638 lines
16 KiB
C++
638 lines
16 KiB
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2018
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#pragma once
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#include "td/actor/actor.h"
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#include "td/utils/Closure.h"
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#include "td/utils/common.h"
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#include "td/utils/invoke.h" // for tuple_for_each
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#include "td/utils/logging.h"
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#include "td/utils/ScopeGuard.h"
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#include "td/utils/Status.h"
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#include <atomic>
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#include <memory>
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#include <tuple>
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#include <type_traits>
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#include <utility>
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namespace td {
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template <class T = Unit>
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class PromiseInterface {
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public:
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PromiseInterface() = default;
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PromiseInterface(const PromiseInterface &) = delete;
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PromiseInterface &operator=(const PromiseInterface &) = delete;
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PromiseInterface(PromiseInterface &&) = default;
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PromiseInterface &operator=(PromiseInterface &&) = default;
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virtual ~PromiseInterface() = default;
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virtual void set_value(T &&value) {
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set_result(std::move(value));
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}
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virtual void set_error(Status &&error) {
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set_result(std::move(error));
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}
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virtual void set_result(Result<T> &&result) {
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if (result.is_ok()) {
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set_value(result.move_as_ok());
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} else {
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set_error(result.move_as_error());
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}
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}
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virtual bool is_cancellable() const {
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return false;
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}
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virtual bool is_cancelled() const {
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return false;
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}
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virtual void start_migrate(int32 sched_id) {
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}
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virtual void finish_migrate() {
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}
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};
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template <class T>
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class SafePromise;
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template <class T = Unit>
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class Promise {
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public:
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void set_value(T &&value) {
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if (!promise_) {
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return;
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}
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promise_->set_value(std::move(value));
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promise_.reset();
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}
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void set_error(Status &&error) {
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if (!promise_) {
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return;
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}
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promise_->set_error(std::move(error));
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promise_.reset();
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}
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void set_result(Result<T> &&result) {
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if (!promise_) {
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return;
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}
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promise_->set_result(std::move(result));
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promise_.reset();
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}
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void reset() {
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promise_.reset();
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}
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void start_migrate(int32 sched_id) {
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if (!promise_) {
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return;
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}
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promise_->start_migrate(sched_id);
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}
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void finish_migrate() {
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if (!promise_) {
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return;
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}
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promise_->finish_migrate();
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}
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bool is_cancellable() const {
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if (!promise_) {
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return false;
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}
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return promise_->is_cancellable();
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}
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bool is_cancelled() const {
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if (!promise_) {
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return false;
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}
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return promise_->is_cancelled();
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}
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unique_ptr<PromiseInterface<T>> release() {
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return std::move(promise_);
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}
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Promise() = default;
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explicit Promise(unique_ptr<PromiseInterface<T>> promise) : promise_(std::move(promise)) {
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}
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Promise(SafePromise<T> &&other);
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Promise &operator=(SafePromise<T> &&other);
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explicit operator bool() {
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return static_cast<bool>(promise_);
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}
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private:
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unique_ptr<PromiseInterface<T>> promise_;
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};
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template <class T>
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void start_migrate(Promise<T> &promise, int32 sched_id) {
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// promise.start_migrate(sched_id);
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}
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template <class T>
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void finish_migrate(Promise<T> &promise) {
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// promise.finish_migrate();
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}
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template <class T = Unit>
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class SafePromise {
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public:
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SafePromise(Promise<T> promise, Result<T> result) : promise_(std::move(promise)), result_(std::move(result)) {
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}
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SafePromise(const SafePromise &other) = delete;
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SafePromise &operator=(const SafePromise &other) = delete;
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SafePromise(SafePromise &&other) = default;
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SafePromise &operator=(SafePromise &&other) = default;
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~SafePromise() {
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if (promise_) {
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promise_.set_result(std::move(result_));
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}
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}
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Promise<T> release() {
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return std::move(promise_);
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}
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private:
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Promise<T> promise_;
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Result<T> result_;
