1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 20:27:45 +00:00

LibWeb: Add support for DOM's TreeWalker

This patch adds TreeWalker (created via Document.createTreeWalker())
which allows you to traverse a filtered view of the DOM in all
directions.
This commit is contained in:
Andreas Kling 2022-03-09 14:37:48 +01:00
parent fabcee016f
commit acbdb95b0a
9 changed files with 487 additions and 0 deletions

View file

@ -302,6 +302,8 @@
#include <LibWeb/Bindings/TextMetricsConstructor.h>
#include <LibWeb/Bindings/TextMetricsPrototype.h>
#include <LibWeb/Bindings/TextPrototype.h>
#include <LibWeb/Bindings/TreeWalkerConstructor.h>
#include <LibWeb/Bindings/TreeWalkerPrototype.h>
#include <LibWeb/Bindings/UIEventConstructor.h>
#include <LibWeb/Bindings/UIEventPrototype.h>
#include <LibWeb/Bindings/URLConstructor.h>
@ -475,6 +477,7 @@
ADD_WINDOW_OBJECT_INTERFACE(TextDecoder) \
ADD_WINDOW_OBJECT_INTERFACE(TextEncoder) \
ADD_WINDOW_OBJECT_INTERFACE(TextMetrics) \
ADD_WINDOW_OBJECT_INTERFACE(TreeWalker) \
ADD_WINDOW_OBJECT_INTERFACE(UIEvent) \
ADD_WINDOW_OBJECT_INTERFACE(URLSearchParams) \
ADD_WINDOW_OBJECT_INTERFACE(URL) \

View file

@ -100,6 +100,7 @@ set(SOURCES
DOM/StaticRange.cpp
DOM/Text.cpp
DOM/Text.idl
DOM/TreeWalker.cpp
DOMParsing/InnerHTML.cpp
DOMTreeModel.cpp
Dump.cpp
@ -444,6 +445,7 @@ libweb_js_wrapper(DOM/Range)
libweb_js_wrapper(DOM/ShadowRoot)
libweb_js_wrapper(DOM/StaticRange)
libweb_js_wrapper(DOM/Text)
libweb_js_wrapper(DOM/TreeWalker)
libweb_js_wrapper(Encoding/TextDecoder)
libweb_js_wrapper(Encoding/TextEncoder)
libweb_js_wrapper(Geometry/DOMRect)

View file

@ -35,6 +35,7 @@
#include <LibWeb/DOM/Range.h>
#include <LibWeb/DOM/ShadowRoot.h>
#include <LibWeb/DOM/Text.h>
#include <LibWeb/DOM/TreeWalker.h>
#include <LibWeb/Dump.h>
#include <LibWeb/HTML/AttributeNames.h>
#include <LibWeb/HTML/BrowsingContext.h>
@ -1467,4 +1468,10 @@ NonnullRefPtr<NodeIterator> Document::create_node_iterator(Node& root, unsigned
return NodeIterator::create(root, what_to_show, move(filter));
}
// https://dom.spec.whatwg.org/#dom-document-createtreewalker
NonnullRefPtr<TreeWalker> Document::create_tree_walker(Node& root, unsigned what_to_show, RefPtr<NodeFilter> filter)
{
return TreeWalker::create(root, what_to_show, move(filter));
}
}

View file

@ -325,6 +325,7 @@ public:
static ExceptionOr<PrefixAndTagName> validate_qualified_name(String const& qualified_name);
NonnullRefPtr<NodeIterator> create_node_iterator(Node& root, unsigned what_to_show, RefPtr<NodeFilter>);
NonnullRefPtr<TreeWalker> create_tree_walker(Node& root, unsigned what_to_show, RefPtr<NodeFilter>);
private:
explicit Document(const AK::URL&);

