IQ.Pilot Release Commit @ 0b96bd5

iqpilot/tools/cabana/core/observable.h

@@ -0,0 +1,83 @@
+#pragma once
+
+#include <functional>
+#include <map>
+#include <memory>
+#include <utility>
+#include <vector>
+
+namespace observable_detail {
+struct HandlerTable {
+  virtual ~HandlerTable() = default;
+  virtual void erase(int id) = 0;
+};
+}
+
+
+class Connection {
+public:
+  Connection() = default;
+  Connection(std::weak_ptr<observable_detail::HandlerTable> table, int id) : table_(std::move(table)), id_(id) {}
+  Connection(Connection &&other) noexcept { *this = std::move(other); }
+  Connection &operator=(Connection &&other) noexcept {
+    if (this != &other) {
+      disconnect();
+      table_ = std::move(other.table_);
+      id_ = std::exchange(other.id_, -1);
+    }
+    return *this;
+  }
+  Connection(const Connection &) = delete;
+  Connection &operator=(const Connection &) = delete;
+  ~Connection() { disconnect(); }
+
+  void disconnect() {
+    if (auto table = table_.lock()) table->erase(id_);
+    table_.reset();
+    id_ = -1;
+  }
+
+private:
+  std::weak_ptr<observable_detail::HandlerTable> table_;
+  int id_ = -1;
+};
+
+using Connections = std::vector<Connection>;
+
+
+template <typename... Args>
+class Observable {
+public:
+  using Handler = std::function<void(Args...)>;
+
+  Observable() = default;
+  Observable(const Observable &) = delete;
+  Observable &operator=(const Observable &) = delete;
+
+  [[nodiscard]] Connection connect(Handler handler) {
+    int id = table_->next_id++;
+    table_->handlers.emplace(id, std::make_shared<Handler>(std::move(handler)));
+    return Connection(table_, id);
+  }
+
+  void operator()(Args... args) const {
+    auto table = table_;
+    std::vector<int> ids;
+    ids.reserve(table->handlers.size());
+    for (const auto &[id, _] : table->handlers) ids.push_back(id);
+    for (int id : ids) {
+      auto it = table->handlers.find(id);
+      if (it == table->handlers.end()) continue;
+      auto handler = it->second;
+      (*handler)(args...);
+    }
+  }
+
+private:
+  struct Table : observable_detail::HandlerTable {
+    std::map<int, std::shared_ptr<Handler>> handlers;
+    int next_id = 0;
+    void erase(int id) override { handlers.erase(id); }
+  };
+  std::shared_ptr<Table> table_ = std::make_shared<Table>();
+};