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};
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template <class T>
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Promise<T>::Promise(SafePromise<T> &&other) : Promise(other.release()) {
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}
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template <class T>
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Promise<T> &Promise<T>::operator=(SafePromise<T> &&other) {
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*this = other.release();
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return *this;
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}
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class CancellationToken {
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public:
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explicit CancellationToken(bool init = false) {
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if (init) {
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ptr_ = std::make_shared<std::atomic<bool>>(false);
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}
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}
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CancellationToken(const CancellationToken &other) = default;
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CancellationToken &operator=(const CancellationToken &other) {
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cancel();
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ptr_ = other.ptr_;
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return *this;
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}
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CancellationToken(CancellationToken &&other) = default;
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CancellationToken &operator=(CancellationToken &&other) {
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cancel();
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ptr_ = std::move(other.ptr_);
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return *this;
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}
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~CancellationToken() {
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cancel();
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}
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bool is_canceled() const {
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return !ptr_ || *ptr_;
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}
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void cancel() {
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if (ptr_) {
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ptr_->store(true, std::memory_order_relaxed);
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ptr_.reset();
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}
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}
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private:
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std::shared_ptr<std::atomic<bool>> ptr_;
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};
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namespace detail {
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class EventPromise : public PromiseInterface<Unit> {
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public:
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void set_value(Unit &&) override {
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ok_.try_emit();
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fail_.clear();
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}
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void set_error(Status &&) override {
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do_set_error();
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}
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EventPromise(const EventPromise &other) = delete;
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EventPromise &operator=(const EventPromise &other) = delete;
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EventPromise(EventPromise &&other) = delete;
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EventPromise &operator=(EventPromise &&other) = delete;
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~EventPromise() override {
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do_set_error();
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}
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EventPromise() = default;
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explicit EventPromise(EventFull ok) : ok_(std::move(ok)), use_ok_as_fail_(true) {
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}
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EventPromise(EventFull ok, EventFull fail) : ok_(std::move(ok)), fail_(std::move(fail)), use_ok_as_fail_(false) {
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}
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private:
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EventFull ok_;
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EventFull fail_;
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bool use_ok_as_fail_ = false;
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void do_set_error() {
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if (use_ok_as_fail_) {
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ok_.try_emit();
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} else {
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ok_.clear();
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fail_.try_emit();
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}
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}
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};
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template <typename T>
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struct GetArg : public GetArg<decltype(&T::operator())> {};
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template <class C, class R, class Arg>
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class GetArg<R (C::*)(Arg)> {
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public:
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using type = Arg;
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};
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template <class C, class R, class Arg>
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class GetArg<R (C::*)(Arg) const> {
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public:
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using type = Arg;
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};
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template <class T>
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using get_arg_t = std::decay_t<typename GetArg<T>::type>;
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template <class T>
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struct DropResult {
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using type = T;
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};
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template <class T>
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struct DropResult<Result<T>> {
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using type = T;
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};
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template <class T>
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using drop_result_t = typename DropResult<T>::type;
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template <class PromiseT>
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class CancellablePromise : public PromiseT {
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public:
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template <class... ArgsT>
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CancellablePromise(CancellationToken cancellation_token, ArgsT &&... args)
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: PromiseT(std::forward<ArgsT>(args)...), cancellation_token_(std::move(cancellation_token)) {
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}
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virtual bool is_cancellable() const {
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return true;
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}
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virtual bool is_cancelled() const {
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return cancellation_token_.is_canceled();
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}
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private:
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CancellationToken cancellation_token_;
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};
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template <class ValueT, class FunctionOkT, class FunctionFailT>
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class LambdaPromise : public PromiseInterface<ValueT> {
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enum OnFail { None, Ok, Fail };
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public:
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void set_value(ValueT &&value) override {
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ok_(std::move(value));
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on_fail_ = None;
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}
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void set_error(Status &&error) override {
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do_error(std::move(error));
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}
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LambdaPromise(const LambdaPromise &other) = delete;
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LambdaPromise &operator=(const LambdaPromise &other) = delete;
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LambdaPromise(LambdaPromise &&other) = delete;
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LambdaPromise &operator=(LambdaPromise &&other) = delete;
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~LambdaPromise() override {
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do_error(Status::Error("Lost promise"));
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}
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template <class FromOkT, class FromFailT>
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LambdaPromise(FromOkT &&ok, FromFailT &&fail, bool use_ok_as_fail)