View file

@ -12,6 +12,7 @@
#import <DOM/NodeList.idl>
#import <DOM/Range.idl>
#import <DOM/Text.idl>
#import <DOM/TreeWalker.idl>
#import <HTML/HTMLElement.idl>
#import <HTML/HTMLHeadElement.idl>
#import <HTML/HTMLScriptElement.idl>
@ -176,5 +177,6 @@ interface Document : Node {
readonly DOMString visibilityState;
[NewObject] NodeIterator createNodeIterator(Node root, optional unsigned long whatToShow = 0xFFFFFFFF, optional NodeFilter? filter = null);
[NewObject] TreeWalker createTreeWalker(Node root, optional unsigned long whatToShow = 0xFFFFFFFF, optional NodeFilter? filter = null);
};

View file

@ -0,0 +1,375 @@
/*
* Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibWeb/Bindings/DOMExceptionWrapper.h>
#include <LibWeb/Bindings/IDLAbstractOperations.h>
#include <LibWeb/Bindings/NodeWrapper.h>
#include <LibWeb/Bindings/NodeWrapperFactory.h>
#include <LibWeb/Bindings/Wrapper.h>
#include <LibWeb/DOM/DOMException.h>
#include <LibWeb/DOM/Node.h>
#include <LibWeb/DOM/NodeFilter.h>
#include <LibWeb/DOM/TreeWalker.h>
namespace Web::DOM {
TreeWalker::TreeWalker(Node& root)
: m_root(root)
, m_current(root)
{
}
TreeWalker::~TreeWalker()
{
}
// https://dom.spec.whatwg.org/#dom-document-createtreewalker
NonnullRefPtr<TreeWalker> TreeWalker::create(Node& root, unsigned what_to_show, RefPtr<NodeFilter> filter)
{
// 1. Let walker be a new TreeWalker object.
// 2. Set walkers root and walkers current to root.
auto walker = adopt_ref(*new TreeWalker(root));
// 3. Set walkers whatToShow to whatToShow.
walker->m_what_to_show = what_to_show;
// 4. Set walkers filter to filter.
walker->m_filter = move(filter);
// 5. Return walker.
return walker;
}
// https://dom.spec.whatwg.org/#dom-treewalker-currentnode
NonnullRefPtr<Node> TreeWalker::current_node() const
{
return *m_current;
}
// https://dom.spec.whatwg.org/#dom-treewalker-currentnode
void TreeWalker::set_current_node(Node& node)
{
m_current = node;
}
// https://dom.spec.whatwg.org/#dom-treewalker-parentnode
JS::ThrowCompletionOr<RefPtr<Node>> TreeWalker::parent_node()
{
// 1. Let node be thiss current.
RefPtr<Node> node = m_current;
// 2. While node is non-null and is not thiss root:
while (node && node != m_root) {
// 1. Set node to nodes parent.
node = node->parent();
// 2. If node is non-null and filtering node within this returns FILTER_ACCEPT,
// then set thiss current to node and return node.
if (node) {
auto result = filter(*node);
if (result.is_throw_completion())
return result.release_error();
if (result.value() == NodeFilter::FILTER_ACCEPT) {
m_current = *node;
return node;
}
}
}
return RefPtr<Node> {};
}
// https://dom.spec.whatwg.org/#dom-treewalker-firstchild
JS::ThrowCompletionOr<RefPtr<Node>> TreeWalker::first_child()
{
return traverse_children(ChildTraversalType::First);
}
// https://dom.spec.whatwg.org/#dom-treewalker-lastchild
JS::ThrowCompletionOr<RefPtr<Node>> TreeWalker::last_child()
{
return traverse_children(ChildTraversalType::Last);
}
// https://dom.spec.whatwg.org/#dom-treewalker-previoussibling
JS::ThrowCompletionOr<RefPtr<Node>> TreeWalker::previous_sibling()
{
return traverse_siblings(SiblingTraversalType::Previous);
}
// https://dom.spec.whatwg.org/#dom-treewalker-nextsibling
JS::ThrowCompletionOr<RefPtr<Node>> TreeWalker::next_sibling()
{
return traverse_siblings(SiblingTraversalType::Next);
}
// https://dom.spec.whatwg.org/#dom-treewalker-previousnode
JS::ThrowCompletionOr<RefPtr<Node>> TreeWalker::previous_node()
{
// 1. Let node be thiss current.
RefPtr<Node> node = m_current;
// 2. While node is not thiss root:
while (node != m_root) {
// 1. Let sibling be nodes previous sibling.
RefPtr<Node> sibling = node->previous_sibling();
// 2. While sibling is non-null:
while (sibling) {
// 1. Set node to sibling.
node = sibling;
