ladybird/Libraries/LibWeb/Parser/HTMLParser.cpp
Andreas Kling e09b83c60c LibTextCodec: Start fleshing out a simple text codec library
We're starting with a very basic decoding API and only ISO-8859-1 and
UTF-8 decoding (and UTF-8 decoding is really a no-op since String is
expected to be UTF-8.)
2020-05-03 23:01:58 +02:00

429 lines
13 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/Function.h>
#include <AK/NonnullRefPtrVector.h>
#include <AK/StringBuilder.h>
#include <LibTextCodec/Decoder.h>
#include <LibWeb/DOM/Comment.h>
#include <LibWeb/DOM/DocumentFragment.h>
#include <LibWeb/DOM/DocumentType.h>
#include <LibWeb/DOM/Element.h>
#include <LibWeb/DOM/ElementFactory.h>
#include <LibWeb/DOM/Event.h>
#include <LibWeb/DOM/Text.h>
#include <LibWeb/Parser/HTMLParser.h>
#include <ctype.h>
#include <stdio.h>
namespace Web {
static bool is_valid_in_attribute_name(char ch)
{
return isalnum(ch) || ch == '_' || ch == '-';
}
static bool is_void_element(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";
}
static bool parse_html_document(const StringView& html, Document& document, ParentNode& root)
{
NonnullRefPtrVector<ParentNode> node_stack;
node_stack.append(root);
enum class State {
Free = 0,
BeforeTagName,
InTagName,
InDoctype,
InComment,
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;
bool is_exclamation_tag = false;
auto commit_text_node = [&] {
auto text_node = adopt(*new Text(document, text_buffer.to_string()));
node_stack.last().append_child(text_node);
text_buffer.clear();
};
auto move_to_state = [&](State new_state) {
if (new_state == State::BeforeTagName) {
is_slash_tag = false;
is_exclamation_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.is_empty()) {
commit_text_node();
}
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);
}
if (is_void_element(new_element->tag_name()))
close_tag();
};
auto commit_doctype = [&] {
node_stack.last().append_child(adopt(*new DocumentType(document)));
};
auto commit_comment = [&] {
node_stack.last().append_child(adopt(*new Comment(document, text_buffer.to_string())));
};
auto commit_tag = [&] {
if (is_slash_tag)
close_tag();
else
open_tag();
};
auto commit_attribute = [&] {
if (!attribute_name_buffer.is_empty()) {
auto name = String::copy(attribute_name_buffer);
String value;
if (attribute_value_buffer.is_empty())
value = String::empty();
else
value = String::copy(attribute_value_buffer);
attributes.empend(name, value);
}
};
for (size_t i = 0; i < html.length(); ++i) {
auto peek = [&](size_t offset) -> char {
if (i + offset >= html.length())
return '\0';
return html[i + offset];
};
char ch = html[i];
switch (state) {
case State::Free:
if (ch == '<') {
bool should_treat_as_text = false;
if (node_stack.last().tag_name() == "script") {
bool is_script_close_tag = peek(1) == '/'
&& tolower(peek(2)) == 's'
&& tolower(peek(3)) == 'c'
&& tolower(peek(4)) == 'r'
&& tolower(peek(5)) == 'i'
&& tolower(peek(6)) == 'p'
&& tolower(peek(7)) == 't'
&& tolower(peek(8)) == '>';
if (!is_script_close_tag)
should_treat_as_text = true;
}
if (!should_treat_as_text) {
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;", "&" },
{ "&mdash;", "-" },
};
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 == '!') {
if (toupper(peek(1)) == 'D'
&& toupper(peek(2)) == 'O'
&& toupper(peek(3)) == 'C'
&& toupper(peek(4)) == 'T'
&& toupper(peek(5)) == 'Y'
&& toupper(peek(6)) == 'P'
&& toupper(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 == '>') {
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 == '/' && peek(1) == '>') {
open_tag();
close_tag();
i += 1;
move_to_state(State::Free);
break;
}
if (ch == '>') {
commit_tag();
move_to_state(State::Free);
break;
}
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();
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_attribute();
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;
}
move_to_state(State::InAttributeValueNoQuote);
[[fallthrough]];
case State::InAttributeValueNoQuote:
if (isspace(ch)) {
commit_attribute();
move_to_state(State::InAttributeList);
break;
}
if (ch == '>') {
commit_attribute();
commit_tag();
move_to_state(State::Free);
break;
}
attribute_value_buffer.append(ch);
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;
default:
fprintf(stderr, "Unhandled state %d\n", (int)state);
ASSERT_NOT_REACHED();
}
}
if (!text_buffer.is_empty())
commit_text_node();
return true;
}
String to_utf8(const StringView& input, const String& encoding)
{
auto* decoder = TextCodec::decoder_for(encoding);
ASSERT(decoder);
return decoder->to_utf8(input);
}
RefPtr<DocumentFragment> parse_html_fragment(Document& document, const StringView& raw_html, const String& encoding)
{
auto fragment = adopt(*new DocumentFragment(document));
if (!parse_html_document(to_utf8(raw_html, encoding), document, *fragment))
return nullptr;
return fragment;
}
RefPtr<Document> parse_html_document(const StringView& raw_html, const URL& url, const String& encoding)
{
String html = to_utf8(raw_html, encoding);
auto document = adopt(*new Document(url));
document->set_source(html);
if (!parse_html_document(html, *document, *document))
return nullptr;
document->fixup();
#if 0
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);
#endif
document->dispatch_event(Event::create("DOMContentLoaded"));
return document;
}
}