file: Add microsecond resolution for mtime: mtimeus

Note that actual support is dependent upon the underlying operating
system and filesystem.

Signed-off-by: Steve Bennett <steveb@workware.net.au>

3 files changed, 78 insertions, 16 deletions

diff --git a/auto.def b/auto.def
index 394cc62..fc937ff 100644
--- a/auto.def
+++ b/auto.def
@@ -130,6 +130,11 @@ if {[cc-check-functions sysinfo]} {
     }
 }
 
+cc-with {-includes {sys/types.h sys/stat.h}} {
+    cc-check-members "struct stat.st_mtimespec"
+    cc-check-members "struct stat.st_mtim"
+}
+
 cc-with {-includes fcntl.h} {
     cc-check-types "struct flock"
 }
diff --git a/jim-file.c b/jim-file.c
index 8185839..dca906d 100644
--- a/jim-file.c
+++ b/jim-file.c
@@ -77,6 +77,13 @@
 #define ISWINDOWS 0
 #endif
 
+/* extract nanosecond resolution mtime from struct stat */
+#if defined(HAVE_STRUCT_STAT_ST_MTIMESPEC)
+    #define STAT_MTIME_US(STAT) ((STAT).st_mtimespec.tv_sec * 1000000ll + (STAT).st_mtimespec.tv_nsec / 1000)
+#elif defined(HAVE_STRUCT_STAT_ST_MTIM)
+    #define STAT_MTIME_US(STAT) ((STAT).st_mtim.tv_sec * 1000000ll + (STAT).st_mtim.tv_nsec / 1000)
+#endif
+
 /*
  *----------------------------------------------------------------------
  *
@@ -169,6 +176,9 @@ static int StoreStatData(Jim_Interp *interp, Jim_Obj *varName, const struct stat
     AppendStatElement(interp, listObj, "atime", sb->st_atime);
     AppendStatElement(interp, listObj, "mtime", sb->st_mtime);
     AppendStatElement(interp, listObj, "ctime", sb->st_ctime);
+#ifdef STAT_MTIME_US
+    AppendStatElement(interp, listObj, "mtimeus", STAT_MTIME_US(*sb));
+#endif
     Jim_ListAppendElement(interp, listObj, Jim_NewStringObj(interp, "type", -1));
     Jim_ListAppendElement(interp, listObj, Jim_NewStringObj(interp, JimGetFileType((int)sb->st_mode), -1));
 
@@ -610,37 +620,65 @@ static int file_cmd_atime(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
     return JIM_OK;
 }
 
+/**
+ * Set file atime/mtime to the given time in microseconds since the epoch.
+ */
+static int JimSetFileTimes(Jim_Interp *interp, const char *filename, jim_wide us)
+{
+#ifdef HAVE_UTIMES
+    struct timeval times[2];
+
+    times[1].tv_sec = times[0].tv_sec = us / 1000000;
+    times[1].tv_usec = times[0].tv_usec = us % 1000000;
+
+    if (utimes(filename, times) != 0) {
+        Jim_SetResultFormatted(interp, "can't set time on \"%s\": %s", filename, strerror(errno));
+        return JIM_ERR;
+    }
+    return JIM_OK;
+#else
+    Jim_SetResultString(interp, "Not implemented", -1);
+    return JIM_ERR;
+#endif
+}
+
 static int file_cmd_mtime(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
     struct stat sb;
 
     if (argc == 2) {
-#ifdef HAVE_UTIMES
-        jim_wide newtime;
-        struct timeval times[2];
-
-        if (Jim_GetWide(interp, argv[1], &newtime) != JIM_OK) {
+        jim_wide secs;
+        if (Jim_GetWide(interp, argv[1], &secs) != JIM_OK) {
             return JIM_ERR;
         }
+        return JimSetFileTimes(interp, Jim_String(argv[0]), secs * 1000000);
+    }
+    if (file_stat(interp, argv[0], &sb) != JIM_OK) {
+        return JIM_ERR;
+    }
+    Jim_SetResultInt(interp, sb.st_mtime);
+    return JIM_OK;
+}
 
