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/*
This file is part of the iText (R) project.
Copyright (c) 1998-2023 Apryse Group NV
Authors: Apryse Software.
This program is offered under a commercial and under the AGPL license.
For commercial licensing, contact us at https://itextpdf.com/sales. For AGPL licensing, see below.
AGPL licensing:
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see
* This implementation does not use recursion, so a deep DOM does not risk blowing the stack.
*/
public class NodeTraversor {
/**
* Start a depth-first traverse of the root and all of its descendants.
* @param visitor Node visitor.
* @param root the root node point to traverse.
*/
public static void traverse(NodeVisitor visitor, Node root) {
Node node = root;
Node parent; // remember parent to find nodes that get replaced in .head
int depth = 0;
while (node != null) {
parent = node.parentNode();
visitor.head(node, depth); // visit current node
if (parent != null && !node.hasParent()) // must have been replaced; find replacement
node = parent.childNode(node.siblingIndex()); // replace ditches parent but keeps sibling index
if (node.childNodeSize() > 0) { // descend
node = node.childNode(0);
depth++;
} else {
while (true) {
assert node != null; // as depth > 0, will have parent
if (!(node.nextSibling() == null && depth > 0)) break;
visitor.tail(node, depth); // when no more siblings, ascend
node = node.parentNode();
depth--;
}
visitor.tail(node, depth);
if (node == root)
break;
node = node.nextSibling();
}
}
}
/**
* Start a depth-first traverse of all elements.
* @param visitor Node visitor.
* @param elements Elements to filter.
*/
public static void traverse(NodeVisitor visitor, Elements elements) {
Validate.notNull(visitor);
Validate.notNull(elements);
for (Element el : elements)
traverse(visitor, el);
}
/**
* Start a depth-first filtering of the root and all of its descendants.
* @param filter Node visitor.
* @param root the root node point to traverse.
* @return The filter result of the root node, or {@link FilterResult#STOP}.
*/
public static FilterResult filter(NodeFilter filter, Node root) {
Node node = root;
int depth = 0;
while (node != null) {
FilterResult result = filter.head(node, depth);
if (result == FilterResult.STOP)
return result;
// Descend into child nodes:
if (result == FilterResult.CONTINUE && node.childNodeSize() > 0) {
node = node.childNode(0);
++depth;
continue;
}
// No siblings, move upwards:
while (true) {
assert node != null; // depth > 0, so has parent
if (!(node.nextSibling() == null && depth > 0)) break;
// 'tail' current node:
if (result == FilterResult.CONTINUE || result == FilterResult.SKIP_CHILDREN) {
result = filter.tail(node, depth);
if (result == FilterResult.STOP)
return result;
}
Node prev = node; // In case we need to remove it below.
node = node.parentNode();
depth--;
if (result == FilterResult.REMOVE)
prev.remove(); // Remove AFTER finding parent.
result = FilterResult.CONTINUE; // Parent was not pruned.
}
// 'tail' current node, then proceed with siblings:
if (result == FilterResult.CONTINUE || result == FilterResult.SKIP_CHILDREN) {
result = filter.tail(node, depth);
if (result == FilterResult.STOP)
return result;
}
if (node == root)
return result;
Node prev = node; // In case we need to remove it below.
node = node.nextSibling();
if (result == FilterResult.REMOVE)
prev.remove(); // Remove AFTER finding sibling.
}
// root == null?
return FilterResult.CONTINUE;
}
/**
* Start a depth-first filtering of all elements.
* @param filter Node filter.
* @param elements Elements to filter.
*/
public static void filter(NodeFilter filter, Elements elements) {
Validate.notNull(filter);
Validate.notNull(elements);
for (Element el : elements)
if (filter(filter, el) == FilterResult.STOP)
break;
}
}