forked from mia/Aegisub
301 lines
10 KiB
C++
301 lines
10 KiB
C++
// Copyright (c) 2010, Thomas Goyne <plorkyeran@aegisub.org>
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//
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// Permission to use, copy, modify, and distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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/// @file signal.h
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/// @brief
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/// @ingroup libaegisub
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#pragma once
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#include <boost/container/map.hpp>
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#include <functional>
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#include <memory>
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namespace agi {
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namespace signal {
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using namespace std::placeholders;
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class Connection;
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/// Implementation details; nothing outside this file should directly touch
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/// anything in the detail namespace
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namespace detail {
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class SignalBase;
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class ConnectionToken {
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friend class agi::signal::Connection;
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friend class SignalBase;
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SignalBase *signal;
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bool blocked;
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bool claimed;
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ConnectionToken(SignalBase *signal) : signal(signal), blocked(false), claimed(false) { }
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inline void Disconnect();
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public:
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~ConnectionToken() { Disconnect(); }
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};
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}
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/// @class Connection
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/// @brief Object representing a connection to a signal
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class Connection {
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std::unique_ptr<detail::ConnectionToken> token;
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public:
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Connection() { }
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Connection(Connection&& that) : token(std::move(that.token)) { }
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Connection(detail::ConnectionToken *token) : token(token) { token->claimed = true; }
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Connection& operator=(Connection&& that) { token = std::move(that.token); return *this; }
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/// @brief End this connection
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///
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/// This normally does not need to be manually called, as a connection is
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/// automatically closed when all Connection objects referring to it are
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/// gone. To temporarily enable or disable a connection, use Block/Unblock
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/// instead
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void Disconnect() { if (token) token->Disconnect(); }
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/// @brief Disable this connection until Unblock is called
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void Block() { if (token) token->blocked = true; }
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/// @brief Reenable this connection after it was disabled by Block
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void Unblock() { if (token) token->blocked = false; }
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};
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/// @class UnscopedConnection
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/// @brief A connection which is not automatically closed
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///
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/// Connections initially start out owned by the signal. If a slot knows that it
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/// will outlive a signal and does not need to be able to block a connection, it
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/// can simply ignore the return value of Connect.
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///
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/// If a slot needs to be able to disconnect from a signal, it should store the
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/// returned connection in a Connection, which transfers ownership of the
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/// connection to the slot. If there is any chance that the signal will outlive
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/// the slot, this must be done.
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class UnscopedConnection {
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detail::ConnectionToken *token;
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public:
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UnscopedConnection(detail::ConnectionToken *token) : token(token) { }
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operator Connection() { return Connection(token); }
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};
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namespace detail {
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/// @brief Polymorphic base class for slots
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///
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/// This class has two purposes: to avoid having to make Connection
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/// templated on what type of connection it is controlling, and to avoid
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/// some messiness with templated friend classes
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class SignalBase {
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friend class ConnectionToken;
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/// @brief Disconnect the passed slot from the signal
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/// @param tok Token to disconnect
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virtual void Disconnect(ConnectionToken *tok)=0;
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/// Signals can't be copied
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SignalBase(SignalBase const&);
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SignalBase& operator=(SignalBase const&);
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protected:
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SignalBase() { }
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/// @brief Notify a slot that it has been disconnected
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/// @param tok Token to disconnect
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///
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/// Used by the signal when the signal wishes to end a connection (such
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/// as if the signal is being destroyed while slots are still connected
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/// to it)
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void DisconnectToken(ConnectionToken *tok) { tok->signal = nullptr; }
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/// @brief Has a token been claimed by a scoped connection object?
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bool TokenClaimed(ConnectionToken *tok) { return tok->claimed; }
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/// @brief Create a new connection to this slot
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ConnectionToken *MakeToken() { return new ConnectionToken(this); }
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/// @brief Check if a connection currently wants to receive signals
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bool Blocked(ConnectionToken *tok) { return tok->blocked; }
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};
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inline void ConnectionToken::Disconnect() {
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if (signal) signal->Disconnect(this);
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signal = nullptr;
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}
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/// @brief Templated common code for signals
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template<class Slot>
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class SignalBaseImpl : public SignalBase {
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protected:
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typedef boost::container::map<ConnectionToken*, Slot> SlotMap;
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SlotMap slots; /// Signals currently connected to this slot
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void Disconnect(ConnectionToken *tok) override {
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slots.erase(tok);
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}
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/// Protected destructor so that we don't need a virtual destructor
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~SignalBaseImpl() {
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for (auto& slot : slots) {
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DisconnectToken(slot.first);
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if (!TokenClaimed(slot.first)) delete slot.first;
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}
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}
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public:
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/// @brief Connect a signal to this slot
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/// @param sig Signal to connect
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/// @return The connection object
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UnscopedConnection Connect(Slot sig) {
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ConnectionToken *token = MakeToken();
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slots.insert(std::make_pair(token, sig));
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return UnscopedConnection(token);
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}
