forked from lix-project/lix
15f7fa59be
Adds a new boolean structured attribute
`outputChecks.<output>.unsafeDiscardReferences` which disables scanning
an output for runtime references.
__structuredAttrs = true;
outputChecks.out.unsafeDiscardReferences = true;
This is useful when creating filesystem images containing their own embedded Nix
store: they are self-contained blobs of data with no runtime dependencies.
Setting this attribute requires the experimental feature
`discard-references` to be enabled.
84 lines
2.4 KiB
C++
84 lines
2.4 KiB
C++
#include "experimental-features.hh"
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#include "util.hh"
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#include "nlohmann/json.hpp"
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namespace nix {
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std::map<ExperimentalFeature, std::string> stringifiedXpFeatures = {
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{ Xp::CaDerivations, "ca-derivations" },
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{ Xp::ImpureDerivations, "impure-derivations" },
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{ Xp::Flakes, "flakes" },
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{ Xp::NixCommand, "nix-command" },
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{ Xp::RecursiveNix, "recursive-nix" },
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{ Xp::NoUrlLiterals, "no-url-literals" },
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{ Xp::FetchClosure, "fetch-closure" },
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{ Xp::ReplFlake, "repl-flake" },
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{ Xp::AutoAllocateUids, "auto-allocate-uids" },
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{ Xp::Cgroups, "cgroups" },
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{ Xp::DiscardReferences, "discard-references" },
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};
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const std::optional<ExperimentalFeature> parseExperimentalFeature(const std::string_view & name)
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{
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using ReverseXpMap = std::map<std::string_view, ExperimentalFeature>;
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static auto reverseXpMap = []()
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{
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auto reverseXpMap = std::make_unique<ReverseXpMap>();
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for (auto & [feature, name] : stringifiedXpFeatures)
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(*reverseXpMap)[name] = feature;
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return reverseXpMap;
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}();
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if (auto feature = get(*reverseXpMap, name))
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return *feature;
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else
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return std::nullopt;
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}
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std::string_view showExperimentalFeature(const ExperimentalFeature feature)
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{
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const auto ret = get(stringifiedXpFeatures, feature);
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assert(ret);
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return *ret;
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}
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std::set<ExperimentalFeature> parseFeatures(const std::set<std::string> & rawFeatures)
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{
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std::set<ExperimentalFeature> res;
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for (auto & rawFeature : rawFeatures) {
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if (auto feature = parseExperimentalFeature(rawFeature))
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res.insert(*feature);
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}
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return res;
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}
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MissingExperimentalFeature::MissingExperimentalFeature(ExperimentalFeature feature)
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: Error("experimental Nix feature '%1%' is disabled; use '--extra-experimental-features %1%' to override", showExperimentalFeature(feature))
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, missingFeature(feature)
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{}
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std::ostream & operator <<(std::ostream & str, const ExperimentalFeature & feature)
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{
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return str << showExperimentalFeature(feature);
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}
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void to_json(nlohmann::json & j, const ExperimentalFeature & feature)
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{
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j = showExperimentalFeature(feature);
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}
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void from_json(const nlohmann::json & j, ExperimentalFeature & feature)
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{
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const std::string input = j;
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const auto parsed = parseExperimentalFeature(input);
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if (parsed.has_value())
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feature = *parsed;
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else
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throw Error("Unknown experimental feature '%s' in JSON input", input);
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}
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}
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