quic: further refinement to StatsDebug

src/quic/node_quic_session.cc

@@ -1347,9 +1347,6 @@ QuicSession::QuicSession(
 
 QuicSession::~QuicSession() {
   CHECK(!Ngtcp2CallbackScope::InNgtcp2CallbackScope(this));
-  StatsDebug stats_debug(this);
-  Debug(this, "Destroyed. %s", stats_debug.ToString().c_str());
-
   crypto_context_->Cancel();
   connection_.reset();
 
@@ -1359,18 +1356,11 @@ QuicSession::~QuicSession() {
     RemoveListener(listener_);
 }
 
-std::string QuicSession::StatsDebug::ToString() {
-#define V(_, name, label)                                                      \
-  "  "## label + ": " +                                                        \
-  std::to_string(session_->GetStat(&QuicSessionStats::name)) + "\n"
-
-  std::string out = "Statistics:\n";
-  out += "  Duration: " +
-         std::to_string(uv_hrtime() -
-             session_->GetStat(&QuicSessionStats::created_at)) + "\n" +
-         SESSION_STATS(V);
-  return out;
-
+void StatsBase<QuicSessionStats, QuicSession>::StatsDebug::ToString(
+    StatsBase<QuicSessionStats, QuicSession>::AddField add_field) const {
+#define V(_n, name, label)                                                     \
+  add_field(label, ptr->GetStat(&QuicSessionStats::name));
+  SESSION_STATS(V)
 #undef V
 }
 

src/quic/node_quic_session.h

@@ -613,7 +613,7 @@ class QuicApplication : public MemoryRetainer {
 // a QuicSession object.
 class QuicSession : public AsyncWrap,
                     public mem::NgLibMemoryManager<QuicSession, ngtcp2_mem>,
-                    public StatsBase<QuicSessionStats> {
+                    public StatsBase<QuicSessionStats, QuicSession> {
  public:
   // The default preferred address strategy is to ignore it
   static void IgnorePreferredAddressStrategy(
@@ -1423,15 +1423,6 @@ class QuicSession : public AsyncWrap,
 
   static const ngtcp2_conn_callbacks callbacks[2];
 
-  class StatsDebug {
-   public:
-    StatsDebug(QuicSession* session) : session_(session) {}
-    std::string ToString();
-   private:
-    QuicSession* session_;
-  };
-
-
   friend class QuicCryptoContext;
   friend class QuicSessionListener;
   friend class JSQuicSessionListener;

src/quic/node_quic_socket.cc

@@ -285,26 +285,17 @@ QuicSocket::QuicSocket(
 
 QuicSocket::~QuicSocket() {
   uint64_t now = uv_hrtime();
-  StatsDebug stats_debug(this);
-  Debug(this, "Destroyed. %s", stats_debug.ToString().c_str());
   QuicSocketListener* listener = listener_;
   listener_->OnDestroy();
   if (listener == listener_)
     RemoveListener(listener_);
 }
 
-std::string QuicSocket::StatsDebug::ToString() {
-#define V(_, name, label)                                                      \
-  "  "## label + ": " +                                                        \
-  std::to_string(socket_->GetStat(&QuicSocketStats::name)) + "\n"
-
-  std::string out = "Statistics:\n";
-  out += "  Duration: " +
-         std::to_string(uv_hrtime() -
-             socket_->GetStat(&QuicSocketStats::created_at)) + "\n" +
-         SOCKET_STATS(V);
-  return out;
-
+void StatsBase<QuicSocketStats, QuicSocket>::StatsDebug::ToString(
+    StatsBase<QuicSocketStats, QuicSocket>::AddField add_field) const {
+#define V(_n, name, label)                                                     \
+  add_field(label, ptr->GetStat(&QuicSocketStats::name));
+  SOCKET_STATS(V)
 #undef V
 }
 

src/quic/node_quic_socket.h

@@ -244,7 +244,7 @@ class QuicEndpoint : public BaseObject,
 class QuicSocket : public AsyncWrap,
                    public QuicEndpointListener,
                    public mem::NgLibMemoryManager<QuicSocket, ngtcp2_mem>,
-                   public StatsBase<QuicSocketStats> {
+                   public StatsBase<QuicSocketStats, QuicSocket> {
  public:
   static void Initialize(
       Environment* env,
@@ -531,14 +531,6 @@ class QuicSocket : public AsyncWrap,
 
   SendWrap* last_created_send_wrap_ = nullptr;
 
