Cpp metrics rewriting

pp/bare_bones/concepts.h

@@ -71,4 +71,7 @@ concept SteadyClockInterface = requires(Clock& clock) {
   { clock.now() };
 };
 
+template <class T>
+concept arithmetic = std::integral<T> || std::floating_point<T>;
+
 }  // namespace BareBones::concepts

pp/bare_bones/snug_composite.h

@@ -79,8 +79,8 @@ class GenericDecodingTable {
     const GenericDecodingTable* decoding_table;
     PROMPP_ALWAYS_INLINE explicit Hasher(const GenericDecodingTable* _decoding_table = nullptr) noexcept : decoding_table(_decoding_table) {}
 
-    PROMPP_ALWAYS_INLINE size_t operator()(const std::string_view& str) const noexcept { return XXHash::hash(str); }
-    PROMPP_ALWAYS_INLINE size_t operator()(const std::string& str) const noexcept { return XXHash::hash(str); }
+    PROMPP_ALWAYS_INLINE size_t operator()(const std::string_view& str) const noexcept { return XXHash3::hash(str); }
+    PROMPP_ALWAYS_INLINE size_t operator()(const std::string& str) const noexcept { return XXHash3::hash(str); }
 
     template <class Class>
     PROMPP_ALWAYS_INLINE size_t operator()(const Class& c) const noexcept {

pp/bare_bones/tests/snug_composite_tests.cpp

@@ -141,7 +141,7 @@ TYPED_TEST(SnugComposite, should_return_same_id_for_same_data_with_hash) {
   this->fill_table_with_random_values(outcomes);
 
   std::string v = "12";
-  auto hash_val = BareBones::XXHash::hash(v);
+  auto hash_val = BareBones::XXHash3::hash(v);
   auto id = outcomes.find_or_emplace(v, hash_val);
 
   EXPECT_EQ(id, outcomes.find_or_emplace(v, hash_val));
@@ -151,7 +151,7 @@ TYPED_TEST(SnugComposite, should_return_same_id_for_same_data_with_hash) {
   EXPECT_EQ(outcomes.find_or_emplace(v, hash_val), outcomes.find(v));
 
   v = "21";
-  hash_val = BareBones::XXHash::hash(v);
+  hash_val = BareBones::XXHash3::hash(v);
   id = outcomes.find_or_emplace(v);
 
   EXPECT_EQ(id, outcomes.find_or_emplace(v, hash_val));

pp/bare_bones/xxhash.h

@@ -12,7 +12,7 @@ PRAGMA_DIAGNOSTIC(pop)
 
 namespace BareBones {
 
-class XXHash {
+class XXHash3 {
  public:
   template <class Number>
     requires std::is_arithmetic_v<Number>
@@ -30,15 +30,15 @@ class XXHash {
   [[nodiscard]] PROMPP_ALWAYS_INLINE uint64_t hash() const noexcept { return hash_; }
   [[nodiscard]] explicit PROMPP_ALWAYS_INLINE operator uint64_t() const noexcept { return hash_; }
 
-  auto operator<=>(const XXHash& other) const noexcept = default;
+  auto operator<=>(const XXHash3& other) const noexcept = default;
 
-  XXHash& operator=(uint64_t hash) noexcept {
+  XXHash3& operator=(uint64_t hash) noexcept {
     hash_ = hash;
     return *this;
   }
 
   PROMPP_ALWAYS_INLINE static uint64_t hash(const char* data, size_t size) noexcept {
-    XXHash hasher;
+    XXHash3 hasher;
     hasher.extend(data, size);
     return hasher.hash();
   }
@@ -50,4 +50,15 @@ class XXHash {
   uint64_t hash_{};
 };
 
+class XXHash {
+ public:
+  PROMPP_ALWAYS_INLINE XXHash() { XXH64_reset(&state_, 0); }
+
+  PROMPP_ALWAYS_INLINE void extend(std::string_view data) noexcept { XXH64_update(&state_, data.data(), data.length()); }
+  [[nodiscard]] PROMPP_ALWAYS_INLINE uint64_t digest() const noexcept { return XXH64_digest(&state_); }
+
+ private:
+  XXH64_state_t state_;
+};
+
 }  // namespace BareBones

pp/entrypoint/go_constants.cpp

@@ -1,6 +1,7 @@
 #include "go_constants.h"
 
 #include "head/serialization.h"
+#include "metrics/storage.h"
 #include "prometheus/relabeler.h"
 
 namespace {
@@ -13,4 +14,6 @@ static_assert(sizeof(PromPP::Prometheus::Relabel::InnerSeries) == Sizeof_InnerSe
 
 static_assert(sizeof(entrypoint::head::SerializedDataIterator) == Sizeof_SerializedDataIterator);
 
