mpd/src/thread/Thread.hxx
2023-03-06 14:59:48 +01:00

101 lines
1.9 KiB
C++

// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright The Music Player Daemon Project
#ifndef MPD_THREAD_HXX
#define MPD_THREAD_HXX
#include "util/BindMethod.hxx"
#include <cassert>
#ifdef _WIN32
#include <processthreadsapi.h>
#else
#include <pthread.h>
#endif
class Thread {
typedef BoundMethod<void() noexcept> Function;
const Function f;
#ifdef _WIN32
HANDLE handle = nullptr;
DWORD id;
#else
pthread_t handle = pthread_t();
#ifndef NDEBUG
/**
* This handle is only used by IsInside(), and is set by the
* thread function. Since #handle is set by pthread_create()
* which is racy, we need this attribute for early checks
* inside the thread function.
*/
pthread_t inside_handle = pthread_t();
#endif
#endif
public:
explicit Thread(Function _f) noexcept:f(_f) {}
Thread(const Thread &) = delete;
Thread &operator=(const Thread &) = delete;
#ifndef NDEBUG
~Thread() noexcept {
/* all Thread objects must be destructed manually by calling
Join(), to clean up */
assert(!IsDefined());
}
#endif
bool IsDefined() const noexcept {
#ifdef _WIN32
return handle != nullptr;
#else
return handle != pthread_t();
#endif
}
#ifndef NDEBUG
/**
* Check if this thread is the current thread.
*/
[[gnu::pure]]
bool IsInside() const noexcept {
#ifdef _WIN32
return GetCurrentThreadId() == id;
#else
/* note: not using pthread_equal() because that
function "is undefined if either thread ID is not
valid so we can't safely use it on
default-constructed values" (comment from
libstdc++) - and if both libstdc++ and libc++ get
away with this, we can do it as well */
return pthread_self() == inside_handle;
#endif
}
#endif
/**
* Start the thread.
*
* Throws on error.
*/
void Start();
void Join() noexcept;
private:
void Run() noexcept;
#ifdef _WIN32
static DWORD WINAPI ThreadProc(LPVOID ctx) noexcept;
#else
static void *ThreadProc(void *ctx) noexcept;
#endif
};
#endif