chore: use C++17 features

core/CMakeLists.txt

@@ -20,7 +20,7 @@ add_library(${PROJECT_NAME}::core ALIAS core)
 
 target_compile_features(core
   PUBLIC
-    cxx_std_11
+    cxx_std_17
 )
 
 target_link_libraries(core

core/include/prometheus/detail/ckms_quantiles.h

@@ -9,8 +9,7 @@
 
 // IWYU pragma: private, include "prometheus/summary.h"
 
-namespace prometheus {
-namespace detail {
+namespace prometheus::detail {
 
 class PROMETHEUS_CPP_CORE_EXPORT CKMSQuantiles {
  public:
@@ -53,5 +52,4 @@ class PROMETHEUS_CPP_CORE_EXPORT CKMSQuantiles {
   std::size_t buffer_count_;
 };
 
-}  // namespace detail
-}  // namespace prometheus
+}  // namespace prometheus::detail

core/include/prometheus/detail/time_window_quantiles.h

@@ -9,8 +9,7 @@
 
 // IWYU pragma: private, include "prometheus/summary.h"
 
-namespace prometheus {
-namespace detail {
+namespace prometheus::detail {
 
 class PROMETHEUS_CPP_CORE_EXPORT TimeWindowQuantiles {
   using Clock = std::chrono::steady_clock;
@@ -33,5 +32,4 @@ class PROMETHEUS_CPP_CORE_EXPORT TimeWindowQuantiles {
   const Clock::duration rotation_interval_;
 };
 
-}  // namespace detail
-}  // namespace prometheus
+}  // namespace prometheus::detail

core/include/prometheus/detail/utils.h

@@ -5,8 +5,7 @@
 #include "prometheus/detail/core_export.h"
 #include "prometheus/labels.h"
 
-namespace prometheus {
-namespace detail {
+namespace prometheus::detail {
 
 /// \brief Label hasher for use in STL containers.
 struct PROMETHEUS_CPP_CORE_EXPORT LabelHasher {
@@ -18,5 +17,4 @@ struct PROMETHEUS_CPP_CORE_EXPORT LabelHasher {
   std::size_t operator()(const Labels& labels) const;
 };
 
-}  // namespace detail
-}  // namespace prometheus
+}  // namespace prometheus::detail

core/include/prometheus/family.h

@@ -9,7 +9,6 @@
 #include "prometheus/client_metric.h"
 #include "prometheus/collectable.h"
 #include "prometheus/detail/core_export.h"
-#include "prometheus/detail/future_std.h"
 #include "prometheus/detail/utils.h"
 #include "prometheus/labels.h"
 #include "prometheus/metric_family.h"
@@ -111,7 +110,7 @@ class PROMETHEUS_CPP_CORE_EXPORT Family : public Collectable {
   /// \throw std::invalid_argument on invalid label names.
   template <typename... Args>
   T& Add(const Labels& labels, Args&&... args) {
-    return Add(labels, detail::make_unique<T>(args...));
+    return Add(labels, std::make_unique<T>(args...));
   }
 
   /// \brief Remove the given dimensional data.

core/src/detail/ckms_quantiles.cc

@@ -5,8 +5,7 @@
 #include <limits>
 #include <memory>
 
-namespace prometheus {
-namespace detail {
+namespace prometheus::detail {
 
 CKMSQuantiles::Quantile::Quantile(double quantile, double error)
     : quantile(quantile),
@@ -149,5 +148,4 @@ void CKMSQuantiles::compress() {
   }
 }
 
-}  // namespace detail
-}  // namespace prometheus
+}  // namespace prometheus::detail

core/src/detail/hash.h

@@ -3,9 +3,7 @@
 #include <cstddef>
 #include <functional>
 
-namespace prometheus {
-
-namespace detail {
+namespace prometheus::detail {
 
 /// \brief Combine a hash value with nothing.
 /// It's the boundary condition of this serial functions.
@@ -34,6 +32,4 @@ inline void hash_combine(std::size_t* seed, const T& value,
   hash_combine(seed, args...);
 }
 
-}  // namespace detail
-
-}  // namespace prometheus
+}  // namespace prometheus::detail

core/src/detail/time_window_quantiles.cc

@@ -3,8 +3,7 @@
 #include <memory>
 #include <ratio>
 
-namespace prometheus {
-namespace detail {
+namespace prometheus::detail {
 
 TimeWindowQuantiles::TimeWindowQuantiles(
     const std::vector<CKMSQuantiles::Quantile>& quantiles,
@@ -42,5 +41,4 @@ CKMSQuantiles& TimeWindowQuantiles::rotate() const {
   return ckms_quantiles_[current_bucket_];
 }
 
-}  // namespace detail
-}  // namespace prometheus
+}  // namespace prometheus::detail

core/src/detail/utils.cc

@@ -6,9 +6,7 @@
 
 #include "hash.h"
 