-  class StatsDebug {
-   public:
-    StatsDebug(QuicSocket* socket) : socket_(socket) {}
-    std::string ToString();
-   private:
-    QuicSocket* socket_;
-  };
-
   friend class QuicSocketListener;
 };
 

src/quic/node_quic_stream-inl.h

@@ -148,7 +148,7 @@ void QuicStream::Unschedule() {
   stream_queue_.Remove();
 }
 
-std::string QuicHeader::ToString() {
+std::string QuicHeader::ToString() const {
   return name() + " = " + value();
 }
 

src/quic/node_quic_stream.cc

@@ -55,23 +55,13 @@ QuicStream::QuicStream(
   IncrementStat(&QuicStreamStats::max_offset, params.initial_max_data);
 }
 
-QuicStream::~QuicStream() {
-  StatsDebug stats_debug(this);
-  Debug(this, "Destroyed. %s", stats_debug.ToString().c_str());
-}
-
-std::string QuicStream::StatsDebug::ToString() {
-#define V(_, name, label)                                                      \
-  "  "## label + ": " +                                                        \
-  std::to_string(stream_->GetStat(&QuicStreamStats::name)) + "\n"
-
-  std::string out = "Statistics:\n";
-  out += "  Duration: " +
-         std::to_string(uv_hrtime() -
-             stream_->GetStat(&QuicStreamStats::created_at)) + "\n" +
-         STREAM_STATS(V);
-  return out;
+QuicStream::~QuicStream() {}
 
+void StatsBase<QuicStreamStats, QuicStream>::StatsDebug::ToString(
+    StatsBase<QuicSocketStats, QuicSocket>::AddField add_field) const {
+#define V(_n, name, label)                                                     \
+  add_field(label, ptr->GetStat(&QuicStreamStats::name));
+  STREAM_STATS(V)
 #undef V
 }
 

src/quic/node_quic_stream.h

@@ -72,8 +72,7 @@ struct QuicStreamStats {
 // per stream must create a specialization of the Header class.
 class QuicHeader : public MemoryRetainer {
  public:
-  QuicHeader() {}
-
+  QuicHeader() = default;
   virtual ~QuicHeader() {}
   virtual v8::MaybeLocal<v8::String> GetName(QuicApplication* app) const = 0;
   virtual v8::MaybeLocal<v8::String> GetValue(QuicApplication* app) const = 0;
@@ -84,7 +83,7 @@ class QuicHeader : public MemoryRetainer {
   // (including the name and value)
   virtual size_t length() const = 0;
 
-  inline std::string ToString();
+  inline std::string ToString() const;
 };
 
 enum QuicStreamStates : uint32_t {
@@ -198,7 +197,7 @@ enum QuicStreamOrigin {
 class QuicStream : public AsyncWrap,
                    public bob::SourceImpl<ngtcp2_vec>,
                    public StreamBase,
-                   public StatsBase<QuicStreamStats> {
+                   public StatsBase<QuicStreamStats, QuicStream> {
  public:
   static void Initialize(
       Environment* env,
@@ -381,14 +380,6 @@ class QuicStream : public AsyncWrap,
 
   ListNode<QuicStream> stream_queue_;
 
-  class StatsDebug {
-   public:
-    StatsDebug(QuicStream* stream) : stream_(stream) {}
-    std::string ToString();
-   private:
-    QuicStream* stream_;
-  };
-
  public:
   // Linked List of QuicStream objects
   using Queue = ListHead<QuicStream, &QuicStream::stream_queue_>;

src/quic/node_quic_util-inl.h

@@ -1,6 +1,7 @@
 #ifndef SRC_QUIC_NODE_QUIC_UTIL_INL_H_
 #define SRC_QUIC_NODE_QUIC_UTIL_INL_H_
 
+#include "debug_utils.h"
 #include "node_internals.h"
 #include "node_quic_util.h"
 #include "memory_tracker-inl.h"
@@ -317,8 +318,8 @@ bool StatelessResetToken::Compare::operator()(
       NGTCP2_STATELESS_RESET_TOKENLEN) == 0;
 }
 
-template <typename T>
-StatsBase<T>::StatsBase(
+template <typename T, typename Q>
+StatsBase<T, Q>::StatsBase(
     Environment* env,
     v8::Local<v8::Object> wrap,
     int options)
@@ -367,29 +368,29 @@ StatsBase<T>::StatsBase(
   }
 }
 
-template <typename T>
-void StatsBase<T>::IncrementStat(uint64_t T::*member, uint64_t amount) {
+template <typename T, typename Q>
+void StatsBase<T, Q>::IncrementStat(uint64_t T::*member, uint64_t amount) {
   static constexpr uint64_t kMax = std::numeric_limits<uint64_t>::max();
   stats_.*member += std::min(amount, kMax - stats_.*member);
 }
 