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template<class F, class Arg1>
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UnscopedConnection Connect(F func, Arg1 a1) {
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return Connect(std::bind(func, a1));
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}
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template<class F, class Arg1, class Arg2>
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UnscopedConnection Connect(F func, Arg1 a1, Arg2 a2) {
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return Connect(std::bind(func, a1, a2));
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}
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template<class F, class Arg1, class Arg2, class Arg3>
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UnscopedConnection Connect(F func, Arg1 a1, Arg2 a2, Arg3 a3) {
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return Connect(std::bind(func, a1, a2, a3));
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}
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};
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}
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#define SIGNALS_H_FOR_EACH_SIGNAL(...) \
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for (auto cur = slots.begin(); cur != slots.end();) { \
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if (Blocked(cur->first)) \
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++cur; \
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else \
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(cur++)->second(__VA_ARGS__); \
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}
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/// @class Signal
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/// @brief Two-argument signal
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/// @param Arg1 Type of first argument to pass to slots
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/// @param Arg2 Type of second argument to pass to slots
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template<class Arg1 = void, class Arg2 = void>
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class Signal final : public detail::SignalBaseImpl<std::function<void (Arg1, Arg2)> > {
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typedef detail::SignalBaseImpl<std::function<void (Arg1, Arg2)> > super;
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using super::Blocked;
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using super::slots;
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public:
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Signal() { }
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/// @brief Trigger this signal
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/// @param a1 First argument to the signal
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/// @param a2 Second argument to the signal
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///
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/// The order in which connected slots are called is undefined and should
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/// not be relied on
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void operator()(Arg1 a1, Arg2 a2) { SIGNALS_H_FOR_EACH_SIGNAL(a1, a2) }
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// Don't hide the base overloads
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using super::Connect;
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/// @brief Connect a member function with the correct signature to this signal
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/// @param func Function to connect
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/// @param a1 Object
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///
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/// This overload is purely for convenience so that classes can do
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/// sig.Connect(&Class::Foo, this) rather than
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/// sig.Connect(&Class::Foo, this, _1, _2)
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template<class T>
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UnscopedConnection Connect(void (T::*func)(Arg1, Arg2), T* a1) {
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return Connect(std::bind(func, a1, _1, _2));
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}
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/// @brief Connect a member function with the correct signature to this signal
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/// @param func Function to connect
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/// @param a1 Object
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///
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/// This overload is purely for convenience so that classes can do
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/// sig.Connect(&Class::Foo, this) rather than
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/// sig.Connect(&Class::Foo, this, _1)
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template<class T>
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UnscopedConnection Connect(void (T::*func)(Arg1), T* a1) {
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return Connect(std::bind(func, a1, _1));
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}
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};
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/// @class Signal
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/// @brief One-argument signal
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/// @param Arg1 Type of the argument to pass to slots
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template<class Arg1>
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class Signal<Arg1, void> : public detail::SignalBaseImpl<std::function<void (Arg1)> > {
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typedef detail::SignalBaseImpl<std::function<void (Arg1)> > super;
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using super::Blocked;
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using super::slots;
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public:
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Signal() { }
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/// @brief Trigger this signal
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/// @param a1 The argument to the signal
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///
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/// The order in which connected slots are called is undefined and should
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/// not be relied on
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void operator()(Arg1 a1) { SIGNALS_H_FOR_EACH_SIGNAL(a1) }
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// Don't hide the base overloads
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using super::Connect;
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/// @brief Connect a member function with the correct signature to this signal
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/// @param func Function to connect
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/// @param a1 Object
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///
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/// This overload is purely for convenience so that classes can do
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/// sig.Connect(&Class::Foo, this) rather than sig.Connect(&Class::Foo, this, _1)
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template<class T>
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UnscopedConnection Connect(void (T::*func)(Arg1), T* a1) {
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return Connect(std::bind(func, a1, _1));
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}
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};
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/// @class Signal
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/// @brief Zero-argument signal
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template<>
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class Signal<void> final : public detail::SignalBaseImpl<std::function<void ()> > {
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typedef detail::SignalBaseImpl<std::function<void ()> > super;
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using super::Blocked;
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using super::slots;
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public:
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Signal() { }
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/// @brief Trigger this signal
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///
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/// The order in which connected slots are called is undefined and should
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/// not be relied on
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void operator()() { SIGNALS_H_FOR_EACH_SIGNAL() }
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};
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#undef SIGNALS_H_FOR_EACH_SIGNAL
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}
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}
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/// @brief Define functions which forward their arguments to the connect method
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/// of the named signal
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/// @param sig Name of the signal
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/// @param method Name of the connect method
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///
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/// When a signal is a member of a class, we typically want other objects to be
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/// able to connect to the signal, but not to be able to trigger it. To do this,
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/// make this signal private then use this macro to create public subscription
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/// methods
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///
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/// Defines AddSignalNameListener
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#define DEFINE_SIGNAL_ADDERS(sig, method) \
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template<class A> agi::signal::UnscopedConnection method(A a) { return sig.Connect(a); } \
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template<class A,class B> agi::signal::UnscopedConnection method(A a,B b) { return sig.Connect(a,b); } \
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template<class A,class B,class C> agi::signal::UnscopedConnection method(A a,B b,C c) { return sig.Connect(a,b,c); } \
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template<class A,class B,class C,class D> agi::signal::UnscopedConnection method(A a,B b,C c,D d) { return sig.Connect(a,b,c,d); }
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