 @Deprecated(since = "7.0.9", forRemoval = true)
244 public final EffectiveStatement<?, ?> original() {
245 return getOriginalCtx().map(StmtContext::buildEffective).orElse(null);
249 // In the next two methods we are looking for an effective statement. If we already have an effective instance,
250 // defer to it's implementation of the equivalent search. Otherwise we search our substatement contexts.
252 // Note that the search function is split, so as to allow InferredStatementContext to do its own thing first.
256 public final <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgument(
257 final @NonNull Class<Z> type) {
258 final E existing = effectiveInstance();
259 return existing != null ? existing.findFirstEffectiveSubstatementArgument(type)
260 : findSubstatementArgumentImpl(type);
264 public final boolean hasSubstatement(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
265 final E existing = effectiveInstance();
266 return existing != null ? existing.findFirstEffectiveSubstatement(type).isPresent() : hasSubstatementImpl(type);
269 private E effectiveInstance() {
270 final Object existing = effectiveInstance;
271 return existing != null ? EffectiveInstances.local(existing) : null;
274 // Visible due to InferredStatementContext's override. At this point we do not have an effective instance available.
275 <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgumentImpl(
276 final @NonNull Class<Z> type) {
277 return allSubstatementsStream()
278 .filter(ctx -> ctx.isSupportedToBuildEffective() && ctx.producesEffective(type))
280 .map(ctx -> (X) ctx.getArgument());
283 // Visible due to InferredStatementContext's override. At this point we do not have an effective instance available.
284 boolean hasSubstatementImpl(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
285 return allSubstatementsStream()
286 .anyMatch(ctx -> ctx.isSupportedToBuildEffective() && ctx.producesEffective(type));
291 @SuppressWarnings("unchecked")
292 public final <Z extends EffectiveStatement<A, D>> StmtContext<A, D, Z> caerbannog() {
293 return (StmtContext<A, D, Z>) this;
297 public final String toString() {
298 return addToStringAttributes(MoreObjects.toStringHelper(this).omitNullValues()).toString();
301 protected ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {
302 return toStringHelper.add("definition", definition()).add("argument", argument()).add("refCount", refString());
305 private String refString() {
306 final int current = refcount;
308 case REFCOUNT_DEFUNCT:
310 case REFCOUNT_SWEEPING:
315 return String.valueOf(refcount);
320 * Return the context in which this statement was defined.
322 * @return statement definition
324 abstract @NonNull StatementDefinitionContext<A, D, E> definition();
328 // NamespaceStorageSupport/Mutable integration methods. Keep these together.
333 public final <K, V, T extends K, N extends ParserNamespace<K, V>> V namespaceItem(final Class<@NonNull N> type,
335 return getBehaviourRegistry().getNamespaceBehaviour(type).getFrom(this, key);
339 public final <K, V, N extends ParserNamespace<K, V>> Map<K, V> namespace(final Class<@NonNull N> type) {
340 return getNamespace(type);
344 public final <K, V, N extends ParserNamespace<K, V>>
345 Map<K, V> localNamespacePortion(final Class<@NonNull N> type) {
346 return getLocalNamespace(type);
350 protected <K, V, N extends ParserNamespace<K, V>> void onNamespaceElementAdded(final Class<N> type, final K key,
352 // definition().onNamespaceElementAdded(this, type, key, value);
356 * Return the effective statement view of a copy operation. This method may return one of:
358 * <li>{@code this}, when the effective view did not change</li>
359 * <li>an InferredStatementContext, when there is a need for inference-equivalent copy</li>
360 * <li>{@code null}, when the statement failed to materialize</li>
363 * @param parent Proposed new parent
364 * @param type Copy operation type
365 * @param targetModule New target module
366 * @return {@link ReactorStmtCtx} holding effective view
368 abstract @Nullable ReactorStmtCtx<?, ?, ?> asEffectiveChildOf(StatementContextBase<?, ?, ?> parent, CopyType type,
369 QNameModule targetModule);
372 public final ReplicaStatementContext<A, D, E> replicaAsChildOf(final Mutable<?, ?, ?> parent) {
373 checkArgument(parent instanceof StatementContextBase, "Unsupported parent %s", parent);
374 final var ret = replicaAsChildOf((StatementContextBase<?, ?, ?>) parent);
375 definition().onStatementAdded(ret);
379 abstract @NonNull ReplicaStatementContext<A, D, E> replicaAsChildOf(@NonNull StatementContextBase<?, ?, ?> parent);
383 // Statement build entry points -- both public and package-private.
