/*
* 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 com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import java.util.Collection;
import java.util.Map.Entry;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import javax.annotation.Nonnull;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
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.NormalizedNodes;
import org.opendaylight.yangtools.yang.data.api.schema.tree.CursorAwareDataTreeModification;
import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModificationCursor;
import org.opendaylight.yangtools.yang.data.api.schema.tree.StoreTreeNodes;
import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.TreeNode;
import org.opendaylight.yangtools.yang.data.api.schema.tree.spi.Version;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
final class InMemoryDataTreeModification extends AbstractCursorAware implements CursorAwareDataTreeModification {
private static final AtomicIntegerFieldUpdater<InMemoryDataTreeModification> SEALED_UPDATER =
AtomicIntegerFieldUpdater.newUpdater(InMemoryDataTreeModification.class, "sealed");
private static final Logger LOG = LoggerFactory.getLogger(InMemoryDataTreeModification.class);
private final RootModificationApplyOperation strategyTree;
private final InMemoryDataTreeSnapshot snapshot;
private final ModifiedNode rootNode;
private final Version version;
private volatile int sealed = 0;
InMemoryDataTreeModification(final InMemoryDataTreeSnapshot snapshot,
final RootModificationApplyOperation resolver) {
this.snapshot = Preconditions.checkNotNull(snapshot);
this.strategyTree = Preconditions.checkNotNull(resolver).snapshot();
this.rootNode = ModifiedNode.createUnmodified(snapshot.getRootNode(), strategyTree.getChildPolicy());
/*
* We could allocate version beforehand, since Version contract
* states two allocated version must be always different.
*
* Preallocating version simplifies scenarios such as
* chaining of modifications, since version for particular
* node in modification and in data tree (if successfully
* committed) will be same and will not change.
*/
this.version = snapshot.getRootNode().getSubtreeVersion().next();
}
ModifiedNode getRootModification() {
return rootNode;
}
ModificationApplyOperation getStrategy() {
return strategyTree;
}
@Override
public void write(final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
checkSealed();
checkIdentifierReferencesData(path, data);
resolveModificationFor(path).write(data);
}
@Override
public void merge(final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
checkSealed();
checkIdentifierReferencesData(path, data);
resolveModificationFor(path).merge(data, version);
}
@Override
public void delete(final YangInstanceIdentifier path) {
checkSealed();
resolveModificationFor(path).delete();
}
@Override
public Optional<NormalizedNode<?, ?>> readNode(final YangInstanceIdentifier path) {
/*
* Walk the tree from the top, looking for the first node between root and
* the requested path which has been modified. If no such node exists,
* we use the node itself.
*/
final Entry<YangInstanceIdentifier, ModifiedNode> entry = StoreTreeNodes.findClosestsOrFirstMatch(rootNode,
path, ModifiedNode.IS_TERMINAL_PREDICATE);
final YangInstanceIdentifier key = entry.getKey();
final ModifiedNode mod = entry.getValue();
final Optional<TreeNode> result = resolveSnapshot(key, mod);
if (result.isPresent()) {
final NormalizedNode<?, ?> data = result.get().getData();
return NormalizedNodes.findNode(key, data, path);
}
return Optional.absent();
}
private Optional<TreeNode> resolveSnapshot(final YangInstanceIdentifier path, final ModifiedNode modification) {
final Optional<TreeNode> potentialSnapshot = modification.getSnapshot();
if (potentialSnapshot != null) {
return potentialSnapshot;
}
try {
return resolveModificationStrategy(path).apply(modification, modification.getOriginal(), version);
} catch (final Exception e) {
LOG.error("Could not create snapshot for {}:{}", path, modification, e);
throw e;
}
}
void upgradeIfPossible() {
if (rootNode.getOperation() == LogicalOperation.NONE) {
strategyTree.upgradeIfPossible();
}
}
private ModificationApplyOperation resolveModificationStrategy(final YangInstanceIdentifier path) {
LOG.trace("Resolving modification apply strategy for {}", path);
upgradeIfPossible();
return StoreTreeNodes.findNodeChecked(strategyTree, path);
}
private OperationWithModification resolveModificationFor(final YangInstanceIdentifier path) {
upgradeIfPossible();
/*
* Walk the strategy and modification trees in-sync, creating modification nodes as needed.
*
* If the user has provided wrong input, we may end up with a bunch of TOUCH nodes present
* ending with an empty one, as we will throw the exception below. This fact could end up
* being a problem, as we'd have bunch of phantom operations.
