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LibWeb: Implement the first half of the Adoption Agency Algorithm

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The AAA is a somewhat daunting algorithm you have to run for certain
tag when inserted inside the <body> element. The purpose of it is to
resolve issues with mismatched tags.

This patch implements the first half of the AAA. We also move the
"list of active formatting elements" to its own class, since it kept
accumulating little behaviors. "Marker" entries are now signified by
null Element pointers in the list.
This commit is contained in:
Andreas Kling 2020-05-27 23:22:42 +02:00
parent 4c9c6b3a7b
commit db6cf9b37d
7 changed files with 248 additions and 16 deletions
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101
Libraries/LibWeb/Parser/HTMLDocumentParser.cpp
View file

@ -492,11 +492,12 @@ void HTMLDocumentParser::reconstruct_the_active_formatting_elements()
if (m_list_of_active_formatting_elements.is_empty())
return;
if (m_stack_of_open_elements.contains(m_list_of_active_formatting_elements.last()))
if (m_stack_of_open_elements.contains(*m_list_of_active_formatting_elements.entries().last().element))
return;
ssize_t index = m_list_of_active_formatting_elements.size() - 1;
RefPtr<Element> entry = m_list_of_active_formatting_elements.at(index);
ssize_t index = m_list_of_active_formatting_elements.entries().size() - 1;
RefPtr<Element> entry = m_list_of_active_formatting_elements.entries().at(index).element;
ASSERT(entry);
Rewind:
if (index == 0) {
@ -504,14 +505,16 @@ Rewind:
}
--index;
entry = m_list_of_active_formatting_elements.at(index);
entry = m_list_of_active_formatting_elements.entries().at(index).element;
ASSERT(entry);
if (!m_stack_of_open_elements.contains(*entry))
goto Rewind;
Advance:
++index;
entry = m_list_of_active_formatting_elements.at(index);
entry = m_list_of_active_formatting_elements.entries().at(index).element;
ASSERT(entry);
Create:
// FIXME: Hold on to the real token!
@ -520,12 +523,74 @@ Create:
fake_token.m_tag.tag_name.append(entry->tag_name());
auto new_element = insert_html_element(fake_token);
m_list_of_active_formatting_elements.ptr_at(index) = *new_element;
m_list_of_active_formatting_elements.entries().at(index).element = *new_element;
if (index != (ssize_t)m_list_of_active_formatting_elements.size() - 1)
if (index != (ssize_t)m_list_of_active_formatting_elements.entries().size() - 1)
goto Advance;
}
void HTMLDocumentParser::run_the_adoption_agency_algorithm(HTMLToken& token)
{
auto subject = token.tag_name();
// If the current node is an HTML element whose tag name is subject,
// and the current node is not in the list of active formatting elements,
// then pop the current node off the stack of open elements, and return.
if (current_node().tag_name() == subject && !m_list_of_active_formatting_elements.contains(current_node())) {
m_stack_of_open_elements.pop();
return;
}
size_t outer_loop_counter = 0;
//OuterLoop:
if (outer_loop_counter >= 8)
return;
++outer_loop_counter;
auto formatting_element = m_list_of_active_formatting_elements.last_element_with_tag_name_before_marker(subject);
if (!formatting_element) {
// FIXME: If there is no such element, then return and instead act as
// described in the "any other end tag" entry above.
TODO();
}
if (!m_stack_of_open_elements.contains(*formatting_element)) {
PARSE_ERROR();
// FIXME: If formatting element is not in the stack of open elements,
// then this is a parse error; remove the element from the list, and return.
TODO();
}
if (!m_stack_of_open_elements.has_in_scope(*formatting_element)) {
PARSE_ERROR();
return;
}
if (formatting_element != &current_node()) {
PARSE_ERROR();
}
// FIXME: Let furthest block be the topmost node in the stack of open elements
// that is lower in the stack than formatting element, and is an element
// in the special category. There might not be one.
RefPtr<Element> furthest_block = nullptr;
if (!furthest_block) {
while (&current_node() != formatting_element)
m_stack_of_open_elements.pop();
m_stack_of_open_elements.pop();
m_list_of_active_formatting_elements.remove(*formatting_element);
return;
}
// FIXME: Implement the rest of the AAA :^)
TODO();
}
void HTMLDocumentParser::handle_in_body(HTMLToken& token)
{
if (token.is_character()) {
@ -602,13 +667,16 @@ void HTMLDocumentParser::handle_in_body(HTMLToken& token)
return;
}
{
if (token.is_start_tag() && token.tag_name().is_one_of("b", "big", "code", "em", "font", "i", "s", "small", "strike", "strong", "tt", "u")) {
reconstruct_the_active_formatting_elements();
auto element = insert_html_element(token);
m_list_of_active_formatting_elements.append(*element);
return;
}
if (token.is_start_tag() && token.tag_name().is_one_of("b", "big", "code", "em", "font", "i", "s", "small", "strike", "strong", "tt", "u")) {
reconstruct_the_active_formatting_elements();
auto element = insert_html_element(token);
m_list_of_active_formatting_elements.add(*element);
return;
}
if (token.is_end_tag() && token.tag_name().is_one_of("a", "b", "big", "code", "em", "font", "i", "nobr", "s", "small", "strike", "strong", "tt", "u")) {
run_the_adoption_agency_algorithm(token);
return;
}
if (token.is_start_tag() && token.tag_name().is_one_of("address", "article", "aside", "blockquote", "center", "details", "dialog", "dir", "div", "dl", "fieldset", "figcaption", "figure", "footer", "header", "hgroup", "main", "menu", "nav", "ol", "p", "section", "summary", "ul")) {
@ -746,6 +814,11 @@ void HTMLDocumentParser::handle_text(HTMLToken& token)
return;
}
if (token.is_end_tag() && token.tag_name() == "style") {
current_node().children_changed();
// NOTE: We don't return here, keep going.
}
if (token.is_end_tag()) {
m_stack_of_open_elements.pop();
m_insertion_mode = m_original_insertion_mode;