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: ok_(std::forward<FromOkT>(ok)), fail_(std::forward<FromFailT>(fail)), on_fail_(use_ok_as_fail ? Ok : Fail) {
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}
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private:
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FunctionOkT ok_;
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FunctionFailT fail_;
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OnFail on_fail_ = None;
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template <class FuncT, class ArgT = detail::get_arg_t<FuncT>>
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std::enable_if_t<std::is_assignable<ArgT, Status>::value> do_error_impl(FuncT &func, Status &&status) {
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func(std::move(status));
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}
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template <class FuncT, class ArgT = detail::get_arg_t<FuncT>>
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std::enable_if_t<!std::is_assignable<ArgT, Status>::value> do_error_impl(FuncT &func, Status &&status) {
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func(Auto());
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}
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void do_error(Status &&error) {
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switch (on_fail_) {
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case None:
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break;
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case Ok:
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do_error_impl(ok_, std::move(error));
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break;
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case Fail:
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fail_(std::move(error));
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break;
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}
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on_fail_ = None;
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}
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};
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template <class... ArgsT>
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class JoinPromise : public PromiseInterface<Unit> {
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public:
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explicit JoinPromise(ArgsT &&... arg) : promises_(std::forward<ArgsT>(arg)...) {
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}
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void set_value(Unit &&) override {
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tuple_for_each(promises_, [](auto &promise) { promise.set_value(Unit()); });
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}
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void set_error(Status &&error) override {
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tuple_for_each(promises_, [&error](auto &promise) { promise.set_error(error.clone()); });
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}
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private:
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std::tuple<std::decay_t<ArgsT>...> promises_;
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};
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} // namespace detail
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/*** FutureActor and PromiseActor ***/
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template <class T>
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class FutureActor;
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template <class T>
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class PromiseActor;
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template <class T>
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class ActorTraits<FutureActor<T>> {
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public:
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static constexpr bool is_lite = true;
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};
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template <class T>
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class PromiseActor final : public PromiseInterface<T> {
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friend class FutureActor<T>;
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enum State { Waiting, Hangup };
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public:
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PromiseActor() = default;
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PromiseActor(const PromiseActor &other) = delete;
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PromiseActor &operator=(const PromiseActor &other) = delete;
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PromiseActor(PromiseActor &&) = default;
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PromiseActor &operator=(PromiseActor &&) = default;
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~PromiseActor() override {
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close();
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}
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void set_value(T &&value) override;
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void set_error(Status &&error) override;
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void close() {
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future_id_.reset();
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}
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// NB: if true is returned no further events will be sent
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bool is_hangup() {
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if (state_ == State::Hangup) {
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return true;
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}
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if (!future_id_.is_alive()) {
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state_ = State::Hangup;
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future_id_.release();
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event_.clear();
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return true;
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}
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return false;
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}
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template <class S>
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friend void init_promise_future(PromiseActor<S> *promise, FutureActor<S> *future);
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bool empty_promise() {
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return future_id_.empty();
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}
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bool empty() {
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return future_id_.empty();
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}
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private:
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ActorOwn<FutureActor<T>> future_id_;
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EventFull event_;
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State state_;
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void init() {
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state_ = State::Waiting;
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event_.clear();
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}
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};
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template <class T>
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class FutureActor final : public Actor {
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friend class PromiseActor<T>;
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enum State { Waiting, Ready };
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public:
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static constexpr int Hangup = 426487;
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FutureActor() = default;
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FutureActor(const FutureActor &other) = delete;
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FutureActor &operator=(const FutureActor &other) = delete;
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FutureActor(FutureActor &&other) = default;
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FutureActor &operator=(FutureActor &&other) = default;
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~FutureActor() override = default;
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bool is_ok() const {
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return is_ready() && result_.is_ok();
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}
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bool is_error() const {
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CHECK(is_ready());
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return is_ready() && result_.is_error();
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}
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T move_as_ok() {
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return move_as_result().move_as_ok();
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}
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Status move_as_error() TD_WARN_UNUSED_RESULT {
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return move_as_result().move_as_error();
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}
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Result<T> move_as_result() TD_WARN_UNUSED_RESULT {
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CHECK(is_ready());
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SCOPE_EXIT {
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do_stop();
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};
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return std::move(result_);
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}
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bool is_ready() const {
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return !empty() && state_ == State::Ready;
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}
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void close() {
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event_.clear();
