/*
* Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.yangtools.yang.data.impl.schema.tree;
import static com.google.common.base.Verify.verifyNotNull;
import static java.util.Objects.requireNonNull;
import com.google.common.base.MoreObjects;
import com.google.common.base.MoreObjects.ToStringHelper;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import java.util.Collection;
import java.util.Map;
import java.util.Optional;
import java.util.function.Predicate;
import org.eclipse.jdt.annotation.NonNull;
import org.eclipse.jdt.annotation.Nullable;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodeContainer;
import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
import org.opendaylight.yangtools.yang.data.api.schema.tree.StoreTreeNode;
import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNode;
import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNodeFactory;
import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.Version;
/**
* Node Modification Node and Tree.
*
*
* Tree which structurally resembles data tree and captures client modifications to the data store tree. This tree is
* lazily created and populated via {@link #modifyChild(PathArgument, ModificationApplyOperation, Version)} and
* {@link TreeNode} which represents original state as tracked by {@link #getOriginal()}.
*
*
* The contract is that the state information exposed here preserves the temporal ordering of whatever modifications
* were executed. A child's effects pertain to data node as modified by its ancestors. This means that in order to
* reconstruct the effective data node presentation, it is sufficient to perform a depth-first pre-order traversal of
* the tree.
*/
final class ModifiedNode extends NodeModification implements StoreTreeNode {
static final Predicate IS_TERMINAL_PREDICATE = input -> {
requireNonNull(input);
switch (input.getOperation()) {
case DELETE:
case MERGE:
case WRITE:
return true;
case TOUCH:
case NONE:
return false;
default:
throw new IllegalArgumentException("Unhandled modification type " + input.getOperation());
}
};
private final Map children;
private final Optional extends TreeNode> original;
private final PathArgument identifier;
private LogicalOperation operation = LogicalOperation.NONE;
private Optional snapshotCache;
private NormalizedNode, ?> value;
private ModificationType modType;
// Alternative history introduced in WRITE nodes. Instantiated when we touch any child underneath such a node.
private TreeNode writtenOriginal;
// Internal cache for TreeNodes created as part of validation
private ModificationApplyOperation validatedOp;
private Optional extends TreeNode> validatedCurrent;
private Optional extends TreeNode> validatedNode;
private ModifiedNode(final PathArgument identifier, final Optional extends TreeNode> original,
final ChildTrackingPolicy childPolicy) {
this.identifier = identifier;
this.original = original;
this.children = childPolicy.createMap();
}
@Override
public PathArgument getIdentifier() {
return identifier;
}
@Override
LogicalOperation getOperation() {
return operation;
}
@Override
Optional extends TreeNode> getOriginal() {
return original;
}
/**
* Return the value which was written to this node. The returned object is only valid for
* {@link LogicalOperation#MERGE} and {@link LogicalOperation#WRITE}.
* operations. It should only be consulted when this modification is going to end up being
* {@link ModificationType#WRITE}.
*
* @return Currently-written value
*/
@NonNull NormalizedNode, ?> getWrittenValue() {
return verifyNotNull(value);
}
/**
* Returns child modification if child was modified.
*
* @return Child modification if direct child or it's subtree was modified.
*/
@Override
public Optional getChild(final PathArgument child) {
return Optional.ofNullable(children.get(child));
}
private Optional extends TreeNode> metadataFromSnapshot(final @NonNull PathArgument child) {
return original.isPresent() ? original.get().getChild(child) : Optional.empty();
}
private Optional extends TreeNode> metadataFromData(final @NonNull PathArgument child, final Version modVersion) {
if (writtenOriginal == null) {
// Lazy instantiation, as we do not want do this for all writes. We are using the modification's version
// here, as that version is what the SchemaAwareApplyOperation will see when dealing with the resulting
// modifications.
writtenOriginal = TreeNodeFactory.createTreeNode(value, modVersion);
}
return writtenOriginal.getChild(child);
}
/**
* Determine the base tree node we are going to apply the operation to. This is not entirely trivial because
* both DELETE and WRITE operations unconditionally detach their descendants from the original snapshot, so we need
* to take the current node's operation into account.
*
* @param child Child we are looking to modify
* @param modVersion Version allocated by the calling {@link InMemoryDataTreeModification}
* @return Before-image tree node as observed by that child.
*/
private Optional extends TreeNode> findOriginalMetadata(final @NonNull PathArgument child,
final Version modVersion) {
switch (operation) {
case DELETE:
// DELETE implies non-presence
return Optional.empty();
case NONE:
case TOUCH:
case MERGE:
return metadataFromSnapshot(child);
case WRITE:
// WRITE implies presence based on written data
return metadataFromData(child, modVersion);
default:
throw new IllegalStateException("Unhandled node operation " + operation);
}
}
/**
* Returns child modification if child was modified, creates {@link ModifiedNode}
* for child otherwise. If this node's {@link ModificationType} is {@link ModificationType#UNMODIFIED}
* changes modification type to {@link ModificationType#SUBTREE_MODIFIED}.
*
* @param child child identifier, may not be null
* @param childOper Child operation
* @param modVersion Version allocated by the calling {@link InMemoryDataTreeModification}
* @return {@link ModifiedNode} for specified child, with {@link #getOriginal()}
* containing child metadata if child was present in original data.
