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Easy Redis Java client and Real-Time Data Platform. Valkey compatible. Sync/Async/RxJava3/Reactive API. Client side caching. Over 50 Redis based Java objects and services: JCache API, Apache Tomcat, Hibernate, Spring, Set, Multimap, SortedSet, Map, List, Queue, Deque, Semaphore, Lock, AtomicLong, Map Reduce, Bloom filter, Scheduler, RPC
/**
* Copyright (c) 2008, SnakeYAML
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package org.yaml.snakeyaml.composer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.yaml.snakeyaml.DumperOptions.FlowStyle;
import org.yaml.snakeyaml.LoaderOptions;
import org.yaml.snakeyaml.comments.CommentEventsCollector;
import org.yaml.snakeyaml.comments.CommentLine;
import org.yaml.snakeyaml.comments.CommentType;
import org.yaml.snakeyaml.error.Mark;
import org.yaml.snakeyaml.error.YAMLException;
import org.yaml.snakeyaml.events.AliasEvent;
import org.yaml.snakeyaml.events.Event;
import org.yaml.snakeyaml.events.MappingStartEvent;
import org.yaml.snakeyaml.events.NodeEvent;
import org.yaml.snakeyaml.events.ScalarEvent;
import org.yaml.snakeyaml.events.SequenceStartEvent;
import org.yaml.snakeyaml.nodes.MappingNode;
import org.yaml.snakeyaml.nodes.Node;
import org.yaml.snakeyaml.nodes.NodeId;
import org.yaml.snakeyaml.nodes.NodeTuple;
import org.yaml.snakeyaml.nodes.ScalarNode;
import org.yaml.snakeyaml.nodes.SequenceNode;
import org.yaml.snakeyaml.nodes.Tag;
import org.yaml.snakeyaml.parser.Parser;
import org.yaml.snakeyaml.resolver.Resolver;
/**
* Creates a node graph from parser events.
*
* Corresponds to the 'Compose' step as described in chapter 3.1 of the
* YAML Specification.
*
*/
public class Composer {
/**
* its parser
*/
protected final Parser parser;
private final Resolver resolver;
private final Map anchors;
private final Set recursiveNodes;
private int nonScalarAliasesCount = 0;
private final LoaderOptions loadingConfig;
private final CommentEventsCollector blockCommentsCollector;
private final CommentEventsCollector inlineCommentsCollector;
// keep the nesting of collections inside other collections
private int nestingDepth = 0;
private final int nestingDepthLimit;
/**
* Create
*
* @param parser - the parser
* @param resolver - the resolver
* @param loadingConfig - options
*/
public Composer(Parser parser, Resolver resolver, LoaderOptions loadingConfig) {
if (parser == null) {
throw new NullPointerException("Parser must be provided");
}
if (resolver == null) {
throw new NullPointerException("Resolver must be provided");
}
if (loadingConfig == null) {
throw new NullPointerException("LoaderOptions must be provided");
}
this.parser = parser;
this.resolver = resolver;
this.anchors = new HashMap();
this.recursiveNodes = new HashSet();
this.loadingConfig = loadingConfig;
this.blockCommentsCollector =
new CommentEventsCollector(parser, CommentType.BLANK_LINE, CommentType.BLOCK);
this.inlineCommentsCollector = new CommentEventsCollector(parser, CommentType.IN_LINE);
nestingDepthLimit = loadingConfig.getNestingDepthLimit();
}
/**
* Checks if further documents are available.
*
* @return true if there is at least one more document.
*/
public boolean checkNode() {
// Drop the STREAM-START event.
if (parser.checkEvent(Event.ID.StreamStart)) {
parser.getEvent();
}
// If there are more documents available?
return !parser.checkEvent(Event.ID.StreamEnd);
}
/**
* Reads and composes the next document.
*
* @return The root node of the document or null if no more documents are available.
*/
public Node getNode() {
// Collect inter-document start comments
blockCommentsCollector.collectEvents();
if (parser.checkEvent(Event.ID.StreamEnd)) {
List commentLines = blockCommentsCollector.consume();
Mark startMark = commentLines.get(0).getStartMark();
List children = Collections.emptyList();
Node node = new MappingNode(Tag.COMMENT, false, children, startMark, null, FlowStyle.BLOCK);
node.setBlockComments(commentLines);
return node;
}
// Drop the DOCUMENT-START event.
parser.getEvent();
// Compose the root node.
