Add --verbose|-v to test-chmtime

This allows us replace perl when getting the mtime of a file because
of time zone conversions, though at the moment only one platform which
does this has been identified: Cygwin when used with ActiveState Perl
(as usual).

The output format is:

    <mtime1> TAB <filename1> <LF>
    <mtime2> TAB <filename2> <LF>
    ...

which, if only mtime is needed can be parsed with cut(1):

    test-chmtime -v +0 filename1 | cut -f 1

Also, the change adds a description of programs features, with examples.

Signed-off-by: Alex Riesen <ariesen@harmanbecker.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/test-chmtime.c b/test-chmtime.c
index 90da448ebec3e5375b7725ba7f297c1c74199b87..d5358cbaac2022483b74366555fc9707a7d8ad97 100644 (file)
--- a/test-chmtime.c
+++ b/test-chmtime.c
@@ -1,39 +1,83 @@
+/*
+ * This program can either change modification time of the given
+ * file(s) or just print it. The program does not change atime nor
+ * ctime (their values are explicitely preserved).
+ *
+ * The mtime can be changed to an absolute value:
+ *
+ *     test-chmtime =<seconds> file...
+ *
+ * Relative to the current time as returned by time(3):
+ *
+ *     test-chmtime =+<seconds> (or =-<seconds>) file...
+ *
+ * Or relative to the current mtime of the file:
+ *
+ *     test-chmtime <seconds> file...
+ *     test-chmtime +<seconds> (or -<seconds>) file...
+ *
+ * Examples:
+ *
+ * To just print the mtime use --verbose and set the file mtime offset to 0:
+ *
+ *     test-chmtime -v +0 file
+ *
+ * To set the mtime to current time:
+ *
+ *     test-chmtime =+0 file
+ *
+ */
 #include "git-compat-util.h"
 #include <utime.h>
 
-static const char usage_str[] = "(+|=|=+|=-|-)<seconds> <file>...";
+static const char usage_str[] = "-v|--verbose (+|=|=+|=-|-)<seconds> <file>...";
 
-int main(int argc, const char *argv[])
+static int timespec_arg(const char *arg, long int *set_time, int *set_eq)
 {
-       int i;
-       int set_eq;
-       long int set_time;
        char *test;
-       const char *timespec;
-
-       if (argc < 3)
-               goto usage;
-
-       timespec = argv[1];
-       set_eq = (*timespec == '=') ? 1 : 0;
-       if (set_eq) {
+       const char *timespec = arg;
+       *set_eq = (*timespec == '=') ? 1 : 0;
+       if (*set_eq) {
                timespec++;
                if (*timespec == '+') {
-                       set_eq = 2; /* relative "in the future" */
+                       *set_eq = 2; /* relative "in the future" */
                        timespec++;
                }
        }
-       set_time = strtol(timespec, &test, 10);
+       *set_time = strtol(timespec, &test, 10);
        if (*test) {
-               fprintf(stderr, "Not a base-10 integer: %s\n", argv[1] + 1);
-               goto usage;
+               fprintf(stderr, "Not a base-10 integer: %s\n", arg + 1);
+               return 0;
        }
-       if ((set_eq && set_time < 0) || set_eq == 2) {
+       if ((*set_eq && *set_time < 0) || *set_eq == 2) {
                time_t now = time(NULL);
-               set_time += now;
+               *set_time += now;
        }
+       return 1;
+}
+
+int main(int argc, const char *argv[])
+{
+       static int verbose;
 
-       for (i = 2; i < argc; i++) {
+       int i = 1;
+       /* no mtime change by default */
+       int set_eq = 0;
+       long int set_time = 0;
+
+       if (argc < 3)
+               goto usage;
+
+       if (strcmp(argv[i], "--verbose") == 0 || strcmp(argv[i], "-v") == 0) {
+               verbose = 1;
+               ++i;
+       }
+       if (timespec_arg(argv[i], &set_time, &set_eq))
+               ++i;
+       else
+               goto usage;
+
+       for (; i < argc; i++) {
                struct stat sb;
                struct utimbuf utb;
 
@@ -46,7 +90,12 @@ int main(int argc, const char *argv[])
                utb.actime = sb.st_atime;
                utb.modtime = set_eq ? set_time : sb.st_mtime + set_time;
 
-               if (utime(argv[i], &utb) < 0) {
+               if (verbose) {
+                       uintmax_t mtime = utb.modtime < 0 ? 0: utb.modtime;
+                       printf("%"PRIuMAX"\t%s\n", mtime, argv[i]);
+               }
+
+               if (utb.modtime != sb.st_mtime && utime(argv[i], &utb) < 0) {
                        fprintf(stderr, "Failed to modify time on %s: %s\n",
                                argv[i], strerror(errno));
                        return -1;