lix/src/nix/command.hh

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#pragma once
#include "args.hh"
namespace nix {
/* A command is an argument parser that can be executed by calling its
run() method. */
struct Command : virtual Args
{
virtual std::string name() = 0;
virtual void prepare() { };
virtual void run() = 0;
};
class Store;
/* A command that require a Nix store. */
struct StoreCommand : virtual Command
{
bool reserveSpace;
StoreCommand(bool reserveSpace = true)
: reserveSpace(reserveSpace) { };
void run() override;
virtual void run(ref<Store>) = 0;
};
typedef std::map<std::string, ref<Command>> Commands;
/* An argument parser that supports multiple subcommands,
i.e. <command> <subcommand>. */
class MultiCommand : virtual Args
{
public:
Commands commands;
std::shared_ptr<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;
};
/* A helper class for registering commands globally. */
struct RegisterCommand
{
static Commands * commands;
RegisterCommand(ref<Command> command)
{
if (!commands) commands = new Commands;
commands->emplace(command->name(), command);
}
};
}