aa84c95253
The idea is that connecting to a signal doesn't change it's state or the state of the object owning the signal (even though it needs to add the functor to the list for later reference). Emitting, on the other hand, is usually done as a result of a state change and therefore remains non-const. Additional benefit of this arrangement is that objects can export const references to signals to allow connecting, while keeping the ability to emit to themselves.
313 lines
9.6 KiB
C++
313 lines
9.6 KiB
C++
// Signal.hh for FbTk, Fluxbox Toolkit
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// Copyright (c) 2008 Henrik Kinnunen (fluxgen at fluxbox dot org)
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the "Software"),
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// to deal in the Software without restriction, including without limitation
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// the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// and/or sell copies of the Software, and to permit persons to whom the
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// Software is furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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#ifndef FBTK_SIGNAL_HH
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#define FBTK_SIGNAL_HH
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#include "RefCount.hh"
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#include "Slot.hh"
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#include <algorithm>
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#include <list>
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#include <map>
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#include <set>
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namespace FbTk {
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/// \namespace Implementation details for signals, do not use anything in this namespace
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namespace SigImpl {
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/**
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* Parent class for all \c Signal template classes.
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* It handles the disconnect and holds all the slots. The connect must be
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* handled by the child class so it can do the type checking.
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*/
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class SignalHolder {
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protected:
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typedef RefCount<SlotBase> SlotPtr;
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typedef std::list<SlotPtr> SlotList;
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public:
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/// Special tracker interface used by SignalTracker.
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class Tracker {
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public:
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virtual ~Tracker() { }
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/// Disconnect this holder.
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virtual void disconnect(SignalHolder& signal) = 0;
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};
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typedef SlotList::iterator Iterator;
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typedef Iterator SlotID;
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typedef SlotList::const_iterator ConstIterator;
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SignalHolder() : m_emitting(0) {}
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~SignalHolder() {
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// Disconnect this holder from all trackers.
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for (Trackers::iterator it = m_trackers.begin(),
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it_end = m_trackers.end();
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it != it_end; ++it ) {
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(*it)->disconnect(*this);
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}
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}
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/// Remove a specific slot \c id from this signal
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void disconnect(SlotID slotIt) const {
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if(m_emitting) {
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// if we are emitting, we must not erase the actual element, as that would
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// invalidate iterators in the emit() function
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*slotIt = SlotPtr();
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} else
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m_slots.erase( slotIt );
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}
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/// Removes all slots connected to this
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void clear() {
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if(m_emitting)
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std::fill(m_slots.begin(), m_slots.end(), SlotPtr());
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else
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m_slots.clear();
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}
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void connectTracker(SignalHolder::Tracker& tracker) const {
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m_trackers.insert(&tracker);
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}
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void disconnectTracker(SignalHolder::Tracker& tracker) const {
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m_trackers.erase(&tracker);
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}
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protected:
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ConstIterator begin() const { return m_slots.begin(); }
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ConstIterator end() const { return m_slots.end(); }
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Iterator begin() { return m_slots.begin(); }
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Iterator end() { return m_slots.end(); }
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/// Connect a slot to this signal. Must only be called by child classes.
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SlotID connect(const SlotPtr& slot) const {
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return m_slots.insert(m_slots.end(), slot);
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}
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void begin_emitting() { ++m_emitting; }
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void end_emitting() {
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if(--m_emitting == 0) {
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// remove elements which belonged slots that detached themselves
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m_slots.erase(std::remove(m_slots.begin(), m_slots.end(), SlotPtr()), m_slots.end());
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}
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}
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private:
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typedef std::set<Tracker*> Trackers;
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mutable SlotList m_slots; ///< all slots connected to a signal
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mutable Trackers m_trackers; ///< all instances that tracks this signal.
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unsigned m_emitting;
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};
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} // namespace SigImpl
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/// Specialization for three arguments.
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template <typename Arg1 = SigImpl::EmptyArg, typename Arg2 = SigImpl::EmptyArg, typename Arg3 = SigImpl::EmptyArg >
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class Signal: public SigImpl::SignalHolder {
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public:
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void emit(Arg1 arg1, Arg2 arg2, Arg3 arg3) {
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begin_emitting();
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for ( Iterator it = begin(); it != end(); ++it ) {
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if(*it)
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static_cast<Slot<void, Arg1, Arg2, Arg3> &>(**it)(arg1, arg2, arg3);
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}
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end_emitting();
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}
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template<typename Functor>
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SlotID connect(const Functor& functor) const {
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return SignalHolder::connect(SlotPtr(
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new SlotImpl<Functor, void, Arg1, Arg2, Arg3>(functor)
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));
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}
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SlotID connectSlot(const RefCount<FbTk::Slot<void, Arg1, Arg2, Arg3> > &slot) const {
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return SignalHolder::connect(slot);
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}
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};
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/// Specialization for two arguments.
