ladybird/Userland/Libraries/LibWebView/SourceHighlighter.cpp
Timothy Flynn c1b0e180ba LibWebView: Insert line numbers before each line in about:srcdoc
The behavior chosen here (fixed-width counters, alignment, etc.) matches
Firefox.
2024-07-29 18:27:16 +01:00

145 lines
3.9 KiB
C++

/*
* Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/StringBuilder.h>
#include <LibURL/URL.h>
#include <LibWeb/HTML/Parser/HTMLTokenizer.h>
#include <LibWebView/SourceHighlighter.h>
namespace WebView {
static String generate_style()
{
StringBuilder builder;
builder.append(HTML_HIGHLIGHTER_STYLE);
builder.append(R"~~~(
.html {
counter-reset: line;
}
.line {
counter-increment: line;
white-space: nowrap;
}
.line::before {
content: counter(line) " ";
display: inline-block;
width: 2.5em;
padding-right: 0.5em;
text-align: right;
}
@media (prefers-color-scheme: dark) {
.line::before {
color: darkgrey;
}
}
@media (prefers-color-scheme: light) {
.line::before {
color: dimgray;
}
}
)~~~"sv);
return MUST(builder.to_string());
}
String highlight_source(URL::URL const& url, StringView source)
{
Web::HTML::HTMLTokenizer tokenizer { source, "utf-8"sv };
StringBuilder builder;
builder.append(R"~~~(
<!DOCTYPE html>
<html>
<head>
<meta name="color-scheme" content="dark light">)~~~"sv);
builder.appendff("<title>View Source - {}</title>", url);
builder.appendff("<style type=\"text/css\">{}</style>", generate_style());
builder.append(R"~~~(
</head>
<body>
<pre class="html">
<span class="line">)~~~"sv);
size_t previous_position = 0;
auto append_source = [&](auto end_position, Optional<StringView> const& class_name = {}) {
if (end_position <= previous_position)
return;
auto segment = source.substring_view(previous_position, end_position - previous_position);
if (class_name.has_value())
builder.appendff("<span class=\"{}\">"sv, *class_name);
for (auto code_point : Utf8View { segment }) {
if (code_point == '&')
builder.append("&amp;"sv);
else if (code_point == 0xA0)
builder.append("&nbsp;"sv);
else if (code_point == '<')
builder.append("&lt;"sv);
else if (code_point == '>')
builder.append("&gt;"sv);
else if (code_point == '\n')
builder.append("</span>\n<span class=\"line\">"sv);
else
builder.append_code_point(code_point);
}
if (class_name.has_value())
builder.append("</span>"sv);
previous_position = end_position;
};
for (auto token = tokenizer.next_token(); token.has_value(); token = tokenizer.next_token()) {
if (token->is_comment()) {
append_source(token->start_position().byte_offset);
append_source(token->end_position().byte_offset, "comment"sv);
} else if (token->is_start_tag() || token->is_end_tag()) {
auto tag_name_start = token->start_position().byte_offset;
append_source(tag_name_start);
append_source(tag_name_start + token->tag_name().bytes().size(), "tag"sv);
token->for_each_attribute([&](auto const& attribute) {
append_source(attribute.name_start_position.byte_offset);
append_source(attribute.name_end_position.byte_offset, "attribute-name"sv);
append_source(attribute.value_start_position.byte_offset);
append_source(attribute.value_end_position.byte_offset, "attribute-value"sv);
return IterationDecision::Continue;
});
append_source(token->end_position().byte_offset);
} else {
append_source(token->end_position().byte_offset);
if (token->is_end_of_file())
break;
}
}
builder.append(R"~~~(
</span>
</pre>
</body>
</html>
)~~~"sv);
return MUST(builder.to_string());
}
}