Signal.hpp

 
//
// TGUI - Texus's Graphical User Interface
// Copyright (C) 2012-2017 Bruno Van de Velde (vdv_b@tgui.eu)
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it freely,
// subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented;
// you must not claim that you wrote the original software.
// If you use this software in a product, an acknowledgment
// in the product documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such,
// and must not be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.
//
 
 
#ifndef TGUI_SIGNAL_HPP
#define TGUI_SIGNAL_HPP
 
 
#include <TGUI/Global.hpp>
#include <TGUI/Callback.hpp>
 
#include <map>
#include <deque>
#include <memory>
#include <cassert>
#include <functional>
 
 
namespace tgui
{
 class Widget;
 class ChildWindow;
 
 
 template <typename... Types>
 struct TypeSet;
 
 
 namespace priv
 {
 extern TGUI_API std::deque<const void*> data;
 
 
 template <typename T>
 std::string convertTypeToString();
 
 template <> inline std::string convertTypeToString<int>() { return "int"; }
 template <> inline std::string convertTypeToString<sf::Vector2f>() { return "sf::Vector2f"; }
 template <> inline std::string convertTypeToString<sf::String>() { return "sf::String"; }
 template <> inline std::string convertTypeToString<std::vector<sf::String>>() { return "std::vector<sf::String>"; }
 template <> inline std::string convertTypeToString<std::shared_ptr<ChildWindow>>() { return "std::shared_ptr<ChildWindow>"; }
 
 
 template <typename... Types>
 struct extractTypes
 {
 static std::vector<std::vector<std::string>> get() { return {}; }
 static std::vector<std::string> getRow() { return {}; }
 };
 
 template <typename Type>
 struct extractTypes<Type>
 {
 static std::vector<std::vector<std::string>> get() { return {{convertTypeToString<Type>()}}; }
 static std::vector<std::string> getRow() { return {convertTypeToString<Type>()}; }
 };
 
 template <typename Type, typename... OtherTypes>
 struct extractTypes<Type, OtherTypes...>
 {
 static std::vector<std::vector<std::string>> get()
 {
 auto types = extractTypes<OtherTypes...>::get();
 types.insert(types.begin(), {convertTypeToString<Type>()});
 return types;
 }
 
 static std::vector<std::string> getRow()
 {
 auto types = extractTypes<OtherTypes...>::getRow();
 types.insert(types.begin(), convertTypeToString<Type>());
 return types;
 }
 };
 
 template <typename... T>
 struct extractTypes<TypeSet<T...>>
 {
 static std::vector<std::vector<std::string>> get() { return {extractTypes<T...>::getRow()}; }
 };
 
 template <typename... T, typename... U>
 struct extractTypes<TypeSet<T...>, U...>
 {
 static std::vector<std::vector<std::string>> get()
 {
 auto types = {extractTypes<T...>::getRow()};
 types.insert(types.end(), extractTypes<U...>::get());
 return types;
 }
 };
 
 
 template <typename Func, typename TypeA, typename TypeB, typename... Args>
 struct isConvertible;
 
 template <typename Func, typename... TypesA, typename... TypesB, typename... Args>
 struct isConvertible<Func, TypeSet<TypesA...>, TypeSet<TypesB...>, Args...>
 {
 using type = typename std::conditional<std::is_convertible<Func, std::function<void(Args..., TypesA...)>>::value, TypeSet<TypesA...>, TypeSet<TypesB...>>::type;
 };
 
 template <typename Func, typename... Type, typename... Args>
 struct isConvertible<Func, TypeSet<>, TypeSet<Type...>, Args...>
 {
 using type = typename std::conditional<std::is_convertible<Func, std::function<void(Args...)>>::value || std::is_convertible<Func, std::function<void(Args...)>>::value, TypeSet<>, TypeSet<Type...>>::type;
 };
 
 
 template <typename Type>
 const Type& dereference(const void* obj)
 {
 return *static_cast<const Type*>(obj);
 }
 
