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LibHTML: Add Comment and CharacterData nodes and improve HTML parsing

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This patch adds the CharacterData subclass of Node, which is now the
parent class of Text and a new Comment class.

A Comment node is one of these in HTML: <!--hello friends-->
Since these occur somewhat frequently on the web, we need to be able
to parse them.

This patch also adds a child rejection mechanism to the DOM tree.
Nodes can now override is_child_allowed(Node) and return false if they
don't want a particular Node to become a child of theirs. This is used
to prevent Document from taking on unwanted children.
This commit is contained in:
Andreas Kling 2019-10-12 23:26:47 +02:00
parent 6d150df58a
commit b083a233d8
Notes: sideshowbarker 2024-07-19 11:43:21 +09:00
15 changed files with 158 additions and 25 deletions
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2
Base/home/anon/www/welcome.html
View file

@ -1,6 +1,8 @@
<!DOCTYPE html>
<html>
<head>
<title>Welcome!</title>
<!-- this is a comment -->
<style type="text/css">
body {
background-color: #fff;

11
Libraries/LibHTML/DOM/CharacterData.cpp Normal file
View file

@ -0,0 +1,11 @@
#include <LibHTML/DOM/CharacterData.h>
CharacterData::CharacterData(Document& document, NodeType type, const String& data)
: Node(document, type)
, m_data(data)
{
}
CharacterData::~CharacterData()
{
}

25
Libraries/LibHTML/DOM/CharacterData.h Normal file
View file

@ -0,0 +1,25 @@
#pragma once
#include <AK/String.h>
#include <LibHTML/DOM/Node.h>
class CharacterData : public Node {
public:
virtual ~CharacterData() override;
const String& data() const { return m_data; }
virtual String text_content() const override { return m_data; }
protected:
explicit CharacterData(Document&, NodeType, const String&);
private:
String m_data;
};
template<>
inline bool is<CharacterData>(const Node& node)
{
return node.is_character_data();
}

11
Libraries/LibHTML/DOM/Comment.cpp Normal file
View file

@ -0,0 +1,11 @@
#include <LibHTML/DOM/Comment.h>
#include <LibHTML/Layout/LayoutText.h>
Comment::Comment(Document& document, const String& data)
: CharacterData(document, NodeType::COMMENT_NODE, data)
{
}
Comment::~Comment()
{
}

18
Libraries/LibHTML/DOM/Comment.h Normal file
View file

@ -0,0 +1,18 @@
#pragma once
#include <AK/String.h>
#include <LibHTML/DOM/CharacterData.h>
class Comment final : public CharacterData {
public:
explicit Comment(Document&, const String&);
virtual ~Comment() override;
virtual String tag_name() const override { return "#comment"; }
};
template<>
inline bool is<Comment>(const Node& node)
{
return node.is_comment();
}

17
Libraries/LibHTML/DOM/Document.cpp
View file

@ -29,6 +29,23 @@ StyleResolver& Document::style_resolver()
return *m_style_resolver;
}
bool Document::is_child_allowed(const Node& node) const
{
switch (node.type()) {
case NodeType::DOCUMENT_NODE:
case NodeType::TEXT_NODE:
return false;
case NodeType::COMMENT_NODE:
return true;
case NodeType::DOCUMENT_TYPE_NODE:
return !first_child_of_type<DocumentType>();
case NodeType::ELEMENT_NODE:
return !first_child_of_type<Element>();
default:
return false;
}
}
void Document::fixup()
{
if (!is<DocumentType>(first_child()))

2
Libraries/LibHTML/DOM/Document.h
View file

@ -67,6 +67,8 @@ public:
void invalidate_layout();
Function<void()> on_invalidate_layout;
virtual bool is_child_allowed(const Node&) const override;
private:
virtual RefPtr<LayoutNode> create_layout_node(const StyleResolver&, const StyleProperties* parent_style) const override;

2
Libraries/LibHTML/DOM/DocumentType.h
View file

@ -7,7 +7,7 @@ public:
explicit DocumentType(Document&);
virtual ~DocumentType() override;
virtual String tag_name() const override { return "!DOCTYPE"; }
virtual String tag_name() const override { return "#doctype"; }
};
template<>

