Function sValidateStagedFileDialogPaths

source/MRViewer/MRFileDialog.cpp:398–432

Validate paths staged by `MR::UI::TestEngine::stageFileDialogPaths` against the dialog's `Parameters`. Empty error means OK. Rules: - paths must be non-empty. - if !multiselect: exactly one path. - saveDialog: target is always a file (no save-folder API). Skip existence check (file may be brand-new), but reject paths that already exist as a directory. - else folderDialog: each path must be an exis

//   - else folderDialog: each path must be an existing directory.
//   - else (open file): each path must be an existing regular file.
MR::Expected<void> sValidateStagedFileDialogPaths(
    const std::vector<std::filesystem::path>& paths,
    const MR::FileDialog::Parameters& parameters )
{
    if ( paths.empty() )
        return MR::unexpected( std::string( "no paths were staged" ) );

    if ( !parameters.multiselect && paths.size() > 1 )
        return MR::unexpected( fmt::format( "dialog expects a single path but {} were staged", paths.size() ) );

    if ( parameters.saveDialog )
    {
        std::error_code ec;
        if ( std::filesystem::is_directory( paths[0], ec ) )
            return MR::unexpected( fmt::format(
                "save target '{}' exists and is a directory, expected a file path",
                MR::utf8string( paths[0] ) ) );
        return {};
    }

    for ( const auto& p : paths )
    {
        std::error_code ec;
        const bool ok = parameters.folderDialog
            ? std::filesystem::is_directory( p, ec )
            : std::filesystem::is_regular_file( p, ec );
        if ( !ok )
        {
            return MR::unexpected( fmt::format( "staged path '{}' is not an existing {}",
                MR::utf8string( p ),
                parameters.folderDialog ? "directory" : "file" ) );
        }
    }
    return {};
}

std::vector<std::filesystem::path> runDialog( const MR::FileDialog::Parameters& parameters )
{