Added simple thread pool executor class

src/util/thread_pool_executor.cc

@@ -0,0 +1,23 @@
+/**
+* src/util/thread_pool_executor.cc
+*
+* Copyright (c) 2021-2022 Bartek Kryza <bkryza@gmail.com>
+*
+* Licensed 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 "thread_pool_executor.h"
+
+namespace clanguml::util {
+
+}

src/util/thread_pool_executor.h

@@ -0,0 +1,109 @@
+/**
+ * src/util/thread_pool_executor.h
+ *
+ * Copyright (c) 2021-2022 Bartek Kryza <bkryza@gmail.com>
+ *
+ * Licensed 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 <deque>
+#include <future>
+#include <thread>
+#include <vector>
+
+namespace clanguml::util {
+class thread_pool_executor {
+public:
+    thread_pool_executor()
+        : thread_pool_executor{0}
+    {
+    }
+
+    thread_pool_executor(unsigned int pool_size)
+        : done_{false}
+    {
+        if (pool_size == 0U)
+            pool_size = std::thread::hardware_concurrency();
+
+        for (auto i = 0U; i < pool_size; i++) {
+            threads_.push_back(
+                std::thread{&thread_pool_executor::worker, this});
+        }
+    }
+
+    ~thread_pool_executor() { stop(); }
+
+    std::future<void> add(std::function<void()> &&task)
+    {
+        std::unique_lock<std::mutex> l(tasks_mutex_);
+
+        std::packaged_task<void()> ptask{std::move(task)};
+        auto res = ptask.get_future();
+
+        tasks_.emplace_back(std::move(ptask));
+
+        l.unlock();
+        tasks_cond_.notify_one();
+
+        return res;
+    }
+
+    void stop()
+    {
+        done_ = true;
+        for (auto &thread : threads_) {
+            if (thread.joinable())
+                thread.join();
+        }
+    }
+
+private:
+    void worker()
+    {
+        try {
+            while (!done_) {
+                auto task = get();
+
+                task();
+            }
+        }
+        catch (std::runtime_error &e) {
+        }
+    }
+
+    std::packaged_task<void()> get()
+    {
+        std::unique_lock<std::mutex> l(tasks_mutex_);
+
+        while (tasks_.empty()) {
+            if (done_)
+                throw std::runtime_error("Thread pool closing...");
+
+            tasks_cond_.wait_for(l, std::chrono::seconds(1));
+        }
+
+        auto res = std::move(tasks_.front());
+        tasks_.pop_front();
+        return res;
+    }
+
+    std::atomic_bool done_;
+
+    std::deque<std::packaged_task<void()>> tasks_;
+    std::mutex tasks_mutex_;
+    std::condition_variable tasks_cond_;
+
+    std::vector<std::thread> threads_;
+};
+}

tests/CMakeLists.txt

@@ -48,6 +48,13 @@ set(CLANG_UML_TEST_CONFIG_HEADER
         catch.h
         )
 
+set(CLANG_UML_TEST_THREAD_POOL_EXECUTOR_SRC
+        test_thread_pool_executor.cc
+        )
+set(CLANG_UML_TEST_THREAD_POOL_EXECUTOR_HEADER
+        catch.h
+        )
+
 add_executable(test_util
     ${CLANG_UML_TEST_UTIL_SRC}
     ${CLANG_UML_TEST_UTIL_HEADER})
@@ -88,6 +95,16 @@ target_link_libraries(test_config
         ${YAML_CPP_LIBRARIES}
         spdlog::spdlog clang-umllib cppast)
 
+add_executable(test_thread_pool_executor
+        ${CLANG_UML_TEST_THREAD_POOL_EXECUTOR_SRC}
+        ${CLANG_UML_TEST_THREAD_POOL_EXECUTOR_HEADER})
+
+target_link_libraries(test_thread_pool_executor
+        PRIVATE
+        ${LIBCLANG_LIBRARIES}
+        ${YAML_CPP_LIBRARIES}
+        spdlog::spdlog clang-umllib cppast)
+
 add_executable(test_cases
     ${CLANG_UML_TEST_CASES_SRC}
     ${CLANG_UML_TEST_CASES_HEADER})

tests/test_thread_pool_executor.cc

@@ -0,0 +1,45 @@
+/**
+ * tests/test_thread_pool_executor.cc
+ *
+ * Copyright (c) 2021-2022 Bartek Kryza <bkryza@gmail.com>
+ *
+ * Licensed 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.
+ */
+#define CATCH_CONFIG_MAIN
+
+#include "catch.h"
+
+#include "util/thread_pool_executor.h"
+
+TEST_CASE("Test thread_pool_executor", "[unit-test]")
+{
+    using clanguml::util::thread_pool_executor;
+
+    thread_pool_executor pool{4};
+
+    std::atomic_int counter{0};
+
+    std::vector<std::future<void>> futs;
+
+    const unsigned int kTaskCount = 1000;
+
+    for (auto i = 0U; i < kTaskCount; i++) {
+        futs.emplace_back(pool.add([&counter]() { counter++; }));
+    }
+
+    for (auto &f : futs) {
+        f.get();
+    }
+
+    CHECK(counter == kTaskCount);
+}