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parseExperimentalFeature(): Initialize atomically

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This commit is contained in:
Eelco Dolstra 2021-10-26 14:29:48 +02:00
parent 9ce84c64c5
commit 0d9e050ba7
1 changed files with 12 additions and 8 deletions
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20
src/libutil/experimental-features.cc
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@ -1,4 +1,6 @@
#include "experimental-features.hh"
#include "util.hh"
#include "nlohmann/json.hpp"
namespace nix {
@ -14,17 +16,19 @@ std::map<ExperimentalFeature, std::string> stringifiedXpFeatures = {
const std::optional<ExperimentalFeature> parseExperimentalFeature(const std::string_view & name)
{
using ReverseXpMap = std::map<std::string_view, ExperimentalFeature>;
static ReverseXpMap * reverseXpMap;
if (!reverseXpMap) {
reverseXpMap = new ReverseXpMap{};
static auto reverseXpMap = []()
{
auto reverseXpMap = std::make_unique<ReverseXpMap>();
for (auto & [feature, name] : stringifiedXpFeatures)
(*reverseXpMap)[name] = feature;
}
return reverseXpMap;
}();
auto featureIter = reverseXpMap->find(name);
if (featureIter == reverseXpMap->end())
if (auto feature = get(*reverseXpMap, name))
return *feature;
else
return std::nullopt;
return {featureIter->second};
}
std::string_view showExperimentalFeature(const ExperimentalFeature feature)
@ -45,7 +49,7 @@ std::set<ExperimentalFeature> parseFeatures(const std::set<std::string> & rawFea
MissingExperimentalFeature::MissingExperimentalFeature(ExperimentalFeature feature)
: Error("experimental Nix feature '%1%' is disabled; use '--extra-experimental-features %1%' to override", showExperimentalFeature(feature))
, missingFeature(feature)
{}
{}
std::ostream & operator <<(std::ostream & str, const ExperimentalFeature & feature)
{