71 lines
2.0 KiB
C++
71 lines
2.0 KiB
C++
#ifndef EVENT_H_
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#define EVENT_H_
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#include <functional>
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#include <unordered_map>
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#include <vector>
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#include <typeindex>
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class EventBus {
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using Type = std::type_index;
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using RawFn = std::function<void(const void*)>;
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struct Slot { std::size_t id; RawFn fn; };
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std::unordered_map<Type, std::vector<Slot>> subs_;
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std::size_t next_id_ = 1;
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public:
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struct Handle {
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std::type_index type{typeid(void)};
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std::size_t id{0};
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explicit operator bool() const { return id != 0; }
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};
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template<class E, class F>
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Handle subscribe(F&& f) {
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auto& vec = subs_[Type(typeid(E))];
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Handle h{ Type(typeid(E)), next_id_++ };
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// Wrap strongly typed callback into type-erased RawFn
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RawFn wrapper = [fn = std::function<void(const E&)>(std::forward<F>(f))](const void* p){
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fn(*static_cast<const E*>(p));
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};
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vec.push_back(Slot{h.id, std::move(wrapper)});
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return h;
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}
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// Unsubscribe with handle
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void unsubscribe(const Handle& h) {
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auto it = subs_.find(h.type);
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if (it == subs_.end()) return;
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auto& vec = it->second;
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vec.erase(std::remove_if(vec.begin(), vec.end(),
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[&](const Slot& s){ return s.id == h.id; }),
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vec.end());
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}
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// Publish immediately
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template<class E>
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void publish(const E& e) const {
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auto it = subs_.find(Type(typeid(E)));
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if (it == subs_.end()) return;
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for (auto& slot : it->second) slot.fn(&e);
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}
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};
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// Optional RAII helper
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struct ScopedSub {
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EventBus* bus{};
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EventBus::Handle h{};
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ScopedSub() = default;
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ScopedSub(EventBus& b, EventBus::Handle hh) : bus(&b), h(hh) {}
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ScopedSub(ScopedSub&& o) noexcept { *this = std::move(o); }
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ScopedSub& operator=(ScopedSub&& o) noexcept {
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if (this != &o) { reset(); bus = o.bus; h = o.h; o.bus = nullptr; }
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return *this;
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}
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~ScopedSub(){ reset(); }
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void reset(){ if (bus && h) bus->unsubscribe(h); bus=nullptr; h={}; }
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};
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#endif // EVENT_H_
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