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LibHTML: Basic element attribute parsing.

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This commit is contained in:
Andreas Kling 2019-06-15 21:08:36 +02:00
parent 581d6b00c8
commit f8a86b5164
5 changed files with 194 additions and 17 deletions
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3
Base/home/anon/small.html
View file

@ -1,6 +1,7 @@
<html>
<head><title>Small test page</title></head>
<body>
<body bgcolor="#408080" text="#ffffff">
<h1>Hello friends!</h1>
<p>This is a <b>very small</b> test page :^)</p>
</body>
</html>

6
LibHTML/Dump.cpp
View file

@ -12,7 +12,11 @@ void dump_tree(Node& node)
if (node.is_document()) {
printf("*Document*\n");
} else if (node.is_element()) {
printf("<%s>\n", static_cast<Element&>(node).tag_name().characters());
printf("<%s", static_cast<Element&>(node).tag_name().characters());
static_cast<Element&>(node).for_each_attribute([](auto& name, auto& value) {
printf(" %s=%s", name.characters(), value.characters());
});
printf(">\n");
} else if (node.is_text()) {
printf("\"%s\"\n", static_cast<Text&>(node).data().characters());
}

37
LibHTML/Element.cpp
View file

@ -10,3 +10,40 @@ Element::~Element()
{
}
Attribute* Element::find_attribute(const String& name)
{
for (auto& attribute : m_attributes) {
if (attribute.name() == name)
return &attribute;
}
return nullptr;
}
const Attribute* Element::find_attribute(const String& name) const
{
for (auto& attribute : m_attributes) {
if (attribute.name() == name)
return &attribute;
}
return nullptr;
}
String Element::attribute(const String& name) const
{
if (auto* attribute = find_attribute(name))
return attribute->value();
return { };
}
void Element::set_attribute(const String& name, const String& value)
{
if (auto* attribute = find_attribute(name))
attribute->set_value(value);
else
m_attributes.append({ name, value });
}
void Element::set_attributes(Vector<Attribute>&& attributes)
{
m_attributes = move(attributes);
}

20
LibHTML/Element.h
View file

@ -11,6 +11,11 @@ public:
{
}
const String& name() const { return m_name; }
const String& value() const { return m_value; }
void set_value(const String& value) { m_value = value; }
private:
String m_name;
String m_value;
@ -23,7 +28,22 @@ public:
const String& tag_name() const { return m_tag_name; }
String attribute(const String& name) const;
void set_attribute(const String& name, const String& value);
void set_attributes(Vector<Attribute>&&);
template<typename Callback>
void for_each_attribute(Callback callback)
{
for (auto& attribute : m_attributes)
callback(attribute.name(), attribute.value());
}
private:
Attribute* find_attribute(const String& name);
const Attribute* find_attribute(const String& name) const;
String m_tag_name;
Vector<Attribute> m_attributes;
};

145
LibHTML/Parser.cpp
View file

@ -2,12 +2,18 @@
#include <LibHTML/Parser.h>
#include <LibHTML/Text.h>
#include <ctype.h>
#include <stdio.h>
static Retained<Element> create_element(const String& tag_name)
{
return adopt(*new Element(tag_name));
}
static bool is_valid_in_attribute_name(char ch)
{
return isalnum(ch) || ch == '_' || ch == '-';
}
static bool is_self_closing_tag(const String& tag_name)
{
return tag_name == "area"
@ -34,11 +40,12 @@ Retained<Document> parse(const String& html)
node_stack.append(doc);
enum class State {
Free,
Free = 0,
BeforeTagName,
InTagName,
InAttributeList,
InAttributeName,
BeforeAttributeValue,
InAttributeValueNoQuote,
InAttributeValueSingleQuote,
InAttributeValueDoubleQuote,
@ -46,19 +53,33 @@ Retained<Document> parse(const String& html)
auto state = State::Free;
Vector<char, 256> buffer;
Vector<char, 256> 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)
if (new_state == State::BeforeTagName) {
is_slash_tag = false;
if (state == State::Free && !buffer.is_empty()) {
auto text_node = adopt(*new Text(String::copy(buffer)));
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()) {
auto text_node = adopt(*new Text(String::copy(text_buffer)));
text_buffer.clear();
node_stack.last()->append_child(text_node);
}
state = new_state;
buffer.clear();
text_buffer.clear();
};
auto close_tag = [&] {
@ -67,7 +88,9 @@ Retained<Document> parse(const String& html)
};
auto open_tag = [&] {
auto new_element = create_element(String::copy(buffer));
auto new_element = create_element(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);
@ -76,15 +99,27 @@ Retained<Document> parse(const String& html)
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;
}
buffer.append(ch);
text_buffer.append(ch);
break;
case State::BeforeTagName:
if (ch == '/') {
@ -95,25 +130,105 @@ Retained<Document> parse(const String& html)
move_to_state(State::Free);
break;
}
if (!isascii(ch))
if (!isalpha(ch))
break;
move_to_state(State::InTagName);
[[fallthrough]];
case State::InTagName:
if (ch == ' ') {
if (isspace(ch)) {
move_to_state(State::InAttributeList);
break;
}
if (ch == '>') {
if (is_slash_tag)
close_tag();
else
open_tag();
commit_tag();
move_to_state(State::Free);
break;
}
buffer.append(ch);
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();
}
}
return doc;