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/* -*- mode: c++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
Copyright (C) 2013 Chris Higgs
Copyright (C) 2015 Klaus Spanderen
This file is part of QuantLib, a free-software/open-source library
for financial quantitative analysts and developers - http://quantlib.org/
QuantLib is free software: you can redistribute it and/or modify it
under the terms of the QuantLib license. You should have received a
copy of the license along with this program; if not, please email
<quantlib-dev@lists.sf.net>. The license is also available online at
<http://quantlib.org/license.shtml>.
This program 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 license for more details.
*/
#include <ql/patterns/observable.hpp>
#ifndef QL_ENABLE_THREAD_SAFE_OBSERVER_PATTERN
namespace QuantLib {
void ObservableSettings::enableUpdates() {
updatesEnabled_ = true;
updatesDeferred_ = false;
// if there are outstanding deferred updates, do the notification
if (!deferredObservers_.empty()) {
bool successful = true;
std::string errMsg;
for (auto* deferredObserver : deferredObservers_) {
try {
deferredObserver->update();
} catch (std::exception& e) {
successful = false;
errMsg = e.what();
} catch (...) {
successful = false;
}
}
deferredObservers_.clear();
QL_ENSURE(successful,
"could not notify one or more observers: " << errMsg);
}
}
void Observable::notifyObservers() {
if (!settings_.updatesEnabled()) {
// if updates are only deferred, flag this for later notification
// these are held centrally by the settings singleton
settings_.registerDeferredObservers(observers_);
} else if (!observers_.empty()) {
bool successful = true;
std::string errMsg;
for (auto* observer : observers_) {
try {
observer->update();
} catch (std::exception& e) {
// quite a dilemma. If we don't catch the exception,
// other observers will not receive the notification
// and might be left in an incorrect state. If we do
// catch it and continue the loop (as we do here) we
// lose the exception. The least evil might be to try
// and notify all observers, while raising an
// exception if something bad happened.
successful = false;
errMsg = e.what();
} catch (...) {
successful = false;
}
}
QL_ENSURE(successful,
"could not notify one or more observers: " << errMsg);
}
}
}
#else
#include <boost/signals2/signal_type.hpp>
namespace QuantLib {
namespace detail {
class Signal {
public:
typedef boost::signals2::signal_type<
void(),
boost::signals2::keywords::mutex_type<std::recursive_mutex> >
::type signal_type;
void connect(const signal_type::slot_type& slot) {
sig_.connect(slot);
}
template <class T>
void disconnect(const T& slot) {
sig_.disconnect(slot);
}
void operator()() const {
sig_();
}
private:
signal_type sig_;
};
template <class T>
class ProxyUpdater {
T* proxy_;
public:
explicit ProxyUpdater(const ext::shared_ptr<T>& observerProxy)
: proxy_(observerProxy.get()) {}
void operator()() const {
proxy_->update();
}
bool operator==(const ProxyUpdater<T>& other) const {
return proxy_ == other.proxy_;
}
bool operator!=(const ProxyUpdater<T>& other) const {
return proxy_ != other.proxy_;
}
};
}
void Observable::registerObserver(const ext::shared_ptr<Observer::Proxy>& observerProxy) {
{
std::lock_guard<std::recursive_mutex> lock(mutex_);
observers_.insert(observerProxy);
}
detail::Signal::signal_type::slot_type slot {detail::ProxyUpdater<Observer::Proxy>(observerProxy)};
#if defined(QL_USE_STD_SHARED_PTR)
sig_->connect(slot.track_foreign(observerProxy));
#else
sig_->connect(slot.track(observerProxy));
#endif
}
void Observable::unregisterObserver(const ext::shared_ptr<Observer::Proxy>& observerProxy,
bool disconnect) {
{
std::lock_guard<std::recursive_mutex> lock(mutex_);
observers_.erase(observerProxy);
}
if (settings_.updatesDeferred()) {
std::lock_guard<std::mutex> sLock(settings_.mutex_);
if (settings_.updatesDeferred()) {
settings_.unregisterDeferredObserver(observerProxy);
}
}
if (disconnect) {
sig_->disconnect(detail::ProxyUpdater<Observer::Proxy>(observerProxy));
}
}
void Observable::notifyObservers() {
if (settings_.updatesEnabled()) {
return (*sig_)();
}
std::lock_guard<std::mutex> sLock(settings_.mutex_);
if (settings_.updatesEnabled()) {
return (*sig_)();
}
else if (settings_.updatesDeferred()) {
std::lock_guard<std::recursive_mutex> lock(mutex_);
// if updates are only deferred, flag this for later notification
// these are held centrally by the settings singleton
settings_.registerDeferredObservers(observers_);
}
}
Observable::Observable()
: sig_(new detail::Signal()),
settings_(ObservableSettings::instance()) { }
Observable::Observable(const Observable&)
: sig_(new detail::Signal()),
settings_(ObservableSettings::instance()) {
// the observer set is not copied; no observer asked to
// register with this object
}
}
#endif
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