[PATCH] Use the gettime module in ls.c.

[James Youngman]

2008-02-16  James Youngman  <address@hidden>

        Implement TODO list item to make ls.c use the gettime module.
        * TODO (ls): Now that we use gettime, remove the TODO entry.
        * src/ls.c: Use timespec.h and the gettime module.
        (current_time): Change type from time_t to struct timespec.
        (current_time_ns): Removed.
        (get_current_time): Removed.
        (print_long_format): Remove when and when_ns, since we have
        when_timespec anyway.  Change type of variable six_months_ago from
        time_t to struct timespec.
---
 TODO     |    4 +--
 src/ls.c |   76 +++++++++++++++++--------------------------------------------
 2 files changed, 22 insertions(+), 58 deletions(-)

diff --git a/TODO b/TODO
index 3cec054..24369c6 100644
--- a/TODO
+++ b/TODO
@@ -177,11 +177,9 @@ Adapt tools like wc, tr, fmt, etc. (most of the textutils) 
to be
 
 pr's use of nstrftime can make it malloc a very large (up to SIZE_MAX) buffer
 
-ls.c: use gettime rather than clock_gettime, gettimeofday, time
-
 -----
 
-Copyright (C) 2002-2007 Free Software Foundation, Inc.
+Copyright (C) 2002-2008 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
diff --git a/src/ls.c b/src/ls.c
index 46713f2..5f466ca 100644
--- a/src/ls.c
+++ b/src/ls.c
@@ -101,6 +101,7 @@
 #include "quotearg.h"
 #include "same.h"
 #include "stat-time.h"
+#include "timespec.h"
 #include "strftime.h"
 #include "strverscmp.h"
 #include "xstrtol.h"
@@ -311,8 +312,7 @@ static struct pending *pending_dirs;
 /* Current time in seconds and nanoseconds since 1970, updated as
    needed when deciding whether a file is recent.  */
 
-static time_t current_time = TYPE_MINIMUM (time_t);
-static int current_time_ns = -1;
+static struct timespec current_time;
 
 static bool print_scontext;
 static char UNKNOWN_SECURITY_CONTEXT[] = "?";
@@ -1155,6 +1155,9 @@ main (int argc, char **argv)
   print_dir_name = true;
   pending_dirs = NULL;
 
+  current_time.tv_sec = TYPE_MINIMUM (time_t);
+  current_time.tv_nsec = -1;
+
   i = decode_switches (argc, argv);
 
   if (print_with_color)
@@ -3306,42 +3309,6 @@ long_time_expected_width (void)
   return width;
 }
 
-/* Get the current time.  */
-
-static void
-get_current_time (void)
-{
-#if HAVE_CLOCK_GETTIME && defined CLOCK_REALTIME
-  {
-    struct timespec timespec;
-    if (clock_gettime (CLOCK_REALTIME, &timespec) == 0)
-      {
-       current_time = timespec.tv_sec;
-       current_time_ns = timespec.tv_nsec;
-       return;
-      }
-  }
-#endif
-
-  /* The clock does not have nanosecond resolution, so get the maximum
-     possible value for the current time that is consistent with the
-     reported clock.  That way, files are not considered to be in the
-     future merely because their time stamps have higher resolution
-     than the clock resolution.  */
-
-#if HAVE_GETTIMEOFDAY
-  {
-    struct timeval timeval;
-    gettimeofday (&timeval, NULL);
-    current_time = timeval.tv_sec;
-    current_time_ns = timeval.tv_usec * 1000 + 999;
-  }
-#else
-  current_time = time (NULL);
-  current_time_ns = 999999999;
-#endif
-}
-
 /* Print the user or group name NAME, with numeric id ID, using a
    print width of WIDTH columns.  */
 
@@ -3441,8 +3408,6 @@ print_long_format (const struct fileinfo *f)
      ];
   size_t s;
   char *p;
-  time_t when;
-  int when_ns;
   struct timespec when_timespec;
   struct tm *when_local;
 
@@ -3476,9 +3441,6 @@ print_long_format (const struct fileinfo *f)
       abort ();
     }
 
-  when = when_timespec.tv_sec;
-  when_ns = when_timespec.tv_nsec;
-
   p = buf;
 
   if (print_inode)
@@ -3579,35 +3541,38 @@ print_long_format (const struct fileinfo *f)
 
   if (f->stat_ok && when_local)
     {
-      time_t six_months_ago;
+      struct timespec six_months_ago;
       bool recent;
       char const *fmt;
 
       /* If the file appears to be in the future, update the current
         time, in case the file happens to have been modified since
         the last time we checked the clock.  */
-      if (current_time < when
-         || (current_time == when && current_time_ns < when_ns))
+      if (timespec_cmp (current_time, when_timespec) < 0)
        {
-         /* Note that get_current_time calls gettimeofday which, on some non-
+         /* Note that gettime calls gettimeofday which, on some non-
             compliant systems, clobbers the buffer used for localtime's result.
             But it's ok here, because we use a gettimeofday wrapper that
             saves and restores the buffer around the gettimeofday call.  */
-         get_current_time ();
+         gettime (&current_time);
        }
 
       /* Consider a time to be recent if it is within the past six
         months.  A Gregorian year has 365.2425 * 24 * 60 * 60 ==
         31556952 seconds on the average.  Write this value as an
         integer constant to avoid floating point hassles.  */
-      six_months_ago = current_time - 31556952 / 2;
-      recent = (six_months_ago <= when
-               && (when < current_time
-                   || (when == current_time && when_ns <= current_time_ns)));
+      six_months_ago.tv_sec = current_time.tv_sec - 31556952 / 2;
+      six_months_ago.tv_nsec = current_time.tv_nsec;
+      
+      recent = (timespec_cmp (six_months_ago, when_timespec) < 0
+               && (timespec_cmp (when_timespec, current_time) < 0));
       fmt = long_time_format[recent];
 
+      /* We assume here that all time zones are offset from UTC by a
+       * whole number of seconds. 
+       */
       s = nstrftime (p, TIME_STAMP_LEN_MAXIMUM + 1, fmt,
-                    when_local, 0, when_ns);
+                    when_local, 0, when_timespec.tv_nsec);
     }
 
   if (s || !*p)
@@ -3627,8 +3592,9 @@ print_long_format (const struct fileinfo *f)
               (! f->stat_ok
                ? "?"
                : (TYPE_SIGNED (time_t)
-                  ? imaxtostr (when, hbuf)
-                  : umaxtostr (when, hbuf))));
+                  ? imaxtostr (when_timespec.tv_sec, hbuf)
+                  : umaxtostr (when_timespec.tv_sec, hbuf))));
+      /* FIXME: (maybe) We discarded when_timespec.tv_nsec. */
       p += strlen (p);
     }
 
-- 
1.5.3.8