Node node = composeNode(null);
// Drop the DOCUMENT-END event.
blockCommentsCollector.collectEvents();
if (!blockCommentsCollector.isEmpty()) {
node.setEndComments(blockCommentsCollector.consume());
}
parser.getEvent();
this.anchors.clear();
this.recursiveNodes.clear();
return node;
}
/**
* Reads a document from a source that contains only one document.
*
* If the stream contains more than one document an exception is thrown.
*
*
* @return The root node of the document or null if no document is available.
*/
public Node getSingleNode() {
// Drop the STREAM-START event.
parser.getEvent();
// Compose a document if the stream is not empty.
Node document = null;
if (!parser.checkEvent(Event.ID.StreamEnd)) {
document = getNode();
}
// Ensure that the stream contains no more documents.
if (!parser.checkEvent(Event.ID.StreamEnd)) {
Event event = parser.getEvent();
Mark contextMark = document != null ? document.getStartMark() : null;
throw new ComposerException("expected a single document in the stream", contextMark,
"but found another document", event.getStartMark());
}
// Drop the STREAM-END event.
parser.getEvent();
return document;
}
private Node composeNode(Node parent) {
blockCommentsCollector.collectEvents();
if (parent != null) {
recursiveNodes.add(parent);
}
final Node node;
if (parser.checkEvent(Event.ID.Alias)) {
AliasEvent event = (AliasEvent) parser.getEvent();
String anchor = event.getAnchor();
if (!anchors.containsKey(anchor)) {
throw new ComposerException(null, null, "found undefined alias " + anchor,
event.getStartMark());
}
node = anchors.get(anchor);
if (!(node instanceof ScalarNode)) {
this.nonScalarAliasesCount++;
if (this.nonScalarAliasesCount > loadingConfig.getMaxAliasesForCollections()) {
throw new YAMLException(
"Number of aliases for non-scalar nodes exceeds the specified max="
+ loadingConfig.getMaxAliasesForCollections());
}
}
if (recursiveNodes.remove(node)) {
node.setTwoStepsConstruction(true);
}
// drop comments, they can not be supported here
blockCommentsCollector.consume();
inlineCommentsCollector.collectEvents().consume();
} else {
NodeEvent event = (NodeEvent) parser.peekEvent();
String anchor = event.getAnchor();
increaseNestingDepth();
// the check for duplicate anchors has been removed (issue 174)
if (parser.checkEvent(Event.ID.Scalar)) {
node = composeScalarNode(anchor, blockCommentsCollector.consume());
} else if (parser.checkEvent(Event.ID.SequenceStart)) {
node = composeSequenceNode(anchor);
} else {
node = composeMappingNode(anchor);
}
decreaseNestingDepth();
}
recursiveNodes.remove(parent);
return node;
}
protected Node composeScalarNode(String anchor, List blockComments) {
ScalarEvent ev = (ScalarEvent) parser.getEvent();
String tag = ev.getTag();
boolean resolved = false;
Tag nodeTag;
if (tag == null || tag.equals("!")) {
nodeTag = resolver.resolve(NodeId.scalar, ev.getValue(),
ev.getImplicit().canOmitTagInPlainScalar());
resolved = true;
} else {
nodeTag = new Tag(tag);
if (nodeTag.isCustomGlobal()
&& !loadingConfig.getTagInspector().isGlobalTagAllowed(nodeTag)) {
throw new ComposerException(null, null, "Global tag is not allowed: " + tag,
ev.getStartMark());
}
}
Node node = new ScalarNode(nodeTag, resolved, ev.getValue(), ev.getStartMark(), ev.getEndMark(),
ev.getScalarStyle());
if (anchor != null) {
node.setAnchor(anchor);
anchors.put(anchor, node);
}
node.setBlockComments(blockComments);
node.setInLineComments(inlineCommentsCollector.collectEvents().consume());
return node;
}
protected Node composeSequenceNode(String anchor) {
SequenceStartEvent startEvent = (SequenceStartEvent) parser.getEvent();
String tag = startEvent.getTag();
Tag nodeTag;
boolean resolved = false;
if (tag == null || tag.equals("!")) {
nodeTag = resolver.resolve(NodeId.sequence, null, startEvent.getImplicit());