388 public final E buildEffective() {
389 final Object existing;
390 return (existing = effectiveInstance) != null ? EffectiveInstances.local(existing) : loadEffective();
393 private @NonNull E loadEffective() {
394 final E ret = createEffective();
395 effectiveInstance = ret;
396 // we have called createEffective(), substatements are no longer guarded by us. Let's see if we can clear up
398 if (refcount == REFCOUNT_NONE) {
404 abstract @NonNull E createEffective();
407 * Attach an effective copy of this statement. This essentially acts as a map, where we make a few assumptions:
409 * <li>{@code copy} and {@code this} statement share {@link #getOriginalCtx()} if it exists</li>
410 * <li>{@code copy} did not modify any statements relative to {@code this}</li>
413 * @param state effective statement state, acting as a lookup key
414 * @param stmt New copy to append
415 * @return {@code stmt} or a previously-created instances with the same {@code state}
417 @SuppressWarnings("unchecked")
418 final @NonNull E attachEffectiveCopy(final @NonNull EffectiveStatementState state, final @NonNull E stmt) {
419 final Object local = effectiveInstance;
420 final EffectiveInstances<E> instances;
421 if (local instanceof EffectiveInstances) {
422 instances = (EffectiveInstances<E>) local;
424 effectiveInstance = instances = new EffectiveInstances<>((E) local);
426 return instances.attachCopy(state, stmt);
430 * Walk this statement's copy history and return the statement closest to original which has not had its effective
431 * statements modified. This statement and returned substatement logically have the same set of substatements, hence
432 * share substatement-derived state.
434 * @return Closest {@link ReactorStmtCtx} with equivalent effective substatements
436 abstract @NonNull ReactorStmtCtx<A, D, E> unmodifiedEffectiveSource();
439 public final ModelProcessingPhase getCompletedPhase() {
440 return ModelProcessingPhase.ofExecutionOrder(executionOrder());
443 abstract byte executionOrder();
446 * Try to execute current {@link ModelProcessingPhase} of source parsing. If the phase has already been executed,
447 * this method does nothing. This must not be called with {@link ExecutionOrder#NULL}.
449 * @param phase to be executed (completed)
450 * @return true if phase was successfully completed
451 * @throws SourceException when an error occurred in source parsing
453 final boolean tryToCompletePhase(final byte executionOrder) {
454 return executionOrder() >= executionOrder || doTryToCompletePhase(executionOrder);
457 abstract boolean doTryToCompletePhase(byte targetOrder);
461 // Flags-based mechanics. These include public interfaces as well as all the crud we have lurking in our alignment
467 public final boolean isSupportedToBuildEffective() {
468 return isSupportedToBuildEffective;
472 public final void setUnsupported() {
473 this.isSupportedToBuildEffective = false;
477 public final boolean isSupportedByFeatures() {
478 final int fl = flags & SET_SUPPORTED_BY_FEATURES;
480 return fl == SET_SUPPORTED_BY_FEATURES;
482 if (isIgnoringIfFeatures()) {
483 flags |= SET_SUPPORTED_BY_FEATURES;
488 * If parent is supported, we need to check if-features statements of this context.
490 if (isParentSupportedByFeatures()) {
491 // If the set of supported features has not been provided, all features are supported by default.
492 final Set<QName> supportedFeatures = getFromNamespace(SupportedFeaturesNamespace.class, Empty.value());
493 if (supportedFeatures == null || StmtContextUtils.checkFeatureSupport(this, supportedFeatures)) {
494 flags |= SET_SUPPORTED_BY_FEATURES;
499 // Either parent is not supported or this statement is not supported
500 flags |= HAVE_SUPPORTED_BY_FEATURES;
504 protected abstract boolean isParentSupportedByFeatures();
507 * Config statements are not all that common which means we are performing a recursive search towards the root
508 * every time {@link #effectiveConfig()} is invoked. This is quite expensive because it causes a linear search
509 * for the (usually non-existent) config statement.
512 * This method maintains a resolution cache, so once we have returned a result, we will keep on returning the same
513 * result without performing any lookups, solely to support {@link #effectiveConfig()}.
516 * Note: use of this method implies that {@link #isIgnoringConfig()} is realized with
517 * {@link #isIgnoringConfig(StatementContextBase)}.