-        times[1].tv_sec = times[0].tv_sec = newtime;
-        times[1].tv_usec = times[0].tv_usec = 0;
+#ifdef STAT_MTIME_US
+static int file_cmd_mtimeus(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
+{
+    struct stat sb;
 
-        if (utimes(Jim_String(argv[0]), times) != 0) {
-            Jim_SetResultFormatted(interp, "can't set time on \"%#s\": %s", argv[0], strerror(errno));
+    if (argc == 2) {
+        jim_wide us;
+        if (Jim_GetWide(interp, argv[1], &us) != JIM_OK) {
             return JIM_ERR;
         }
-#else
-        Jim_SetResultString(interp, "Not implemented", -1);
-        return JIM_ERR;
-#endif
+        return JimSetFileTimes(interp, Jim_String(argv[0]), us);
     }
     if (file_stat(interp, argv[0], &sb) != JIM_OK) {
         return JIM_ERR;
     }
-    Jim_SetResultInt(interp, sb.st_mtime);
+    Jim_SetResultInt(interp, STAT_MTIME_US(sb));
     return JIM_OK;
 }
+#endif
 
 static int file_cmd_copy(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
@@ -765,6 +803,15 @@ static const jim_subcmd_type file_command_table[] = {
         2,
         /* Description: Get or set last modification time */
     },
+#ifdef STAT_MTIME_US
+    {   "mtimeus",
+        "name ?time?",
+        file_cmd_mtimeus,
+        1,
+        2,
+        /* Description: Get or set last modification time in microseconds */
+    },
+#endif
     {   "copy",
         "?-force? source dest",
         file_cmd_copy,
diff --git a/jim_tcl.txt b/jim_tcl.txt
index efe13c5..64642a9 100644
--- a/jim_tcl.txt
+++ b/jim_tcl.txt
@@ -3,7 +3,7 @@ Jim Tcl(n)
 
 NAME
 ----
-Jim Tcl v0.78 - reference manual for the Jim Tcl scripting language
+Jim Tcl v0.78+ - reference manual for the Jim Tcl scripting language
 
 SYNOPSIS
 --------
@@ -52,6 +52,10 @@ Some notable differences with Tcl 8.5/8.6 are:
 
 RECENT CHANGES
 --------------
+Changes since 0.78
+~~~~~~~~~~~~~~~~~~
+1. Add `file mtimeus` for high resolution file timestamps
+
 Changes between 0.77 and 0.78
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1. Add serial/tty support with `aio tty`
@@ -2373,6 +2377,12 @@ abbreviation for +'option'+ is acceptable.  The valid options are:
     error is generated. If +'time'+ is given, sets the modification time
     of the file to the given value.
 
++*file mtimeus* 'name ?time_us?'+::
+    As for `file mtime` except the time value is in microseconds
+	since the epoch (see also `clock microseconds`).
+	Note that some platforms and some filesystems don't support high
+	resolution timestamps for files.
+
 +*file normalize* 'name'+::
     Return the normalized path of +'name'+. See 'realpath(3)'.
 
@@ -2410,7 +2420,7 @@ abbreviation for +'option'+ is acceptable.  The valid options are:
     Invoke the 'stat' kernel call on +'name'+, and return the result
     as a dictionary with the following keys: 'atime',
     'ctime', 'dev', 'gid', 'ino', 'mode', 'mtime',
-    'nlink', 'size', 'type', 'uid'.
+    'nlink', 'size', 'type', 'uid', 'mtimeus' (if supported - see `file mtimeus`)
     Each element except 'type' is a decimal string with the value of
     the corresponding field from the 'stat' return structure; see the
     manual entry for 'stat' for details on the meanings of the values.