nix-super/src/libstore/derived-path.hh

128 lines
3.3 KiB
C++

#pragma once
#include "util.hh"
#include "path.hh"
#include "realisation.hh"
#include <optional>
#include <nlohmann/json_fwd.hpp>
namespace nix {
class Store;
/**
* An opaque derived path.
*
* Opaque derived paths are just store paths, and fully evaluated. They
* cannot be simplified further. Since they are opaque, they cannot be
* built, but they can fetched.
*/
struct DerivedPathOpaque {
StorePath path;
nlohmann::json toJSON(ref<Store> store) const;
std::string to_string(const Store & store) const;
static DerivedPathOpaque parse(const Store & store, std::string_view);
bool operator < (const DerivedPathOpaque & b) const
{ return path < b.path; }
};
/**
* A derived path that is built from a derivation
*
* Built derived paths are pair of a derivation and some output names.
* They are evaluated by building the derivation, and then replacing the
* output names with the resulting outputs.
*
* Note that does mean a derived store paths evaluates to multiple
* opaque paths, which is sort of icky as expressions are supposed to
* evaluate to single values. Perhaps this should have just a single
* output name.
*/
struct DerivedPathBuilt {
StorePath drvPath;
std::set<std::string> outputs;
std::string to_string(const Store & store) const;
static DerivedPathBuilt parse(const Store & store, std::string_view, std::string_view);
nlohmann::json toJSON(ref<Store> store) const;
bool operator < (const DerivedPathBuilt & b) const
{ return std::make_pair(drvPath, outputs) < std::make_pair(b.drvPath, b.outputs); }
};
using _DerivedPathRaw = std::variant<
DerivedPathOpaque,
DerivedPathBuilt
>;
/**
* A "derived path" is a very simple sort of expression that evaluates
* to (concrete) store path. It is either:
*
* - opaque, in which case it is just a concrete store path with
* possibly no known derivation
*
* - built, in which case it is a pair of a derivation path and an
* output name.
*/
struct DerivedPath : _DerivedPathRaw {
using Raw = _DerivedPathRaw;
using Raw::Raw;
using Opaque = DerivedPathOpaque;
using Built = DerivedPathBuilt;
inline const Raw & raw() const {
return static_cast<const Raw &>(*this);
}
std::string to_string(const Store & store) const;
static DerivedPath parse(const Store & store, std::string_view);
};
/**
* A built derived path with hints in the form of optional concrete output paths.
*
* See 'BuiltPath' for more an explanation.
*/
struct BuiltPathBuilt {
StorePath drvPath;
std::map<std::string, StorePath> outputs;
nlohmann::json toJSON(ref<Store> store) const;
static BuiltPathBuilt parse(const Store & store, std::string_view);
};
using _BuiltPathRaw = std::variant<
DerivedPath::Opaque,
BuiltPathBuilt
>;
/**
* A built path. Similar to a `DerivedPath`, but enriched with the corresponding
* output path(s).
*/
struct BuiltPath : _BuiltPathRaw {
using Raw = _BuiltPathRaw;
using Raw::Raw;
using Opaque = DerivedPathOpaque;
using Built = BuiltPathBuilt;
inline const Raw & raw() const {
return static_cast<const Raw &>(*this);
}
StorePathSet outPaths() const;
RealisedPath::Set toRealisedPaths(Store & store) const;
};
typedef std::vector<DerivedPath> DerivedPaths;
typedef std::vector<BuiltPath> BuiltPaths;
}