2002-03-03 01:19:43 +01:00
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/*
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2003-03-05 06:51:27 +01:00
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* $RCSId: xc/lib/fontconfig/src/fcatomic.c,v 1.2 2002/03/04 21:15:28 tsi Exp $
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2002-03-03 01:19:43 +01:00
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*
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2004-12-07 02:14:46 +01:00
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* Copyright © 2002 Keith Packard
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2002-03-03 01:19:43 +01:00
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*
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* Permission to use, copy, modify, distribute, and sell this software and its
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* documentation for any purpose is hereby granted without fee, provided that
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* the above copyright notice appear in all copies and that both that
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* copyright notice and this permission notice appear in supporting
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* documentation, and that the name of Keith Packard not be used in
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* advertising or publicity pertaining to distribution of the software without
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* specific, written prior permission. Keith Packard makes no
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* representations about the suitability of this software for any purpose. It
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* is provided "as is" without express or implied warranty.
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*
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* KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
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* EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
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* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* fcatomic.c
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*
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* Lock cache and configuration files for atomic update
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*
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* Uses only regular filesystem calls so it should
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* work even in the absense of functioning file locking
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*
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2003-03-22 22:25:34 +01:00
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* On Unix, four files are used:
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2002-03-03 01:19:43 +01:00
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* file - the data file accessed by other apps.
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* new - a new version of the data file while it's being written
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* lck - the lock file
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* tmp - a temporary file made unique with mkstemp
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*
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* Here's how it works:
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* Create 'tmp' and store our PID in it
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* Attempt to link it to 'lck'
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* Unlink 'tmp'
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* If the link succeeded, the lock is held
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2003-03-22 22:25:34 +01:00
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*
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* On Windows, where there are no links, no tmp file is used, and lck
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* is a directory that's mkdir'ed. If the mkdir succeeds, the lock is
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* held.
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2002-03-03 01:19:43 +01:00
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*/
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#include "fcint.h"
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <time.h>
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2003-03-22 22:25:34 +01:00
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#ifdef _WIN32
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#define mkdir(path,mode) _mkdir(path)
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#endif
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2002-03-03 01:19:43 +01:00
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#define NEW_NAME ".NEW"
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#define LCK_NAME ".LCK"
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#define TMP_NAME ".TMP-XXXXXX"
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FcAtomic *
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FcAtomicCreate (const FcChar8 *file)
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{
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int file_len = strlen ((char *) file);
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int new_len = file_len + sizeof (NEW_NAME);
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int lck_len = file_len + sizeof (LCK_NAME);
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int tmp_len = file_len + sizeof (TMP_NAME);
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int total_len = (sizeof (FcAtomic) +
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file_len + 1 +
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new_len + 1 +
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lck_len + 1 +
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tmp_len + 1);
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FcAtomic *atomic = malloc (total_len);
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if (!atomic)
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return 0;
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2002-09-01 00:17:32 +02:00
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FcMemAlloc (FC_MEM_ATOMIC, total_len);
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2002-03-03 01:19:43 +01:00
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atomic->file = (FcChar8 *) (atomic + 1);
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strcpy ((char *) atomic->file, (char *) file);
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atomic->new = atomic->file + file_len + 1;
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strcpy ((char *) atomic->new, (char *) file);
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strcat ((char *) atomic->new, NEW_NAME);
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atomic->lck = atomic->new + new_len + 1;
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strcpy ((char *) atomic->lck, (char *) file);
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strcat ((char *) atomic->lck, LCK_NAME);
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atomic->tmp = atomic->lck + lck_len + 1;
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return atomic;
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}
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FcBool
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FcAtomicLock (FcAtomic *atomic)
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{
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int fd = -1;
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FILE *f = 0;
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int ret;
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struct stat lck_stat;
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2003-03-22 22:25:34 +01:00
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#ifdef HAVE_LINK
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2002-03-03 01:19:43 +01:00
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strcpy ((char *) atomic->tmp, (char *) atomic->file);
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strcat ((char *) atomic->tmp, TMP_NAME);
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fd = mkstemp ((char *) atomic->tmp);
