open_file() [2/2]

template<typename T >

T MayaFlux::Portal::System::Dialog::open_file	(	std::function< T(std::filesystem::path)>	on_success,
		std::function< void(Core::SystemDialogError)>	on_error,
		std::vector< ChooserFilter >	filters = {},
		std::filesystem::path	start_dir = {}
	)

Present a native open-file dialog, returning T produced by on_success.

Blocks until the user completes or dismisses the dialog. on_success is called with the chosen path and its return value is returned directly to the caller. on_error is called on cancellation or backend failure; in that case the return value is a default-constructed T.

auto tex = open_file<std::shared_ptr<TextureBuffer>>(
    [](std::filesystem::path p) {
        IO::ImageReader r;
        r.open(p.string());
        return r.create_texture_buffer();
    },
    [](Core::SystemDialogError) {}
);

Template Parameters

T	Return type of on_success.

Parameters

on_success	Called with the chosen path on success. Must return T.
on_error	Called with the error on cancellation or failure.
filters	Extension filter groups shown in the dialog.
start_dir	Directory the dialog opens in. Platform default if empty.

Returns

The value returned by on_success, or a default T on error.

Todo:

Post-0.4: when C++23 is the minimum, add a non-blocking overload using std::expected::transform / and_then on a future-returning variant.

Definition at line 79 of file Chooser.hpp.

                                       {},
    std::filesystem::path start_dir = {})
{
    std::promise<T> promise;
    auto future = promise.get_future();
 
    open_file(
        [&promise, on_success = std::move(on_success), on_error = std::move(on_error)](ChooserResult result) {
            if (result) {
                promise.set_value(on_success(std::move(*result)));
            } else {
                on_error(result.error());
                promise.set_value(T {});
            }
        },
        std::move(filters),
        std::move(start_dir));
 
    return future.get();
}