ladybird/Userland/Libraries/LibCpp/SyntaxHighlighter.cpp

/*
 * Copyright (c) 2020-2022, the SerenityOS developers.
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <AK/Debug.h>
#include <LibCpp/Lexer.h>
#include <LibCpp/SyntaxHighlighter.h>
#include <LibGUI/TextEditor.h>
#include <LibGfx/Font/Font.h>
#include <LibGfx/Palette.h>

namespace Cpp {

static Gfx::TextAttributes style_for_token_type(Gfx::Palette const& palette, Cpp::Token::Type type)
{
    switch (type) {
    case Cpp::Token::Type::Keyword:
        return { palette.syntax_keyword(), {}, true };
    case Cpp::Token::Type::KnownType:
        return { palette.syntax_type(), {}, true };
    case Cpp::Token::Type::Identifier:
        return { palette.syntax_identifier() };
    case Cpp::Token::Type::DoubleQuotedString:
    case Cpp::Token::Type::SingleQuotedString:
    case Cpp::Token::Type::RawString:
        return { palette.syntax_string() };
    case Cpp::Token::Type::Integer:
    case Cpp::Token::Type::Float:
        return { palette.syntax_number() };
    case Cpp::Token::Type::IncludePath:
        return { palette.syntax_preprocessor_value() };
    case Cpp::Token::Type::EscapeSequence:
        return { palette.syntax_keyword(), {}, true };
    case Cpp::Token::Type::PreprocessorStatement:
    case Cpp::Token::Type::IncludeStatement:
        return { palette.syntax_preprocessor_statement() };
    case Cpp::Token::Type::Comment:
        return { palette.syntax_comment() };
    default:
        return { palette.base_text() };
    }
}

bool SyntaxHighlighter::is_identifier(u64 token) const
{
    auto cpp_token = static_cast<Cpp::Token::Type>(token);
    return cpp_token == Cpp::Token::Type::Identifier;
}

bool SyntaxHighlighter::is_navigatable(u64 token) const
{
    auto cpp_token = static_cast<Cpp::Token::Type>(token);
    return cpp_token == Cpp::Token::Type::IncludePath;
}

void SyntaxHighlighter::rehighlight(Palette const& palette)
{
    auto text = m_client->get_text();
    Cpp::Lexer lexer(text);

    Vector<Token> folding_region_start_tokens;
    Vector<GUI::TextDocumentFoldingRegion> folding_regions;
    Vector<GUI::TextDocumentSpan> spans;
    lexer.lex_iterable([&](auto token) {
        // FIXME: The +1 for the token end column is a quick hack due to not wanting to modify the lexer (which is also used by the parser). Maybe there's a better way to do this.
        dbgln_if(SYNTAX_HIGHLIGHTING_DEBUG, "{} @ {}:{} - {}:{}", token.type_as_byte_string(), token.start().line, token.start().column, token.end().line, token.end().column + 1);
        GUI::TextDocumentSpan span;
        span.range.set_start({ token.start().line, token.start().column });
        span.range.set_end({ token.end().line, token.end().column + 1 });
        span.attributes = style_for_token_type(palette, token.type());
        span.is_skippable = token.type() == Cpp::Token::Type::Whitespace;
        span.data = static_cast<u64>(token.type());
        spans.append(span);

        if (token.type() == Token::Type::LeftCurly) {
            folding_region_start_tokens.append(token);
        } else if (token.type() == Token::Type::RightCurly) {
            if (!folding_region_start_tokens.is_empty()) {
                auto start_token = folding_region_start_tokens.take_last();
                GUI::TextDocumentFoldingRegion folding_region;
                folding_region.range.set_start({ start_token.end().line, start_token.end().column });
                folding_region.range.set_end({ token.start().line, token.start().column });
                folding_regions.append(move(folding_region));
            }
        }
    });
    m_client->do_set_spans(move(spans));
    m_client->do_set_folding_regions(move(folding_regions));

    m_has_brace_buddies = false;
    highlight_matching_token_pair();

    m_client->do_update();
}

Vector<SyntaxHighlighter::MatchingTokenPair> SyntaxHighlighter::matching_token_pairs_impl() const
{
    static Vector<SyntaxHighlighter::MatchingTokenPair> pairs;
    if (pairs.is_empty()) {
        pairs.append({ static_cast<u64>(Cpp::Token::Type::LeftCurly), static_cast<u64>(Cpp::Token::Type::RightCurly) });
        pairs.append({ static_cast<u64>(Cpp::Token::Type::LeftParen), static_cast<u64>(Cpp::Token::Type::RightParen) });
        pairs.append({ static_cast<u64>(Cpp::Token::Type::LeftBracket), static_cast<u64>(Cpp::Token::Type::RightBracket) });
    }
    return pairs;
}

bool SyntaxHighlighter::token_types_equal(u64 token1, u64 token2) const
{
    return static_cast<Cpp::Token::Type>(token1) == static_cast<Cpp::Token::Type>(token2);
}

}