src: use string_view for FastStringKey implementation

PR-URL: #45914
Reviewed-By: Yagiz Nizipli <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Chengzhong Wu <[email protected]>
Reviewed-By: Tobias Nießen <[email protected]>

Author: addaleax

src/debug_utils-inl.h

@@ -26,6 +26,9 @@ struct ToStringHelper {
     return value != nullptr ? value : "(null)";
   }
   static std::string Convert(const std::string& value) { return value; }
+  static std::string Convert(std::string_view value) {
+    return std::string(value);
+  }
   static std::string Convert(bool value) { return value ? "true" : "false"; }
   template <unsigned BASE_BITS,
             typename T,

src/node_snapshotable.cc

@@ -1280,11 +1280,11 @@ SnapshotableObject::SnapshotableObject(Environment* env,
     : BaseObject(env, wrap), type_(type) {
 }
 
-const char* SnapshotableObject::GetTypeNameChars() const {
+std::string_view SnapshotableObject::GetTypeName() const {
   switch (type_) {
 #define V(PropertyName, NativeTypeName)                                        \
   case EmbedderObjectType::k_##PropertyName: {                                 \
-    return NativeTypeName::type_name.c_str();                                  \
+    return NativeTypeName::type_name.as_string_view();                         \
   }
     SERIALIZABLE_OBJECT_TYPES(V)
 #undef V
@@ -1325,7 +1325,7 @@ void DeserializeNodeInternalFields(Local<Object> holder,
     per_process::Debug(DebugCategory::MKSNAPSHOT,                              \
                        "Object %p is %s\n",                                    \
                        (*holder),                                              \
-                       NativeTypeName::type_name.c_str());                     \
+                       NativeTypeName::type_name.as_string_view());            \
     env_ptr->EnqueueDeserializeRequest(                                        \
         NativeTypeName::Deserialize,                                           \
         holder,                                                                \
@@ -1387,7 +1387,7 @@ StartupData SerializeNodeContextInternalFields(Local<Object> holder,
   per_process::Debug(DebugCategory::MKSNAPSHOT,
                      "Object %p is %s, ",
                      *holder,
-                     obj->GetTypeNameChars());
+                     obj->GetTypeName());
   InternalFieldInfoBase* info = obj->Serialize(index);
 
   per_process::Debug(DebugCategory::MKSNAPSHOT,
@@ -1412,7 +1412,7 @@ void SerializeSnapshotableObjects(Realm* realm,
     }
     SnapshotableObject* ptr = static_cast<SnapshotableObject*>(obj);
 
-    const char* type_name = ptr->GetTypeNameChars();
+    std::string type_name{ptr->GetTypeName()};
     per_process::Debug(DebugCategory::MKSNAPSHOT,
                        "Serialize snapshotable object %i (%p), "
                        "object=%p, type=%s\n",

src/node_snapshotable.h

@@ -101,7 +101,7 @@ class SnapshotableObject : public BaseObject {
   SnapshotableObject(Environment* env,
                      v8::Local<v8::Object> wrap,
                      EmbedderObjectType type);
-  const char* GetTypeNameChars() const;
+  std::string_view GetTypeName() const;
 
   // If returns false, the object will not be serialized.
   virtual bool PrepareForSerialization(v8::Local<v8::Context> context,

src/util-inl.h

@@ -574,11 +574,11 @@ inline bool IsSafeJsInt(v8::Local<v8::Value> v) {
   return false;
 }
 
-constexpr size_t FastStringKey::HashImpl(const char* str) {
+constexpr size_t FastStringKey::HashImpl(std::string_view str) {
   // Low-quality hash (djb2), but just fine for current use cases.
   size_t h = 5381;
-  while (*str != '\0') {
-    h = h * 33 + *(str++);  // NOLINT(readability/pointer_notation)
+  for (const char c : str) {
+    h = h * 33 + c;
   }
   return h;
 }
@@ -589,19 +589,13 @@ constexpr size_t FastStringKey::Hash::operator()(
 }
 
 constexpr bool FastStringKey::operator==(const FastStringKey& other) const {
-  const char* p1 = name_;
-  const char* p2 = other.name_;
-  if (p1 == p2) return true;
-  do {
-    if (*(p1++) != *(p2++)) return false;
-  } while (*p1 != '\0');
-  return *p2 == '\0';
+  return name_ == other.name_;
 }
 
-constexpr FastStringKey::FastStringKey(const char* name)
-  : name_(name), cached_hash_(HashImpl(name)) {}
+constexpr FastStringKey::FastStringKey(std::string_view name)
+    : name_(name), cached_hash_(HashImpl(name)) {}
 
-constexpr const char* FastStringKey::c_str() const {
+constexpr std::string_view FastStringKey::as_string_view() const {
   return name_;
 }
 

src/util.h

@@ -837,20 +837,20 @@ class PersistentToLocal {
 // computations.
 class FastStringKey {
  public:
-  constexpr explicit FastStringKey(const char* name);
+  constexpr explicit FastStringKey(std::string_view name);
 
   struct Hash {
     constexpr size_t operator()(const FastStringKey& key) const;
   };
   constexpr bool operator==(const FastStringKey& other) const;
 
-  constexpr const char* c_str() const;
+  constexpr std::string_view as_string_view() const;
 
  private:
-  static constexpr size_t HashImpl(const char* str);
+  static constexpr size_t HashImpl(std::string_view str);
 
-  const char* name_;
-  size_t cached_hash_;
+  const std::string_view name_;
+  const size_t cached_hash_;
 };
 
 // Like std::static_pointer_cast but for unique_ptr with the default deleter.