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if (fd < 0)
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return FcFalse;
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f = fdopen (fd, "w");
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if (!f)
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{
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close (fd);
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unlink ((char *) atomic->tmp);
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return FcFalse;
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}
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2002-03-04 22:15:28 +01:00
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ret = fprintf (f, "%ld\n", (long)getpid());
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2002-03-03 01:19:43 +01:00
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if (ret <= 0)
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{
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fclose (f);
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unlink ((char *) atomic->tmp);
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return FcFalse;
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}
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if (fclose (f) == EOF)
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{
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unlink ((char *) atomic->tmp);
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return FcFalse;
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}
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ret = link ((char *) atomic->tmp, (char *) atomic->lck);
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(void) unlink ((char *) atomic->tmp);
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2003-03-22 22:25:34 +01:00
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#else
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ret = mkdir ((char *) atomic->lck, 0600);
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#endif
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2002-03-03 01:19:43 +01:00
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if (ret < 0)
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{
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/*
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* If the file is around and old (> 10 minutes),
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* assume the lock is stale. This assumes that any
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* machines sharing the same filesystem will have clocks
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* reasonably close to each other.
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*/
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if (stat ((char *) atomic->lck, &lck_stat) >= 0)
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{
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time_t now = time (0);
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if ((long int) (now - lck_stat.st_mtime) > 10 * 60)
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{
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2003-03-22 22:25:34 +01:00
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#ifdef HAVE_LINK
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2002-03-03 01:19:43 +01:00
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if (unlink ((char *) atomic->lck) == 0)
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return FcAtomicLock (atomic);
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2003-03-22 22:25:34 +01:00
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#else
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if (rmdir ((char *) atomic->lck) == 0)
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return FcAtomicLock (atomic);
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#endif
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2002-03-03 01:19:43 +01:00
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}
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}
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return FcFalse;
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}
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(void) unlink ((char *) atomic->new);
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return FcTrue;
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}
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FcChar8 *
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FcAtomicNewFile (FcAtomic *atomic)
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{
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return atomic->new;
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}
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FcChar8 *
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FcAtomicOrigFile (FcAtomic *atomic)
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{
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return atomic->file;
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}
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FcBool
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FcAtomicReplaceOrig (FcAtomic *atomic)
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{
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2006-03-23 05:22:28 +01:00
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#ifdef _WIN32
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unlink (atomic->file);
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#endif
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2002-03-03 01:19:43 +01:00
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if (rename ((char *) atomic->new, (char *) atomic->file) < 0)
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return FcFalse;
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return FcTrue;
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}
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void
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FcAtomicDeleteNew (FcAtomic *atomic)
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{
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unlink ((char *) atomic->new);
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}
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void
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FcAtomicUnlock (FcAtomic *atomic)
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{
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2003-03-22 22:25:34 +01:00
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#ifdef HAVE_LINK
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2002-03-03 01:19:43 +01:00
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unlink ((char *) atomic->lck);
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2003-03-22 22:25:34 +01:00
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#else
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rmdir ((char *) atomic->lck);
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#endif
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2002-03-03 01:19:43 +01:00
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}
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void
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FcAtomicDestroy (FcAtomic *atomic)
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{
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2002-09-01 00:17:32 +02:00
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FcMemFree (FC_MEM_ATOMIC, sizeof (FcAtomic) +
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strlen ((char *) atomic->file) * 4 + 1 +
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sizeof (NEW_NAME) + sizeof (LCK_NAME) +
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sizeof (TMP_NAME));
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2002-03-03 01:19:43 +01:00
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free (atomic);
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}
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2006-09-05 11:24:01 +02:00
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#define __fcatomic__
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#include "fcaliastail.h"
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#undef __fcatomic__
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