Use std::shared_ptr in Epoll's callback list. (2cf268ab) · Commits · e / os / android_system_core

init/Android.bp

+1 −0

Original line number	Diff line number	Diff line
		@@ -239,6 +239,7 @@ cc_test {

		srcs: [
		"devices_test.cpp",
		"epoll_test.cpp",
		"firmware_handler_test.cpp",
		"init_test.cpp",
		"keychords_test.cpp",

init/epoll.cpp

+7 −5

Original line number	Diff line number	Diff line
		@@ -38,11 +38,12 @@ Result<void> Epoll::Open() {
		return {};
		}

		Result<void> Epoll::RegisterHandler(int fd, std::function<void()> handler, uint32_t events) {
		Result<void> Epoll::RegisterHandler(int fd, Handler handler, uint32_t events) {
		if (!events) {
		return Error() << "Must specify events";
		}
		auto [it, inserted] = epoll_handlers_.emplace(fd, std::move(handler));
		auto sp = std::make_shared<decltype(handler)>(std::move(handler));
		auto [it, inserted] = epoll_handlers_.emplace(fd, std::move(sp));
		if (!inserted) {
		return Error() << "Cannot specify two epoll handlers for a given FD";
		}
		@@ -69,7 +70,7 @@ Result<void> Epoll::UnregisterHandler(int fd) {
		return {};
		}

		Result<std::vector<std::function<void()>*>> Epoll::Wait(
		Result<std::vector<std::shared_ptr<Epoll::Handler>>> Epoll::Wait(
		std::optional<std::chrono::milliseconds> timeout) {
		int timeout_ms = -1;
		if (timeout && timeout->count() < INT_MAX) {
		@@ -81,9 +82,10 @@ Result<std::vector<std::function<void()>*>> Epoll::Wait(
		if (num_events == -1) {
		return ErrnoError() << "epoll_wait failed";
		}
		std::vector<std::function<void()>*> pending_functions;
		std::vector<std::shared_ptr<Handler>> pending_functions;
		for (int i = 0; i < num_events; ++i) {
		pending_functions.emplace_back(reinterpret_cast<std::function<void()>*>(ev[i].data.ptr));
		auto sp = reinterpret_cast<std::shared_ptr<Handler>>(ev[i].data.ptr);
		pending_functions.emplace_back(std::move(sp));
		}

		return pending_functions;

init/epoll.h

+6 −3

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@
		#include <chrono>
		#include <functional>
		#include <map>
		#include <memory>
		#include <optional>
		#include <vector>

		@@ -36,15 +37,17 @@ class Epoll {
		public:
		Epoll();

		typedef std::function<void()> Handler;

		Result<void> Open();
		Result<void> RegisterHandler(int fd, std::function<void()> handler, uint32_t events = EPOLLIN);
		Result<void> RegisterHandler(int fd, Handler handler, uint32_t events = EPOLLIN);
		Result<void> UnregisterHandler(int fd);
		Result<std::vector<std::function<void()>*>> Wait(
		Result<std::vector<std::shared_ptr<Handler>>> Wait(
		std::optional<std::chrono::milliseconds> timeout);

		private:
		android::base::unique_fd epoll_fd_;
		std::map<int, std::function<void()>> epoll_handlers_;
		std::map<int, std::shared_ptr<Handler>> epoll_handlers_;
		};

		} // namespace init

init/epoll_test.cpp

0 → 100644

+76 −0

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		/*
		* Copyright (C) 2021 The Android Open Source Project
		*
		* 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 "epoll.h"

		#include <sys/unistd.h>

		#include <unordered_set>

		#include <android-base/file.h>
		#include <gtest/gtest.h>

		namespace android {
		namespace init {

		std::unordered_set<void*> sValidObjects;

		class CatchDtor final {
		public:
		CatchDtor() { sValidObjects.emplace(this); }
		CatchDtor(const CatchDtor&) { sValidObjects.emplace(this); }
		~CatchDtor() {
		auto iter = sValidObjects.find(this);
		if (iter != sValidObjects.end()) {
		sValidObjects.erase(iter);
		}
		}
		};

		TEST(epoll, UnregisterHandler) {
		Epoll epoll;
		ASSERT_RESULT_OK(epoll.Open());

		int fds[2];
		ASSERT_EQ(pipe(fds), 0);

		CatchDtor catch_dtor;
		bool handler_invoked;
		auto handler = [&, catch_dtor]() -> void {
		auto result = epoll.UnregisterHandler(fds[0]);
		ASSERT_EQ(result.ok(), !handler_invoked);
		handler_invoked = true;
		ASSERT_NE(sValidObjects.find((void*)&catch_dtor), sValidObjects.end());
		};

		epoll.RegisterHandler(fds[0], std::move(handler));

		uint8_t byte = 0xee;
		ASSERT_TRUE(android::base::WriteFully(fds[1], &byte, sizeof(byte)));

		auto results = epoll.Wait({});
		ASSERT_RESULT_OK(results);
		ASSERT_EQ(results->size(), size_t(1));

		for (const auto& function : *results) {
		(*function)();
		(*function)();
		}
		ASSERT_TRUE(handler_invoked);
		}

		} // namespace init
		} // namespace android