diff options
author | Jörg Frings-Fürst <debian@jff.email> | 2022-02-07 06:57:44 +0100 |
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committer | Jörg Frings-Fürst <debian@jff.email> | 2022-02-07 06:57:44 +0100 |
commit | 6ffaa52cf732a84c0f8259dbc9b8183960ec5c33 (patch) | |
tree | d3136c22e3e805cfc0efe78412cce905a17e0c8d /lib/mbtowc-lock.c | |
parent | 591cbf5878b7d4105b275585b9db1324c9dfce56 (diff) | |
parent | af151c593704a40e10efb28d1e3dd59a23a661f3 (diff) |
Merge branch 'release/debian/1.0-1'debian/1.0-1
Diffstat (limited to 'lib/mbtowc-lock.c')
-rw-r--r-- | lib/mbtowc-lock.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/lib/mbtowc-lock.c b/lib/mbtowc-lock.c new file mode 100644 index 0000000..06d3224 --- /dev/null +++ b/lib/mbtowc-lock.c @@ -0,0 +1,150 @@ +/* Return the internal lock used by mbrtowc and mbrtoc32. + Copyright (C) 2019-2022 Free Software Foundation, Inc. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + This file is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2019-2020. */ + +#include <config.h> + +/* When it is known that the gl_get_mbtowc_lock function is defined + by a dependency library, it should not be defined here. */ +#if OMIT_MBTOWC_LOCK + +/* This declaration is solely to ensure that after preprocessing + this file is never empty. */ +typedef int dummy; + +#else + +/* This file defines the internal lock used by mbrtowc and mbrtoc32. + It is a separate compilation unit, so that only one copy of it is + present when linking statically. */ + +/* Prohibit renaming this symbol. */ +# undef gl_get_mbtowc_lock + +/* Macro for exporting a symbol (function, not variable) defined in this file, + when compiled into a shared library. */ +# ifndef DLL_EXPORTED +# if HAVE_VISIBILITY + /* Override the effect of the compiler option '-fvisibility=hidden'. */ +# define DLL_EXPORTED __attribute__((__visibility__("default"))) +# elif defined _WIN32 || defined __CYGWIN__ +# define DLL_EXPORTED __declspec(dllexport) +# else +# define DLL_EXPORTED +# endif +# endif + +# if defined _WIN32 && !defined __CYGWIN__ + +# define WIN32_LEAN_AND_MEAN /* avoid including junk */ +# include <windows.h> + +# include "windows-initguard.h" + +/* The return type is a 'CRITICAL_SECTION *', not a 'glwthread_mutex_t *', + because the latter is not guaranteed to be a stable ABI in the future. */ + +/* Make sure the function gets exported from DLLs. */ +DLL_EXPORTED CRITICAL_SECTION *gl_get_mbtowc_lock (void); + +static glwthread_initguard_t guard = GLWTHREAD_INITGUARD_INIT; +static CRITICAL_SECTION lock; + +/* Returns the internal lock used by mbrtowc and mbrtoc32. */ +CRITICAL_SECTION * +gl_get_mbtowc_lock (void) +{ + if (!guard.done) + { + if (InterlockedIncrement (&guard.started) == 0) + { + /* This thread is the first one to need the lock. Initialize it. */ + InitializeCriticalSection (&lock); + guard.done = 1; + } + else + { + /* Don't let guard.started grow and wrap around. */ + InterlockedDecrement (&guard.started); + /* Yield the CPU while waiting for another thread to finish + initializing this mutex. */ + while (!guard.done) + Sleep (0); + } + } + return &lock; +} + +# elif HAVE_PTHREAD_API + +# include <pthread.h> + +static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; + +/* Make sure the function gets exported from shared libraries. */ +DLL_EXPORTED pthread_mutex_t *gl_get_mbtowc_lock (void); + +/* Returns the internal lock used by mbrtowc and mbrtoc32. */ +pthread_mutex_t * +gl_get_mbtowc_lock (void) +{ + return &mutex; +} + +# elif HAVE_THREADS_H + +# include <threads.h> +# include <stdlib.h> + +static int volatile init_needed = 1; +static once_flag init_once = ONCE_FLAG_INIT; +static mtx_t mutex; + +static void +atomic_init (void) +{ + if (mtx_init (&mutex, mtx_plain) != thrd_success) + abort (); + init_needed = 0; +} + +/* Make sure the function gets exported from shared libraries. */ +DLL_EXPORTED mtx_t *gl_get_mbtowc_lock (void); + +/* Returns the internal lock used by mbrtowc and mbrtoc32. */ +mtx_t * +gl_get_mbtowc_lock (void) +{ + if (init_needed) + call_once (&init_once, atomic_init); + return &mutex; +} + +# endif + +# if (defined _WIN32 || defined __CYGWIN__) && !defined _MSC_VER +/* Make sure the '__declspec(dllimport)' in mbrtowc.c and mbrtoc32.c does not + cause a link failure when no DLLs are involved. */ +# if defined _WIN64 || defined _LP64 +# define IMP(x) __imp_##x +# else +# define IMP(x) _imp__##x +# endif +void * IMP(gl_get_mbtowc_lock) = &gl_get_mbtowc_lock; +# endif + +#endif |