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#pragma once
#include <iostream>
#include <map>
#include <memory>
#include "util.hh"
namespace nix {
MakeError(UsageError, Error);
enum struct HashType : char;
class Args
{
public:
/* Parse the command line, throwing a UsageError if something goes
wrong. */
void parseCmdline(const Strings & cmdline);
virtual void printHelp(const string & programName, std::ostream & out);
virtual std::string description() { return ""; }
protected:
static const size_t ArityAny = std::numeric_limits<size_t>::max();
/* Flags. */
struct Flag
{
typedef std::shared_ptr<Flag> ptr;
struct Handler
{
std::function<void(std::vector<std::string>)> fun;
size_t arity;
Handler() {}
Handler(std::function<void(std::vector<std::string>)> && fun)
: fun(std::move(fun))
, arity(ArityAny)
{ }
Handler(std::function<void()> && handler)
: fun([handler{std::move(handler)}](std::vector<std::string>) { handler(); })
, arity(0)
{ }
Handler(std::function<void(std::string)> && handler)
: fun([handler{std::move(handler)}](std::vector<std::string> ss) {
handler(std::move(ss[0]));
})
, arity(1)
{ }
Handler(std::function<void(std::string, std::string)> && handler)
: fun([handler{std::move(handler)}](std::vector<std::string> ss) {
handler(std::move(ss[0]), std::move(ss[1]));
})
, arity(2)
{ }
template<class T>
Handler(T * dest)
: fun([=](std::vector<std::string> ss) { *dest = ss[0]; })
, arity(1)
{ }
template<class T>
Handler(T * dest, const T & val)
: fun([=](std::vector<std::string> ss) { *dest = val; })
, arity(0)
{ }
};
std::string longName;
char shortName = 0;
std::string description;
std::string category;
Strings labels;
Handler handler;
static Flag mkHashTypeFlag(std::string && longName, HashType * ht);
};
std::map<std::string, Flag::ptr> longFlags;
std::map<char, Flag::ptr> shortFlags;
virtual bool processFlag(Strings::iterator & pos, Strings::iterator end);
virtual void printFlags(std::ostream & out);
/* Positional arguments. */
struct ExpectedArg
{
std::string label;
size_t arity; // 0 = any
bool optional;
std::function<void(std::vector<std::string>)> handler;
};
std::list<ExpectedArg> expectedArgs;
virtual bool processArgs(const Strings & args, bool finish);
std::set<std::string> hiddenCategories;
public:
void addFlag(Flag && flag);
/* Helper functions for constructing flags / positional
arguments. */
void mkFlag1(char shortName, const std::string & longName,
const std::string & label, const std::string & description,
std::function<void(std::string)> fun)
{
addFlag({
.longName = longName,
.shortName = shortName,
.description = description,
.labels = {label},
.handler = {[=](std::string s) { fun(s); }}
});
}
void mkFlag(char shortName, const std::string & name,
const std::string & description, bool * dest)
{
mkFlag(shortName, name, description, dest, true);
}
template<class T>
void mkFlag(char shortName, const std::string & longName, const std::string & description,
T * dest, const T & value)
{
addFlag({
.longName = longName,
.shortName = shortName,
.description = description,
.handler = {[=]() { *dest = value; }}
});
}
template<class I>
void mkIntFlag(char shortName, const std::string & longName,
const std::string & description, I * dest)
{
mkFlag<I>(shortName, longName, description, [=](I n) {
*dest = n;
});
}
template<class I>
void mkFlag(char shortName, const std::string & longName,
const std::string & description, std::function<void(I)> fun)
{
addFlag({
.longName = longName,
.shortName = shortName,
.description = description,
.labels = {"N"},
.handler = {[=](std::string s) {
I n;
if (!string2Int(s, n))
throw UsageError("flag '--%s' requires a integer argument", longName);
fun(n);
}}
});
}
/* Expect a string argument. */
void expectArg(const std::string & label, string * dest, bool optional = false)
{
expectedArgs.push_back(ExpectedArg{label, 1, optional, [=](std::vector<std::string> ss) {
*dest = ss[0];
}});
}
/* Expect 0 or more arguments. */
void expectArgs(const std::string & label, std::vector<std::string> * dest)
{
expectedArgs.push_back(ExpectedArg{label, 0, false, [=](std::vector<std::string> ss) {
*dest = std::move(ss);
}});
}
friend class MultiCommand;
};
/* A command is an argument parser that can be executed by calling its
run() method. */
struct Command : virtual Args
{
friend class MultiCommand;
virtual ~Command() { }
virtual void prepare() { };
virtual void run() = 0;
struct Example
{
std::string description;
std::string command;
};
typedef std::list<Example> Examples;
virtual Examples examples() { return Examples(); }
typedef int Category;
static constexpr Category catDefault = 0;
virtual Category category() { return catDefault; }
void printHelp(const string & programName, std::ostream & out) override;
};
typedef std::map<std::string, std::function<ref<Command>()>> Commands;
/* An argument parser that supports multiple subcommands,
i.e. ‘<command> <subcommand>’. */
class MultiCommand : virtual Args
{
public:
Commands commands;
std::map<Command::Category, std::string> categories;
// Selected command, if any.
std::optional<std::pair<std::string, ref<Command>>> command;
MultiCommand(const Commands & commands);
void printHelp(const string & programName, std::ostream & out) override;
bool processFlag(Strings::iterator & pos, Strings::iterator end) override;
bool processArgs(const Strings & args, bool finish) override;
};
Strings argvToStrings(int argc, char * * argv);
/* Helper function for rendering argument labels. */
std::string renderLabels(const Strings & labels);
/* Helper function for printing 2-column tables. */
typedef std::vector<std::pair<std::string, std::string>> Table2;
void printTable(std::ostream & out, const Table2 & table);
}
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