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// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
#ifndef SRC_BASE_OBJECT_H_
#define SRC_BASE_OBJECT_H_
#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
#include "memory_tracker.h"
#include "v8.h"
#include <type_traits> // std::remove_reference
namespace node {
class Environment;
class BaseObject : public MemoryRetainer {
public:
// Associates this object with `object`. It uses the 0th internal field for
// that, and in particular aborts if there is no such field.
inline BaseObject(Environment* env, v8::Local<v8::Object> object);
inline ~BaseObject() override;
BaseObject() = delete;
// Returns the wrapped object. Returns an empty handle when
// persistent.IsEmpty() is true.
inline v8::Local<v8::Object> object() const;
// Same as the above, except it additionally verifies that this object
// is associated with the passed Isolate in debug mode.
inline v8::Local<v8::Object> object(v8::Isolate* isolate) const;
inline v8::Global<v8::Object>& persistent();
inline Environment* env() const;
// Get a BaseObject* pointer, or subclass pointer, for the JS object that
// was also passed to the `BaseObject()` constructor initially.
// This may return `nullptr` if the C++ object has not been constructed yet,
// e.g. when the JS object used `MakeLazilyInitializedJSTemplate`.
static inline BaseObject* FromJSObject(v8::Local<v8::Object> object);
template <typename T>
static inline T* FromJSObject(v8::Local<v8::Object> object);
// Make the `v8::Global` a weak reference and, `delete` this object once
// the JS object has been garbage collected.
inline void MakeWeak();
// Undo `MakeWeak()`, i.e. turn this into a strong reference.
inline void ClearWeak();
// Utility to create a FunctionTemplate with one internal field (used for
// the `BaseObject*` pointer) and a constructor that initializes that field
// to `nullptr`.
static inline v8::Local<v8::FunctionTemplate> MakeLazilyInitializedJSTemplate(
Environment* env);
// Setter/Getter pair for internal fields that can be passed to SetAccessor.
template <int Field>
static void InternalFieldGet(v8::Local<v8::String> property,
const v8::PropertyCallbackInfo<v8::Value>& info);
template <int Field, bool (v8::Value::* typecheck)() const>
static void InternalFieldSet(v8::Local<v8::String> property,
v8::Local<v8::Value> value,
const v8::PropertyCallbackInfo<void>& info);
// This is a bit of a hack. See the override in async_wrap.cc for details.
virtual bool IsDoneInitializing() const;
protected:
// Can be used to avoid the automatic object deletion when the Environment
// exits, for example when this object is owned and deleted by another
// BaseObject at that point.
inline void RemoveCleanupHook();
private:
v8::Local<v8::Object> WrappedObject() const override;
static void DeleteMe(void* data);
// persistent_handle_ needs to be at a fixed offset from the start of the
// class because it is used by src/node_postmortem_metadata.cc to calculate
// offsets and generate debug symbols for BaseObject, which assumes that the
// position of members in memory are predictable. For more information please
// refer to `doc/guides/node-postmortem-support.md`
friend int GenDebugSymbols();
friend class CleanupHookCallback;
v8::Global<v8::Object> persistent_handle_;
Environment* env_;
};
// Global alias for FromJSObject() to avoid churn.
template <typename T>
inline T* Unwrap(v8::Local<v8::Object> obj) {
return BaseObject::FromJSObject<T>(obj);
}
#define ASSIGN_OR_RETURN_UNWRAP(ptr, obj, ...) \
do { \
*ptr = static_cast<typename std::remove_reference<decltype(*ptr)>::type>( \
BaseObject::FromJSObject(obj)); \
if (*ptr == nullptr) \
return __VA_ARGS__; \
} while (0)
} // namespace node
#endif // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
#endif // SRC_BASE_OBJECT_H_
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