 
// Ignore warning "C4800: 'const int': forcing value to bool 'true' or 'false' (performance warning)" in Visual Studio
#if defined SFML_SYSTEM_WINDOWS && defined _MSC_VER
 #pragma warning(push)
 #pragma warning(disable : 4800)
#endif
 
 template <typename... T>
 struct connector;
 
 template <typename Func, typename... Args>
 struct connector<TypeSet<>, Func, Args...>
 {
 static std::function<void()> connect(Func func, std::size_t, Args... args)
 {
 return std::bind(func, args...);
 }
 };
 
 template <typename Func, typename... Args, typename Type>
 struct connector<TypeSet<Type>, Func, Args...>
 {
 static std::function<void()> connect(Func func, std::size_t argPos, Args... args)
 {
 return std::bind(func, args..., std::bind(dereference<Type>, std::cref(data[argPos])));
 }
 };
 
 template <typename Func, typename... Args, typename TypeA, typename TypeB>
 struct connector<TypeSet<TypeA, TypeB>, Func, Args...>
 {
 static std::function<void()> connect(Func func, std::size_t argPos, Args... args)
 {
 return std::bind(func, args...,
 std::bind(dereference<TypeA>, std::cref(data[argPos])),
 std::bind(dereference<TypeB>, std::cref(data[argPos+1])));
 }
 };
 
#if defined SFML_SYSTEM_WINDOWS && defined _MSC_VER
 #pragma warning(pop)
#endif
 
 
 template <typename Arg, typename = void>
 struct bindRemover
 {
 static Arg remove(Arg arg)
 {
 return arg;
 }
 };
 
 template <typename Arg>
 struct bindRemover<Arg, typename std::enable_if<std::is_bind_expression<Arg>::value>::type>
 {
 static auto remove(Arg arg) -> decltype(arg())
 {
 return arg();
 }
 };
 
 
 template <typename Func, typename... Args>
 struct isFunctionConvertible
 {
 using type = typename isConvertible<Func, TypeSet<>,
 typename isConvertible<Func, TypeSet<int>,
 typename isConvertible<Func, TypeSet<sf::Vector2f>,
 typename isConvertible<Func, TypeSet<sf::String>,
 typename isConvertible<Func, TypeSet<std::vector<sf::String>>,
 typename isConvertible<Func, TypeSet<std::shared_ptr<ChildWindow>>,
 typename isConvertible<Func, TypeSet<sf::String, sf::String>,
 TypeSet<void>,
 Args...>::type,
 Args...>::type,
 Args...>::type,
 Args...>::type,
 Args...>::type,
 Args...>::type,
 Args...>::type;
 };
 
 }
 
 
 // Stores the actual callback functions and checks if their parameters are valid
 class TGUI_API Signal
 {
 public:
 
 Signal(std::vector<std::vector<std::string>>&& types);
 
 template <typename Func, typename... Args>
 void connect(unsigned int id, Func func, Args... args)
 {
 using type = typename priv::isFunctionConvertible<Func, decltype(priv::bindRemover<Args>::remove(args))...>::type;
 static_assert(!std::is_same<type, TypeSet<void>>::value, "Parameters passed to the connect function are wrong!");
 
 auto argPos = checkCompatibleParameterType<type>();
 m_functions[id] = priv::connector<type, Func, Args...>::connect(func, argPos, args...);
 }
 
 template <typename Func, typename... Args>
 void connectEx(unsigned int id, Func func, Args... args)
 {
 m_functionsEx[id] = std::bind(func, args..., std::placeholders::_1);
 }
 
 bool disconnect(unsigned int id);
 
 void disconnectAll();
 
 bool isEmpty() const;
 
 void operator()(unsigned int count);
 
 template <typename T, typename... Args>
 void operator()(unsigned int count, const T& value, Args... args)
 {
 priv::data[count] = static_cast<const void*>(&value);
 (*this)(count+1, args...);
 }
 
 protected:
 
 template <typename Type>
 std::size_t checkCompatibleParameterType()
 {
 if (std::is_same<Type, TypeSet<>>::value)
 return 0;
 
 auto acceptedType = priv::extractTypes<Type>::get();
 assert(acceptedType.size() == 1);
 
 std::size_t count = 0;
 for (std::size_t i = 0; i < m_allowedTypes.size(); ++i)
 {
 if (acceptedType[0] == m_allowedTypes[i])
 return count;
 
 count += m_allowedTypes[i].size();
 }
 
 throw Exception{"Failed to bind parameter to callback function. Parameter is of wrong type."};
 }
 
 private:
 
 std::map<unsigned int, std::function<void()>> m_functions;
 std::map<unsigned int, std::function<void(const Callback&)>> m_functionsEx;
 
 std::vector<std::vector<std::string>> m_allowedTypes;
 
 friend class SignalWidgetBase; // Only needed for m_functionsEx
 };
 
 
 class TGUI_API SignalWidgetBase
 {
 public:
 