*/
ModifiedNode modifyChild(final @NonNull PathArgument child, final @NonNull ModificationApplyOperation childOper,
final @NonNull Version modVersion) {
clearSnapshot();
if (operation == LogicalOperation.NONE) {
updateOperationType(LogicalOperation.TOUCH);
}
final ModifiedNode potential = children.get(child);
if (potential != null) {
return potential;
}
final Optional extends TreeNode> currentMetadata = findOriginalMetadata(child, modVersion);
final ModifiedNode newlyCreated = new ModifiedNode(child, currentMetadata, childOper.getChildPolicy());
if (operation == LogicalOperation.MERGE && value != null) {
/*
* We are attempting to modify a previously-unmodified part of a MERGE node. If the
* value contains this component, we need to materialize it as a MERGE modification.
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
final Optional> childData = ((NormalizedNodeContainer)value).getChild(child);
if (childData.isPresent()) {
childOper.mergeIntoModifiedNode(newlyCreated, childData.get(), modVersion);
}
}
children.put(child, newlyCreated);
return newlyCreated;
}
/**
* Returns all recorded direct child modifications.
*
* @return all recorded direct child modifications
*/
@Override
Collection getChildren() {
return children.values();
}
/**
* Records a delete for associated node.
*/
void delete() {
final LogicalOperation newType;
switch (operation) {
case DELETE:
case NONE:
// We need to record this delete.
newType = LogicalOperation.DELETE;
break;
case MERGE:
// In case of merge - delete needs to be recored and must not to be changed into NONE, because lazy
// expansion of parent MERGE node would reintroduce it again.
newType = LogicalOperation.DELETE;
break;
case TOUCH:
case WRITE:
/*
* We are canceling a previous modification. This is a bit tricky, as the original write may have just
* introduced the data, or it may have modified it.
*
* As documented in BUG-2470, a delete of data introduced in this transaction needs to be turned into
* a no-op.
*/
newType = original.isPresent() ? LogicalOperation.DELETE : LogicalOperation.NONE;
break;
default:
throw new IllegalStateException("Unhandled deletion of node with " + operation);
}
clearSnapshot();
children.clear();
this.value = null;
updateOperationType(newType);
}
/**
* Records a write for associated node.
*
* @param newValue new value
*/
void write(final NormalizedNode, ?> newValue) {
updateValue(LogicalOperation.WRITE, newValue);
children.clear();
}
/**
* Seal the modification node and prune any children which has not been modified.
*
* @param schema associated apply operation
* @param version target version
*/
void seal(final ModificationApplyOperation schema, final Version version) {
clearSnapshot();
writtenOriginal = null;
switch (operation) {
case TOUCH:
// A TOUCH node without any children is a no-op
if (children.isEmpty()) {
updateOperationType(LogicalOperation.NONE);
}
break;
case WRITE:
// A WRITE can collapse all of its children
if (!children.isEmpty()) {
value = schema.apply(this, getOriginal(), version).map(TreeNode::getData).orElse(null);
children.clear();
}
if (value == null) {
// The write has ended up being empty, such as a write of an empty list.
updateOperationType(LogicalOperation.DELETE);
} else {
schema.fullVerifyStructure(value);
}
break;
default:
break;
}
}
private void clearSnapshot() {
snapshotCache = null;
}
Optional getSnapshot() {
return snapshotCache;
}
Optional setSnapshot(final Optional snapshot) {
snapshotCache = requireNonNull(snapshot);
return snapshot;
}
void updateOperationType(final LogicalOperation type) {
operation = type;
modType = null;
// Make sure we do not reuse previously-instantiated data-derived metadata
writtenOriginal = null;
clearSnapshot();
}
@Override
public String toString() {
final ToStringHelper helper = MoreObjects.toStringHelper(this).omitNullValues()
.add("identifier", identifier).add("operation", operation).add("modificationType", modType);
if (!children.isEmpty()) {
helper.add("childModification", children);
}
return helper.toString();
}
void resolveModificationType(final @NonNull ModificationType type) {
modType = type;
}
/**
* Update this node's value and operation type without disturbing any of its child modifications.
*
* @param type New operation type
* @param newValue New node value
*/
void updateValue(final LogicalOperation type, final NormalizedNode, ?> newValue) {
this.value = requireNonNull(newValue);
updateOperationType(type);
}
/**
* Return the physical modification done to data. May return null if the
* operation has not been applied to the underlying tree. This is different
* from the logical operation in that it can actually be a no-op if the
* operation has no side-effects (like an empty merge on a container).
*
* @return Modification type.
*/
ModificationType getModificationType() {
return modType;
}
public static ModifiedNode createUnmodified(final TreeNode metadataTree, final ChildTrackingPolicy childPolicy) {
return new ModifiedNode(metadataTree.getIdentifier(), Optional.of(metadataTree), childPolicy);
}
void setValidatedNode(final ModificationApplyOperation op, final Optional extends TreeNode> current,
final Optional extends TreeNode> node) {
this.validatedOp = requireNonNull(op);
this.validatedCurrent = requireNonNull(current);
this.validatedNode = requireNonNull(node);
}
/**
* Acquire pre-validated node assuming a previous operation and node. This is a counterpart to
* {@link #setValidatedNode(ModificationApplyOperation, Optional, Optional)}.
*
* @param op Currently-executing operation
* @param current Currently-used tree node
* @return {@code null} if there is a mismatch with previously-validated node (if present) or the result of previous
* validation.
*/
@SuppressFBWarnings(value = "NP_OPTIONAL_RETURN_NULL",
justification = "The contract is package-internal and well documented, we do not need a separate wrapper")
@Nullable Optional extends TreeNode> getValidatedNode(final ModificationApplyOperation op,
final Optional extends TreeNode> current) {
return op.equals(validatedOp) && current.equals(validatedCurrent) ? validatedNode : null;
}
}