electron/shell/common/key_weak_map.h
trop[bot] 0a13e40fab
refactor: simplify KeyWeakMap impl (#43485)
Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Charles Kerr <charles@charleskerr.com>
2024-08-26 17:29:21 -04:00

77 lines
2.1 KiB
C++

// Copyright (c) 2016 GitHub, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#ifndef ELECTRON_SHELL_COMMON_KEY_WEAK_MAP_H_
#define ELECTRON_SHELL_COMMON_KEY_WEAK_MAP_H_
#include <unordered_map>
#include <vector>
#include "base/containers/to_vector.h"
#include "base/memory/raw_ptr.h"
#include "v8/include/v8.h"
namespace electron {
// Like ES6's WeakMap, with a K key and Weak Pointer value.
template <typename K>
class KeyWeakMap {
public:
KeyWeakMap() = default;
~KeyWeakMap() {
for (auto& p : map_)
p.second.value.ClearWeak();
}
// disable copy
KeyWeakMap(const KeyWeakMap&) = delete;
KeyWeakMap& operator=(const KeyWeakMap&) = delete;
// Sets the object to WeakMap with the given |key|.
void Set(v8::Isolate* isolate, const K& key, v8::Local<v8::Object> value) {
auto& mapped = map_[key] =
Mapped{this, key, v8::Global<v8::Object>(isolate, value)};
mapped.value.SetWeak(&mapped, OnObjectGC, v8::WeakCallbackType::kParameter);
}
// Gets the object from WeakMap by its |key|.
v8::MaybeLocal<v8::Object> Get(v8::Isolate* isolate, const K& key) {
if (auto iter = map_.find(key); iter != map_.end())
return v8::Local<v8::Object>::New(isolate, iter->second.value);
return {};
}
// Returns all objects.
std::vector<v8::Local<v8::Object>> Values(v8::Isolate* isolate) const {
return base::ToVector(map_, [isolate](const auto& iter) {
return v8::Local<v8::Object>::New(isolate, iter.second.value);
});
}
// Remove object with |key| in the WeakMap.
void Remove(const K& key) {
if (auto item = map_.extract(key))
item.mapped().value.ClearWeak();
}
private:
// Records the key and self, used by SetWeak.
struct Mapped {
raw_ptr<KeyWeakMap> self;
K key;
v8::Global<v8::Object> value;
};
static void OnObjectGC(const v8::WeakCallbackInfo<Mapped>& data) {
auto* mapped = data.GetParameter();
mapped->self->Remove(mapped->key);
}
// Map of stored objects.
std::unordered_map<K, Mapped> map_;
};
} // namespace electron
#endif // ELECTRON_SHELL_COMMON_KEY_WEAK_MAP_H_