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serenity/Libraries/LibHTML/Parser/HTMLParser.cpp
Andreas Kling 94ca55cefd Meta: Add license header to source files
As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.

For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.

Going forward, all new source files should include a license header.
2020-01-18 09:45:54 +01:00

396 lines
12 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 <LibHTML/DOM/Comment.h>
#include <LibHTML/DOM/DocumentFragment.h>
#include <LibHTML/DOM/DocumentType.h>
#include <LibHTML/DOM/Element.h>
#include <LibHTML/DOM/ElementFactory.h>
#include <LibHTML/DOM/Text.h>
#include <LibHTML/Parser/HTMLParser.h>
#include <ctype.h>
#include <stdio.h>
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";
}
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 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.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_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_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 == '<') {
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 == '>') {
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();
}
}
return true;
}
RefPtr<DocumentFragment> parse_html_fragment(Document& document, const StringView& html)
{
auto fragment = adopt(*new DocumentFragment(document));
if (!parse_html_document(html, document, *fragment))
return nullptr;
return fragment;
}
RefPtr<Document> parse_html_document(const StringView& html, const URL& url)
{
auto document = adopt(*new Document);
document->set_url(url);
document->set_source(html);
if (!parse_html_document(html, *document, *document))
return nullptr;
document->fixup();
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;
}
String escape_html_entities(const StringView& html)
{
StringBuilder builder;
for (size_t i = 0; i < html.length(); ++i) {
if (html[i] == '<')
builder.append("&lt;");
else if (html[i] == '>')
builder.append("&gt;");
else if (html[i] == '&')
builder.append("&amp;");
else
builder.append(html[i]);
}
return builder.to_string();
}