-namespace prometheus {
-
-namespace detail {
+namespace prometheus::detail {
 
 std::size_t LabelHasher::operator()(const Labels& labels) const {
   std::size_t seed = 0;
@@ -19,6 +17,4 @@ std::size_t LabelHasher::operator()(const Labels& labels) const {
   return seed;
 }
 
-}  // namespace detail
-
-}  // namespace prometheus
+}  // namespace prometheus::detail

core/src/family.cc

@@ -22,8 +22,7 @@ Family<T>::Family(const std::string& name, const std::string& help,
   if (!CheckMetricName(name_)) {
     throw std::invalid_argument("Invalid metric name");
   }
-  for (auto& label_pair : constant_labels_) {
-    auto& label_name = label_pair.first;
+  for (auto& [label_name, label_value] : constant_labels_) {
     if (!CheckLabelName(label_name, T::metric_type)) {
       throw std::invalid_argument("Invalid label name");
     }
@@ -34,25 +33,23 @@ template <typename T>
 T& Family<T>::Add(const Labels& labels, std::unique_ptr<T> object) {
   std::lock_guard<std::mutex> lock{mutex_};
 
-  auto insert_result =
-      metrics_.insert(std::make_pair(labels, std::move(object)));
+  auto [it, inserted] = metrics_.emplace(labels, std::move(object));
 
-  if (insert_result.second) {
+  if (inserted) {
     // insertion took place, retroactively check for unlikely issues
-    for (auto& label_pair : labels) {
-      const auto& label_name = label_pair.first;
+    for (auto& [label_name, label_value] : labels) {
       if (!CheckLabelName(label_name, T::metric_type)) {
-        metrics_.erase(insert_result.first);
+        metrics_.erase(it);
         throw std::invalid_argument("Invalid label name");
       }
       if (constant_labels_.count(label_name)) {
-        metrics_.erase(insert_result.first);
+        metrics_.erase(it);
         throw std::invalid_argument("Duplicate label name");
       }
     }
   }
 
-  auto& stored_object = insert_result.first->second;
+  auto& stored_object = it->second;
   assert(stored_object);
   return *stored_object;
 }
@@ -61,11 +58,11 @@ template <typename T>
 void Family<T>::Remove(T* metric) {
   std::lock_guard<std::mutex> lock{mutex_};
 
-  for (auto it = metrics_.begin(); it != metrics_.end(); ++it) {
-    if (it->second.get() == metric) {
-      metrics_.erase(it);
-      break;
-    }
+  const auto it = std::find_if(
+      metrics_.begin(), metrics_.end(),
+      [metric](const auto& entry) { return entry.second.get() == metric; });
+  if (it != metrics_.end()) {
+    metrics_.erase(it);
   }
 }
 
@@ -98,8 +95,8 @@ std::vector<MetricFamily> Family<T>::Collect() const {
   family.help = help_;
   family.type = T::metric_type;
   family.metric.reserve(metrics_.size());
-  for (const auto& m : metrics_) {
-    family.metric.push_back(std::move(CollectMetric(m.first, m.second.get())));
+  for (const auto& [metric_labels, metric] : metrics_) {
+    family.metric.push_back(CollectMetric(metric_labels, metric.get()));
   }
   return {family};
 }

core/src/registry.cc

@@ -6,7 +6,6 @@
 #include <tuple>
 
 #include "prometheus/counter.h"
-#include "prometheus/detail/future_std.h"
 #include "prometheus/gauge.h"
 #include "prometheus/histogram.h"
 #include "prometheus/info.h"
@@ -135,7 +134,7 @@ Family<T>& Registry::Add(const std::string& name, const std::string& help,
     }
   }
 
-  auto family = detail::make_unique<Family<T>>(name, help, labels);
+  auto family = std::make_unique<Family<T>>(name, help, labels);
   auto& ref = *family;
   families.push_back(std::move(family));
   return ref;

core/tests/family_test.cc

@@ -7,7 +7,6 @@
 
 #include "prometheus/client_metric.h"
 #include "prometheus/counter.h"
-#include "prometheus/detail/future_std.h"
 #include "prometheus/histogram.h"
 #include "prometheus/labels.h"
 #include "prometheus/summary.h"
@@ -82,14 +81,14 @@ TEST(FamilyTest, add_twice) {
 
 TEST(FamilyTest, throw_on_invalid_metric_name) {
   auto create_family_with_invalid_name = []() {
-    return detail::make_unique<Family<Counter>>("", "empty name", Labels{});
+    return std::make_unique<Family<Counter>>("", "empty name", Labels{});
   };
   EXPECT_ANY_THROW(create_family_with_invalid_name());
 }
 