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result_.clear();
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do_stop();
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}
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void set_event(EventFull &&event) {
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CHECK(!empty());
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event_ = std::move(event);
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if (state_ != State::Waiting) {
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event_.try_emit_later();
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}
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}
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template <class S>
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friend void init_promise_future(PromiseActor<S> *promise, FutureActor<S> *future);
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private:
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EventFull event_;
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Result<T> result_ = Status::Error(500, "Empty FutureActor");
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State state_;
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void set_value(T &&value) {
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set_result(std::move(value));
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}
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void set_error(Status &&error) {
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set_result(std::move(error));
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}
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void set_result(Result<T> &&result) {
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CHECK(state_ == State::Waiting);
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result_ = std::move(result);
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state_ = State::Ready;
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event_.try_emit_later();
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}
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void hangup() override {
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set_error(Status::Error<Hangup>());
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}
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void start_up() override {
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// empty
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}
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void init() {
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CHECK(empty());
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state_ = State::Waiting;
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event_.clear();
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}
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};
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template <class T>
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void PromiseActor<T>::set_value(T &&value) {
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if (state_ == State::Waiting && !future_id_.empty()) {
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send_closure(std::move(future_id_), &FutureActor<T>::set_value, std::move(value));
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}
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}
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template <class T>
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void PromiseActor<T>::set_error(Status &&error) {
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if (state_ == State::Waiting && !future_id_.empty()) {
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send_closure(std::move(future_id_), &FutureActor<T>::set_error, std::move(error));
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}
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}
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template <class S>
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void init_promise_future(PromiseActor<S> *promise, FutureActor<S> *future) {
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promise->init();
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future->init();
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promise->future_id_ = register_actor("FutureActor", future);
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CHECK(future->get_info() != nullptr);
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}
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template <class T>
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class PromiseFuture {
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public:
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PromiseFuture() {
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init_promise_future(&promise_, &future_);
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}
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PromiseActor<T> &promise() {
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return promise_;
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}
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FutureActor<T> &future() {
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return future_;
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}
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PromiseActor<T> &&move_promise() {
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return std::move(promise_);
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}
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FutureActor<T> &&move_future() {
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return std::move(future_);
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}
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private:
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PromiseActor<T> promise_;
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FutureActor<T> future_;
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};
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template <ActorSendType send_type, class T, class ActorAT, class ActorBT, class ResultT, class... DestArgsT,
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class... ArgsT>
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FutureActor<T> send_promise(ActorId<ActorAT> actor_id, ResultT (ActorBT::*func)(PromiseActor<T> &&, DestArgsT...),
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ArgsT &&... args) {
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PromiseFuture<T> pf;
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Scheduler::instance()->send_closure<send_type>(
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std::move(actor_id), create_immediate_closure(func, pf.move_promise(), std::forward<ArgsT>(args)...));
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return pf.move_future();
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}
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class PromiseCreator {
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public:
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struct Ignore {
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void operator()(Status &&error) {
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error.ignore();
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}
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};
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template <class OkT, class ArgT = detail::drop_result_t<detail::get_arg_t<OkT>>>
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static Promise<ArgT> lambda(OkT &&ok) {
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return Promise<ArgT>(
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td::make_unique<detail::LambdaPromise<ArgT, std::decay_t<OkT>, Ignore>>(std::forward<OkT>(ok), Ignore(), true));
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}
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template <class OkT, class FailT, class ArgT = detail::get_arg_t<OkT>>
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static Promise<ArgT> lambda(OkT &&ok, FailT &&fail) {
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return Promise<ArgT>(td::make_unique<detail::LambdaPromise<ArgT, std::decay_t<OkT>, std::decay_t<FailT>>>(
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std::forward<OkT>(ok), std::forward<FailT>(fail), false));
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}
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template <class OkT, class ArgT = detail::drop_result_t<detail::get_arg_t<OkT>>>
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static auto cancellable_lambda(CancellationToken cancellation_token, OkT &&ok) {
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return Promise<ArgT>(
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td::make_unique<detail::CancellablePromise<detail::LambdaPromise<ArgT, std::decay_t<OkT>, Ignore>>>(
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std::move(cancellation_token), std::forward<OkT>(ok), Ignore(), true));
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}
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static Promise<> event(EventFull &&ok) {
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return Promise<>(td::make_unique<detail::EventPromise>(std::move(ok)));
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}
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static Promise<> event(EventFull ok, EventFull fail) {
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return Promise<>(td::make_unique<detail::EventPromise>(std::move(ok), std::move(fail)));
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}
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template <class... ArgsT>
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static Promise<> join(ArgsT &&... args) {
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return Promise<>(td::make_unique<detail::JoinPromise<ArgsT...>>(std::forward<ArgsT>(args)...));
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}
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template <class T>
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static Promise<T> from_promise_actor(PromiseActor<T> &&from) {
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return Promise<T>(td::make_unique<PromiseActor<T>>(std::move(from)));
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}
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};
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} // namespace td
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