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Swirlds is a software platform designed to build fully-distributed applications that harness the power of the cloud without servers. Now you can develop applications with fairness in decision making, speed, trust and reliability, at a fraction of the cost of traditional server-based platforms.
/*
* Copyright (C) 2022-2024 Hedera Hashgraph, LLC
*
* 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 com.swirlds.common.io.streams.internal;
import static com.swirlds.common.io.streams.SerializableStreamConstants.NULL_CLASS_ID;
import java.util.Deque;
import java.util.LinkedList;
/**
* An element on a serialization debug stack.
*/
public class SerializationStackElement {
public static final int MAX_CHILD_COUNT = 10;
public static final int SECOND_TO_LAST_MAX_CHILD_COUNT = 5;
private static final int MAX_STRING_REPRESENTATION_LENGTH = 30;
private static final String INDENT = " ";
private final SerializationOperation operation;
private final StackTraceElement callLocation;
private Long classId;
private Class clazz;
private String stringRepresentation;
private final Deque children = new LinkedList<>();
private SerializationStackElement secondToLastChild;
private long currentChildCount;
private long totalChildCount;
/**
* Create a new serialization element for the debug stack.
*
* @param operation
* the operation being performed
*/
public SerializationStackElement(final SerializationOperation operation, final StackTraceElement callLocation) {
this.operation = operation;
this.callLocation = callLocation;
}
/**
* Get the operation for this element.
*/
public SerializationOperation getOperation() {
return operation;
}
/**
* Add a child operation.
*
* @param child
* the child operation
*/
public void addChild(final SerializationStackElement child) {
// Only the last two children are permitted to have children of their own.
final SerializationStackElement newThirdToLastChild = secondToLastChild;
if (newThirdToLastChild != null) {
newThirdToLastChild.children.clear();
newThirdToLastChild.currentChildCount = 0;
}
// The second to last child is permitted to have a limited number of children of its own.
if (currentChildCount > 0) {
final SerializationStackElement newSecondToLastChild = children.getLast();
newSecondToLastChild.reduceChildCount(SECOND_TO_LAST_MAX_CHILD_COUNT);
// Only the last child of the second to last child is permitted to have children.
if (newSecondToLastChild.secondToLastChild != null) {
newSecondToLastChild.secondToLastChild.children.clear();
newSecondToLastChild.secondToLastChild.currentChildCount = 0;
}
secondToLastChild = newSecondToLastChild;
}
currentChildCount++;
totalChildCount++;
children.addLast(child);
reduceChildCount(MAX_CHILD_COUNT);
}
/**
* Set the class ID of the element if it becomes known
*
* @param classId
* the class ID of the element
*/
public void setClassId(final long classId) {
this.classId = classId;
}
/**
* Set the class of the element if it becomes known
*
* @param clazz
* the class of the element
*/
public void setClass(final Class clazz) {
this.clazz = clazz;
}
/**
* Set a string that represents the value. Should only be set with very short strings.
*
* @param stringRepresentation
* the string representation of the value
*/
public void setStringRepresentation(final String stringRepresentation) {
if (stringRepresentation.length() > MAX_STRING_REPRESENTATION_LENGTH) {
this.stringRepresentation = stringRepresentation.substring(0, MAX_STRING_REPRESENTATION_LENGTH) + "...";
} else {
this.stringRepresentation = stringRepresentation;
}
}
/**
* Reduce the child count by dropping children. Earlier children are dropped before later children.
*/
private void reduceChildCount(final int maxChildCount) {
while (currentChildCount > maxChildCount) {
children.removeFirst();
currentChildCount--;
}
}
/**
* Write this element to a deserialization stack trace.
*
* @param sb
* a string builder where the stack trace is being written
* @param indent
* the indentation level of this element
*/
public void writeStackTrace(final StringBuilder sb, final int indent) {
sb.append(INDENT.repeat(indent));
sb.append(operation.name());
if (stringRepresentation != null) {
sb.append(" [value=").append(stringRepresentation).append("]");
}
if (clazz != null) {
sb.append(" ").append(clazz.getSimpleName());
} else if (classId != null) {
if (classId == NULL_CLASS_ID) {
sb.append(" NULL");
} else {
sb.append(String.format(" class ID = %d(0x%08X)", classId, classId));
}
}
sb.append(" @ ").append(callLocation.getFileName()).append(":").append(callLocation.getLineNumber());
sb.append("\n");
final int childIndent = indent + 1;
final long undisplayed = totalChildCount - currentChildCount;
if (undisplayed > 0) {
sb.append(INDENT.repeat(childIndent));
sb.append("(").append(undisplayed).append(" hidden)\n");
}
for (final SerializationStackElement child : children) {
child.writeStackTrace(sb, childIndent);
}
}
/**
* Get the location where this operation was invoked.
*/
public StackTraceElement getCallLocation() {
return callLocation;
}
/**
* Get the class ID of this object, if it is known. Some elements (e.g. primitives) will not have a class ID.
*/
public Long getClassId() {
return classId;
}
/**
* Get the class of this object, if it is knwon. Some elements (e.g. primitives) will not have a class set.
*/
public Class getClazz() {
return clazz;
}
/**
* Get the string representation of this object. Not all objects will have a string representation.
*/
public String getStringRepresentation() {
return stringRepresentation;
}
/**
* Get the children belonging to this object, if it has any.
*/
public Deque getChildren() {
return children;
}
/**
* Get the current (un-purged) child count of this object.
*/
public long getCurrentChildCount() {
return currentChildCount;
}
/**
* Get the total child count of this object, including purged children.
*/
public long getTotalChildCount() {
return totalChildCount;
}
/**
* {@inheritDoc}
*/
@Override
public String toString() {
final StringBuilder sb = new StringBuilder();
writeStackTrace(sb, 0);
return sb.toString();
}
}