[coro_file][improve]do some improvement

[qicosmos]

Why

allow use fread and pread at the same time. support random read for uring.

open file with read_type:

• read_type::uring : io_uring stream file;
• read_type::uring_random : io_uring random file;
• read_type::fread : FILE;
• read_type::pread : fd;

enum class read_type {
#if defined(YLT_ENABLE_FILE_IO_URING)
  uring,
  uring_random,
#else
  fread,
#endif
#if defined(__GNUC__)
  pread,
#endif
};

pread

{
    coro_io::coro_file file{};
    co_await file.async_open(
            filename.data(), coro_io::flags::read_only, coro_io::read_type::pread);
    
    char buf[100];
    co_await file.async_pread(10, buf, 100);
}

{
    coro_io::coro_file file{};
    co_await file.async_open(
            filename.data(), coro_io::flags::read_write, coro_io::read_type::pread);
    
    std::string buf = "cccccccccc";
    co_await file.async_pwrite(10, buf.data(), buf.size());
}

uring random read

{
  coro_io::coro_file file{};
  co_await file.async_open(filename.data(), coro_io::flags::read_only,
                        coro_io::read_type::uring_random);

  char buf[100];
  file.async_read_some_at(10, buf, 100);
}

{
  coro_io::coro_file file{};
  co_await file.async_open(filename.data(), coro_io::flags::read_write,
                        coro_io::read_type::uring_random);

  std::string buf = "cccccccccc";
  file.async_write_some_at(10, buf.data(), buf.size());
}

uring read

{
  coro_io::coro_file file{};
  co_await file.async_open(filename.data(), coro_io::flags::read_only,
                        coro_io::read_type::uring);

  char buf[100];
  file.async_read(buf, 100);
}

{
  coro_io::coro_file file{};
  co_await file.async_open(filename.data(), coro_io::flags::read_write,
                        coro_io::read_type::uring);

  std::string buf = "cccccccccc";
  file.async_write(buf.data(), buf.size());
}

fread

{
  coro_io::coro_file file{};
  co_await file.async_open(filename.data(), coro_io::flags::read_only,
                        coro_io::read_type::fread);

  char buf[100];
  file.async_read(buf, 100);
}

{
  coro_io::coro_file file{};
  co_await file.async_open(filename.data(), coro_io::flags::read_write,
                        coro_io::read_type::fread);

  std::string buf = "cccccccccc";
  file.async_write(buf.data(), buf.size());
}

What is changing

Example