lix/src/nix/command.hh
Eelco Dolstra 2da6a42448
nix dump-path: Add
This is primarily useful for extracting NARs from other stores (like
binary caches), which "nix-store --dump" cannot do.
2017-05-04 14:21:22 +02:00

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#pragma once
#include "args.hh"
namespace nix {
struct Value;
class EvalState;
/* 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;
struct Example
{
std::string description;
std::string command;
};
typedef std::list<Example> Examples;
virtual Examples examples() { return Examples(); }
void printHelp(const string & programName, std::ostream & out) override;
};
class Store;
/* A command that require a Nix store. */
struct StoreCommand : virtual Command
{
std::string storeUri;
StoreCommand();
void run() override;
ref<Store> getStore();
virtual ref<Store> createStore();
virtual void run(ref<Store>) = 0;
private:
std::shared_ptr<Store> _store;
};
struct Installable
{
virtual std::string what() = 0;
virtual PathSet toBuildable()
{
throw Error("argument %s cannot be built", what());
}
virtual Value * toValue(EvalState & state)
{
throw Error("argument %s cannot be evaluated", what());
}
};
/* A command that operates on a list of "installables", which can be
store paths, attribute paths, Nix expressions, etc. */
struct InstallablesCommand : virtual Args, StoreCommand
{
std::vector<std::shared_ptr<Installable>> installables;
Path file;
InstallablesCommand()
{
mkFlag('f', "file", "file", "evaluate FILE rather than the default", &file);
expectArgs("installables", &_installables);
}
/* Return a value representing the Nix expression from which we
are installing. This is either the file specified by --file,
or an attribute set constructed from $NIX_PATH, e.g. { nixpkgs
= import ...; bla = import ...; }. */
Value * getSourceExpr(EvalState & state);
std::vector<std::shared_ptr<Installable>> parseInstallables(ref<Store> store, Strings ss);
PathSet buildInstallables(ref<Store> store, bool dryRun);
ref<EvalState> getEvalState();
void prepare() override;
virtual bool useDefaultInstallables() { return true; }
private:
Strings _installables;
std::shared_ptr<EvalState> evalState;
Value * vSourceExpr = 0;
};
/* A command that operates on zero or more store paths. */
struct StorePathsCommand : public InstallablesCommand
{
private:
bool recursive = false;
bool all = false;
public:
StorePathsCommand();
using StoreCommand::run;
virtual void run(ref<Store> store, Paths storePaths) = 0;
void run(ref<Store> store) override;
bool useDefaultInstallables() override { return !all; }
};
/* A command that operates on exactly one store path. */
struct StorePathCommand : public InstallablesCommand
{
using StoreCommand::run;
virtual void run(ref<Store> store, const Path & storePath) = 0;
void run(ref<Store> store) override;
};
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);
}
};
}