curl/lib/easy_lock.h
Viktor Szakats 38029101e2
mingw: delete support for legacy mingw.org toolchain
Drop support for "old" / "legacy" / "classic" / "v1" / "mingw32" MinGW:
  https://en.wikipedia.org/wiki/MinGW, https://osdn.net/projects/mingw/
Its homepage used to be http://mingw.org/ [no HTTPS], and broken now.
It supported the x86 CPU only and used a old Windows API header and
implib set, often causing issues. It also misses most modern Windows
features, offering old versions of both binutils and gcc (no llvm/clang
support). It was last updated 2 years ago.

curl now relies on toolchains based on the mingw-w64 project:
https://www.mingw-w64.org/  https://sourceforge.net/projects/mingw-w64/
https://www.msys2.org/  https://github.com/msys2/msys2
https://github.com/mstorsjo/llvm-mingw
(Also available via Linux and macOS package managers.)

Closes #11625
2023-09-23 09:12:57 +00:00

103 lines
2.9 KiB
C

#ifndef HEADER_CURL_EASY_LOCK_H
#define HEADER_CURL_EASY_LOCK_H
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
#include "curl_setup.h"
#define GLOBAL_INIT_IS_THREADSAFE
#if defined(_WIN32_WINNT) && _WIN32_WINNT >= 0x600
#ifdef __MINGW32__
#ifndef SRWLOCK_INIT
#define SRWLOCK_INIT NULL
#endif
#endif /* __MINGW32__ */
#define curl_simple_lock SRWLOCK
#define CURL_SIMPLE_LOCK_INIT SRWLOCK_INIT
#define curl_simple_lock_lock(m) AcquireSRWLockExclusive(m)
#define curl_simple_lock_unlock(m) ReleaseSRWLockExclusive(m)
#elif defined(HAVE_ATOMIC) && defined(HAVE_STDATOMIC_H)
#include <stdatomic.h>
#if defined(HAVE_SCHED_YIELD)
#include <sched.h>
#endif
#define curl_simple_lock atomic_int
#define CURL_SIMPLE_LOCK_INIT 0
/* a clang-thing */
#ifndef __has_builtin
#define __has_builtin(x) 0
#endif
#ifndef __INTEL_COMPILER
/* The Intel compiler tries to look like GCC *and* clang *and* lies in its
__has_builtin() function, so override it. */
/* if GCC on i386/x86_64 or if the built-in is present */
#if ( (defined(__GNUC__) && !defined(__clang__)) && \
(defined(__i386__) || defined(__x86_64__))) || \
__has_builtin(__builtin_ia32_pause)
#define HAVE_BUILTIN_IA32_PAUSE
#endif
#endif
static inline void curl_simple_lock_lock(curl_simple_lock *lock)
{
for(;;) {
if(!atomic_exchange_explicit(lock, true, memory_order_acquire))
break;
/* Reduce cache coherency traffic */
while(atomic_load_explicit(lock, memory_order_relaxed)) {
/* Reduce load (not mandatory) */
#ifdef HAVE_BUILTIN_IA32_PAUSE
__builtin_ia32_pause();
#elif defined(__aarch64__)
__asm__ volatile("yield" ::: "memory");
#elif defined(HAVE_SCHED_YIELD)
sched_yield();
#endif
}
}
}
static inline void curl_simple_lock_unlock(curl_simple_lock *lock)
{
atomic_store_explicit(lock, false, memory_order_release);
}
#else
#undef GLOBAL_INIT_IS_THREADSAFE
#endif
#endif /* HEADER_CURL_EASY_LOCK_H */