maint: remove fstimeprec (variable precision time stamp) support

The implementation of variable-precision time stamps relied
on heuristics that made the output subtly nondeterministic,
or at least hard to reproduce:
http://thread.gmane.org/gmane.comp.gnu.coreutils.bugs/21531/focus=21538
So, for now at least, we're removing that feature.
* bootstrap.conf (gnulib_modules): Remove fstimeprec.
* gl/lib/fstimeprec.c, gl/lib/fstimeprec.h: Remove files.
* gl/modules/fstimeprec, gl/modules/fstimeprec-tests: Likewise.
* gl/tests/test-fstimeprec.c: Remove file.

2 files changed, 0 insertions, 200 deletions

diff --git a/gl/lib/fstimeprec.c b/gl/lib/fstimeprec.c
deleted file mode 100644
index fd6305476..000000000
--- a/gl/lib/fstimeprec.c
+++ /dev/null
@@ -1,178 +0,0 @@
-/* Determine a file system's time stamp precision.
-
-   Copyright 2010 Free Software Foundation, Inc.
-
-   This program is free software: you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 3 of the License, or
-   (at your option) any later version.
-
-   This program 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 General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
-
-/* written by Paul Eggert */
-
-#include <config.h>
-#include "fstimeprec.h"
-
-#include "hash.h"
-#include "stat-time.h"
-#include <limits.h>
-#include <stdlib.h>
-
-/* A hash table that maps device numbers to precisions.  */
-struct fstimeprec
-{
-  /* Map device numbers to precisions.  */
-  struct hash_table *map;
-
-  /* Cache of the most recently allocated and otherwise-unused storage
-     for probing this table.  */
-  struct ent *probe;
-};
-
-/* A pair that maps a device number to a precision.  */
-struct ent
-{
-  dev_t dev;
-  int prec;
-};
-
-/* Hash an entry.  */
-static size_t
-ent_hash (void const *x, size_t table_size)
-{
-  struct ent const *p = x;
-  dev_t dev = p->dev;
-
-  /* FIXME: This code is duplicated from di-set.c.  */
-  /* When DEV is wider than size_t, exclusive-OR the words of DEV into H.
-     This avoids loss of info, without applying % to the wider type,
-     which could be quite slow on some systems.  */
-  size_t h = dev;
-  unsigned int i;
-  unsigned int n_words = sizeof dev / sizeof h + (sizeof dev % sizeof h != 0);
-  for (i = 1; i < n_words; i++)
-    h ^= dev >> CHAR_BIT * sizeof h * i;
-
-  return h % table_size;
-}
-
-/* Return true if two entries are the same.  */
-static bool
-ent_compare (void const *x, void const *y)
-{
-  struct ent const *a = x;
-  struct ent const *b = y;
-  return a->dev == b->dev;
-}
-
-/* Using the SET table, map a device to an entry that represents
-   the file system precision.  Return NULL on error.  */
-static struct ent *
-map_device (struct fstimeprec *tab, dev_t dev)
-{
-  /* Find space for the probe, reusing the cache if available.  */
-  struct ent *ent;
-  struct ent *probe = tab->probe;
-  if (probe)
-    {
-      /* If repeating a recent query, return the cached result.   */
-      if (probe->dev == dev)
-        return probe;
-    }
-  else
-    {
-      tab->probe = probe = malloc (sizeof *probe);
-      if (! probe)
-        return NULL;
-      probe->prec = 0;
-    }
-
-  /* Probe for the device.  */
-  probe->dev = dev;
-  ent = hash_insert (tab->map, probe);
-  if (ent == probe)
-    tab->probe = NULL;
-  return ent;
-}
-
-/* Return a newly allocated table of file system time stamp
-   resolutions, or NULL if out of memory.  */
-struct fstimeprec *
-fstimeprec_alloc (void)
-{
-  struct fstimeprec *tab = malloc (sizeof *tab);
-  if (tab)
-    {
-      enum { INITIAL_DEV_MAP_SIZE = 11 };
-      tab->map = hash_initialize (INITIAL_DEV_MAP_SIZE, NULL,
-                                  ent_hash, ent_compare, free);
-      if (! tab->map)
-        {
-          free (tab);
-          return NULL;
-        }
-      tab->probe = NULL;
-    }
-  return tab;
-}
-
-/* Free TAB.  */
-void
-fstimeprec_free (struct fstimeprec *tab)
-{
-  hash_free (tab->map);
-  free (tab->probe);
-  free (tab);
-}
-
-/* Using the cached information in TAB, return the estimated precision
-   of time stamps for the file system containing the file whose status
-   info is in ST.  The returned value counts the number of decimal
-   fraction digits.  Return 0 on failure.
-
-   If TAB is null, the guess is based purely on ST.  */
-int
-fstimeprec (struct fstimeprec *tab, struct stat const *st)
-{
-  /* Map the device number to an entry.  */
-  struct ent *ent = (tab ? map_device (tab, st->st_dev) : NULL);
-
-  /* Guess the precision based on what has been seen so far.  */
-  int prec = (ent ? ent->prec : 0);
-
-  /* If the current file's timestamp resolution is higher than the
-     guess, increase the guess.  */
-  if (prec < 9)
-    {
-      struct timespec ats = get_stat_atime (st);
-      struct timespec mts = get_stat_mtime (st);
-      struct timespec cts = get_stat_ctime (st);
-      struct timespec bts = get_stat_birthtime (st);
-      unsigned int ans = ats.tv_nsec;
-      unsigned int mns = mts.tv_nsec;
-      unsigned int cns = cts.tv_nsec;
-      unsigned int bns = bts.tv_nsec < 0 ? 0 : bts.tv_nsec;
-      unsigned int power = 10;
-      int p;
-      for (p = prec + 1; p < 9; p++)
-        power *= 10;
-
-      while (ans % power | mns % power | cns % power | bns % power)
-        {
-          power /= 10;
-          prec++;
-        }
-
-      if (ent)
-        ent->prec = prec;
-    }
-
-  return prec;
-}
diff --git a/gl/lib/fstimeprec.h b/gl/lib/fstimeprec.h
deleted file mode 100644
index 8ec24df76..000000000
--- a/gl/lib/fstimeprec.h
+++ /dev/null
@@ -1,22 +0,0 @@
-#include <sys/stat.h>
-
-#ifndef ATTRIBUTE_MALLOC
-# if __GNUC__ >= 3
-#  define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
-# else
-#  define ATTRIBUTE_MALLOC
-# endif
-#endif
-
-#ifndef _GL_ARG_NONNULL
-# if (__GNUC__ == 3 && __GNUC_MINOR__ >= 3) || __GNUC__ > 3
-#  define _GL_ARG_NONNULL(params) __attribute__ ((__nonnull__ params))
-# else
-#  define _GL_ARG_NONNULL(params)
-# endif
-#endif
-
-struct fstimeprec *fstimeprec_alloc (void) ATTRIBUTE_MALLOC;
-void fstimeprec_free (struct fstimeprec *) _GL_ARG_NONNULL ((1));
-int fstimeprec (struct fstimeprec *, struct stat const *)
-  _GL_ARG_NONNULL ((2));