+static_assert(sizeof(metrics::Storage::Iterator) == Sizeof_MetricsIterator);
+
 }  // namespace

pp/entrypoint/go_constants.h

@@ -5,3 +5,5 @@
 #define Sizeof_InnerSeries (Sizeof_SizeT + Sizeof_BareBonesVector + Sizeof_RoaringBitset)
 
 #define Sizeof_SerializedDataIterator 192
+
+#define Sizeof_MetricsIterator 24

pp/entrypoint/metrics.cpp

@@ -1,69 +1,47 @@
 #include "metrics.h"
 
-#include <memory>
-
-#include "metrics/counter.h"
-#include "metrics/serializer.h"
 #include "metrics/storage.h"
 #include "primitives/go_model.h"
 #include "primitives/go_slice.h"
 
-struct MetricsIterator {
-  metrics::Storage::Iterator iterator{metrics::storage().begin()};
-  metrics::Serializer serializer;
-};
-
-using MetricsIteratorPtr = std::unique_ptr<MetricsIterator>;
-
 using PromPP::Primitives::Go::Label;
 using PromPP::Primitives::Go::SliceView;
 using PromPP::Primitives::Go::String;
 
-extern "C" void prompp_metrics_iterator_ctor(void* res) {
-  struct Result {
-    MetricsIteratorPtr iterator;
-  };
-
+extern "C" void prompp_metrics_iterator_ctor(void* args) {
   metrics::storage().remove_unused_pages();
 
-  new (res) Result{.iterator = std::make_unique<MetricsIterator>()};
+  std::construct_at(static_cast<metrics::Storage::Iterator*>(args), metrics::storage().begin());
 }
 
-extern "C" void prompp_metrics_iterator_dtor(void* args) {
+extern "C" void prompp_metrics_iterator_next(void* args, void* res) {
   struct Arguments {
-    MetricsIteratorPtr iterator;
-  };
-
-  static_cast<Arguments*>(args)->~Arguments();
-}
-
-extern "C" void prompp_metrics_iterator_serialize(void* args, void* res) {
-  struct Arguments {
-    MetricsIteratorPtr iterator;
+    metrics::Storage::Iterator* iterator;
   };
   struct Result {
-    SliceView<const char> buffer;
+    const PromPP::Primitives::Go::Metric* metric;
   };
 
-  const auto it = static_cast<Arguments*>(args)->iterator.get();
+  const auto in = static_cast<Arguments*>(args);
   const auto out = static_cast<Result*>(res);
 
-  if (it->iterator == metrics::Storage::end()) [[unlikely]] {
-    out->buffer.reset_to(nullptr, 0, 0);
+  if (*in->iterator == metrics::Storage::end()) [[unlikely]] {
+    out->metric = nullptr;
   } else {
-    const auto& buffer = it->serializer.serialize(it->iterator->page->labels(), it->iterator->metric);
-    out->buffer.reset_to(buffer.c_str(), buffer.size(), buffer.capacity());
-    ++it->iterator;
+    out->metric = (*in->iterator)->go_metric();
+    ++(*in->iterator);
   }
 }
 
 struct MetricsPageForTest final : metrics::MetricsPage<MetricsPageForTest> {
   using MetricsPage::MetricsPage;
 
-  MetricsPageForTest(PromPP::Primitives::LabelViewSet&& label_set, const String& counter_name, uint64_t counter_value)
-      : MetricsPage(std::move(label_set)), emplace_count(static_cast<std::string_view>(counter_name), counter_value) {}
+  MetricsPageForTest(const SliceView<Label>& labels, const String& counter_name, uint64_t counter_value)
+      : emplace_count(labels, static_cast<std::string_view>(counter_name), counter_value),
+        emplace_gauge(labels, static_cast<std::string_view>(counter_name), counter_value) {}
 
-  metrics::Counter<> emplace_count;
+  metrics::Counter emplace_count;
+  metrics::Gauge emplace_gauge;
 };
 
 extern "C" void prompp_metrics_page_for_test_ctor(void* args, void* res) {
@@ -78,11 +56,8 @@ extern "C" void prompp_metrics_page_for_test_ctor(void* args, void* res) {
 
   const auto in = static_cast<Arguments*>(args);
 
-  PromPP::Primitives::LabelViewSet label_set;
-  label_set.append_unsorted(in->labels);
-
   new (res) Result{
-      .page = metrics::CreateMetricsPage<MetricsPageForTest>(std::move(label_set), in->counter_name, in->counter_value),
+      .page = metrics::CreateMetricsPage<MetricsPageForTest>(in->labels, in->counter_name, in->counter_value),
   };
 }
 

pp/entrypoint/metrics.h

@@ -3,35 +3,24 @@ extern "C" {
 #endif
 
 /**
- * @brief Create metrics iterator
+ * @brief Initialize metrics iterator
  *
- * @param res {
- *   iterator uintptr // Pointer to constructed iterator
- * }
- */
-void prompp_metrics_iterator_ctor(void* res);
-
-/**
- * @brief Destroy metrics iterator
- *
- * @param args {
- *   iterator uintptr // Pointer to constructed iterator
- * }
+ * @param args *MetricIterator
  */
-void prompp_metrics_iterator_dtor(void* args);
+void prompp_metrics_iterator_ctor(void* args);
 
