77 lines
2.1 KiB
C++
77 lines
2.1 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 <vector>
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#include "base/containers/to_vector.h"
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#include "base/memory/raw_ptr.h"
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#include "v8/include/v8-forward.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() = default;
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~KeyWeakMap() {
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for (auto& p : map_)
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p.second.value.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> value) {
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auto& mapped = map_[key] =
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Mapped{this, key, v8::Global<v8::Object>(isolate, value)};
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mapped.value.SetWeak(&mapped, 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.value);
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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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return base::ToVector(map_, [isolate](const auto& iter) {
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return v8::Local<v8::Object>::New(isolate, iter.second.value);
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});
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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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if (auto item = map_.extract(key))
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item.mapped().value.ClearWeak();
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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 Mapped {
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raw_ptr<KeyWeakMap> self;
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K key;
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v8::Global<v8::Object> value;
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};
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static void OnObjectGC(const v8::WeakCallbackInfo<Mapped>& data) {
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auto* mapped = data.GetParameter();
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mapped->self->Remove(mapped->key);
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}
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// Map of stored objects.
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std::unordered_map<K, Mapped> 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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