lix/src/libutil/args.hh
Eelco Dolstra df552ff53e Remove std::string alias (for real this time)
Also use std::string_view in a few more places.
2022-02-25 16:13:02 +01:00

255 lines
6.4 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

#pragma once
#include <iostream>
#include <map>
#include <memory>
#include <nlohmann/json_fwd.hpp>
#include "util.hh"
namespace nix {
enum HashType : char;
class MultiCommand;
class Args
{
public:
/* Parse the command line, throwing a UsageError if something goes
wrong. */
void parseCmdline(const Strings & cmdline);
/* Return a short one-line description of the command. */
virtual std::string description() { return ""; }
/* Return documentation about this command, in Markdown format. */
virtual std::string doc() { return ""; }
protected:
static const size_t ArityAny = std::numeric_limits<size_t>::max();
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)
{ }
Handler(std::vector<std::string> * dest)
: fun([=](std::vector<std::string> ss) { *dest = ss; })
, arity(ArityAny)
{ }
Handler(std::string * dest)
: fun([=](std::vector<std::string> ss) { *dest = ss[0]; })
, arity(1)
{ }
Handler(std::optional<std::string> * 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)
{ }
template<class I>
Handler(I * dest)
: fun([=](std::vector<std::string> ss) {
*dest = string2IntWithUnitPrefix<I>(ss[0]);
})
, arity(1)
{ }
template<class I>
Handler(std::optional<I> * dest)
: fun([=](std::vector<std::string> ss) {
*dest = string2IntWithUnitPrefix<I>(ss[0]);
})
, arity(1)
{ }
};
/* Options. */
struct Flag
{
typedef std::shared_ptr<Flag> ptr;
std::string longName;
std::set<std::string> aliases;
char shortName = 0;
std::string description;
std::string category;
Strings labels;
Handler handler;
std::function<void(size_t, std::string_view)> completer;
static Flag mkHashTypeFlag(std::string && longName, HashType * ht);
static Flag mkHashTypeOptFlag(std::string && longName, std::optional<HashType> * oht);
};
std::map<std::string, Flag::ptr> longFlags;
std::map<char, Flag::ptr> shortFlags;
virtual bool processFlag(Strings::iterator & pos, Strings::iterator end);
/* Positional arguments. */
struct ExpectedArg
{
std::string label;
bool optional = false;
Handler handler;
std::function<void(size_t, std::string_view)> completer;
};
std::list<ExpectedArg> expectedArgs;
virtual bool processArgs(const Strings & args, bool finish);
virtual Strings::iterator rewriteArgs(Strings & args, Strings::iterator pos)
{ return pos; }
std::set<std::string> hiddenCategories;
/* Called after all command line flags before the first non-flag
argument (if any) have been processed. */
virtual void initialFlagsProcessed() {}
public:
void addFlag(Flag && flag);
void removeFlag(const std::string & longName);
void expectArgs(ExpectedArg && arg)
{
expectedArgs.emplace_back(std::move(arg));
}
/* Expect a string argument. */
void expectArg(const std::string & label, std::string * dest, bool optional = false)
{
expectArgs({
.label = label,
.optional = optional,
.handler = {dest}
});
}
/* Expect 0 or more arguments. */
void expectArgs(const std::string & label, std::vector<std::string> * dest)
{
expectArgs({
.label = label,
.handler = {dest}
});
}
virtual nlohmann::json toJSON();
friend class MultiCommand;
MultiCommand * parent = nullptr;
};
/* A command is an argument parser that can be executed by calling its
run() method. */
struct Command : virtual public Args
{
friend class MultiCommand;
virtual ~Command() { }
virtual void prepare() { };
virtual void run() = 0;
typedef int Category;
static constexpr Category catDefault = 0;
virtual Category category() { return catDefault; }
};
typedef std::map<std::string, std::function<ref<Command>()>> Commands;
/* An argument parser that supports multiple subcommands,
i.e. <command> <subcommand>. */
class MultiCommand : virtual public 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);
bool processFlag(Strings::iterator & pos, Strings::iterator end) override;
bool processArgs(const Strings & args, bool finish) override;
nlohmann::json toJSON() override;
};
Strings argvToStrings(int argc, char * * argv);
struct Completion {
std::string completion;
std::string description;
bool operator<(const Completion & other) const;
};
class Completions : public std::set<Completion> {
public:
void add(std::string completion, std::string description = "");
};
extern std::shared_ptr<Completions> completions;
enum CompletionType {
ctNormal,
ctFilenames,
ctAttrs
};
extern CompletionType completionType;
std::optional<std::string> needsCompletion(std::string_view s);
void completePath(size_t, std::string_view prefix);
void completeDir(size_t, std::string_view prefix);
}