src: use constant strings for memory info names

PR-URL: #46087
Reviewed-By: Paolo Insogna <paolo@cowtech.it>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

src/async_wrap.cc

@@ -671,13 +671,19 @@ MaybeLocal<Value> AsyncWrap::MakeCallback(const Local<Function> cb,
   return ret;
 }
 
-std::string AsyncWrap::MemoryInfoName() const {
+const char* AsyncWrap::MemoryInfoName() const {
   return provider_names[provider_type()];
 }
 
 std::string AsyncWrap::diagnostic_name() const {
-  return MemoryInfoName() + " (" + std::to_string(env()->thread_id()) + ":" +
-      std::to_string(static_cast<int64_t>(async_id_)) + ")";
+  char buf[64];
+  snprintf(buf,
+           sizeof(buf),
+           "%s(%" PRIu64 ":%.0f)",
+           MemoryInfoName(),
+           env()->thread_id(),
+           async_id_);
+  return buf;
 }
 
 Local<Object> AsyncWrap::GetOwner() {

src/async_wrap.h

@@ -207,7 +207,7 @@ class AsyncWrap : public BaseObject {
       v8::Local<v8::Value>* argv);
 
   virtual std::string diagnostic_name() const;
-  std::string MemoryInfoName() const override;
+  const char* MemoryInfoName() const override;
 
   static void WeakCallback(const v8::WeakCallbackInfo<DestroyParam> &info);
 

src/crypto/crypto_util.h

@@ -398,7 +398,7 @@ class CryptoJob : public AsyncWrap, public ThreadPoolWork {
 
   AdditionalParams* params() { return &params_; }
 
-  std::string MemoryInfoName() const override {
+  const char* MemoryInfoName() const override {
     return CryptoJobTraits::JobName;
   }
 

src/memory_tracker-inl.h

@@ -44,7 +44,7 @@ class MemoryRetainerNode : public v8::EmbedderGraph::Node {
     is_root_node_ = is_root_node;
   }
 
-  const char* Name() override { return name_.c_str(); }
+  const char* Name() override { return name_; }
   const char* NamePrefix() override { return "Node /"; }
   size_t SizeInBytes() override { return size_; }
   // TODO(addaleax): Merging this with the "official" WrapperNode() method
@@ -75,7 +75,7 @@ class MemoryRetainerNode : public v8::EmbedderGraph::Node {
 
   // Otherwise (retainer == nullptr), we set these fields in an ad-hoc way
   bool is_root_node_ = false;
-  std::string name_;
+  const char* name_;
   size_t size_ = 0;
   v8::EmbedderGraph::Node::Detachedness detachedness_ =
       v8::EmbedderGraph::Node::Detachedness::kUnknown;

src/memory_tracker.h

@@ -17,7 +17,7 @@ namespace node {
 
 // Set the node name of a MemoryRetainer to klass
 #define SET_MEMORY_INFO_NAME(Klass)                                            \
-  inline std::string MemoryInfoName() const override { return #Klass; }
+  inline const char* MemoryInfoName() const override { return #Klass; }
 
 // Set the self size of a MemoryRetainer to the stack-allocated size of a
 // certain class
@@ -68,7 +68,7 @@ class CleanupHookCallback;
  *     }
  *
  *     // Or use SET_MEMORY_INFO_NAME(ExampleRetainer)
- *     std::string MemoryInfoName() const override {
+ *     const char* MemoryInfoName() const override {
  *       return "ExampleRetainer";
  *     }
  *
@@ -119,7 +119,7 @@ class MemoryRetainer {
   // where all the edges start from the node of the current retainer,
   // and point to the nodes as specified by tracker->Track* calls.
   virtual void MemoryInfo(MemoryTracker* tracker) const = 0;
-  virtual std::string MemoryInfoName() const = 0;
+  virtual const char* MemoryInfoName() const = 0;
   virtual size_t SelfSize() const = 0;
 
   virtual v8::Local<v8::Object> WrappedObject() const {

src/node_process_methods.cc

@@ -282,14 +282,14 @@ static void GetActiveResourcesInfo(const FunctionCallbackInfo<Value>& args) {
     AsyncWrap* w = req_wrap->GetAsyncWrap();
     if (w->persistent().IsEmpty()) continue;
     resources_info.emplace_back(
-        OneByteString(env->isolate(), w->MemoryInfoName().c_str()));
+        OneByteString(env->isolate(), w->MemoryInfoName()));
   }
 
   // Active handles
   for (HandleWrap* w : *env->handle_wrap_queue()) {
     if (w->persistent().IsEmpty() || !HandleWrap::HasRef(w)) continue;
     resources_info.emplace_back(
-        OneByteString(env->isolate(), w->MemoryInfoName().c_str()));
+        OneByteString(env->isolate(), w->MemoryInfoName()));
   }
 
   // Active timeouts

src/node_realm.cc

@@ -366,7 +366,7 @@ void Realm::VerifyNoStrongBaseObjects() {
     if (obj->IsNotIndicativeOfMemoryLeakAtExit()) return;
     fprintf(stderr,
             "Found bad BaseObject during clean exit: %s\n",
-            obj->MemoryInfoName().c_str());
+            obj->MemoryInfoName());
     fflush(stderr);
     ABORT();
   });

src/tcp_wrap.h

@@ -50,7 +50,7 @@ class TCPWrap : public ConnectionWrap<TCPWrap, uv_tcp_t> {
 
   SET_NO_MEMORY_INFO()
   SET_SELF_SIZE(TCPWrap)
-  std::string MemoryInfoName() const override {
+  const char* MemoryInfoName() const override {
     switch (provider_type()) {
       case ProviderType::PROVIDER_TCPWRAP:
         return "TCPSocketWrap";