gnulib/import/mbtowc-lock.h

   1 /* Use the internal lock used by mbrtowc and mbrtoc32.
   2    Copyright (C) 2019-2020 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>, 2019-2020.  */
  18
  19 /* Use a lock, so that no two threads can invoke mbtowc at the same time.  */
  20
  21 static inline int
  22 mbtowc_unlocked (wchar_t *pwc, const char *p, size_t m)
  23 {
  24   /* Put the hidden internal state of mbtowc into its initial state.
  25      This is needed at least with glibc, uClibc, and MSVC CRT.
  26      See <https://sourceware.org/bugzilla/show_bug.cgi?id=9674>.  */
  27   mbtowc (NULL, NULL, 0);
  28
  29   return mbtowc (pwc, p, m);
  30 }
  31
  32 /* Prohibit renaming this symbol.  */
  33 #undef gl_get_mbtowc_lock
  34
  35 #if defined _WIN32 && !defined __CYGWIN__
  36
  37 extern __declspec(dllimport) CRITICAL_SECTION *gl_get_mbtowc_lock (void);
  38
  39 static int
  40 mbtowc_with_lock (wchar_t *pwc, const char *p, size_t m)
  41 {
  42   CRITICAL_SECTION *lock = gl_get_mbtowc_lock ();
  43   int ret;
  44
  45   EnterCriticalSection (lock);
  46   ret = mbtowc_unlocked (pwc, p, m);
  47   LeaveCriticalSection (lock);
  48
  49   return ret;
  50 }
  51
  52 #elif HAVE_PTHREAD_API /* AIX, IRIX, Cygwin */
  53
  54 extern
  55 # if defined _WIN32 || defined __CYGWIN__
  56   __declspec(dllimport)
  57 # endif
  58   pthread_mutex_t *gl_get_mbtowc_lock (void);
  59
  60 # if HAVE_WEAK_SYMBOLS /* IRIX */
  61
  62    /* Avoid the need to link with '-lpthread'.  */
  63 #  pragma weak pthread_mutex_lock
  64 #  pragma weak pthread_mutex_unlock
  65
  66    /* Determine whether libpthread is in use.  */
  67 #  pragma weak pthread_mutexattr_gettype
  68    /* See the comments in lock.h.  */
  69 #  define pthread_in_use() \
  70      (pthread_mutexattr_gettype != NULL || c11_threads_in_use ())
  71
  72 # else
  73 #  define pthread_in_use() 1
  74 # endif
  75
  76 static int
  77 mbtowc_with_lock (wchar_t *pwc, const char *p, size_t m)
  78 {
  79   if (pthread_in_use())
  80     {
  81       pthread_mutex_t *lock = gl_get_mbtowc_lock ();
  82       int ret;
  83
  84       if (pthread_mutex_lock (lock))
  85         abort ();
  86       ret = mbtowc_unlocked (pwc, p, m);
  87       if (pthread_mutex_unlock (lock))
  88         abort ();
  89
  90       return ret;
  91     }
  92   else
  93     return mbtowc_unlocked (pwc, p, m);
  94 }
  95
  96 #elif HAVE_THREADS_H
  97
  98 extern mtx_t *gl_get_mbtowc_lock (void);
  99
 100 static int
 101 mbtowc_with_lock (wchar_t *pwc, const char *p, size_t m)
 102 {
 103   mtx_t *lock = gl_get_mbtowc_lock ();
 104   int ret;
 105
 106   if (mtx_lock (lock) != thrd_success)
 107     abort ();
 108   ret = mbtowc_unlocked (pwc, p, m);
 109   if (mtx_unlock (lock) != thrd_success)
 110     abort ();
 111
 112   return ret;
 113 }
 114
 115 #endif