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ladybird/Libraries/LibHTML/Parser/HTMLParser.cpp
Andreas Kling edbf09ea29 LibHTML: Make the CSS and HTML parsers take StringViews 
This allows us to avoid unnecessary making unnecessary String copies of
all the source text.
2019-10-07 19:11:33 +02:00

313 lines
9.8 KiB
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#include <AK/Function.h>
#include <AK/NonnullRefPtrVector.h>
#include <AK/StringBuilder.h>
#include <LibHTML/DOM/Element.h>
#include <LibHTML/DOM/HTMLAnchorElement.h>
#include <LibHTML/DOM/HTMLBodyElement.h>
#include <LibHTML/DOM/HTMLFontElement.h>
#include <LibHTML/DOM/HTMLHRElement.h>
#include <LibHTML/DOM/HTMLHeadElement.h>
#include <LibHTML/DOM/HTMLHeadingElement.h>
#include <LibHTML/DOM/HTMLHtmlElement.h>
#include <LibHTML/DOM/HTMLImageElement.h>
#include <LibHTML/DOM/HTMLStyleElement.h>
#include <LibHTML/DOM/HTMLTitleElement.h>
#include <LibHTML/DOM/HTMLLinkElement.h>
#include <LibHTML/DOM/Text.h>
#include <LibHTML/Parser/HTMLParser.h>
#include <ctype.h>
#include <stdio.h>
static NonnullRefPtr<Element> create_element(Document& document, const String& tag_name)
{
auto lowercase_tag_name = tag_name.to_lowercase();
if (lowercase_tag_name == "a")
return adopt(*new HTMLAnchorElement(document, tag_name));
if (lowercase_tag_name == "html")
return adopt(*new HTMLHtmlElement(document, tag_name));
if (lowercase_tag_name == "head")
return adopt(*new HTMLHeadElement(document, tag_name));
if (lowercase_tag_name == "body")
return adopt(*new HTMLBodyElement(document, tag_name));
if (lowercase_tag_name == "font")
return adopt(*new HTMLFontElement(document, tag_name));
if (lowercase_tag_name == "hr")
return adopt(*new HTMLHRElement(document, tag_name));
if (lowercase_tag_name == "style")
return adopt(*new HTMLStyleElement(document, tag_name));
if (lowercase_tag_name == "title")
return adopt(*new HTMLTitleElement(document, tag_name));
if (lowercase_tag_name == "link")
return adopt(*new HTMLLinkElement(document, tag_name));
if (lowercase_tag_name == "img")
return adopt(*new HTMLImageElement(document, tag_name));
if (lowercase_tag_name == "h1"
|| lowercase_tag_name == "h2"
|| lowercase_tag_name == "h3"
|| lowercase_tag_name == "h4"
|| lowercase_tag_name == "h5"
|| lowercase_tag_name == "h6") {
return adopt(*new HTMLHeadingElement(document, tag_name));
}
return adopt(*new Element(document, tag_name));
}
static bool is_valid_in_attribute_name(char ch)
{
return isalnum(ch) || ch == '_' || ch == '-';
}
static bool is_self_closing_tag(const StringView& tag_name)
{
return tag_name == "area"
|| tag_name == "base"
|| tag_name == "br"
|| tag_name == "col"
|| tag_name == "embed"
|| tag_name == "hr"
|| tag_name == "img"
|| tag_name == "input"
|| tag_name == "link"
|| tag_name == "meta"
|| tag_name == "param"
|| tag_name == "source"
|| tag_name == "track"
|| tag_name == "wbr";
}
NonnullRefPtr<Document> parse_html(const StringView& html, const URL& url)
{
NonnullRefPtrVector<ParentNode> node_stack;
auto document = adopt(*new Document);
document->set_url(url);
node_stack.append(document);
enum class State {
Free = 0,
BeforeTagName,
InTagName,
InAttributeList,
InAttributeName,
BeforeAttributeValue,
InAttributeValueNoQuote,
InAttributeValueSingleQuote,
InAttributeValueDoubleQuote,
};
auto state = State::Free;
StringBuilder text_buffer;
Vector<char, 32> tag_name_buffer;
Vector<Attribute> attributes;
Vector<char, 256> attribute_name_buffer;
Vector<char, 256> attribute_value_buffer;
bool is_slash_tag = false;
auto move_to_state = [&](State new_state) {
if (new_state == State::BeforeTagName) {
is_slash_tag = false;
tag_name_buffer.clear();
attributes.clear();
}
if (new_state == State::InAttributeName)
attribute_name_buffer.clear();
if (new_state == State::BeforeAttributeValue)
attribute_value_buffer.clear();