519 final @NonNull EffectiveConfig effectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
520 return (flags & HAVE_CONFIG) != 0 ? EFFECTIVE_CONFIGS[flags & MASK_CONFIG] : loadEffectiveConfig(parent);
523 private @NonNull EffectiveConfig loadEffectiveConfig(final ReactorStmtCtx<?, ?, ?> parent) {
524 final EffectiveConfig parentConfig = parent.effectiveConfig();
526 final EffectiveConfig myConfig;
527 if (parentConfig != EffectiveConfig.IGNORED && !definition().support().isIgnoringConfig()) {
528 final Optional<Boolean> optConfig = findSubstatementArgument(ConfigEffectiveStatement.class);
529 if (optConfig.isPresent()) {
530 if (optConfig.orElseThrow()) {
531 // Validity check: if parent is config=false this cannot be a config=true
532 InferenceException.throwIf(parentConfig == EffectiveConfig.FALSE, this,
533 "Parent node has config=false, this node must not be specifed as config=true");
534 myConfig = EffectiveConfig.TRUE;
536 myConfig = EffectiveConfig.FALSE;
539 // If "config" statement is not specified, the default is the same as the parent's "config" value.
540 myConfig = parentConfig;
543 myConfig = EffectiveConfig.IGNORED;
546 flags = (byte) (flags & ~MASK_CONFIG | HAVE_CONFIG | myConfig.ordinal());
550 protected abstract boolean isIgnoringConfig();
553 * This method maintains a resolution cache for ignore config, so once we have returned a result, we will
554 * keep on returning the same result without performing any lookups. Exists only to support
555 * {@link SubstatementContext#isIgnoringConfig()}.
558 * Note: use of this method implies that {@link #isConfiguration()} is realized with
559 * {@link #effectiveConfig(StatementContextBase)}.
561 final boolean isIgnoringConfig(final StatementContextBase<?, ?, ?> parent) {
562 return EffectiveConfig.IGNORED == effectiveConfig(parent);
565 protected abstract boolean isIgnoringIfFeatures();
568 * This method maintains a resolution cache for ignore if-feature, so once we have returned a result, we will
569 * keep on returning the same result without performing any lookups. Exists only to support
570 * {@link SubstatementContext#isIgnoringIfFeatures()}.
572 final boolean isIgnoringIfFeatures(final StatementContextBase<?, ?, ?> parent) {
573 final int fl = flags & SET_IGNORE_IF_FEATURE;
575 return fl == SET_IGNORE_IF_FEATURE;
577 if (definition().support().isIgnoringIfFeatures() || parent.isIgnoringIfFeatures()) {
578 flags |= SET_IGNORE_IF_FEATURE;
582 flags |= HAVE_IGNORE_IF_FEATURE;
586 // These two exist only due to memory optimization, should live in AbstractResumedStatement.
587 final boolean fullyDefined() {
591 final void setFullyDefined() {
595 // This exists only due to memory optimization, should live in ReplicaStatementContext. In this context the flag
596 // indicates the need to drop source's reference count when we are being swept.
597 final boolean haveSourceReference() {
601 // These three exist due to memory optimization, should live in InferredStatementContext. In this context the flag
602 // indicates whether or not this statement's substatement file was modified, i.e. it is not quite the same as the
604 final boolean isModified() {
608 final void setModified() {
612 final void setUnmodified() {
616 // These two exist only for StatementContextBase. Since we are squeezed for size, with only a single bit available
617 // in flags, we default to 'false' and only set the flag to true when we are absolutely sure -- and all other cases
618 // err on the side of caution by taking the time to evaluate each substatement separately.
619 final boolean allSubstatementsContextIndependent() {
620 return (flags & ALL_INDEPENDENT) != 0;
623 final void setAllSubstatementsContextIndependent() {
624 flags |= ALL_INDEPENDENT;
629 // Various functionality from AbstractTypeStatementSupport. This used to work on top of SchemaPath, now it still
630 // lives here. Ultimate future is either proper graduation or (more likely) move to AbstractTypeStatementSupport.
