mpoeter commented on code in PR #5532: URL: https://github.com/apache/ignite-3/pull/5532#discussion_r2022573722
########## modules/platforms/cpp/ignite/client/detail/cancellation_token_impl.cpp: ########## @@ -0,0 +1,121 @@ +/* +* Licensed to the Apache Software Foundation (ASF) under one or more +* contributor license agreements. See the NOTICE file distributed with +* this work for additional information regarding copyright ownership. +* The ASF licenses this file to You under the Apache License, Version 2.0 +* (the "License"); you may not use this file except in compliance with +* the License. You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +#include "ignite/client/detail/cancellation_token_impl.h" + +#include <sstream> + +namespace ignite +{ + +void cancellation_token_impl::cancel_async(ignite_callback<void> callback) { + std::lock_guard guard(m_mutex); + + if (is_cancelled()) { + if (m_result) { + callback(ignite_result<void>{*m_result}); + } else { + m_callbacks.push_back(std::move(callback)); + } + return; + } + + m_cancelled = true; + m_callbacks.push_back(std::move(callback)); + + if (m_actions.empty()) { + m_result = ignite_result<void>{}; + for (auto &cb : m_callbacks) { + cb(ignite_result<void>{*m_result}); + } + return; + } + + auto results = std::make_shared<std::vector<ignite_result<void>>>(); + auto results_mutex = std::make_shared<std::mutex>(); + auto expected_results = m_actions.size(); + for (auto &action : m_actions) { + action([this, results, results_mutex, expected_results] (ignite_result<void> res) { + bool all_done{false}; Review Comment: We are capturing `this` here and we use some mutex to protect the results list, so I take it that this action callback might be called concurrently/asynchronously. How do we make sure that `this` lives long enough? Since we inherit from `enabled_shared_from_this` I think we should capture a `shared_ptr` instead. ########## modules/platforms/cpp/ignite/client/detail/cancellation_token_impl.cpp: ########## @@ -0,0 +1,121 @@ +/* +* Licensed to the Apache Software Foundation (ASF) under one or more +* contributor license agreements. See the NOTICE file distributed with +* this work for additional information regarding copyright ownership. +* The ASF licenses this file to You under the Apache License, Version 2.0 +* (the "License"); you may not use this file except in compliance with +* the License. You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +#include "ignite/client/detail/cancellation_token_impl.h" + +#include <sstream> + +namespace ignite +{ + +void cancellation_token_impl::cancel_async(ignite_callback<void> callback) { + std::lock_guard guard(m_mutex); + + if (is_cancelled()) { + if (m_result) { + callback(ignite_result<void>{*m_result}); Review Comment: Why do we create a new ignite_result here? Wouldn't this suffice? ```suggestion callback(*m_result); ``` ########## modules/platforms/cpp/ignite/client/detail/cancellation_token_impl.cpp: ########## @@ -0,0 +1,121 @@ +/* +* Licensed to the Apache Software Foundation (ASF) under one or more +* contributor license agreements. See the NOTICE file distributed with +* this work for additional information regarding copyright ownership. +* The ASF licenses this file to You under the Apache License, Version 2.0 +* (the "License"); you may not use this file except in compliance with +* the License. You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +#include "ignite/client/detail/cancellation_token_impl.h" + +#include <sstream> + +namespace ignite +{ + +void cancellation_token_impl::cancel_async(ignite_callback<void> callback) { + std::lock_guard guard(m_mutex); + + if (is_cancelled()) { + if (m_result) { + callback(ignite_result<void>{*m_result}); + } else { + m_callbacks.push_back(std::move(callback)); + } + return; + } + + m_cancelled = true; + m_callbacks.push_back(std::move(callback)); + + if (m_actions.empty()) { + m_result = ignite_result<void>{}; + for (auto &cb : m_callbacks) { + cb(ignite_result<void>{*m_result}); Review Comment: Same as above. ```suggestion cb(*m_result); ``` ########## modules/platforms/cpp/ignite/client/detail/cancellation_token_impl.cpp: ########## @@ -0,0 +1,121 @@ +/* +* Licensed to the Apache Software Foundation (ASF) under one or more +* contributor license agreements. See the NOTICE file distributed with +* this work for additional information regarding copyright ownership. +* The ASF licenses this file to You under the Apache License, Version 2.0 +* (the "License"); you may not use this file except in compliance with +* the License. You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +#include "ignite/client/detail/cancellation_token_impl.h" + +#include <sstream> + +namespace ignite +{ + +void cancellation_token_impl::cancel_async(ignite_callback<void> callback) { + std::lock_guard guard(m_mutex); + + if (is_cancelled()) { + if (m_result) { + callback(ignite_result<void>{*m_result}); + } else { + m_callbacks.push_back(std::move(callback)); + } + return; + } + + m_cancelled = true; + m_callbacks.push_back(std::move(callback)); + + if (m_actions.empty()) { + m_result = ignite_result<void>{}; + for (auto &cb : m_callbacks) { + cb(ignite_result<void>{*m_result}); + } + return; + } + + auto results = std::make_shared<std::vector<ignite_result<void>>>(); + auto results_mutex = std::make_shared<std::mutex>(); + auto expected_results = m_actions.size(); + for (auto &action : m_actions) { + action([this, results, results_mutex, expected_results] (ignite_result<void> res) { + bool all_done{false}; + { // Mutex locking scope + std::lock_guard guard0(*results_mutex); + results->push_back(std::move(res)); + all_done = results->size() == expected_results; + + if (all_done) { + bool error_found{false}; + std::stringstream msg_builder; + for (auto &result : *results) { + if (!result.has_error()) { + continue; + } + + if (!error_found) { + msg_builder << "One or more cancel actions failed: " << result.error().what_str(); + error_found = true; + continue; + } + + msg_builder << ", " << result.error().what_str(); + } + + { // Result mutex locking scope. + std::lock_guard guard1(m_mutex); + if (error_found) { + m_result = {ignite_error(msg_builder.str())}; + } else { + m_result = ignite_result<void>{}; + } + } + } + } + + if (all_done) { + std::lock_guard guard0(m_mutex); + for (auto &cb : m_callbacks) { + cb(ignite_result<void>{*m_result}); + } + } + }); + } +} Review Comment: Can we create the action callback lambda outside the loop? ```suggestion auto action_callback = [this, results, results_mutex, expected_results] (ignite_result<void> res) { bool all_done{false}; { // Mutex locking scope std::lock_guard guard0(*results_mutex); results->push_back(std::move(res)); all_done = results->size() == expected_results; if (all_done) { bool error_found{false}; std::stringstream msg_builder; for (auto &result : *results) { if (!result.has_error()) { continue; } if (!error_found) { msg_builder << "One or more cancel actions failed: " << result.error().what_str(); error_found = true; continue; } msg_builder << ", " << result.error().what_str(); } { // Result mutex locking scope. std::lock_guard guard1(m_mutex); if (error_found) { m_result = {ignite_error(msg_builder.str())}; } else { m_result = ignite_result<void>{}; } } } } if (all_done) { std::lock_guard guard0(m_mutex); for (auto &cb : m_callbacks) { cb(ignite_result<void>{*m_result}); } } } for (auto &action : m_actions) { action(action_callback); } } ``` ########## modules/platforms/cpp/ignite/client/detail/cancellation_token_impl.cpp: ########## @@ -0,0 +1,121 @@ +/* +* Licensed to the Apache Software Foundation (ASF) under one or more +* contributor license agreements. See the NOTICE file distributed with +* this work for additional information regarding copyright ownership. +* The ASF licenses this file to You under the Apache License, Version 2.0 +* (the "License"); you may not use this file except in compliance with +* the License. You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +#include "ignite/client/detail/cancellation_token_impl.h" + +#include <sstream> + +namespace ignite +{ + +void cancellation_token_impl::cancel_async(ignite_callback<void> callback) { + std::lock_guard guard(m_mutex); + + if (is_cancelled()) { + if (m_result) { + callback(ignite_result<void>{*m_result}); + } else { + m_callbacks.push_back(std::move(callback)); + } + return; + } + + m_cancelled = true; + m_callbacks.push_back(std::move(callback)); + + if (m_actions.empty()) { + m_result = ignite_result<void>{}; + for (auto &cb : m_callbacks) { + cb(ignite_result<void>{*m_result}); + } + return; + } + + auto results = std::make_shared<std::vector<ignite_result<void>>>(); + auto results_mutex = std::make_shared<std::mutex>(); + auto expected_results = m_actions.size(); + for (auto &action : m_actions) { + action([this, results, results_mutex, expected_results] (ignite_result<void> res) { + bool all_done{false}; + { // Mutex locking scope + std::lock_guard guard0(*results_mutex); + results->push_back(std::move(res)); + all_done = results->size() == expected_results; + + if (all_done) { + bool error_found{false}; + std::stringstream msg_builder; + for (auto &result : *results) { + if (!result.has_error()) { + continue; + } + + if (!error_found) { + msg_builder << "One or more cancel actions failed: " << result.error().what_str(); + error_found = true; + continue; + } + + msg_builder << ", " << result.error().what_str(); + } + + { // Result mutex locking scope. + std::lock_guard guard1(m_mutex); + if (error_found) { + m_result = {ignite_error(msg_builder.str())}; + } else { + m_result = ignite_result<void>{}; + } + } + } + } + + if (all_done) { + std::lock_guard guard0(m_mutex); + for (auto &cb : m_callbacks) { + cb(ignite_result<void>{*m_result}); + } + } + }); + } +} + +void cancellation_token_impl::add_action(std::shared_ptr<ignite_logger> logger, + std::function<void(ignite_callback<void>)> action) { + auto callback = [logger](ignite_result<void> res) { + if (res.has_error()) { + logger->log_warning( + "Cancellation action that was added after the token was already canceled: " + res.error().what_str()); + } + }; + + if (is_cancelled()) { + action(callback); + return; + } + + std::unique_lock lock(m_mutex); + if (is_cancelled()) { + lock.unlock(); + action(callback); + return; + } + Review Comment: If we remove the first check outside the lock then `m_cancelled` does not have to be an atomic. If you want to leave it in, it has to be an atomic. ########## modules/platforms/cpp/ignite/client/detail/cancellation_token_impl.h: ########## @@ -0,0 +1,85 @@ +/* +* Licensed to the Apache Software Foundation (ASF) under one or more +* contributor license agreements. See the NOTICE file distributed with +* this work for additional information regarding copyright ownership. +* The ASF licenses this file to You under the Apache License, Version 2.0 +* (the "License"); you may not use this file except in compliance with +* the License. You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +#pragma once + +#include "ignite/common/ignite_result.h" +#include "ignite/client/cancellation_token.h" + +#include <optional> +#include <mutex> +#include <vector> +#include <functional> +#include <ignite/client/ignite_logger.h> + +namespace ignite +{ + +/** + * A cancellation token implementation. + */ +class cancellation_token_impl : public cancellation_token, public std::enable_shared_from_this<cancellation_token_impl> +{ +public: + /** + * Destructor. + */ + ~cancellation_token_impl() override = default; + + /** + * Abruptly terminates an execution of an associated process. + * + * @param callback A callback that will be called after the process has been terminated and the resources associated + * with that process have been freed. + */ + void cancel_async(ignite_callback<void> callback); + + /** + * Adds an action to perform on cancellation. + * + * @param logger Logger to use if the operation was already canceled. + * @param action An action to perform on cancellation. + */ + void add_action(std::shared_ptr<ignite_logger> logger, std::function<void(ignite_callback<void>)> action); + + /** + * Flag indicating whether cancellation was requested or not. + * + * This method will return true even if cancellation has not been completed yet. + * + * @return @c true if the cancellation was requested. + */ + bool is_cancelled() const { return m_cancelled; } + +private: + /** Mutex. */ + std::mutex m_mutex{}; + + /** Cancel flag. */ + bool m_cancelled{false}; Review Comment: We can have concurrent accesses to this field, so this probably needs to be atomic. ```suggestion std::atomic<bool> m_cancelled{false}; ``` -- This is an automated message from the Apache Git Service. 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