-template <typename T>
-void StatsBase<T>::SetStat(uint64_t T::*member, uint64_t value) {
+template <typename T, typename Q>
+void StatsBase<T, Q>::SetStat(uint64_t T::*member, uint64_t value) {
   stats_.*member = value;
 }
 
-template <typename T>
-void StatsBase<T>::RecordTimestamp(uint64_t T::*member) {
+template <typename T, typename Q>
+void StatsBase<T, Q>::RecordTimestamp(uint64_t T::*member) {
   stats_.*member = uv_hrtime();
 }
 
-template <typename T>
-uint64_t StatsBase<T>::GetStat(uint64_t T::*member) const {
+template <typename T, typename Q>
+uint64_t StatsBase<T, Q>::GetStat(uint64_t T::*member) const {
   return stats_.*member;
 }
 
-template <typename T>
-inline void StatsBase<T>::RecordRate(uint64_t T::*member) {
+template <typename T, typename Q>
+inline void StatsBase<T, Q>::RecordRate(uint64_t T::*member) {
   CHECK(rate_);
 
   uint64_t received_at = GetStat(member);
@@ -399,14 +400,14 @@ inline void StatsBase<T>::RecordRate(uint64_t T::*member) {
   SetStat(member, now);
 }
 
-template <typename T>
-inline void StatsBase<T>::RecordSize(uint64_t val) {
+template <typename T, typename Q>
+inline void StatsBase<T, Q>::RecordSize(uint64_t val) {
   CHECK(size_);
   size_->Record(val);
 }
 
-template <typename T>
-inline void StatsBase<T>::RecordAck(uint64_t T::*member) {
+template <typename T, typename Q>
+inline void StatsBase<T, Q>::RecordAck(uint64_t T::*member) {
   CHECK(ack_);
   uint64_t acked_at = GetStat(member);
   uint64_t now = uv_hrtime();
@@ -415,14 +416,35 @@ inline void StatsBase<T>::RecordAck(uint64_t T::*member) {
   SetStat(member, now);
 }
 
-template <typename T>
-void StatsBase<T>::StatsMemoryInfo(MemoryTracker* tracker) const {
+template <typename T, typename Q>
+void StatsBase<T, Q>::StatsMemoryInfo(MemoryTracker* tracker) const {
   tracker->TrackField("stats_buffer", stats_buffer_);
   tracker->TrackField("rate_histogram", rate_);
   tracker->TrackField("size_histogram", size_);
   tracker->TrackField("ack_histogram", ack_);
 }
 
+template <typename T, typename Q>
+StatsBase<T, Q>::~StatsBase() {
+  StatsBase<T, Q>::StatsDebug stats_debug(static_cast<Q*>(this));
+  Debug(static_cast<Q*>(this), "Destroyed. %s", stats_debug.ToString().c_str());
+}
+
+template <typename T, typename Q>
+std::string StatsBase<T, Q>::StatsDebug::ToString() const {
+  std::string out = "Statistics:\n";
+  auto add_field = [&out](const char* name, uint64_t val) {
+    out += "  ";
+    out += std::string(name);
+    out += ": ";
+    out += std::to_string(val);
+    out += "\n";
+  };
+  add_field("Duration", uv_hrtime() - ptr->GetStat(&T::created_at));
+  ToString(add_field);
+  return out;
+}
+
 template <typename T>
 size_t get_length(const T* vec, size_t count) {
   CHECK_NOT_NULL(vec);

src/quic/node_quic_util.h

@@ -73,7 +73,7 @@ enum QuicErrorFamily : int32_t {
 
 // StatsBase is a utility help for classes (like QuicSession)
 // that record performance statistics
-template <typename T>
+template <typename T, typename Q>
 class StatsBase {
  public:
   enum HistogramOptions {
@@ -87,6 +87,19 @@ class StatsBase {
       v8::Local<v8::Object> wrap,
       int options = HistogramOptions::NONE);
 
+  inline ~StatsBase();
+
+  using AddField = std::function<void(const char*, uint64_t)>;
+
+  // The StatsDebug utility is used when StatsBase is destroyed
+  // to output statistical information.
+  struct StatsDebug {
+    Q* ptr;
+    explicit StatsDebug(Q* ptr_) : ptr(ptr_) {}
+    std::string ToString() const;
+    void ToString(AddField add_field) const;
+  };
+
  protected:
   // Increments the given stat field by the given amount
   inline void IncrementStat(uint64_t T::*member, uint64_t amount = 1);