635 public final QName argumentAsTypeQName() {
636 // FIXME: This may yield illegal argument exceptions
637 return StmtContextUtils.qnameFromArgument(getOriginalCtx().orElse(this), getRawArgument());
641 public final QNameModule effectiveNamespace() {
642 if (StmtContextUtils.isUnknownStatement(this)) {
643 return publicDefinition().getStatementName().getModule();
645 if (producesDeclared(UsesStatement.class)) {
646 return coerceParent().effectiveNamespace();
649 final Object argument = argument();
650 if (argument instanceof QName) {
651 return ((QName) argument).getModule();
653 if (argument instanceof String) {
654 // FIXME: This may yield illegal argument exceptions
655 return StmtContextUtils.qnameFromArgument(getOriginalCtx().orElse(this), (String) argument).getModule();
657 if (argument instanceof SchemaNodeIdentifier
658 && (producesDeclared(AugmentStatement.class) || producesDeclared(RefineStatement.class)
659 || producesDeclared(DeviationStatement.class))) {
660 return ((SchemaNodeIdentifier) argument).lastNodeIdentifier().getModule();
663 return coerceParent().effectiveNamespace();
666 private ReactorStmtCtx<?, ?, ?> coerceParent() {
667 return (ReactorStmtCtx<?, ?, ?>) coerceParentContext();
672 // Reference counting mechanics start. Please keep these methods in one block for clarity. Note this does not
673 // contribute to state visible outside of this package.
678 * Local knowledge of {@link #refcount} values up to statement root. We use this field to prevent recursive lookups
679 * in {@link #noParentRefs(StatementContextBase)} -- once we discover a parent reference once, we keep that
680 * knowledge and update it when {@link #sweep()} is invoked.
682 private byte parentRef = PARENTREF_UNKNOWN;
683 private static final byte PARENTREF_UNKNOWN = -1;
684 private static final byte PARENTREF_ABSENT = 0;
685 private static final byte PARENTREF_PRESENT = 1;
688 * Acquire a reference on this context. As long as there is at least one reference outstanding,
689 * {@link #buildEffective()} will not result in {@link #effectiveSubstatements()} being discarded.
691 * @throws VerifyException if {@link #effectiveSubstatements()} has already been discarded
693 final void incRef() {
694 final int current = refcount;
695 verify(current >= REFCOUNT_NONE, "Attempted to access reference count of %s", this);
696 if (current != REFCOUNT_DEFUNCT) {
697 // Note: can end up becoming REFCOUNT_DEFUNCT on overflow
698 refcount = current + 1;
700 LOG.debug("Disabled refcount increment of {}", this);
705 * Release a reference on this context. This call may result in {@link #effectiveSubstatements()} becoming
708 final void decRef() {
709 final int current = refcount;
710 if (current == REFCOUNT_DEFUNCT) {
712 LOG.debug("Disabled refcount decrement of {}", this);
715 if (current <= REFCOUNT_NONE) {
716 // Underflow, become defunct
717 // FIXME: add a global 'warn once' flag
718 LOG.warn("Statement refcount underflow, reference counting disabled for {}", this, new Throwable());
719 refcount = REFCOUNT_DEFUNCT;
723 refcount = current - 1;
724 LOG.trace("Refcount {} on {}", refcount, this);
726 if (refcount == REFCOUNT_NONE) {
732 * Return {@code true} if this context has no outstanding references.
734 * @return True if this context has no outstanding references.
736 final boolean noRefs() {
737 final int local = refcount;
738 return local < REFCOUNT_NONE || local == REFCOUNT_NONE && noParentRef();
741 private void lastDecRef() {
742 if (noImplictRef()) {
743 // We are no longer guarded by effective instance
748 final byte prevRefs = parentRef;
749 if (prevRefs == PARENTREF_ABSENT) {
750 // We are the last reference towards root, any children who observed PARENTREF_PRESENT from us need to be
753 } else if (prevRefs == PARENTREF_UNKNOWN) {
754 // Noone observed our parentRef, just update it
755 loadParentRefcount();
759 static final void markNoParentRef(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
760 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
761 final byte prevRef = stmt.parentRef;
762 stmt.parentRef = PARENTREF_ABSENT;
763 if (prevRef == PARENTREF_PRESENT && stmt.refcount == REFCOUNT_NONE) {
764 // Child thinks it is pinned down, update its perspective
765 stmt.markNoParentRef();
770 abstract void markNoParentRef();
772 static final void sweep(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
773 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
779 * Sweep this statement context as a result of {@link #sweepSubstatements()}, i.e. when parent is also being swept.
781 private void sweep() {
782 parentRef = PARENTREF_ABSENT;
783 if (refcount == REFCOUNT_NONE && noImplictRef()) {
784 LOG.trace("Releasing {}", this);
789 static final int countUnswept(final Collection<? extends ReactorStmtCtx<?, ?, ?>> substatements) {
791 for (ReactorStmtCtx<?, ?, ?> stmt : substatements) {
792 if (stmt.refcount > REFCOUNT_NONE || !stmt.noImplictRef()) {
800 * Implementation-specific sweep action. This is expected to perform a recursive {@link #sweep(Collection)} on all
801 * {@link #declaredSubstatements()} and {@link #effectiveSubstatements()} and report the result of the sweep
805 * {@link #effectiveSubstatements()} as well as namespaces may become inoperable as a result of this operation.