if (state == State::Free && !text_buffer.string_view().is_empty()) {
auto text_node = adopt(*new Text(document, text_buffer.to_string()));
node_stack.last().append_child(text_node, false);
}
state = new_state;
text_buffer.clear();
};
auto close_tag = [&] {
if (node_stack.size() > 1)
node_stack.take_last();
};
auto open_tag = [&] {
auto new_element = create_element(document, String::copy(tag_name_buffer));
tag_name_buffer.clear();
new_element->set_attributes(move(attributes));
node_stack.append(new_element);
if (node_stack.size() != 1)
node_stack[node_stack.size() - 2].append_child(new_element, false);
if (is_self_closing_tag(new_element->tag_name()))
close_tag();
};
auto commit_tag = [&] {
if (is_slash_tag)
close_tag();
else
open_tag();
};
auto commit_attribute = [&] {
attributes.append({ String::copy(attribute_name_buffer), String::copy(attribute_value_buffer) });
};
for (int i = 0; i < html.length(); ++i) {
char ch = html[i];
switch (state) {
case State::Free:
if (ch == '<') {
is_slash_tag = false;
move_to_state(State::BeforeTagName);
break;
}
if (ch != '&') {
text_buffer.append(ch);
} else {
struct Escape {
const char* code;
const char* value;
};
static Escape escapes[] = {
{ "&lt;", "<" },
{ "&gt;", ">" },
{ "&amp;", "&" }
};
auto rest_of_html = html.substring_view(i, html.length() - i);
bool found = false;
for (auto& escape : escapes) {
if (rest_of_html.starts_with(escape.code)) {
text_buffer.append(escape.value);
found = true;
i += strlen(escape.code) - 1;
break;
}
}
if (!found)
dbg() << "Unhandled escape sequence";
}
break;
case State::BeforeTagName:
if (ch == '/') {
is_slash_tag = true;
break;
}
if (ch == '>') {
move_to_state(State::Free);
break;
}
if (!isalpha(ch))
break;
move_to_state(State::InTagName);
[[fallthrough]];
case State::InTagName:
if (isspace(ch)) {
move_to_state(State::InAttributeList);
break;
}
if (ch == '>') {
commit_tag();
move_to_state(State::Free);
break;
}
tag_name_buffer.append(ch);
break;
case State::InAttributeList:
if (ch == '>') {
commit_tag();
move_to_state(State::Free);
break;
}
if (!isalpha(ch))
break;
move_to_state(State::InAttributeName);
[[fallthrough]];
case State::InAttributeName:
if (is_valid_in_attribute_name(ch)) {
attribute_name_buffer.append(ch);
break;
}
if (isspace(ch)) {
commit_attribute();
break;
}
if (ch == '>') {
commit_tag();
move_to_state(State::Free);
break;
}
if (ch == '=') {
move_to_state(State::BeforeAttributeValue);
break;
}
break;
case State::BeforeAttributeValue:
if (ch == '\'') {
move_to_state(State::InAttributeValueSingleQuote);
break;
}
if (ch == '"') {
move_to_state(State::InAttributeValueDoubleQuote);
break;
}
if (ch == '>') {
commit_tag();
move_to_state(State::Free);
break;
}
if (isspace(ch)) {
commit_attribute();
move_to_state(State::InAttributeList);
break;
}
break;
case State::InAttributeValueSingleQuote:
if (ch == '\'') {
commit_attribute();
move_to_state(State::InAttributeList);
break;
}
attribute_value_buffer.append(ch);
break;
case State::InAttributeValueDoubleQuote:
if (ch == '"') {
commit_attribute();
move_to_state(State::InAttributeList);
break;
}
attribute_value_buffer.append(ch);
break;
case State::InAttributeValueNoQuote:
if (isspace(ch)) {
commit_attribute();
move_to_state(State::InAttributeList);
break;
}
if (ch == '>') {
commit_tag();
move_to_state(State::Free);
break;
}
attribute_value_buffer.append(ch);
break;
default:
fprintf(stderr, "Unhandled state %d\n", (int)state);
ASSERT_NOT_REACHED();
}
}
Function<void(Node&)> fire_insertion_callbacks = [&](Node& node) {
for (auto* child = node.first_child(); child; child = child->next_sibling()) {
fire_insertion_callbacks(*child);
}
if (node.parent())
node.inserted_into(*node.parent());
};
fire_insertion_callbacks(*document);
return document;
}
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