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