- void SetWeak(P *parameter,
- typename WeakCallbackInfo::Callback callback,
- WeakCallbackType type);
-
- void ClearWeak();
-
- /**
- * Marks the reference to this object independent. Garbage collector is free
- * to ignore any object groups containing this object. Weak callback for an
- * independent handle should not assume that it will be preceded by a global
- * GC prologue callback or followed by a global GC epilogue callback.
- */
- void MarkIndependent() const;
-
- bool IsIndependent() const;
-
- /** Checks if the handle holds the only reference to an object. */
- bool IsNearDeath() const;
-
- /** Returns true if the handle's reference is weak. */
- bool IsWeak() const
-};
-```
-
-See the V8 documentation for [`PersistentBase`](https://v8docs.nodesource.com/node-8.11/d4/dca/classv8_1_1_persistent_base.html) for further information.
-
-**Tip:** To get a `v8::Local` reference to the original object back from a `PersistentBase` or `Persistent` object:
-
-```c++
-v8::Local object = Nan::New(persistent);
-```
-
-
-### Nan::NonCopyablePersistentTraits & v8::NonCopyablePersistentTraits
-
-Default traits for `Nan::Persistent`. This class does not allow use of the a copy constructor or assignment operator. At present `kResetInDestructor` is not set, but that will change in a future version.
-
-Definition:
-
-_(note: this is implemented as `Nan::NonCopyablePersistentTraits` for older versions of V8 and the native `v8::NonCopyablePersistentTraits` is used for newer versions of V8)_
-
-```c++
-template class NonCopyablePersistentTraits {
- public:
- typedef Persistent > NonCopyablePersistent;
-
- static const bool kResetInDestructor = false;
-
- template
- static void Copy(const Persistent &source,
- NonCopyablePersistent *dest);
-
- template static void Uncompilable();
-};
-```
-
-See the V8 documentation for [`NonCopyablePersistentTraits`](https://v8docs.nodesource.com/node-8.11/de/d73/classv8_1_1_non_copyable_persistent_traits.html) for further information.
-
-
-### Nan::CopyablePersistentTraits & v8::CopyablePersistentTraits
-
-A helper class of traits to allow copying and assignment of `Persistent`. This will clone the contents of storage cell, but not any of the flags, etc..
-
-Definition:
-
-_(note: this is implemented as `Nan::CopyablePersistentTraits` for older versions of V8 and the native `v8::NonCopyablePersistentTraits` is used for newer versions of V8)_
-
-```c++
-template
-class CopyablePersistentTraits {
- public:
- typedef Persistent > CopyablePersistent;
-
- static const bool kResetInDestructor = true;
-
- template
- static void Copy(const Persistent &source,
- CopyablePersistent *dest);
-};
-```
-
-See the V8 documentation for [`CopyablePersistentTraits`](https://v8docs.nodesource.com/node-8.11/da/d5c/structv8_1_1_copyable_persistent_traits.html) for further information.
-
-
-### Nan::Persistent
-
-A type of `PersistentBase` which allows copy and assignment. Copy, assignment and destructor behavior is controlled by the traits class `M`.
-
-Definition:
-
-```c++
-template >
-class Persistent;
-
-template class Persistent : public PersistentBase {
- public:
- /**
- * A Persistent with no storage cell.
- */
- Persistent();
-
- /**
- * Construct a Persistent from a v8::Local. When the v8::Local is non-empty, a
- * new storage cell is created pointing to the same object, and no flags are
- * set.
- */
- template Persistent(v8::Local that);
-
- /**
- * Construct a Persistent from a Persistent. When the Persistent is non-empty,
- * a new storage cell is created pointing to the same object, and no flags are
- * set.
- */
- Persistent(const Persistent &that);
-
- /**
- * The copy constructors and assignment operator create a Persistent exactly
- * as the Persistent constructor, but the Copy function from the traits class
- * is called, allowing the setting of flags based on the copied Persistent.
- */
- Persistent &operator=(const Persistent &that);
-
- template
- Persistent &operator=(const Persistent &that);
-
- /**
- * The destructor will dispose the Persistent based on the kResetInDestructor
- * flags in the traits class. Since not calling dispose can result in a
- * memory leak, it is recommended to always set this flag.
- */
- ~Persistent();
-};
-```
-
-See the V8 documentation for [`Persistent`](https://v8docs.nodesource.com/node-8.11/d2/d78/classv8_1_1_persistent.html) for further information.
-
-
-### Nan::Global
-
-A type of `PersistentBase` which has move semantics.
-
-```c++
-template class Global : public PersistentBase {
- public:
- /**
- * A Global with no storage cell.
- */
- Global();
-
- /**
- * Construct a Global from a v8::Local. When the v8::Local is non-empty, a new
- * storage cell is created pointing to the same object, and no flags are set.
- */
- template Global(v8::Local that);
- /**
- * Construct a Global from a PersistentBase. When the Persistent is non-empty,
- * a new storage cell is created pointing to the same object, and no flags are
- * set.
- */
- template Global(const PersistentBase &that);
-
- /**
- * Pass allows returning globals from functions, etc.
- */
- Global Pass();
-};
-```
-
-See the V8 documentation for [`Global`](https://v8docs.nodesource.com/node-8.11/d5/d40/classv8_1_1_global.html) for further information.
-
-
-### Nan::WeakCallbackInfo
-
-`Nan::WeakCallbackInfo` is used as an argument when setting a persistent reference as weak. You may need to free any external resources attached to the object. It is a mirror of `v8:WeakCallbackInfo` as found in newer versions of V8.
-
-Definition:
-
-```c++
-template class WeakCallbackInfo {
- public:
- typedef void (*Callback)(const WeakCallbackInfo& data);
-
- v8::Isolate *GetIsolate() const;
-
- /**
- * Get the parameter that was associated with the weak handle.
- */
- T *GetParameter() const;
-
- /**
- * Get pointer from internal field, index can be 0 or 1.
- */
- void *GetInternalField(int index) const;
-};
-```
-
-Example usage:
-
-```c++
-void weakCallback(const WeakCallbackInfo &data) {
- int *parameter = data.GetParameter();
- delete parameter;
-}
-
-Persistent obj;
-int *data = new int(0);
-obj.SetWeak(data, callback, WeakCallbackType::kParameter);
-```
-
-See the V8 documentation for [`WeakCallbackInfo`](https://v8docs.nodesource.com/node-8.11/d8/d06/classv8_1_1_weak_callback_info.html) for further information.
-
-
-### Nan::WeakCallbackType
-
-Represents the type of a weak callback.
-A weak callback of type `kParameter` makes the supplied parameter to `Nan::PersistentBase::SetWeak` available through `WeakCallbackInfo::GetParameter`.
-A weak callback of type `kInternalFields` uses up to two internal fields at indices 0 and 1 on the `Nan::PersistentBase` being made weak.
-Note that only `v8::Object`s and derivatives can have internal fields.
-
-Definition:
-
-```c++
-enum class WeakCallbackType { kParameter, kInternalFields };
-```