tdesktop/Telegram/SourceFiles/rpl/event_stream.h

93 lines
2.4 KiB
C++

/*
This file is part of Telegram Desktop,
the official desktop version of Telegram messaging app, see https://telegram.org
Telegram Desktop is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
It 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
GNU General Public License for more details.
In addition, as a special exception, the copyright holders give permission
to link the code of portions of this program with the OpenSSL library.
Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
*/
#pragma once
#include "producer.h"
#include "base/algorithm.h"
namespace rpl {
template <typename Value>
class event_stream {
public:
event_stream();
void fire(Value value);
producer<Value, no_error> events();
~event_stream();
private:
std::weak_ptr<event_stream*> weak() const {
return _strong;
}
void addConsumer(consumer<Value, no_error> &&consumer) {
_consumers.push_back(std::move(consumer));
}
void removeConsumer(const consumer<Value, no_error> &consumer) {
auto it = base::find(_consumers, consumer);
if (it != _consumers.end()) {
it->terminate();
}
}
std::shared_ptr<event_stream*> _strong;
std::vector<consumer<Value, no_error>> _consumers;
};
template <typename Value>
event_stream<Value>::event_stream()
: _strong(std::make_shared<event_stream*>(this)) {
}
template <typename Value>
void event_stream<Value>::fire(Value value) {
base::push_back_safe_remove_if(_consumers, [&](auto &consumer) {
return !consumer.putNext(value);
});
}
template <typename Value>
producer<Value, no_error> event_stream<Value>::events() {
return producer<Value, no_error>([weak = weak()](consumer<Value, no_error> consumer) {
if (auto strong = weak.lock()) {
auto result = [weak, consumer] {
if (auto strong = weak.lock()) {
(*strong)->removeConsumer(consumer);
}
};
(*strong)->addConsumer(std::move(consumer));
return lifetime(std::move(result));
}
return lifetime();
});
}
template <typename Value>
event_stream<Value>::~event_stream() {
for (auto &consumer : _consumers) {
consumer.putDone();
}
}
} // namespace rpl