libcruft-util/cmdopt.hpp

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/*
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* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* Copyright 2013-2016 Danny Robson <danny@nerdcruft.net>
*/
#pragma once
#include "introspection/name.hpp"
#include "introspection/enum.hpp"
#include "iterator/infix.hpp"
#include <exception>
#include <functional>
#include <memory>
#include <string>
#include <vector>
#include <map>
#include <sstream>
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///////////////////////////////////////////////////////////////////////////////
namespace cruft::cmdopt {
///////////////////////////////////////////////////////////////////////////
class error : public std::exception { };
//-------------------------------------------------------------------------
class invalid_key : public error {
public:
explicit invalid_key (std::string _key);
const char* what (void) const noexcept override;
private:
const std::string m_key;
};
//-------------------------------------------------------------------------
class invalid_value : public error {
public:
explicit invalid_value (std::string _value);
const char* what (void) const noexcept override;
private:
const std::string m_value;
};
//-------------------------------------------------------------------------
class invalid_null : public error {
public:
const char* what (void) const noexcept override;
};
//-------------------------------------------------------------------------
class invalid_required : public error {
public:
const char* what (void) const noexcept override;
};
//-------------------------------------------------------------------------
class unhandled_argument : public error {
public:
explicit unhandled_argument (int index);
const char* what (void) const noexcept override;
int index (void) const noexcept;
private:
const int m_index;
};
namespace option { class base; }
///////////////////////////////////////////////////////////////////////////
namespace option {
class base {
public:
base ();
// we deal almost exclusively with vtables, so disable copying
// just in case we do something stupid.
base (const base&) = delete;
base& operator= (const base&) = delete;
virtual ~base ();
virtual void execute (void);
virtual void execute (const char *restrict);
virtual void start (void);
virtual void finish (void);
virtual const std::string& example (void) const = 0;
/// Sets a callback query to determine if the option is required.
///
/// The default is `return false;`
void required (std::function<bool(void)>);
/// Sets a constant value function for the required query.
/// The value provided will be unconditionally returned.
void required (bool);
/// Tests if the option is required by invoking the stored query.
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bool required (void) const;
/// Tests if the option has been seen.
///
/// Not to be confused with `fulfilled` which describes whether
/// the `seen` and `required` constraints are both satisfied.
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bool seen (void) const;
/// Sets the seen flag of the option to the value provided.
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bool seen (bool);
/// Tests if all `required` and `seen` constraints have been
/// satisfied.
///
/// If there are no `required` constraints it return true.
bool fulfilled (void) const;
private:
std::function<bool(void)> m_required;
bool m_seen = false;
};
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class null : public base {
public:
virtual void execute (void) override;
virtual void execute (const char *restrict) override;
virtual const std::string& example (void) const override;
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};
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class present : public base {
public:
explicit present (bool&);
explicit present (bool&&) = delete;
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using base::execute;
virtual void execute (void) override;
virtual const std::string& example (void) const override;
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virtual void finish (void) override;
private:
bool &m_data;
};
namespace detail {
template <typename T>
std::enable_if_t<!std::is_enum<T>::value, const std::string&>
value_example (void)
{
static const std::string EXAMPLE =
std::string {"<"} +
std::string {cruft::introspection::name::bare<T> ()} +
std::string {">"};
return EXAMPLE;
}
template <typename T>
std::enable_if_t<std::is_enum<T>::value, const std::string&>
value_example (void)
{
static const std::string EXAMPLE = [] (void) {
std::ostringstream os;
std::copy (std::cbegin (introspection::enum_traits<T>::names),
std::cend (introspection::enum_traits<T>::names),
iterator::infix_iterator<const char*> (os, "|"));
return os.str ();
} ();
return EXAMPLE;
}
}
template <typename T>
class value : public base {
public:
explicit value (T &_data): m_data (_data) { }
explicit value (T&&) = delete;
using base::execute;
void execute (const char *restrict str) override
{
try {
std::istringstream is (str);
is.exceptions (
std::istringstream::failbit
| std::istringstream::badbit
);
is >> m_data;
} catch (...) {
throw invalid_value (__func__);
}
seen (true);
}
/// Returns a callback that tests if this option has been set to
/// a specified value.
///
/// If the option has not been seen it is treated as
/// unconditionally not equal.
///
/// The returned function is handy to use in the `required`
/// clauses of dependent options.
template <typename TargetT>
std::function<bool(void)>
is (TargetT &&_target)&
{
return [&, target = std::forward<TargetT>(_target)] (void) {
return seen () && m_data == target;
};
}
const std::string& example (void) const override
{
return detail::value_example<T> ();
}
const T& data (void) const&
{
return m_data;
}
T& data (void) &
{
return m_data;
}
T& data (T _data) &
{
return m_data = _data;
}
private:
T& m_data;
};
template <>
inline void
value<bool>::execute (const char *restrict str)
{
static const std::string TRUE_STRING[] = {
"true",
"yes",
"y",
"1"
};
if (std::any_of (std::begin (TRUE_STRING),
std::end (TRUE_STRING),
[str] (auto i) { return i == str; }))
{
m_data = true;
return;
}
static const std::string FALSE_STRING[] = {
"false",
"no",
"n",
"0"
};
if (std::any_of (std::begin (FALSE_STRING),
std::end (FALSE_STRING),
[str] (auto i) { return i == str; }))
{
m_data = false;
return;
}
base::execute (str);
seen (true);
}
template <typename T = unsigned>
class count : public value<T> {
public:
explicit count (T&);
explicit count (T&&) = delete;
using value<T>::execute;
void execute (void) override;
};
class bytes : public value<size_t> {
public:
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explicit bytes (size_t &_value): value (_value) { }
using value<size_t>::execute;
void execute (const char *restrict) override;
};
}
//-------------------------------------------------------------------------
class parser {
public:
template <typename T, typename ...Args>
T& add (char shortname,
std::string longname,
std::string description,
Args&&... args)
{
auto handler = std::make_unique<T> (std::forward<Args> (args)...);
T& ref = *handler;
m_short.insert({ shortname, ref });
m_long.insert({ std::move (longname), ref });
m_options.push_back ({ std::move (description), std::move (handler) });
return ref;
}
template <typename T, typename ...Args>
T&
append (std::string description, Args&&...args)
{
auto handler = std::make_unique<T> (std::forward<Args> (args)...);
auto &ref = *handler;
m_positional.push_back (ref);
m_options.push_back ({ std::move (description), std::move (handler) });
return ref;
}
int scan (int argc, const char *const *argv);
private:
int parse_long (int pos, int argc, const char *const *argv);
int parse_short (int pos, int argc, const char *const *argv);
void print_help [[noreturn]] (int argc, const char *const *argv) const;
std::map<char,std::reference_wrapper<option::base>> m_short;
std::map<std::string,std::reference_wrapper<option::base>> m_long;
std::vector<std::reference_wrapper<option::base>> m_positional;
struct entry {
std::string description;
std::unique_ptr<option::base> handler;
};
std::vector<entry> m_options;
};
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}