5
Libraries/LibHTML/DOM/Node.h
View file

@ -10,6 +10,7 @@ enum class NodeType : unsigned {
INVALID = 0,
ELEMENT_NODE = 1,
TEXT_NODE = 3,
COMMENT_NODE = 8,
DOCUMENT_NODE = 9,
DOCUMENT_TYPE_NODE = 10,
};
@ -32,6 +33,8 @@ public:
bool is_text() const { return type() == NodeType::TEXT_NODE; }
bool is_document() const { return type() == NodeType::DOCUMENT_NODE; }
bool is_document_type() const { return type() == NodeType::DOCUMENT_TYPE_NODE; }
bool is_comment() const { return type() == NodeType::COMMENT_NODE; }
bool is_character_data() const { return type() == NodeType::TEXT_NODE || type() == NodeType::COMMENT_NODE; }
bool is_parent_node() const { return is_element() || is_document(); }
virtual RefPtr<LayoutNode> create_layout_node(const StyleResolver&, const StyleProperties* parent_style) const;
@ -66,6 +69,8 @@ public:
const Element* previous_element_sibling() const;
const Element* next_element_sibling() const;
virtual bool is_child_allowed(const Node&) const { return true; }
protected:
Node(Document&, NodeType);

3
Libraries/LibHTML/DOM/Text.cpp
View file

@ -2,8 +2,7 @@
#include <LibHTML/Layout/LayoutText.h>
Text::Text(Document& document, const String& data)
: Node(document, NodeType::TEXT_NODE)
, m_data(data)
: CharacterData(document, NodeType::TEXT_NODE, data)
{
}

10
Libraries/LibHTML/DOM/Text.h
View file

@ -1,23 +1,17 @@
#pragma once
#include <AK/String.h>
#include <LibHTML/DOM/Node.h>
#include <LibHTML/DOM/CharacterData.h>
class Text final : public Node {
class Text final : public CharacterData {
public:
explicit Text(Document&, const String&);
virtual ~Text() override;
const String& data() const { return m_data; }
virtual String tag_name() const override { return "#text"; }
virtual String text_content() const override { return m_data; }
private:
virtual RefPtr<LayoutNode> create_layout_node(const StyleResolver&, const StyleProperties* parent_style) const override;
String m_data;
};
template<>

3
Libraries/LibHTML/Dump.cpp
View file

@ -1,5 +1,6 @@
#include <AK/Utf8View.h>
#include <LibHTML/CSS/StyleSheet.h>
#include <LibHTML/DOM/Comment.h>
#include <LibHTML/DOM/Document.h>
#include <LibHTML/DOM/DocumentType.h>
#include <LibHTML/DOM/Element.h>
@ -27,6 +28,8 @@ void dump_tree(const Node& node)
dbgprintf("\"%s\"\n", static_cast<const Text&>(node).data().characters());
} else if (is<DocumentType>(node)) {
dbgprintf("<!DOCTYPE>\n");
} else if (is<Comment>(node)) {
dbgprintf("<!--%s-->\n", to<Comment>(node).data().characters());
}
++indent;
if (is<ParentNode>(node)) {

2
Libraries/LibHTML/Makefile.shared
View file

@ -17,6 +17,8 @@ LIBHTML_OBJS = \
DOM/HTMLBlinkElement.o \
DOM/HTMLBRElement.o \
DOM/Document.o \
DOM/CharacterData.o \
DOM/Comment.o \
DOM/Text.o \
DOM/DocumentType.o \
DOM/ElementFactory.o \