// 2. Let result be the result of filtering node within this.
auto result = TRY(filter(*node));
// 3. While result is not FILTER_REJECT and node has a child:
while (result != NodeFilter::FILTER_REJECT && node->has_children()) {
// 1. Set node to nodes last child.
node = node->last_child();
// 2. Set result to the result of filtering node within this.
result = TRY(filter(*node));
}
// 4. If result is FILTER_ACCEPT, then set thiss current to node and return node.
if (result == NodeFilter::FILTER_ACCEPT) {
m_current = *node;
return node;
}
// 5. Set sibling to nodes previous sibling.
sibling = node->previous_sibling();
}
// 3. If node is thiss root or nodes parent is null, then return null.
if (node == m_root || !node->parent())
return nullptr;
// 4. Set node to nodes parent.
node = node->parent();
// 5. If the return value of filtering node within this is FILTER_ACCEPT, then set thiss current to node and return node.
if (TRY(filter(*node)) == NodeFilter::FILTER_ACCEPT) {
m_current = *node;
return node;
}
}
// 3. Return null.
return nullptr;
}
// https://dom.spec.whatwg.org/#dom-treewalker-nextnode
JS::ThrowCompletionOr<RefPtr<Node>> TreeWalker::next_node()
{
// 1. Let node be thiss current.
RefPtr<Node> node = m_current;
// 2. Let result be FILTER_ACCEPT.
auto result = NodeFilter::FILTER_ACCEPT;
// 3. While true:
while (true) {
// 1. While result is not FILTER_REJECT and node has a child:
while (result != NodeFilter::FILTER_REJECT && node->has_children()) {
// 1. Set node to its first child.
node = node->first_child();
// 2. Set result to the result of filtering node within this.
auto result = TRY(filter(*node));
// 3. If result is FILTER_ACCEPT, then set thiss current to node and return node.
if (result == NodeFilter::FILTER_ACCEPT) {
m_current = *node;
return node;
}
}
// 2. Let sibling be null.
RefPtr<Node> sibling = nullptr;
// 3. Let temporary be node.
RefPtr<Node> temporary = node;
// 4. While temporary is non-null:
while (temporary) {
// 1. If temporary is thiss root, then return null.
if (temporary == m_root)
return nullptr;
// 2. Set sibling to temporarys next sibling.
sibling = temporary->next_sibling();
// 3. If sibling is non-null, then set node to sibling and break.
if (sibling) {
node = sibling;
break;
}
// 4. Set temporary to temporarys parent.
temporary = temporary->parent();
}
// 5. Set result to the result of filtering node within this.
result = TRY(filter(*node));
// 6. If result is FILTER_ACCEPT, then set thiss current to node and return node.
if (result == NodeFilter::FILTER_ACCEPT) {
m_current = *node;
return node;
}
}
}
// https://dom.spec.whatwg.org/#concept-node-filter
JS::ThrowCompletionOr<NodeFilter::Result> TreeWalker::filter(Node& node)
{
VERIFY(wrapper());
auto& global_object = wrapper()->global_object();
// 1. If traversers active flag is set, then throw an "InvalidStateError" DOMException.
if (m_active)
return JS::throw_completion(wrap(global_object, InvalidStateError::create("NodeIterator is already active")));
// 2. Let n be nodes nodeType attribute value 1.
auto n = node.node_type() - 1;
// 3. If the nth bit (where 0 is the least significant bit) of traversers whatToShow is not set, then return FILTER_SKIP.
if (!(m_what_to_show & (1u << n)))
return NodeFilter::FILTER_SKIP;
// 4. If traversers filter is null, then return FILTER_ACCEPT.
if (!m_filter)
return NodeFilter::FILTER_ACCEPT;
// 5. Set traversers active flag.
m_active = true;
// 6. Let result be the return value of call a user objects operation with traversers filter, "acceptNode", and « node ».
// If this throws an exception, then unset traversers active flag and rethrow the exception.
auto result = Bindings::IDL::call_user_object_operation(m_filter->callback(), "acceptNode", {}, wrap(global_object, node));