resolved = true;
} else {
nodeTag = new Tag(tag);
if (nodeTag.isCustomGlobal()
&& !loadingConfig.getTagInspector().isGlobalTagAllowed(nodeTag)) {
throw new ComposerException(null, null, "Global tag is not allowed: " + tag,
startEvent.getStartMark());
}
}
final ArrayList children = new ArrayList();
SequenceNode node = new SequenceNode(nodeTag, resolved, children, startEvent.getStartMark(),
null, startEvent.getFlowStyle());
if (startEvent.isFlow()) {
node.setBlockComments(blockCommentsCollector.consume());
}
if (anchor != null) {
node.setAnchor(anchor);
anchors.put(anchor, node);
}
while (!parser.checkEvent(Event.ID.SequenceEnd)) {
blockCommentsCollector.collectEvents();
if (parser.checkEvent(Event.ID.SequenceEnd)) {
break;
}
children.add(composeNode(node));
}
if (startEvent.isFlow()) {
node.setInLineComments(inlineCommentsCollector.collectEvents().consume());
}
Event endEvent = parser.getEvent();
node.setEndMark(endEvent.getEndMark());
inlineCommentsCollector.collectEvents();
if (!inlineCommentsCollector.isEmpty()) {
node.setInLineComments(inlineCommentsCollector.consume());
}
return node;
}
protected Node composeMappingNode(String anchor) {
MappingStartEvent startEvent = (MappingStartEvent) parser.getEvent();
String tag = startEvent.getTag();
Tag nodeTag;
boolean resolved = false;
if (tag == null || tag.equals("!")) {
nodeTag = resolver.resolve(NodeId.mapping, null, startEvent.getImplicit());
resolved = true;
} else {
nodeTag = new Tag(tag);
if (nodeTag.isCustomGlobal()
&& !loadingConfig.getTagInspector().isGlobalTagAllowed(nodeTag)) {
throw new ComposerException(null, null, "Global tag is not allowed: " + tag,
startEvent.getStartMark());
}
}
final List children = new ArrayList();
MappingNode node = new MappingNode(nodeTag, resolved, children, startEvent.getStartMark(), null,
startEvent.getFlowStyle());
if (startEvent.isFlow()) {
node.setBlockComments(blockCommentsCollector.consume());
}
if (anchor != null) {
node.setAnchor(anchor);
anchors.put(anchor, node);
}
while (!parser.checkEvent(Event.ID.MappingEnd)) {
blockCommentsCollector.collectEvents();
if (parser.checkEvent(Event.ID.MappingEnd)) {
break;
}
composeMappingChildren(children, node);
}
if (startEvent.isFlow()) {
node.setInLineComments(inlineCommentsCollector.collectEvents().consume());
}
Event endEvent = parser.getEvent();
node.setEndMark(endEvent.getEndMark());
inlineCommentsCollector.collectEvents();
if (!inlineCommentsCollector.isEmpty()) {
node.setInLineComments(inlineCommentsCollector.consume());
}
return node;
}
/**
* Compose the members of mapping
*
* @param children - the data to fill
* @param node - the source
*/
protected void composeMappingChildren(List children, MappingNode node) {
Node itemKey = composeKeyNode(node);
if (itemKey.getTag().equals(Tag.MERGE)) {
node.setMerged(true);
}
Node itemValue = composeValueNode(node);
children.add(new NodeTuple(itemKey, itemValue));
}
/**
* To be able to override composeNode(node) which is a key
*
* @param node - the source
* @return node
*/
protected Node composeKeyNode(MappingNode node) {
return composeNode(node);
}
/**
* To be able to override composeNode(node) which is a value
*
* @param node - the source
* @return node
*/
protected Node composeValueNode(MappingNode node) {
return composeNode(node);
}
/**
* Increase nesting depth and fail when it exceeds the denied limit
*/
private void increaseNestingDepth() {
if (nestingDepth > nestingDepthLimit) {
throw new YAMLException("Nesting Depth exceeded max " + nestingDepthLimit);
}
nestingDepth++;
}
/**
* Indicate that the collection is finished and the nesting is decreased
*/
private void decreaseNestingDepth() {
if (nestingDepth > 0) {
nestingDepth--;
} else {
throw new YAMLException("Nesting Depth cannot be negative");
}
}
}
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