seqan3::output_directory_validator Class Reference

A validator that checks if a given path is a valid output directory. More...

#include <seqan3/argument_parser/validators.hpp>

Inheritance diagram for seqan3::output_directory_validator:

Public Types
using	option_value_type
	Type of values that are tested by validator.
Public Types inherited from seqan3::file_validator_base
using	option_value_type = std::string
	Type of values that are tested by validator.

Public Member Functions
std::string	get_help_page_message () const
	Returns a message that can be appended to the (positional) options help page info.
template<std::ranges::forward_range range_type> requires (std::convertible_to<std::ranges::range_value_t<range_type>, std::filesystem::path const &> && !std::convertible_to<range_type, std::filesystem::path const &>)
void	operator() (range_type const &v) const
	Tests whether every path in list v passes validation. See operator()(option_value_type const & value) for further information.
virtual void	operator() (std::filesystem::path const &dir) const override
	Tests whether path is writable.
Constructors, destructor and assignment
	output_directory_validator ()=default
	Defaulted.
	output_directory_validator (output_directory_validator const &)=default
	Defaulted.
	output_directory_validator (output_directory_validator &&)=default
	Defaulted.
output_directory_validator &	operator= (output_directory_validator const &)=default
	Defaulted.
output_directory_validator &	operator= (output_directory_validator &&)=default
	Defaulted.
virtual	~output_directory_validator ()=default
	Virtual Destructor.
	file_validator_base ()=default
	Defaulted.
	file_validator_base (file_validator_base const &)=default
	Defaulted.
	file_validator_base (file_validator_base &&)=default
	Defaulted.
Public Member Functions inherited from seqan3::file_validator_base
template<std::ranges::forward_range range_type> requires (std::convertible_to<std::ranges::range_value_t<range_type>, std::filesystem::path const &> && !std::convertible_to<range_type, std::filesystem::path const &>)
void	operator() (range_type const &v) const
	Tests whether every path in list v passes validation. See operator()(option_value_type const & value) for further information.
	file_validator_base ()=default
	Defaulted.
	file_validator_base (file_validator_base const &)=default
	Defaulted.
	file_validator_base (file_validator_base &&)=default
	Defaulted.
file_validator_base &	operator= (file_validator_base const &)=default
	Defaulted.
file_validator_base &	operator= (file_validator_base &&)=default
	Defaulted.
virtual	~file_validator_base ()=default
	Virtual destructor.

Additional Inherited Members
Protected Member Functions inherited from seqan3::file_validator_base
bool	case_insensitive_string_ends_with (std::string_view str, std::string_view suffix) const
	Helper function that checks if a string is a suffix of another string. Case insensitive.
std::string	valid_extensions_help_page_message () const
	Returns the information of valid file extensions.
void	validate_filename (std::filesystem::path const &path) const
	Validates the given filename path based on the specified extensions.
void	validate_readability (std::filesystem::path const &path) const
	Checks if the given path is readable.
void	validate_writeability (std::filesystem::path const &path) const
	Checks if the given path is writable.
Protected Attributes inherited from seqan3::file_validator_base
std::vector< std::string >	extensions {}
	Stores the extensions.
Related Symbols inherited from validator
using	option_value_type
	The type of value on which the validator is called on.
void	operator() (option_value_type const &cmp) const
	Validates the value 'cmp' and throws a seqan3::validation_error on failure.

Detailed Description

A validator that checks if a given path is a valid output directory.

The class acts as a functor that throws a seqan3::validation_error exception whenever a given path (std::filesystem::path) is not writable. This can happen if either the parent path does not exists, or the path doesn't have the proper write permissions.

// SPDX-FileCopyrightText: 2006-2025 Knut Reinert & Freie Universität Berlin
// SPDX-FileCopyrightText: 2016-2025 Knut Reinert & MPI für molekulare Genetik
// SPDX-License-Identifier: CC0-1.0
 
#include <filesystem>
 
#include <seqan3/argument_parser/all.hpp>
#include <seqan3/core/debug_stream.hpp>
 
int main(int argc, char const ** argv)
{
    seqan3::argument_parser myparser{"Test", argc, argv}; // initialize

    std::filesystem::path mydir{};
 
    myparser.add_option(mydir,
                        'd',
                        "dir",
                        "The output directory for storing the files.",
                        seqan3::option_spec::standard,
                        seqan3::output_directory_validator{});
 
    // an exception will be thrown if the user specifies a directory that cannot be created by the filesystem either
    // because the parent path does not exists or the path has insufficient write permissions.
    try
    {
        myparser.parse();
    }
    catch (seqan3::argument_parser_error const & ext) // the user did something wrong
    {
        std::cerr << "[PARSER ERROR] " << ext.what() << "\n"; // customize your error message
        return -1;
    }
 
    seqan3::debug_stream << "directory given by user passed validation: " << mydir << "\n";
    return 0;
}

Note

The validator works on every type that can be implicitly converted to std::filesystem::path.

Remarks

For a complete overview, take a look at Argument Parser

Member Function Documentation

get_help_page_message()

std::string seqan3::output_directory_validator::get_help_page_message ( ) const

inline

Returns a message that can be appended to the (positional) options help page info.

Implements validator.

operator()() [1/2]

template<std::ranges::forward_range range_type>
requires (std::convertible_to<std::ranges::range_value_t<range_type>, std::filesystem::path const &> && !std::convertible_to<range_type, std::filesystem::path const &>)

void seqan3::file_validator_base::operator() ( range_type const & v ) const

inline

Tests whether every path in list v passes validation. See operator()(option_value_type const & value) for further information.

Template Parameters

range_type

The type of range to check; must model std::ranges::forward_range and the value type must be convertible to std::filesystem::path.

Parameters

v	The input range to iterate over and check every element.

Exceptions

seqan3::validation_error

operator()() [2/2]

virtual void seqan3::output_directory_validator::operator() ( std::filesystem::path const & dir ) const

inlineoverridevirtual

Tests whether path is writable.

Parameters

dir	The input value to check.

Exceptions

seqan3::validation_error

if the validation process failed. Might be nested with std::filesystem::filesystem_error on unhandled OS API errors.

Implements seqan3::file_validator_base.

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The documentation for this class was generated from the following file:

• validators.hpp