From 5e779ce4ac4f4c9d6f14f5c56dbfcfd7a32501ec Mon Sep 17 00:00:00 2001
From: Eugene Lazutkin <eugene.lazutkin@gmail.com>
Date: Wed, 5 Jun 2024 12:02:16 -0500
Subject: [PATCH] Added a guard against calling a weak callback on already
 deleted instance. Refs #210.

---
 lib/addon.cc      | 36 +++++++++++++++++++++++++++++++-----
 lib/wrapped_re2.h | 20 +++++++++++++-------
 2 files changed, 44 insertions(+), 12 deletions(-)

diff --git a/lib/addon.cc b/lib/addon.cc
index 7b22159..d446385 100644
--- a/lib/addon.cc
+++ b/lib/addon.cc
@@ -94,8 +94,29 @@ NODE_MODULE_INIT()
 	Nan::Set(module->ToObject(context).ToLocalChecked(), Nan::New("exports").ToLocalChecked(), WrappedRE2::Init());
 }
 
+WrappedRE2::~WrappedRE2()
+{
+	for (auto ptr : callbackRegistry)
+	{
+		*ptr = nullptr;
+	}
+	dropLastString();
+}
+
 // private methods
 
+WrappedRE2::PtrWrappedRE2 *WrappedRE2::registerCallback()
+{
+	PtrWrappedRE2 *ptr = new PtrWrappedRE2(this);
+	callbackRegistry.insert(ptr);
+	return ptr;
+}
+
+void WrappedRE2::unregisterCallback(PtrWrappedRE2 *ptr)
+{
+	callbackRegistry.erase(ptr);
+}
+
 void WrappedRE2::dropLastString()
 {
 	lastString.Reset();
@@ -106,10 +127,15 @@ void WrappedRE2::dropLastString()
 	}
 }
 
-void WrappedRE2::weakLastStringCallback(const Nan::WeakCallbackInfo<WrappedRE2> &data)
+void WrappedRE2::weakLastStringCallback(const Nan::WeakCallbackInfo<PtrWrappedRE2> &data)
 {
-	WrappedRE2* re2 = data.GetParameter();
-	re2->dropLastString();
+	PtrWrappedRE2 *re2 = data.GetParameter();
+	if (*re2)
+	{
+		(*re2)->unregisterCallback(re2);
+		(*re2)->dropLastString();
+	}
+	delete re2;
 }
 
 void WrappedRE2::prepareLastString(const v8::Local<v8::Value> &arg, bool ignoreLastIndex)
@@ -137,10 +163,10 @@ void WrappedRE2::prepareLastString(const v8::Local<v8::Value> &arg, bool ignoreL
 	dropLastString();
 
 	lastString.Reset(arg);
-	static_cast<v8::PersistentBase<v8::Value>&>(lastString).SetWeak();
+	static_cast<v8::PersistentBase<v8::Value> &>(lastString).SetWeak();
 
 	Nan::Persistent<v8::Value> dummy(arg);
-	dummy.SetWeak(this, weakLastStringCallback, Nan::WeakCallbackType::kParameter);
+	dummy.SetWeak(registerCallback(), weakLastStringCallback, Nan::WeakCallbackType::kParameter);
 
 	lastStringValue = new StrValString(arg, startFrom);
 };
diff --git a/lib/wrapped_re2.h b/lib/wrapped_re2.h
index 33ed15a..89fa68a 100644
--- a/lib/wrapped_re2.h
+++ b/lib/wrapped_re2.h
@@ -6,6 +6,7 @@
 #include <re2/re2.h>
 
 #include <string>
+#include <unordered_set>
 
 struct StrValBase;
 
@@ -67,10 +68,7 @@ class WrappedRE2 : public Nan::ObjectWrap
 	static NAN_SETTER(SetUnicodeWarningLevel);
 
 public:
-	~WrappedRE2()
-	{
-		dropLastString();
-	}
+	~WrappedRE2();
 
 	static v8::Local<v8::Function> Init();
 
@@ -108,7 +106,13 @@ class WrappedRE2 : public Nan::ObjectWrap
 	Nan::Persistent<v8::Value> lastString; // weak pointer
 	StrValBase *lastStringValue;
 
-	static void weakLastStringCallback(const Nan::WeakCallbackInfo<WrappedRE2> &data);
+	typedef WrappedRE2 *PtrWrappedRE2;
+
+	std::unordered_set<PtrWrappedRE2 *> callbackRegistry;
+	PtrWrappedRE2 *registerCallback();
+	void unregisterCallback(PtrWrappedRE2 *re2);
+
+	static void weakLastStringCallback(const Nan::WeakCallbackInfo<PtrWrappedRE2> &data);
 
 	void dropLastString();
 	void prepareLastString(const v8::Local<v8::Value> &arg, bool ignoreLastIndex = false);
@@ -116,11 +120,13 @@ class WrappedRE2 : public Nan::ObjectWrap
 
 struct PrepareLastString
 {
-	PrepareLastString(WrappedRE2 *re2, const v8::Local<v8::Value> &arg, bool ignoreLastIndex = false) : re2(re2) {
+	PrepareLastString(WrappedRE2 *re2, const v8::Local<v8::Value> &arg, bool ignoreLastIndex = false) : re2(re2)
+	{
 		re2->prepareLastString(arg, ignoreLastIndex);
 	}
 
-	~PrepareLastString() {
+	~PrepareLastString()
+	{
 		if (!re2->enabledCache || !(re2->global || re2->sticky))
 			re2->dropLastString();
 	}