posix_utils.cpp

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#include <arkanjo/utils/os_utils.hpp>
 
#include <termios.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <sys/utsname.h>
#include <tuple>
 
int convert_16_bit_to_8_bit(const std::string& hex16) {
    try {
        unsigned long value = std::stoul(hex16, nullptr, 16);
        return static_cast<int>(value / 256);
    } catch (...) {
        return 0;
    }
}
 
std::tuple<int, int, int> UtilsOSDependable::parse_terminal_color_response(const std::string& response) {
    const size_t start_pos = response.find("rgb:");
    if (start_pos == std::string::npos) {
        return {0, 0, 0};
    }
 
    const size_t end_pos = response.find("\033\\", start_pos);
    if (end_pos == std::string::npos) {
        return {0, 0, 0};
    }
 
    std::string rgb_str = response.substr(start_pos + 4, end_pos - (start_pos + 4));
 
    replace(rgb_str.begin(), rgb_str.end(), '/', ' ');
 
    std::istringstream iss(rgb_str);
    std::string r_hex, g_hex, b_hex;
    iss >> r_hex >> g_hex >> b_hex;
 
    int r = convert_16_bit_to_8_bit(r_hex);
    int g = convert_16_bit_to_8_bit(g_hex);
    int b = convert_16_bit_to_8_bit(b_hex);
 
    return {r, g, b};
}
 
std::string UtilsOSDependable::capture_terminal_response() {
    int tty = open("/dev/tty", O_RDWR);
    if (tty < 0)
        return "";
 
    termios oldt, newt;
    tcgetattr(tty, &oldt);
 
    newt = oldt;
    newt.c_lflag &= ~(ICANON | ECHO);
 
    tcsetattr(tty, TCSANOW, &newt);
 
    int oldf = fcntl(tty, F_GETFL, 0);
    fcntl(tty, F_SETFL, oldf | O_NONBLOCK);
 
    // OSC 11 query (background color)
    write(tty, "\033]11;?\033\\", 8);
 
    std::string response;
    char ch;
 
    fd_set readfds;
    timeval tv{};
 
    while (true) {
        FD_ZERO(&readfds);
        FD_SET(tty, &readfds);
 
        tv.tv_sec = 0;
        tv.tv_usec = 100000; // 100ms timeout
 
        int ret = select(tty + 1, &readfds, nullptr, nullptr, &tv);
 
        if (ret <= 0)
            break;
 
        if (read(tty, &ch, 1) > 0) {
            response += ch;
        } else {
            break;
        }
    }
 
    tcsetattr(tty, TCSANOW, &oldt);
    fcntl(tty, F_SETFL, oldf);
    close(tty);
 
    return response;
}
 
float UtilsOSDependable::get_terminal_bg_color_luminance() {
    if (!isatty(fileno(stdout)) || !isatty(fileno(stdin))) {
        return 0;
    }
 
    std::string color_str = capture_terminal_response();
    auto [r, g, b] = parse_terminal_color_response(color_str);
    float luminance = 0.2126 * (r / 255.0) + 0.7152 * (g / 255.0) + 0.0722 * (b / 255.0);
 
    return luminance;
}
 
bool UtilsOSDependable::is_bg_color_dark() {
    return get_terminal_bg_color_luminance() <= 0.5;
}
 
int UtilsOSDependable::run_process(const char* cmd, char* const argv[]) {
    execvp(cmd, argv);
    return -1;
}