 TEST(FamilyTest, throw_on_invalid_constant_label_name) {
   auto create_family_with_invalid_labels = []() {
-    return detail::make_unique<Family<Counter>>(
+    return std::make_unique<Family<Counter>>(
         "total_requests", "Counts all requests",
         Labels{{"__inavlid", "counter1"}});
   };
@@ -120,7 +119,7 @@ TEST(FamilyTest, query_family_if_metric_already_exists) {
 TEST(FamilyTest, reject_histogram_with_constant_le_label) {
   auto labels = Labels{{"le", "test"}};
   EXPECT_ANY_THROW(
-      detail::make_unique<Family<Histogram>>("name", "help", labels));
+      std::make_unique<Family<Histogram>>("name", "help", labels));
 }
 
 TEST(FamilyTest, reject_histogram_with_le_label) {
@@ -132,7 +131,7 @@ TEST(FamilyTest, reject_histogram_with_le_label) {
 TEST(FamilyTest, reject_summary_with_constant_quantile_label) {
   auto labels = Labels{{"quantile", "test"}};
   EXPECT_ANY_THROW(
-      detail::make_unique<Family<Summary>>("name", "help", labels));
+      std::make_unique<Family<Summary>>("name", "help", labels));
 }
 
 TEST(FamilyTest, reject_summary_with_quantile_label) {

core/tests/serializer_test.cc

@@ -7,7 +7,6 @@
 #include <vector>
 
 #include "prometheus/counter.h"
-#include "prometheus/detail/future_std.h"
 #include "prometheus/family.h"
 #include "prometheus/metric_family.h"
 #include "prometheus/text_serializer.h"
@@ -40,8 +39,7 @@ TEST_F(SerializerTest, shouldSerializeLocaleIndependent) {
 
   // ignore missing locale and skip test if setup fails
   try {
-    localeWithCommaDecimalSeparator =
-        detail::make_unique<RAIILocale>("de_DE.UTF-8");
+    localeWithCommaDecimalSeparator = std::make_unique<RAIILocale>("de_DE.UTF-8");
   } catch (std::runtime_error&) {
     GTEST_SKIP();
   }

pull/CMakeLists.txt

@@ -37,7 +37,7 @@ add_library(${PROJECT_NAME}::pull ALIAS pull)
 
 target_compile_features(pull
   PUBLIC
-    cxx_std_11
+    cxx_std_17
 )
 
 target_link_libraries(pull

pull/src/endpoint.cc

@@ -4,17 +4,15 @@
 
 #include "basic_auth.h"
 #include "handler.h"
-#include "prometheus/detail/future_std.h"
 
-namespace prometheus {
-namespace detail {
+namespace prometheus::detail {
 
 Endpoint::Endpoint(CivetServer& server, std::string uri)
     : server_(server),
       uri_(std::move(uri)),
       endpoint_registry_(std::make_shared<Registry>()),
       metrics_handler_(
-          detail::make_unique<MetricsHandler>(*endpoint_registry_)) {
+          std::make_unique<MetricsHandler>(*endpoint_registry_)) {
   RegisterCollectable(endpoint_registry_);
   server_.addHandler(uri_, metrics_handler_.get());
 }
@@ -37,7 +35,7 @@ void Endpoint::RegisterAuth(
   // split creating, assigning, and storing to avoid a race-condition when
   // being called the second time and the handler is replaced
   auto new_handler =
-      detail::make_unique<BasicAuthHandler>(std::move(authCB), realm);
+      std::make_unique<BasicAuthHandler>(std::move(authCB), realm);
   server_.addAuthHandler(uri_, new_handler.get());
   auth_handler_ = std::move(new_handler);
 }
@@ -49,5 +47,4 @@ void Endpoint::RemoveCollectable(
 
 const std::string& Endpoint::GetURI() const { return uri_; }
 
-}  // namespace detail
-}  // namespace prometheus
+}  // namespace prometheus::detail

pull/src/endpoint.h

@@ -9,8 +9,7 @@
 #include "prometheus/collectable.h"
 #include "prometheus/registry.h"
 
-namespace prometheus {
-namespace detail {
+namespace prometheus::detail {
 class MetricsHandler;
 
 class Endpoint {
@@ -40,5 +39,4 @@ class Endpoint {
   std::unique_ptr<BasicAuthHandler> auth_handler_;
 };
 
-}  // namespace detail
-}  // namespace prometheus
+}  // namespace prometheus::detail

pull/src/exposer.cc

@@ -7,7 +7,6 @@
 
 #include "CivetServer.h"
 #include "endpoint.h"
-#include "prometheus/detail/future_std.h"
 
 namespace prometheus {
 
@@ -67,7 +66,7 @@ detail::Endpoint& Exposer::GetEndpointForUri(const std::string& uri) {
     return *it->get();
   }
 
-  endpoints_.emplace_back(detail::make_unique<detail::Endpoint>(*server_, uri));
+  endpoints_.emplace_back(std::make_unique<detail::Endpoint>(*server_, uri));
   return *endpoints_.back().get();
 }