if (result.is_abrupt()) {
m_active = false;
return result;
}
// 7. Unset traversers active flag.
m_active = false;
// 8. Return result.
auto result_value = TRY(result.value()->to_i32(global_object));
return static_cast<NodeFilter::Result>(result_value);
}
// https://dom.spec.whatwg.org/#concept-traverse-children
JS::ThrowCompletionOr<RefPtr<Node>> TreeWalker::traverse_children(ChildTraversalType type)
{
// 1. Let node be walkers current.
RefPtr<Node> node = m_current;
// 2. Set node to nodes first child if type is first, and nodes last child if type is last.
node = type == ChildTraversalType::First ? node->first_child() : node->last_child();
// 3. While node is non-null:
while (node) {
// 1. Let result be the result of filtering node within walker.
auto result = TRY(filter(*node));
// 2. If result is FILTER_ACCEPT, then set walkers current to node and return node.
if (result == NodeFilter::FILTER_ACCEPT) {
m_current = *node;
return node;
}
// 3. If result is FILTER_SKIP, then:
if (result == NodeFilter::FILTER_SKIP) {
// 1. Let child be nodes first child if type is first, and nodes last child if type is last.
RefPtr<Node> child = type == ChildTraversalType::First ? node->first_child() : node->last_child();
// 2. If child is non-null, then set node to child and continue.
if (child) {
node = child.release_nonnull();
continue;
}
}
// 4. While node is non-null:
while (node) {
// 1. Let sibling be nodes next sibling if type is first, and nodes previous sibling if type is last.
RefPtr<Node> sibling = type == ChildTraversalType::First ? node->next_sibling() : node->previous_sibling();
// 2. If sibling is non-null, then set node to sibling and break.
if (sibling) {
node = sibling.release_nonnull();
break;
}
// 3. Let parent be nodes parent.
RefPtr<Node> parent = node->parent();
// 4. If parent is null, walkers root, or walkers current, then return null.
if (!parent || parent == m_root || parent == m_current)
return nullptr;
// 5. Set node to parent.
node = parent.release_nonnull();
}
}
// 4. Return null.
return nullptr;
}
// https://dom.spec.whatwg.org/#concept-traverse-siblings
JS::ThrowCompletionOr<RefPtr<Node>> TreeWalker::traverse_siblings(SiblingTraversalType type)
{
// 1. Let node be walkers current.
RefPtr<Node> node = m_current;
// 2. If node is root, then return null.
if (node == m_root)
return nullptr;
// 3. While true:
while (true) {
// 1. Let sibling be nodes next sibling if type is next, and nodes previous sibling if type is previous.
RefPtr<Node> sibling = type == SiblingTraversalType::Next ? node->next_sibling() : node->previous_sibling();
// 2. While sibling is non-null:
while (sibling) {
// 1. Set node to sibling.
node = sibling;
// 2. Let result be the result of filtering node within walker.
auto result = TRY(filter(*node));
// 3. If result is FILTER_ACCEPT, then set walkers current to node and return node.
if (result == NodeFilter::FILTER_ACCEPT) {
m_current = *node;
return node;
}
// 4. Set sibling to nodes first child if type is next, and nodes last child if type is previous.
sibling = type == SiblingTraversalType::Next ? node->first_child() : node->last_child();
// 5. If result is FILTER_REJECT or sibling is null, then set sibling to nodes next sibling if type is next, and nodes previous sibling if type is previous.
if (result == NodeFilter::FILTER_REJECT || !sibling)
sibling = type == SiblingTraversalType::Next ? node->next_sibling() : node->previous_sibling();
}
// 3. Set node to nodes parent.
node = node->parent();
// 4. If node is null or walkers root, then return null.
if (!node || node == m_root)
return nullptr;
// 5. If the return value of filtering node within walker is FILTER_ACCEPT, then return null.
if (TRY(filter(*node)) == NodeFilter::FILTER_ACCEPT)
return nullptr;
}
}
}