 SignalWidgetBase() = default;
 
 
 SignalWidgetBase(const SignalWidgetBase& copy);
 
 
 SignalWidgetBase& operator=(const SignalWidgetBase& right);
 
 
 template <typename Func, typename... Args>
 unsigned int connect(const std::string& signalNames, Func func, Args... args)
 {
 auto signalNameList = extractSignalNames(signalNames);
 if (signalNameList.empty())
 throw Exception{"connect function called with empty string"};
 
 for (auto& signalName : signalNameList)
 {
 if (m_signals.find(toLower(signalName)) != m_signals.end())
 {
 try {
 m_signals[toLower(signalName)]->connect(m_lastId, func, args...);
 m_lastId++;
 }
 catch (const Exception& e) {
 throw Exception{e.what() + (" The parameters are not valid for the '" + signalName + "' signal.")};
 }
 }
 else
 {
 if (toLower(signalName) != "all")
 throw Exception{"Cannot connect to unknown signal '" + signalName + "'."};
 else
 {
 assert(!m_signals.empty());
 
 for (auto& signal : m_signals)
 {
 try {
 signal.second->connect(m_lastId, func, args...);
 m_lastId++;
 }
 catch (const Exception& e) {
 throw Exception{e.what() + (" The parameters are not valid for the '" + signalName + "' signal.")};
 }
 }
 }
 }
 }
 
 return m_lastId - 1;
 }
 
 
 template <typename Func, typename... Args>
 unsigned int connectEx(const std::string& signalName, Func func, Args... args)
 {
 auto signalNameList = extractSignalNames(signalName);
 if (signalNameList.empty())
 throw Exception{"connect function called with empty string"};
 
 for (auto& name : signalNameList)
 {
 if (m_signals.find(toLower(name)) != m_signals.end())
 {
 try {
 m_signals[toLower(name)]->connectEx(m_lastId, func, args...);
 m_lastId++;
 }
 catch (const Exception& e) {
 throw Exception{e.what() + (" since it is not valid for the '" + name + "' signal.")};
 }
 }
 else // Signal name does not exist
 {
 if (toLower(name) != "all")
 throw Exception{"Cannot connect to unknown signal '" + name + "'."};
 else
 {
 assert(!m_signals.empty());
 
 for (auto& signal : m_signals)
 {
 try {
 signal.second->connectEx(m_lastId, func, args...);
 m_lastId++;
 }
 catch (const Exception& e) {
 throw Exception{e.what() + (" since it is not valid for the '" + name + "' signal.")};
 }
 }
 }
 }
 }
 
 return m_lastId - 1;
 }
 
 
 void disconnect(unsigned int id);
 
 
 void disconnectAll(const std::string& signalName);
 
 
 void disconnectAll();
 
 
 protected:
 
 // Add a new signal that people can bind.
 template <typename... T>
 void addSignal(std::string&& name)
 {
 assert(m_signals[toLower(name)] == nullptr);
 m_signals[toLower(name)] = std::make_shared<Signal>(priv::extractTypes<T...>::get());
 }
 
 
 // Check if some signal handler has been bound to the signal.
 bool isSignalBound(std::string&& name);
 
 
 // Send a signal to all signal handlers that are connected with this signal.
 template <typename... Args>
 void sendSignal(std::string&& name, Args... args)
 {
 assert(m_signals[toLower(name)] != nullptr);
 auto& signal = *m_signals[toLower(name)];
 
 if (signal.m_functionsEx.empty())
 {
 if (!signal.isEmpty())
 signal(0, args...);
 }
 else // Legacy functions are used
 {
 // Copy signal to avoid problems with lifetime when signal handler destroys this object
 Signal signalCopy = signal;
 
 m_callback.trigger = name;
 for (const auto& function : signalCopy.m_functionsEx)
 function.second(m_callback);
 
 if (!signalCopy.isEmpty())
 signalCopy(0, args...);
 }
 }
 
 
 protected:
 
 std::vector<std::string> extractSignalNames(std::string input);
 
 protected:
 
 std::map<std::string, std::shared_ptr<Signal>> m_signals;
 
 static unsigned int m_lastId;
 
 Callback m_callback;
 
 };
 
 
}
 
 
#endif // TGUI_SIGNAL_HPP