59
Libraries/LibHTML/Parser/HTMLParser.cpp
View file

@ -1,6 +1,7 @@
#include <AK/Function.h>
#include <AK/NonnullRefPtrVector.h>
#include <AK/StringBuilder.h>
#include <LibHTML/DOM/Comment.h>
#include <LibHTML/DOM/DocumentType.h>
#include <LibHTML/DOM/Element.h>
#include <LibHTML/DOM/ElementFactory.h>
@ -44,6 +45,8 @@ NonnullRefPtr<Document> parse_html(const StringView& html, const URL& url)
Free = 0,
BeforeTagName,
InTagName,
InDoctype,
InComment,
InAttributeList,
InAttributeName,
BeforeAttributeValue,
@ -101,19 +104,16 @@ NonnullRefPtr<Document> parse_html(const StringView& html, const URL& url)
close_tag();
};
auto handle_exclamation_tag = [&] {
auto name = String::copy(tag_name_buffer);
tag_name_buffer.clear();
ASSERT(name == "DOCTYPE");
if (node_stack.size() != 1)
node_stack[node_stack.size() - 2].append_child(adopt(*new DocumentType(document)), false);
close_tag();
auto commit_doctype = [&] {
node_stack.last().append_child(adopt(*new DocumentType(document)), false);
};
auto commit_comment = [&] {
node_stack.last().append_child(adopt(*new Comment(document, text_buffer.to_string())), false);
};
auto commit_tag = [&] {
if (is_exclamation_tag)
handle_exclamation_tag();
else if (is_slash_tag)
if (is_slash_tag)
close_tag();
else
open_tag();
@ -124,12 +124,16 @@ NonnullRefPtr<Document> parse_html(const StringView& html, const URL& url)
};
for (int i = 0; i < html.length(); ++i) {
auto peek = [&](int offset) -> char {
if (i + offset >= html.length())
return '\0';
return html[i + offset];
};
char ch = html[i];
switch (state) {
case State::Free:
if (ch == '<') {
is_slash_tag = false;
is_exclamation_tag = false;
move_to_state(State::BeforeTagName);
break;
}
@ -165,7 +169,22 @@ NonnullRefPtr<Document> parse_html(const StringView& html, const URL& url)
break;
}
if (ch == '!') {
is_exclamation_tag = true;
if (peek(1) == 'D'
&& peek(2) == 'O'
&& peek(3) == 'C'
&& peek(4) == 'T'
&& peek(5) == 'Y'
&& peek(6) == 'P'
&& peek(7) == 'E') {
i += 7;
move_to_state(State::InDoctype);
break;
}
if (peek(1) == '-' && peek(2) == '-') {
i += 2;
move_to_state(State::InComment);
break;
}
break;
}
if (ch == '>') {
@ -188,6 +207,22 @@ NonnullRefPtr<Document> parse_html(const StringView& html, const URL& url)
}
tag_name_buffer.append(ch);
break;
case State::InDoctype:
if (ch == '>') {
commit_doctype();
move_to_state(State::Free);
break;
}
break;
case State::InComment:
if (ch == '-' && peek(1) == '-' && peek(2) == '>') {
commit_comment();
i += 2;
move_to_state(State::Free);
break;
}
text_buffer.append(ch);
break;
case State::InAttributeList:
if (ch == '>') {
commit_tag();

13
Libraries/LibHTML/TreeNode.h
View file

@ -50,8 +50,10 @@ public:
void append_child(NonnullRefPtr<T> node, bool call_inserted_into = true);
void donate_all_children_to(T& node);
bool is_child_allowed(const T&) const { return true; }
protected:
TreeNode() { }
TreeNode() {}
private:
int m_ref_count { 1 };
@ -66,6 +68,10 @@ template<typename T>
inline void TreeNode<T>::append_child(NonnullRefPtr<T> node, bool call_inserted_into)
{
ASSERT(!node->m_parent);
if (!static_cast<T*>(this)->is_child_allowed(*node))
return;
if (m_last_child)
m_last_child->m_next_sibling = node.ptr();
node->m_previous_sibling = m_last_child;
@ -82,6 +88,10 @@ template<typename T>
inline void TreeNode<T>::prepend_child(NonnullRefPtr<T> node, bool call_inserted_into)
{
ASSERT(!node->m_parent);
if (!static_cast<T*>(this)->is_child_allowed(*node))
return;
if (m_first_child)
m_first_child->m_previous_sibling = node.ptr();
node->m_next_sibling = m_first_child;
@ -112,7 +122,6 @@ inline void TreeNode<T>::donate_all_children_to(T& node)
m_last_child = nullptr;
}
template<typename T>
inline bool TreeNode<T>::is_ancestor_of(const TreeNode<T>& other) const
{