807 * @return True if the entire tree has been completely swept, false otherwise.
809 abstract int sweepSubstatements();
811 // Called when this statement does not have an implicit reference and have reached REFCOUNT_NONE
812 private void sweepOnDecrement() {
813 LOG.trace("Sweeping on decrement {}", this);
815 // No further parent references, sweep our state.
819 // Propagate towards parent if there is one
823 private void sweepParent() {
824 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
825 if (parent != null) {
826 parent.sweepOnChildDecrement();
830 // Called from child when it has lost its final reference
831 private void sweepOnChildDecrement() {
832 if (isAwaitingChildren()) {
833 // We are a child for which our parent is waiting. Notify it and we are done.
838 // Check parent reference count
839 final int refs = refcount;
840 if (refs > REFCOUNT_NONE || refs <= REFCOUNT_SWEEPING || !noImplictRef()) {
845 // parent is potentially reclaimable
847 LOG.trace("Cleanup {} of parent {}", refs, this);
854 private boolean noImplictRef() {
855 return effectiveInstance != null || !isSupportedToBuildEffective();
858 private boolean noParentRef() {
859 return parentRefcount() == PARENTREF_ABSENT;
862 private byte parentRefcount() {
864 return (refs = parentRef) != PARENTREF_UNKNOWN ? refs : loadParentRefcount();
867 private byte loadParentRefcount() {
868 return parentRef = calculateParentRefcount();
871 private byte calculateParentRefcount() {
872 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
873 if (parent == null) {
874 return PARENTREF_ABSENT;
877 // A slight wrinkle here is that our machinery handles only PRESENT -> ABSENT invalidation and we can reach here
878 // while inference is still ongoing and hence we may not have a complete picture about existing references. We
879 // could therefore end up caching an ABSENT result and then that information becoming stale as a new reference
881 if (parent.executionOrder() < ExecutionOrder.EFFECTIVE_MODEL) {
882 return PARENTREF_UNKNOWN;
885 // There are three possibilities:
886 // - REFCOUNT_NONE, in which case we need to search next parent
887 // - negative (< REFCOUNT_NONE), meaning parent is in some stage of sweeping, hence it does not have
889 // - positive (> REFCOUNT_NONE), meaning parent has an explicit refcount which is holding us down
890 final int refs = parent.refcount;
891 if (refs == REFCOUNT_NONE) {
892 return parent.parentRefcount();
894 return refs < REFCOUNT_NONE ? PARENTREF_ABSENT : PARENTREF_PRESENT;
897 private boolean isAwaitingChildren() {
898 return refcount > REFCOUNT_SWEEPING && refcount < REFCOUNT_NONE;
901 private void sweepOnChildDone() {
902 LOG.trace("Sweeping on child done {}", this);
903 final int current = refcount;
904 if (current >= REFCOUNT_NONE) {
905 // no-op, perhaps we want to handle some cases differently?
906 LOG.trace("Ignoring child sweep of {} for {}", this, current);
909 verify(current != REFCOUNT_SWEPT, "Attempt to sweep a child of swept %s", this);
911 refcount = current + 1;
912 LOG.trace("Child refcount {}", refcount);
913 if (refcount == REFCOUNT_NONE) {
915 final ReactorStmtCtx<?, ?, ?> parent = getParentContext();
916 LOG.trace("Propagating to parent {}", parent);
917 if (parent != null && parent.isAwaitingChildren()) {
918 parent.sweepOnChildDone();
923 private void sweepDone() {
924 LOG.trace("Sweep done for {}", this);
925 refcount = REFCOUNT_SWEPT;
929 private boolean sweepState() {
930 refcount = REFCOUNT_SWEEPING;
931 final int childRefs = sweepSubstatements();
932 if (childRefs == 0) {
936 if (childRefs < 0 || childRefs >= REFCOUNT_DEFUNCT) {
937 // FIXME: add a global 'warn once' flag
938 LOG.warn("Negative child refcount {} cannot be stored, reference counting disabled for {}", childRefs, this,
940 refcount = REFCOUNT_DEFUNCT;
942 LOG.trace("Still {} outstanding children of {}", childRefs, this);
943 refcount = -childRefs;