src/tint/utils/text/styled_text_printer_ansi.cc

// Copyright 2024 The Dawn & Tint Authors
//
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// 1. Redistributions of source code must retain the above copyright notice, this
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//    this list of conditions and the following disclaimer in the documentation
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#include <cstring>

#include "src/tint/utils/text/styled_text.h"
#include "src/tint/utils/text/styled_text_printer.h"
#include "src/tint/utils/text/styled_text_theme.h"
#include "src/tint/utils/text/text_style.h"

namespace tint {
namespace {

template <typename T>
bool Equal(const std::optional<T>& lhs, const std::optional<T>& rhs) {
    if (lhs.has_value() != rhs.has_value()) {
        return false;
    }
    if (!lhs.has_value()) {
        return true;
    }
    return lhs.value() == rhs.value();
}

#define ESCAPE "\u001b"

class Printer : public StyledTextPrinter {
  public:
    Printer(FILE* f, const StyledTextTheme& t) : file_(f), theme_(t) {}

    void Print(const StyledText& style_text) override {
        StyledTextTheme::Attributes current;

        style_text.Walk([&](std::string_view text, TextStyle text_style) {
            auto style = theme_.Get(text_style);
            if (!Equal(current.foreground, style.foreground)) {
                current.foreground = style.foreground;
                if (current.foreground.has_value()) {
                    fprintf(file_, ESCAPE "[38;2;%d;%d;%dm",  //
                            static_cast<int>(style.foreground->r),
                            static_cast<int>(style.foreground->g),
                            static_cast<int>(style.foreground->b));
                } else {
                    fprintf(file_, ESCAPE "[39m");
                }
            }
            if (!Equal(current.background, style.background)) {
                current.background = style.background;
                if (current.background.has_value()) {
                    fprintf(file_, ESCAPE "[48;2;%d;%d;%dm",  //
                            static_cast<int>(style.background->r),
                            static_cast<int>(style.background->g),
                            static_cast<int>(style.background->b));
                } else {
                    fprintf(file_, ESCAPE "[49m");
                }
            }
            if (!Equal(current.underlined, style.underlined)) {
                current.underlined = style.underlined;
                if (current.underlined == true) {
                    fprintf(file_, ESCAPE "[4m");
                } else {
                    fprintf(file_, ESCAPE "[24m");
                }
            }
            if (!Equal(current.bold, style.bold)) {
                current.bold = style.bold;
                if (current.bold == true) {
                    fprintf(file_, ESCAPE "[1m");
                } else {
                    fprintf(file_, ESCAPE "[22m");
                }
            }
            fwrite(text.data(), 1, text.size(), file_);
        });
        fprintf(file_, ESCAPE "[m");
        fflush(file_);
    }

  private:
    FILE* const file_;
    const StyledTextTheme& theme_;
};

}  // namespace

std::unique_ptr<StyledTextPrinter> StyledTextPrinter::CreateANSI(FILE* out,
                                                                 const StyledTextTheme& theme) {
    return std::make_unique<Printer>(out, theme);
}

}  // namespace tint