70 lines
1.8 KiB
Plaintext
70 lines
1.8 KiB
Plaintext
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/**
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* osgEarth
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* Copyright Pelican Mapping
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* MIT License
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*/
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#pragma once
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#include <osgEarth/Common>
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#include <atomic>
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#include <mutex>
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#include <functional>
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#include <vector>
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namespace osgEarth
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{
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/**
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* Easy way to add a thread-safe callback to a class.
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*
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* Developer defines a callback, usually as a class member:
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* Callback<void(int)> onClick;
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*
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* User adds a callback:
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* instance->onClick([](int a) { ... });
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*
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* Class fires a callback:
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* onClick(a);
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*/
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template<typename F>
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class Callback
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{
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private:
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using Entry = typename std::pair<int, std::function<F>>;
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mutable int uidgen = 0;
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mutable std::vector<Entry> entries;
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mutable std::mutex mutex;
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mutable std::atomic_bool firing = { false };
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public:
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//! Adds a callback function
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int operator()(std::function<F>&& func) const {
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std::lock_guard<std::mutex> lock(mutex);
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auto uid = ++uidgen;
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entries.emplace_back(uid, func);
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return uid;
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}
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//! Removed a callback function with the UID returned from ()
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void remove(int uid) const {
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std::lock_guard<std::mutex> lock(mutex);
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for (auto iter = entries.begin(); iter != entries.end(); ++iter) {
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if (iter->first == uid) {
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entries.erase(iter);
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break;
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}
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}
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}
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//! Executes all callback functions with the provided args
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template<typename... Args>
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void fire(Args&&... args) const {
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if (firing.exchange(true) == false) {
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std::lock_guard<std::mutex> lock(mutex);
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for (auto& e : entries)
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e.second(args...);
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firing = false;
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}
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}
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};
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}
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