electron/atom/browser/api/trackable_object.h
2015-06-24 17:58:12 +08:00

116 lines
3.1 KiB
C++

// Copyright (c) 2015 GitHub, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#ifndef ATOM_BROWSER_API_TRACKABLE_OBJECT_H_
#define ATOM_BROWSER_API_TRACKABLE_OBJECT_H_
#include <vector>
#include "atom/browser/api/event_emitter.h"
#include "atom/common/id_weak_map.h"
namespace base {
class SupportsUserData;
}
namespace mate {
// Users should use TrackableObject instead.
class TrackableObjectBase : public mate::EventEmitter {
public:
TrackableObjectBase();
// The ID in weak map.
int32_t weak_map_id() const { return weak_map_id_; }
// Wrap TrackableObject into a class that SupportsUserData.
void AttachAsUserData(base::SupportsUserData* wrapped);
protected:
~TrackableObjectBase() override;
// mate::Wrappable:
void AfterInit(v8::Isolate* isolate) override;
// Get the weak_map_id from SupportsUserData.
static int32_t GetIDFromWrappedClass(base::SupportsUserData* wrapped);
// Register a callback that should be destroyed before JavaScript environment
// gets destroyed.
static void RegisterDestructionCallback(void (*callback)());
int32_t weak_map_id_;
base::SupportsUserData* wrapped_;
private:
DISALLOW_COPY_AND_ASSIGN(TrackableObjectBase);
};
// All instances of TrackableObject will be kept in a weak map and can be got
// from its ID.
template<typename T>
class TrackableObject : public TrackableObjectBase {
public:
// Finds out the TrackableObject from its ID in weak map.
static T* FromWeakMapID(v8::Isolate* isolate, int32_t id) {
v8::MaybeLocal<v8::Object> object = weak_map_.Get(isolate, id);
if (object.IsEmpty())
return nullptr;
T* self = nullptr;
mate::ConvertFromV8(isolate, object.ToLocalChecked(), &self);
return self;
}
// Finds out the TrackableObject from the class it wraps.
static T* FromWrappedClass(v8::Isolate* isolate,
base::SupportsUserData* wrapped) {
int32_t id = GetIDFromWrappedClass(wrapped);
if (!id)
return nullptr;
return FromWeakMapID(isolate, id);
}
// Returns all objects in this class's weak map.
static std::vector<v8::Local<v8::Object>> GetAll(v8::Isolate* isolate) {
return weak_map_.Values(isolate);
}
TrackableObject() {
RegisterDestructionCallback(&TrackableObject<T>::ReleaseAllWeakReferences);
}
// Removes this instance from the weak map.
void RemoveFromWeakMap() {
if (weak_map_.Has(weak_map_id()))
weak_map_.Remove(weak_map_id());
}
protected:
~TrackableObject() override {
RemoveFromWeakMap();
}
void AfterInit(v8::Isolate* isolate) override {
weak_map_id_ = weak_map_.Add(isolate, GetWrapper(isolate));
TrackableObjectBase::AfterInit(isolate);
}
private:
// Releases all weak references in weak map, called when app is terminating.
static void ReleaseAllWeakReferences() {
weak_map_.Clear();
}
static atom::IDWeakMap weak_map_;
DISALLOW_COPY_AND_ASSIGN(TrackableObject);
};
template<typename T>
atom::IDWeakMap TrackableObject<T>::weak_map_;
} // namespace mate
#endif // ATOM_BROWSER_API_TRACKABLE_OBJECT_H_