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2fcb713037
This replaces all state-related variables with a single ThreadState. These are simplified over what the Kernel has, but capture all userspace-available thread state. Locking the state behind an atomic and using proper atomic operations also gets rid of quite some deadlocks and race conditions that have existed around m_tid and others beforehand. In terms of behavior, this introduces the following changes: - All thread state mishandling (e.g. joining a detached thread) crashes the program. Mishandling thread state is a severe kind of concurrency bug that might also be indeterministic, so letting it silently disappear with the return value of pthread_ APIs is a bad idea. The thread state can always be checked beforehand to ensure that no crash happens. - Destructing a still-running thread will crash in AK/Function, so the Thread destructor issues its own warning for debugging purposes. - Thread issues warnings before crashes in many places to aid concurrency debugging (the most difficult kind of debugging). - Joining dead but not detached threads is legal, as per POSIX APIs. - The thread ID is never reset to 0 after the thread has been started and subsequently been assigned a valid thread ID. The thread's exit state is still obtainable. - Detaching threads that are about to exit is considered a programming bug and will often (not always, as we can't catch all execution sequences involved in such a situation) crash the program on purpose. If you want to detach a thread that will definitely exit on its own, you have to prevent it from exiting before detach() was called (e.g. with an "exit requested" flag). |
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| .. | ||
| BackgroundAction.cpp | ||
| BackgroundAction.h | ||
| CMakeLists.txt | ||
| ConditionVariable.h | ||
| Mutex.h | ||
| MutexProtected.h | ||
| Thread.cpp | ||
| Thread.h | ||