Split include.hpp

include/rtc/utils.hpp

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+/**
+ * Copyright (c) 2019-2021 Paul-Louis Ageneau
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef RTC_UTILS_H
+#define RTC_UTILS_H
+
+#include <functional>
+#include <memory>
+#include <mutex>
+
+namespace rtc {
+
+// overloaded helper
+template <class... Ts> struct overloaded : Ts... { using Ts::operator()...; };
+template <class... Ts> overloaded(Ts...) -> overloaded<Ts...>;
+
+// weak_ptr bind helper
+template <typename F, typename T, typename... Args> auto weak_bind(F &&f, T *t, Args &&..._args) {
+	return [bound = std::bind(f, t, _args...), weak_this = t->weak_from_this()](auto &&...args) {
+		using result_type = typename decltype(bound)::result_type;
+		if (auto shared_this = weak_this.lock())
+			return bound(args...);
+		else
+			return static_cast<result_type>(false);
+	};
+}
+
+// scope_guard helper
+class scope_guard {
+public:
+	scope_guard(std::function<void()> func) : function(std::move(func)) {}
+	scope_guard(scope_guard &&other) = delete;
+	scope_guard(const scope_guard &) = delete;
+	void operator=(const scope_guard &) = delete;
+
+	~scope_guard() {
+		if (function)
+			function();
+	}
+
+private:
+	std::function<void()> function;
+};
+
+// callback with built-in synchronization
+template <typename... Args> class synchronized_callback {
+public:
+	synchronized_callback() = default;
+	synchronized_callback(synchronized_callback &&cb) { *this = std::move(cb); }
+	synchronized_callback(const synchronized_callback &cb) { *this = cb; }
+	synchronized_callback(std::function<void(Args...)> func) { *this = std::move(func); }
+	~synchronized_callback() { *this = nullptr; }
+
+	synchronized_callback &operator=(synchronized_callback &&cb) {
+		std::scoped_lock lock(mutex, cb.mutex);
+		callback = std::move(cb.callback);
+		cb.callback = nullptr;
+		return *this;
+	}
+
+	synchronized_callback &operator=(const synchronized_callback &cb) {
+		std::scoped_lock lock(mutex, cb.mutex);
+		callback = cb.callback;
+		return *this;
+	}
+
+	synchronized_callback &operator=(std::function<void(Args...)> func) {
+		std::lock_guard lock(mutex);
+		callback = std::move(func);
+		return *this;
+	}
+
+	void operator()(Args... args) const {
+		std::lock_guard lock(mutex);
+		if (callback)
+			callback(std::move(args)...);
+	}
+
+	operator bool() const {
+		std::lock_guard lock(mutex);
+		return callback ? true : false;
+	}
+
+	std::function<void(Args...)> wrap() const {
+		return [this](Args... args) { (*this)(std::move(args)...); };
+	}
+
+private:
+	std::function<void(Args...)> callback;
+	mutable std::recursive_mutex mutex;
+};
+
+// pimpl base class
+template <typename T> using impl_ptr = std::shared_ptr<T>;
+template <typename T> class CheshireCat {
+public:
+	CheshireCat(impl_ptr<T> impl) : mImpl(std::move(impl)) {}
+	template <typename... Args>
+	CheshireCat(Args... args) : mImpl(std::make_shared<T>(std::move(args)...)) {}
+
+	virtual ~CheshireCat() = default;
+
+protected:
+	impl_ptr<T> impl() { return mImpl; }
+	impl_ptr<const T> impl() const { return mImpl; }
+
+private:
+	impl_ptr<T> mImpl;
+};
+
+} // namespace rtc
+
+#endif