diff --git a/adb/sysdeps/mutex.h b/adb/sysdeps/mutex.h new file mode 100644 index 0000000000000000000000000000000000000000..73c9e6e064fb78be2763c4e60246881e2592376b --- /dev/null +++ b/adb/sysdeps/mutex.h @@ -0,0 +1,107 @@ +#pragma once + +/* + * Copyright (C) 2016 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. + */ + +#if defined(_WIN32) + +#include <windows.h> + +#include <android-base/macros.h> + +#include "adb.h" + +// The prebuilt version of mingw we use doesn't support mutex or recursive_mutex. +// Therefore, implement our own using the Windows primitives. +// Put them directly into the std namespace, so that when they're actually available, the build +// breaks until they're removed. + +#include <mutex> +namespace std { + +// CRITICAL_SECTION is recursive, so just wrap it in a Mutex-compatible class. +class recursive_mutex { + public: + recursive_mutex() { + InitializeCriticalSection(&mutex_); + } + + ~recursive_mutex() { + DeleteCriticalSection(&mutex_); + } + + void lock() { + EnterCriticalSection(&mutex_); + } + + bool try_lock() { + return TryEnterCriticalSection(&mutex_); + } + + void unlock() { + LeaveCriticalSection(&mutex_); + } + + private: + CRITICAL_SECTION mutex_; + + DISALLOW_COPY_AND_ASSIGN(recursive_mutex); +}; + +class mutex { + public: + mutex() { + } + + ~mutex() { + } + + void lock() { + mutex_.lock(); + if (++lock_count_ != 1) { + fatal("non-recursive mutex locked reentrantly"); + } + } + + void unlock() { + if (--lock_count_ != 0) { + fatal("non-recursive mutex unlock resulted in unexpected lock count: %d", lock_count_); + } + mutex_.unlock(); + } + + bool try_lock() { + if (!mutex_.try_lock()) { + return false; + } + + if (lock_count_ != 0) { + mutex_.unlock(); + return false; + } + + ++lock_count_; + return true; + } + + private: + recursive_mutex mutex_; + size_t lock_count_ = 0; +}; + +} + +#endif diff --git a/adb/sysdeps_test.cpp b/adb/sysdeps_test.cpp index fde344abf242652da55fc95c59c1a2be29ee6fad..395d22d2a8069563f7ffe99b885ba61c7af8bacf 100644 --- a/adb/sysdeps_test.cpp +++ b/adb/sysdeps_test.cpp @@ -244,3 +244,60 @@ TEST_F(sysdeps_poll, fd_count) { adb_close(fd); } } + +#include "sysdeps/mutex.h" +TEST(sysdeps_mutex, mutex_smoke) { + static std::atomic<bool> finished(false); + static std::mutex &m = *new std::mutex(); + m.lock(); + ASSERT_FALSE(m.try_lock()); + adb_thread_create([](void*) { + ASSERT_FALSE(m.try_lock()); + m.lock(); + finished.store(true); + adb_sleep_ms(200); + m.unlock(); + }, nullptr); + + ASSERT_FALSE(finished.load()); + adb_sleep_ms(100); + ASSERT_FALSE(finished.load()); + m.unlock(); + adb_sleep_ms(100); + m.lock(); + ASSERT_TRUE(finished.load()); + m.unlock(); +} + +// Our implementation on Windows aborts on double lock. +#if defined(_WIN32) +TEST(sysdeps_mutex, mutex_reentrant_lock) { + std::mutex &m = *new std::mutex(); + + m.lock(); + ASSERT_FALSE(m.try_lock()); + EXPECT_DEATH(m.lock(), "non-recursive mutex locked reentrantly"); +} +#endif + +TEST(sysdeps_mutex, recursive_mutex_smoke) { + static std::recursive_mutex &m = *new std::recursive_mutex(); + + m.lock(); + ASSERT_TRUE(m.try_lock()); + m.unlock(); + + adb_thread_create([](void*) { + ASSERT_FALSE(m.try_lock()); + m.lock(); + adb_sleep_ms(500); + m.unlock(); + }, nullptr); + + adb_sleep_ms(100); + m.unlock(); + adb_sleep_ms(100); + ASSERT_FALSE(m.try_lock()); + m.lock(); + m.unlock(); +}