View file

@ -0,0 +1,75 @@
/*
* Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/RefCounted.h>
#include <LibWeb/Bindings/Wrappable.h>
#include <LibWeb/DOM/NodeFilter.h>
namespace Web::DOM {
// https://dom.spec.whatwg.org/#treewalker
class TreeWalker
: public RefCounted<TreeWalker>
, public Bindings::Wrappable {
public:
using WrapperType = Bindings::TreeWalkerWrapper;
static NonnullRefPtr<TreeWalker> create(Node& root, unsigned what_to_show, RefPtr<NodeFilter>);
virtual ~TreeWalker() override;
NonnullRefPtr<Node> current_node() const;
void set_current_node(Node&);
JS::ThrowCompletionOr<RefPtr<Node>> parent_node();
JS::ThrowCompletionOr<RefPtr<Node>> first_child();
JS::ThrowCompletionOr<RefPtr<Node>> last_child();
JS::ThrowCompletionOr<RefPtr<Node>> previous_sibling();
JS::ThrowCompletionOr<RefPtr<Node>> next_sibling();
JS::ThrowCompletionOr<RefPtr<Node>> previous_node();
JS::ThrowCompletionOr<RefPtr<Node>> next_node();
NonnullRefPtr<Node> root() { return m_root; }
NodeFilter* filter() { return m_filter; }
unsigned what_to_show() const { return m_what_to_show; }
private:
TreeWalker(Node& root);
enum class ChildTraversalType {
First,
Last,
};
JS::ThrowCompletionOr<RefPtr<Node>> traverse_children(ChildTraversalType);
enum class SiblingTraversalType {
Next,
Previous,
};
JS::ThrowCompletionOr<RefPtr<Node>> traverse_siblings(SiblingTraversalType);
JS::ThrowCompletionOr<NodeFilter::Result> filter(Node&);
// https://dom.spec.whatwg.org/#concept-traversal-root
NonnullRefPtr<DOM::Node> m_root;
// https://dom.spec.whatwg.org/#treewalker-current
NonnullRefPtr<DOM::Node> m_current;
// https://dom.spec.whatwg.org/#concept-traversal-whattoshow
unsigned m_what_to_show { 0 };
// https://dom.spec.whatwg.org/#concept-traversal-filter
RefPtr<DOM::NodeFilter> m_filter;
// https://dom.spec.whatwg.org/#concept-traversal-active
bool m_active { false };
};
}

View file

@ -0,0 +1,20 @@
#import <DOM/Node.idl>
#import <DOM/NodeFilter.idl>
[Exposed=Window]
interface TreeWalker {
[SameObject] readonly attribute Node root;
readonly attribute unsigned long whatToShow;
readonly attribute NodeFilter? filter;
attribute Node currentNode;
Node? parentNode();
Node? firstChild();
Node? lastChild();
Node? previousSibling();
Node? nextSibling();
Node? previousNode();
Node? nextNode();
};

View file

@ -121,6 +121,7 @@ class ShadowRoot;
class StaticNodeList;
class StaticRange;
class Text;
class TreeWalker;
enum class QuirksMode;
struct EventListenerOptions;
struct AddEventListenerOptions;
@ -508,6 +509,7 @@ class TextDecoderWrapper;
class TextEncoderWrapper;
class TextMetricsWrapper;
class TextWrapper;
class TreeWalkerWrapper;
class UIEventWrapper;
class URLConstructor;
class URLPrototype;