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template <typename Arg1, typename Arg2>
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class Signal<Arg1, Arg2, SigImpl::EmptyArg>: public SigImpl::SignalHolder {
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public:
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void emit(Arg1 arg1, Arg2 arg2) {
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begin_emitting();
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for ( Iterator it = begin(); it != end(); ++it ) {
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if(*it)
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static_cast<Slot<void, Arg1, Arg2> &>(**it)(arg1, arg2);
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}
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end_emitting();
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}
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template<typename Functor>
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SlotID connect(const Functor& functor) const {
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return SignalHolder::connect(SlotPtr(
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new SlotImpl<Functor, void, Arg1, Arg2>(functor)
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));
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}
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SlotID connectSlot(const RefCount<FbTk::Slot<void, Arg1, Arg2> > &slot) const {
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return SignalHolder::connect(slot);
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}
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};
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/// Specialization for one argument.
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template <typename Arg1>
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class Signal<Arg1, SigImpl::EmptyArg, SigImpl::EmptyArg>: public SigImpl::SignalHolder {
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public:
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void emit(Arg1 arg) {
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begin_emitting();
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for ( Iterator it = begin(); it != end(); ++it ) {
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if(*it)
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static_cast<Slot<void, Arg1> &>(**it)(arg);
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}
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end_emitting();
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}
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template<typename Functor>
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SlotID connect(const Functor& functor) const {
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return SignalHolder::connect(SlotPtr(
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new SlotImpl<Functor, void, Arg1>(functor)
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));
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}
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SlotID connectSlot(const RefCount<FbTk::Slot<void, Arg1> > &slot) const {
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return SignalHolder::connect(slot);
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}
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};
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/// Specialization for no arguments.
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template <>
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class Signal<SigImpl::EmptyArg, SigImpl::EmptyArg, SigImpl::EmptyArg>: public SigImpl::SignalHolder {
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public:
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void emit() {
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begin_emitting();
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for ( Iterator it = begin(); it != end(); ++it ) {
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if(*it)
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static_cast<Slot<void> &>(**it)();
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}
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end_emitting();
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}
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template<typename Functor>
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SlotID connect(const Functor& functor) const {
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return SignalHolder::connect(SlotPtr(
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new SlotImpl<Functor, void>(functor)
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));
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}
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SlotID connectSlot(const RefCount<FbTk::Slot<void> > &slot) const {
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return SignalHolder::connect(slot);
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}
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};
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/**
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* Tracks a signal during it's life time. All signals connected using \c
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* SignalTracker::join will be erased when this instance dies.
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*/
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class SignalTracker: public SigImpl::SignalHolder::Tracker {
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public:
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/// Internal type, do not use.
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typedef std::map<const SigImpl::SignalHolder*,
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SigImpl::SignalHolder::SlotID> Connections;
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typedef Connections::iterator TrackID; ///< \c ID type for join/leave.
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~SignalTracker() {
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leaveAll();
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}
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/// Starts tracking a signal.
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/// @return A tracking ID
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template<typename Arg1, typename Arg2, typename Arg3, typename Functor>
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TrackID join(const Signal<Arg1, Arg2, Arg3> &sig, const Functor &functor) {
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return joinSlot(sig, RefCount<Slot<void, Arg1, Arg2, Arg3> >(
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new SlotImpl<Functor, void, Arg1, Arg2, Arg3>(functor)
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));
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}
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template<typename Arg1, typename Arg2, typename Arg3>
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TrackID
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joinSlot(const Signal<Arg1, Arg2, Arg3> &sig,
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const RefCount<Slot<void, Arg1, Arg2, Arg3> > &slot) {
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ValueType value = ValueType(&sig, sig.connectSlot(slot));
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std::pair<TrackID, bool> ret = m_connections.insert(value);
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if ( !ret.second ) {
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// failed to insert this functor
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sig.disconnect(value.second);
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}
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sig.connectTracker(*this);
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return ret.first;
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}
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/// Leave tracking for a signal
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/// @param id the \c id from the previous \c join
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void leave(TrackID id) {
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// keep temporary, while disconnecting we can
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// in some strange cases get a call to this again
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ValueType tmp = *id;
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m_connections.erase(id);
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tmp.first->disconnect(tmp.second);
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tmp.first->disconnectTracker(*this);
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}
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/// Leave tracking for a signal
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/// @param sig the signal to leave
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template <typename Signal>
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void leave(Signal &sig) {
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Iterator it = m_connections.find(&sig);
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if (it != m_connections.end()) {
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leave(it);
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}
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}
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void leaveAll() {
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// disconnect all connections
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for ( ; !m_connections.empty(); ) {
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leave(m_connections.begin());
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}
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}
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protected:
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virtual void disconnect(SigImpl::SignalHolder& signal) {
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m_connections.erase(&signal);
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}
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private:
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typedef Connections::value_type ValueType;
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typedef Connections::iterator Iterator;
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/// holds all connections to different signals and slots.
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Connections m_connections;
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};
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} // namespace FbTk
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#endif // FBTK_SIGNAL_HH
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