src: prefer v8::Global over node::Persistent

`v8::Global` is essentially a nicer variant of `node::Persistent` that,
in addition to reset-on-destroy, also implements move semantics.

This commit makes the necessary replacements, removes
`node::Persistent` and (now-)unnecessary inclusions of the
`node_persistent.h` header, and makes some of the functions that
take Persistents as arguments more generic so that they work with all
`v8::PersistentBase` flavours.

PR-URL: #27287
Reviewed-By: Gus Caplan <[email protected]>
Reviewed-By: Eugene Ostroukhov <[email protected]>
Reviewed-By: Joyee Cheung <[email protected]>
Reviewed-By: Ben Noordhuis <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>

Author: addaleax

node.gyp

@@ -606,7 +606,6 @@
         'src/node_options-inl.h',
         'src/node_perf.h',
         'src/node_perf_common.h',
-        'src/node_persistent.h',
         'src/node_platform.h',
         'src/node_process.h',
         'src/node_revert.h',

src/async_wrap.cc

@@ -35,6 +35,7 @@ using v8::EscapableHandleScope;
 using v8::Function;
 using v8::FunctionCallbackInfo;
 using v8::FunctionTemplate;
+using v8::Global;
 using v8::HandleScope;
 using v8::Integer;
 using v8::Isolate;
@@ -346,8 +347,8 @@ class DestroyParam {
  public:
   double asyncId;
   Environment* env;
-  Persistent<Object> target;
-  Persistent<Object> propBag;
+  Global<Object> target;
+  Global<Object> propBag;
 };
 
 void AsyncWrap::WeakCallback(const WeakCallbackInfo<DestroyParam>& info) {

src/base_object-inl.h

@@ -56,7 +56,7 @@ BaseObject::~BaseObject() {
 }
 
 
-Persistent<v8::Object>& BaseObject::persistent() {
+v8::Global<v8::Object>& BaseObject::persistent() {
   return persistent_handle_;
 }
 

src/base_object.h

@@ -24,7 +24,6 @@
 
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
-#include "node_persistent.h"
 #include "memory_tracker-inl.h"
 #include "v8.h"
 #include <type_traits>  // std::remove_reference
@@ -50,7 +49,7 @@ class BaseObject : public MemoryRetainer {
   // is associated with the passed Isolate in debug mode.
   inline v8::Local<v8::Object> object(v8::Isolate* isolate) const;
 
-  inline Persistent<v8::Object>& persistent();
+  inline v8::Global<v8::Object>& persistent();
 
   inline Environment* env() const;
 
@@ -62,7 +61,7 @@ class BaseObject : public MemoryRetainer {
   template <typename T>
   static inline T* FromJSObject(v8::Local<v8::Object> object);
 
-  // Make the `Persistent` a weak reference and, `delete` this object once
+  // Make the `v8::Global` a weak reference and, `delete` this object once
   // the JS object has been garbage collected.
   inline void MakeWeak();
 
@@ -96,7 +95,7 @@ class BaseObject : public MemoryRetainer {
   friend int GenDebugSymbols();
   friend class CleanupHookCallback;
 
-  Persistent<v8::Object> persistent_handle_;
+  v8::Global<v8::Object> persistent_handle_;
   Environment* env_;
 };
 

src/env.h

@@ -929,7 +929,7 @@ class Environment : public MemoryRetainer {
   std::unordered_map<uint32_t, contextify::ContextifyScript*>
       id_to_script_map;
   std::unordered_set<CompileFnEntry*> compile_fn_entries;
-  std::unordered_map<uint32_t, Persistent<v8::Function>> id_to_function_map;
+  std::unordered_map<uint32_t, v8::Global<v8::Function>> id_to_function_map;
 
   inline uint32_t get_next_module_id();
   inline uint32_t get_next_script_id();
@@ -1292,7 +1292,7 @@ class Environment : public MemoryRetainer {
   template <typename T>
   void ForEachBaseObject(T&& iterator);
 
-#define V(PropertyName, TypeName) Persistent<TypeName> PropertyName ## _;
+#define V(PropertyName, TypeName) v8::Global<TypeName> PropertyName ## _;
   ENVIRONMENT_STRONG_PERSISTENT_VALUES(V)
   ENVIRONMENT_STRONG_PERSISTENT_PROPERTIES(V)
 #undef V

src/heap_utils.cc

@@ -8,6 +8,7 @@ using v8::EmbedderGraph;
 using v8::EscapableHandleScope;
 using v8::FunctionCallbackInfo;
 using v8::FunctionTemplate;
+using v8::Global;
 using v8::HandleScope;
 using v8::HeapSnapshot;
 using v8::Isolate;
@@ -56,7 +57,7 @@ class JSGraphJSNode : public EmbedderGraph::Node {
   };
 
  private:
-  Persistent<Value> persistent_;
+  Global<Value> persistent_;
 };
 
 class JSGraph : public EmbedderGraph {

src/inspector_agent.cc

@@ -34,6 +34,7 @@ using node::FatalError;
 
 using v8::Context;
 using v8::Function;
+using v8::Global;
 using v8::HandleScope;
 using v8::Isolate;
 using v8::Local;
@@ -834,7 +835,7 @@ void Agent::DisableAsyncHook() {
 }
 
 void Agent::ToggleAsyncHook(Isolate* isolate,
-                            const node::Persistent<Function>& fn) {
+                            const Global<Function>& fn) {
   CHECK(parent_env_->has_run_bootstrapping_code());
   HandleScope handle_scope(isolate);
   CHECK(!fn.IsEmpty());

src/inspector_agent.h

@@ -7,7 +7,6 @@
 #endif
 
 #include "node_options-inl.h"
-#include "node_persistent.h"
 #include "v8.h"
 
 #include <cstddef>
@@ -114,7 +113,7 @@ class Agent {
 
  private:
   void ToggleAsyncHook(v8::Isolate* isolate,
-                       const node::Persistent<v8::Function>& fn);
+                       const v8::Global<v8::Function>& fn);
 
   node::Environment* parent_env_;
   // Encapsulates majority of the Inspector functionality
@@ -133,8 +132,8 @@ class Agent {
 
   bool pending_enable_async_hook_ = false;
   bool pending_disable_async_hook_ = false;
-  node::Persistent<v8::Function> enable_async_hook_function_;
-  node::Persistent<v8::Function> disable_async_hook_function_;
+  v8::Global<v8::Function> enable_async_hook_function_;
+  v8::Global<v8::Function> disable_async_hook_function_;
 };
 
 }  // namespace inspector

src/inspector_js_api.cc

@@ -15,6 +15,7 @@ using v8::Context;
 using v8::Function;
 using v8::FunctionCallbackInfo;
 using v8::FunctionTemplate;
+using v8::Global;
 using v8::HandleScope;
 using v8::Isolate;
 using v8::Local;
@@ -116,7 +117,7 @@ class JSBindingsConnection : public AsyncWrap {
 
  private:
   std::unique_ptr<InspectorSession> session_;
-  Persistent<Function> callback_;
+  Global<Function> callback_;
 };
 
 static bool InspectorEnabled(Environment* env) {

src/js_native_api_v8_internals.h

@@ -29,7 +29,7 @@
 namespace v8impl {
 
 template <typename T>
-using Persistent = node::Persistent<T>;
+using Persistent = v8::Global<T>;
 
 using PersistentToLocal = node::PersistentToLocal;