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// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
#pragma once
#if !defined(RXCPP_RX_SUBJECT_HPP)
#define RXCPP_RX_SUBJECT_HPP
#include "../rx-includes.hpp"
namespace rxcpp {
namespace subjects {
namespace detail {
template<class T>
class multicast_observer
{
typedef subscriber<T> observer_type;
typedef std::vector<observer_type> list_type;
struct mode
{
enum type {
Invalid = 0,
Casting,
Disposed,
Completed,
Errored
};
};
struct state_type
: public std::enable_shared_from_this<state_type>
{
explicit state_type(composite_subscription cs)
: current(mode::Casting)
, lifetime(cs)
{
}
std::mutex lock;
typename mode::type current;
rxu::error_ptr error;
composite_subscription lifetime;
};
struct completer_type
: public std::enable_shared_from_this<completer_type>
{
~completer_type()
{
}
completer_type(std::shared_ptr<state_type> s, const std::shared_ptr<completer_type>& old, observer_type o)
: state(s)
{
retain(old);
observers.push_back(o);
}
completer_type(std::shared_ptr<state_type> s, const std::shared_ptr<completer_type>& old)
: state(s)
{
retain(old);
}
void retain(const std::shared_ptr<completer_type>& old) {
if (old) {
observers.reserve(old->observers.size() + 1);
std::copy_if(
old->observers.begin(), old->observers.end(),
std::inserter(observers, observers.end()),
[](const observer_type& o){
return o.is_subscribed();
});
}
}
std::shared_ptr<state_type> state;
list_type observers;
};
// this type prevents a circular ref between state and completer
struct binder_type
: public std::enable_shared_from_this<binder_type>
{
explicit binder_type(composite_subscription cs)
: state(std::make_shared<state_type>(cs))
, id(trace_id::make_next_id_subscriber())
{
}
std::shared_ptr<state_type> state;
trace_id id;
// used to avoid taking lock in on_next
mutable std::weak_ptr<completer_type> current_completer;
// must only be accessed under state->lock
mutable std::shared_ptr<completer_type> completer;
};
std::shared_ptr<binder_type> b;
public:
typedef subscriber<T, observer<T, detail::multicast_observer<T>>> input_subscriber_type;
explicit multicast_observer(composite_subscription cs)
: b(std::make_shared<binder_type>(cs))
{
std::weak_ptr<binder_type> binder = b;
b->state->lifetime.add([binder](){
auto b = binder.lock();
if (b && b->state->current == mode::Casting){
b->state->current = mode::Disposed;
b->current_completer.reset();
b->completer.reset();
}
});
}
trace_id get_id() const {
return b->id;
}
composite_subscription get_subscription() const {
return b->state->lifetime;
}
input_subscriber_type get_subscriber() const {
return make_subscriber<T>(get_id(), get_subscription(), observer<T, detail::multicast_observer<T>>(*this));
}
bool has_observers() const {
std::unique_lock<std::mutex> guard(b->state->lock);
return b->completer && !b->completer->observers.empty();
}
template<class SubscriberFrom>
void add(const SubscriberFrom& sf, observer_type o) const {
trace_activity().connect(sf, o);
std::unique_lock<std::mutex> guard(b->state->lock);
switch (b->state->current) {
case mode::Casting:
{
if (o.is_subscribed()) {
std::weak_ptr<binder_type> binder = b;
o.add([=](){
auto b = binder.lock();
if (b) {
std::unique_lock<std::mutex> guard(b->state->lock);
b->completer = std::make_shared<completer_type>(b->state, b->completer);
}
});
b->completer = std::make_shared<completer_type>(b->state, b->completer, o);
}
}
break;
case mode::Completed:
{
guard.unlock();
o.on_completed();
return;
}
break;
case mode::Errored:
{
auto e = b->state->error;
guard.unlock();
o.on_error(e);
return;
}
break;
case mode::Disposed:
{
guard.unlock();
o.unsubscribe();
return;
}
break;
default:
std::terminate();
}
}
template<class V>
void on_next(V v) const {
auto current_completer = b->current_completer.lock();
if (!current_completer) {
std::unique_lock<std::mutex> guard(b->state->lock);
b->current_completer = b->completer;
current_completer = b->current_completer.lock();
}
if (!current_completer || current_completer->observers.empty()) {
return;
}
for (auto& o : current_completer->observers) {
if (o.is_subscribed()) {
o.on_next(v);
}
}
}
void on_error(rxu::error_ptr e) const {
std::unique_lock<std::mutex> guard(b->state->lock);
if (b->state->current == mode::Casting) {
b->state->error = e;
b->state->current = mode::Errored;
auto s = b->state->lifetime;
auto c = std::move(b->completer);
b->current_completer.reset();
guard.unlock();
if (c) {
for (auto& o : c->observers) {
if (o.is_subscribed()) {
o.on_error(e);
}
}
}
s.unsubscribe();
}
}
void on_completed() const {
std::unique_lock<std::mutex> guard(b->state->lock);
if (b->state->current == mode::Casting) {
b->state->current = mode::Completed;
auto s = b->state->lifetime;
auto c = std::move(b->completer);
b->current_completer.reset();
guard.unlock();
if (c) {
for (auto& o : c->observers) {
if (o.is_subscribed()) {
o.on_completed();
}
}
}
s.unsubscribe();
}
}
};
}
template<class T>
class subject
{
detail::multicast_observer<T> s;
public:
typedef subscriber<T, observer<T, detail::multicast_observer<T>>> subscriber_type;
typedef observable<T> observable_type;
subject()
: s(composite_subscription())
{
}
explicit subject(composite_subscription cs)
: s(cs)
{
}
bool has_observers() const {
return s.has_observers();
}
composite_subscription get_subscription() const {
return s.get_subscription();
}
subscriber_type get_subscriber() const {
return s.get_subscriber();
}
observable<T> get_observable() const {
auto keepAlive = s;
return make_observable_dynamic<T>([=](subscriber<T> o){
keepAlive.add(keepAlive.get_subscriber(), std::move(o));
});
}
};
}
}
#endif
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