notcurses/include/ncpp/Root.hh
Marek Habersack b5d8549bb3 [C++] Allow multiple instances of NotCurses
This is to make it possible, in the future, to create multiple instances
of `NotCurses` for multiple terminals.  The first instance of
`NotCurses` becomes the default one, so that any instances of other
classes that aren't explicitly created with a pointer to another
`NotCurses` instance still work as expected.

Note that currently trying to call `notcurses_init` twice results in the
following error for me:

    0x55555559bfc0 is already registered for signals
    Couldn't drop signals: 0x55555559bfc0 != 0x5555555b6720
    terminate called after throwing an instance of 'ncpp::init_error*'

    Program received signal SIGABRT, Aborted.

The error is signalled by `setup_signals` and the pointer shown in the
message points to the first `struct notcurses` instance created.
2020-05-26 04:34:31 -04:00

105 lines
2.4 KiB
C++

#ifndef __NCPP_ROOT_HH
#define __NCPP_ROOT_HH
#include <type_traits>
#include <string>
#include <notcurses/notcurses.h>
#include "_helpers.hh"
#include "_exceptions.hh"
namespace ncpp {
#if defined (NCPP_EXCEPTIONS_PLEASE)
#define NOEXCEPT_MAYBE
#else
#define NOEXCEPT_MAYBE noexcept
#endif
class NotCurses;
class NCPP_API_EXPORT Root
{
protected:
static constexpr char ncpp_invalid_state_message[] = "notcurses++ is in an invalid state (already stopped?)";
public:
notcurses* get_notcurses () const;
NotCurses* get_notcurses_cpp () const
{
return nc;
}
protected:
explicit Root (NotCurses *ncinst)
: nc (ncinst)
{}
template<typename TRet = bool, typename TValue = int>
TRet error_guard (TValue ret, TValue error_value) const
{
static constexpr bool ret_is_bool = std::is_same_v<TRet, bool>;
if constexpr (!ret_is_bool) {
static_assert (std::is_same_v<TRet, TValue>, "Both TRet and TValue must be the same type unless TValue is 'bool'");
}
if (ret != error_value) {
if constexpr (ret_is_bool) {
return true;
} else {
return ret;
}
}
#if defined (NCPP_EXCEPTIONS_PLEASE)
throw call_error ("Call returned an error value");
#else
if constexpr (ret_is_bool) {
return false;
} else {
return ret;
}
#endif
}
template<typename TRet = bool, typename TValue = int>
TRet error_guard_cond ([[maybe_unused]] TValue ret, bool error_value) const
{
static constexpr bool ret_is_bool = std::is_same_v<TRet, bool>;
if constexpr (!ret_is_bool) {
static_assert (std::is_same_v<TRet, TValue>, "Both TRet and TValue must be the same type unless TValue is 'bool'");
}
if (!error_value) {
if constexpr (ret_is_bool) {
return true;
} else {
return ret;
}
}
#if defined (NCPP_EXCEPTIONS_PLEASE)
throw call_error ("Call returned an error value");
#else
if constexpr (ret_is_bool) {
return false;
} else {
return ret;
}
#endif
}
// All the objects which need to destroy notcurses entities (planes, panelreel etc etc) **have to** call this
// function before calling to notcurses from their destructor. This is to prevent a segfault when
// NotCurses::stop has been called and the app uses smart pointers holding NotCurses objects which may be
// destructed **after** notcurses is stopped.
bool is_notcurses_stopped () const noexcept;
private:
NotCurses *nc = nullptr;
};
}
#endif