*
* That is fine, as we will prune any empty TOUCH nodes in the last phase of the ready
* process.
*/
ModificationApplyOperation operation = strategyTree;
ModifiedNode modification = rootNode;
int i = 1;
for (final PathArgument pathArg : path.getPathArguments()) {
final Optional<ModificationApplyOperation> potential = operation.getChild(pathArg);
if (!potential.isPresent()) {
throw new SchemaValidationFailedException(String.format("Child %s is not present in schema tree.",
path.getAncestor(i)));
}
operation = potential.get();
++i;
modification = modification.modifyChild(pathArg, operation, version);
}
return OperationWithModification.from(operation, modification);
}
private void checkSealed() {
Preconditions.checkState(sealed == 0, "Data Tree is sealed. No further modifications allowed.");
}
@Override
public String toString() {
return "MutableDataTree [modification=" + rootNode + "]";
}
@Override
public InMemoryDataTreeModification newModification() {
Preconditions.checkState(sealed == 1, "Attempted to chain on an unsealed modification");
if (rootNode.getOperation() == LogicalOperation.NONE) {
// Simple fast case: just use the underlying modification
return snapshot.newModification();
}
/*
* We will use preallocated version, this means returned snapshot will
* have same version each time this method is called.
*/
final TreeNode originalSnapshotRoot = snapshot.getRootNode();
final Optional<TreeNode> tempRoot = strategyTree.apply(rootNode, Optional.of(originalSnapshotRoot), version);
Preconditions.checkState(tempRoot.isPresent(),
"Data tree root is not present, possibly removed by previous modification");
final InMemoryDataTreeSnapshot tempTree = new InMemoryDataTreeSnapshot(snapshot.getSchemaContext(),
tempRoot.get(), strategyTree);
return tempTree.newModification();
}
Version getVersion() {
return version;
}
boolean isSealed() {
return sealed == 1;
}
private static void applyChildren(final DataTreeModificationCursor cursor, final ModifiedNode node) {
final Collection<ModifiedNode> children = node.getChildren();
if (!children.isEmpty()) {
cursor.enter(node.getIdentifier());
for (final ModifiedNode child : children) {
applyNode(cursor, child);
}
cursor.exit();
}
}
private static void applyNode(final DataTreeModificationCursor cursor, final ModifiedNode node) {
switch (node.getOperation()) {
case NONE:
break;
case DELETE:
cursor.delete(node.getIdentifier());
break;
case MERGE:
cursor.merge(node.getIdentifier(), node.getWrittenValue());
applyChildren(cursor, node);
break;
case TOUCH:
// TODO: we could improve efficiency of cursor use if we could understand
// nested TOUCH operations. One way of achieving that would be a proxy
// cursor, which would keep track of consecutive enter and exit calls
// and coalesce them.
applyChildren(cursor, node);
break;
case WRITE:
cursor.write(node.getIdentifier(), node.getWrittenValue());
applyChildren(cursor, node);
break;
default:
throw new IllegalArgumentException("Unhandled node operation " + node.getOperation());
}
}
@Override
public void applyToCursor(@Nonnull final DataTreeModificationCursor cursor) {
for (final ModifiedNode child : rootNode.getChildren()) {
applyNode(cursor, child);
}
}
static void checkIdentifierReferencesData(final PathArgument arg, final NormalizedNode<?, ?> data) {
Preconditions.checkArgument(arg.equals(data.getIdentifier()),
"Instance identifier references %s but data identifier is %s", arg, data.getIdentifier());
}
private void checkIdentifierReferencesData(final YangInstanceIdentifier path,
final NormalizedNode<?, ?> data) {
final PathArgument arg;
if (!path.isEmpty()) {
arg = path.getLastPathArgument();
Preconditions.checkArgument(arg != null, "Instance identifier %s has invalid null path argument", path);
} else {
arg = rootNode.getIdentifier();
}
checkIdentifierReferencesData(arg, data);
}
@Override
public DataTreeModificationCursor createCursor(@Nonnull final YangInstanceIdentifier path) {
final OperationWithModification op = resolveModificationFor(path);
return openCursor(new InMemoryDataTreeModificationCursor(this, path, op));
}
@Override
public void ready() {
final boolean wasRunning = SEALED_UPDATER.compareAndSet(this, 0, 1);
Preconditions.checkState(wasRunning, "Attempted to seal an already-sealed Data Tree.");
AbstractReadyIterator current = AbstractReadyIterator.create(rootNode, strategyTree);
do {
current = current.process(version);
} while (current != null);
}
}