 /**
  * @brief Serialize metric into protobuf and advance iterator to next metric
  *
  * @param args {
- *   iterator uintptr // Pointer to constructed iterator
+ *   iterator *MetricIterator // Pointer to constructed iterator
  * }
  *
  * @param res {
- *   buffer []bytes // serialized data
+ *   metric *cppbridge.CppMetric // Pointer to go metric
  * }
  */
-void prompp_metrics_iterator_serialize(void* args, void* res);
+void prompp_metrics_iterator_next(void* args, void* res);
 
 /**
  * @brief Create metrics page for test

pp/go/cppbridge/entrypoint.go

@@ -32,6 +32,7 @@ type (
 	CppBareBonesVector        = [C.Sizeof_BareBonesVector]byte
 	CppRoaringBitset          = [C.Sizeof_RoaringBitset]byte
 	CppSerializedDataIterator = [C.Sizeof_SerializedDataIterator]byte
+	CppMetricsIterator        = [C.Sizeof_MetricsIterator]byte
 )
 
 var (
@@ -3447,49 +3448,35 @@ func prometheusRemapStaleNansState(staleNansState, lsIdsMapping uintptr) {
 	)
 }
 
-func prometheusMetricsIteratorCtor() uintptr {
-	var res struct {
-		iterator uintptr
-	}
+func prometheusMetricsIteratorCtor() CppMetricsIterator {
+	var iterator CppMetricsIterator
 
 	testGC()
 	fastcgo.UnsafeCall1(
 		C.prompp_metrics_iterator_ctor,
-		uintptr(unsafe.Pointer(&res)),
+		uintptr(unsafe.Pointer(&iterator)),
 	)
 
-	return res.iterator
+	return iterator
 }
 
-func prometheusMetricsIteratorDtor(iterator uintptr) {
+func prometheusMetricsIteratorNext(iterator *CppMetricsIterator) *CppMetric {
 	args := struct {
 		iterator uintptr
-	}{iterator}
-
-	testGC()
-	fastcgo.UnsafeCall1(
-		C.prompp_metrics_iterator_dtor,
-		uintptr(unsafe.Pointer(&args)),
-	)
-}
-
-func prometheusMetricsIteratorSerialize(iterator uintptr) []byte {
-	args := struct {
-		iterator uintptr
-	}{iterator}
+	}{uintptr(unsafe.Pointer(iterator))}
 
 	var res struct {
-		data []byte
+		metric *CppMetric
 	}
 
 	testGC()
 	fastcgo.UnsafeCall2(
-		C.prompp_metrics_iterator_serialize,
+		C.prompp_metrics_iterator_next,
 		uintptr(unsafe.Pointer(&args)),
 		uintptr(unsafe.Pointer(&res)),
 	)
 
-	return res.data
+	return res.metric
 }
 
 func prometheusMetricsPageForTestCtor(labels Labels, counterName string, counterValue uint64) uintptr {

pp/go/cppbridge/entrypoint.h

@@ -40,6 +40,8 @@ void prompp_dump_memory_profile(void* args, void* res);
 #define Sizeof_InnerSeries (Sizeof_SizeT + Sizeof_BareBonesVector + Sizeof_RoaringBitset)
 
 #define Sizeof_SerializedDataIterator 192
+
+#define Sizeof_MetricsIterator 24
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -481,35 +483,24 @@ extern "C" {
 #endif
 
 /**
- * @brief Create metrics iterator
+ * @brief Initialize metrics iterator
  *
- * @param res {
- *   iterator uintptr // Pointer to constructed iterator
- * }
- */
-void prompp_metrics_iterator_ctor(void* res);
-
-/**
- * @brief Destroy metrics iterator
- *
- * @param args {
- *   iterator uintptr // Pointer to constructed iterator
- * }
+ * @param args *MetricIterator
  */
-void prompp_metrics_iterator_dtor(void* args);
+void prompp_metrics_iterator_ctor(void* args);
 
 /**
  * @brief Serialize metric into protobuf and advance iterator to next metric
  *
  * @param args {
- *   iterator uintptr // Pointer to constructed iterator
+ *   iterator *MetricIterator // Pointer to constructed iterator
  * }
  *
  * @param res {
- *   buffer []bytes // serialized data
+ *   metric *cppbridge.CppMetric // Pointer to go metric
  * }
  */
-void prompp_metrics_iterator_serialize(void* args, void* res);
+void prompp_metrics_iterator_next(void* args, void* res);
 
 /**
  * @brief Create metrics page for test