stat: support high resolution time stamps.

* configure (have_sys_stat): New variable. Set to y when our
test detects <sys/stat.h>. New test added for the presence of
high resolution time stamps in struct stat. If we have these,
we #define HAVE_STAT_NSEC 1 in config.h.

* share/txr/stdlib/path-test.tl (path-newer): Compare
nanosecond parts of the modification time if the seconds are
equal, improving the resolution of the test.

* sysif.c (atime_nsec_s, mtime_nsec_s, ctime_nsec_s): New
symbol variables.
(stat_to_struct): If nanosecond resolution is available, set
the new nanosecond slots from the three tv_nsec fields in
struct stat. Otherwise, set the new slots to zero.
(sysif_init): Initialize the new symbol variables. Add the
three new slots to the stat struct.

* sysif.c (atime_nsec_s, mtime_nsec_s, ctime_nsec_s):
Declared.

* txr.1: Documented new atime-nsec, mtime-nsec and ctime-nsec
slots of stat structure. Added note to path-newer mentioning
high resolution support.

1 files changed, 19 insertions, 3 deletions

diff --git a/sysif.c b/sysif.c
index f1eb5fa4..667e3ad9 100644
--- a/sysif.c
+++ b/sysif.c
@@ -101,7 +101,9 @@ val gid_k, rdev_k, size_k, blksize_k, blocks_k;
 val atime_k, mtime_k, ctime_k;
 val dev_s, ino_s, mode_s, nlink_s, uid_s;
 val gid_s, rdev_s, size_s, blksize_s, blocks_s;
-val atime_s, mtime_s, ctime_s, path_s;
+val atime_s, mtime_s, ctime_s;
+val atime_nsec_s, mtime_nsec_s, ctime_nsec_s;
+val path_s;
 
 #if HAVE_PWUID
 val passwd_s, gecos_s, dir_s, shell_s;
@@ -822,6 +824,15 @@ val stat_to_struct(struct stat st, val path)
   slotset(strct, atime_s, num(st.st_atime));
   slotset(strct, mtime_s, num(st.st_mtime));
   slotset(strct, ctime_s, num(st.st_ctime));
+#if HAVE_STAT_NSEC
+  slotset(strct, atime_nsec_s, num(st.st_atim.tv_nsec));
+  slotset(strct, mtime_nsec_s, num(st.st_mtim.tv_nsec));
+  slotset(strct, ctime_nsec_s, num(st.st_ctim.tv_nsec));
+#else
+  slotset(strct, atime_nsec_s, zero);
+  slotset(strct, mtime_nsec_s, zero);
+  slotset(strct, ctime_nsec_s, zero);
+#endif
   if (path)
     slotset(strct, path_s, path);
 
@@ -1719,6 +1730,9 @@ void sysif_init(void)
   atime_s = intern(lit("atime"), user_package);
   mtime_s = intern(lit("mtime"), user_package);
   ctime_s = intern(lit("ctime"), user_package);
+  atime_nsec_s = intern(lit("atime-nsec"), user_package);
+  mtime_nsec_s = intern(lit("mtime-nsec"), user_package);
+  ctime_nsec_s = intern(lit("ctime-nsec"), user_package);
   path_s = intern(lit("path"), user_package);
 #if HAVE_PWUID
   passwd_s = intern(lit("passwd"), user_package);
@@ -1750,8 +1764,10 @@ void sysif_init(void)
 
   make_struct_type(stat_s, nil, nil,
                    list(dev_s, ino_s, mode_s, nlink_s, uid_s, gid_s,
-                        rdev_s, size_s, blksize_s, blocks_s, atime_s,
-                        mtime_s, ctime_s, path_s, nao), nil, nil, nil, nil);
+                        rdev_s, size_s, blksize_s, blocks_s,
+                        atime_s, atime_nsec_s, mtime_s, mtime_nsec_s,
+                        ctime_s, ctime_nsec_s, path_s, nao),
+                   nil, nil, nil, nil);
 #if HAVE_PWUID
   make_struct_type(passwd_s, nil, nil,
                    list(name_s, passwd_s, uid_s, gid_s,