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tdactor/td/actor/MultiPromise.cpp

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+/*
+    This file is part of TON Blockchain Library.
+
+    TON Blockchain Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    TON Blockchain Library 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 Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright 2017-2019 Telegram Systems LLP
+*/
+#include "td/actor/MultiPromise.h"
+
+#include <mutex>
+
+namespace td {
+namespace detail {
+class MultiPromiseImpl {
+ public:
+  explicit MultiPromiseImpl(MultiPromise::Options options) : options_(options) {
+  }
+  ~MultiPromiseImpl() {
+    for (auto &promise : pending_) {
+      promise.set_value(Unit());
+    }
+  }
+
+  void on_status(Status status) {
+    if (status.is_ok() || options_.ignore_errors) {
+      return;
+    }
+    std::vector<Promise<>> promises;
+    {
+      std::unique_lock<std::mutex> lock(mutex_);
+      if (pending_error_.is_ok()) {
+        pending_error_ = status.clone();
+        std::swap(promises, pending_);
+      } else {
+        CHECK(pending_.empty());
+      }
+    }
+    for (auto &promise : promises) {
+      promise.set_error(status.clone());
+    }
+  }
+  void add_promise(Promise<> promise) {
+    if (options_.ignore_errors) {
+      pending_.push_back(std::move(promise));
+    }
+    Status status;
+    {
+      std::unique_lock<std::mutex> lock(mutex_);
+      if (pending_error_.is_error()) {
+        status = pending_error_.clone();
+      } else {
+        pending_.push_back(std::move(promise));
+      }
+    }
+    if (status.is_error()) {
+      promise.set_error(std::move(status));
+    }
+  }
+
+ private:
+  std::mutex mutex_;
+  std::vector<Promise<>> pending_;
+  MultiPromise::Options options_;
+  Status pending_error_;
+};
+}  // namespace detail
+void MultiPromise::InitGuard::add_promise(Promise<> promise) {
+  impl_->add_promise(std::move(promise));
+}
+Promise<> MultiPromise::InitGuard::get_promise() {
+  return [impl = impl_](Result<Unit> result) {
+    if (result.is_ok()) {
+      impl->on_status(Status::OK());
+    } else {
+      impl->on_status(result.move_as_error());
+    }
+  };
+}
+bool MultiPromise::InitGuard::empty() const {
+  return !impl_;
+}
+MultiPromise::InitGuard::operator bool() const {
+  return !empty();
+}
+MultiPromise::InitGuard MultiPromise::init_guard() {
+  CHECK(!impl_.lock());
+  auto impl = std::make_shared<Impl>(options_);
+  impl_ = impl;
+  return InitGuard(std::move(impl));
+}
+MultiPromise::InitGuard MultiPromise::add_promise_or_init(Promise<> promise) {
+  auto impl = impl_.lock();
+  if (!impl) {
+    auto guard = init_guard();
+    guard.add_promise(std::move(promise));
+    return guard;
+  }
+  impl->add_promise(std::move(promise));
+  return {};
+}
+}  // namespace td