Introduce usagef() that takes a printf-style format

diff --git a/builtin-archive.c b/builtin-archive.c
index 3c5a5a7822afebf87ef6eb1f89c7c54d76844161..12351e9dd5c481fddc8db07c00a211b4620250bd 100644 (file)
--- a/builtin-archive.c
+++ b/builtin-archive.c
@@ -13,10 +13,10 @@ static void create_output_file(const char *output_file)
 {
        int output_fd = open(output_file, O_CREAT | O_WRONLY | O_TRUNC, 0666);
        if (output_fd < 0)
-               die("could not create archive file: %s ", output_file);
+               die_errno("could not create archive file '%s'", output_file);
        if (output_fd != 1) {
                if (dup2(output_fd, 1) < 0)
-                       die("could not redirect output");
+                       die_errno("could not redirect output");
                else
                        close(output_fd);
        }
@@ -60,6 +60,17 @@ static int run_remote_archiver(int argc, const char **argv,
        return !!rv;
 }
 
+static const char *format_from_name(const char *filename)
+{
+       const char *ext = strrchr(filename, '.');
+       if (!ext)
+               return NULL;
+       ext++;
+       if (!strcasecmp(ext, "zip"))
+               return "zip";
+       return NULL;
+}
+
 #define PARSE_OPT_KEEP_ALL ( PARSE_OPT_KEEP_DASHDASH |         \
                             PARSE_OPT_KEEP_ARGV0 |     \
                             PARSE_OPT_KEEP_UNKNOWN |   \
@@ -70,21 +81,39 @@ int cmd_archive(int argc, const char **argv, const char *prefix)
        const char *exec = "git-upload-archive";
        const char *output = NULL;
        const char *remote = NULL;
+       const char *format = NULL;
        struct option local_opts[] = {
-               OPT_STRING(0, "output", &output, "file",
+               OPT_STRING('o', "output", &output, "file",
                        "write the archive to this file"),
                OPT_STRING(0, "remote", &remote, "repo",
                        "retrieve the archive from remote repository <repo>"),
                OPT_STRING(0, "exec", &exec, "cmd",
                        "path to the remote git-upload-archive command"),
+               OPT_STRING(0, "format", &format, "fmt", "archive format"),
                OPT_END()
        };
+       char fmt_opt[32];
 
        argc = parse_options(argc, argv, prefix, local_opts, NULL,
                             PARSE_OPT_KEEP_ALL);
 
-       if (output)
+       if (output) {
                create_output_file(output);
+               if (!format)
+                       format = format_from_name(output);
+       }
+
+       if (format) {
+               sprintf(fmt_opt, "--format=%s", format);
+               /*
+                * This is safe because either --format and/or --output must
+                * have been given on the original command line if we get to
+                * this point, and parse_options() must have eaten at least
+                * one argument, i.e. we have enough room to append to argv[].
+                */
+               argv[argc++] = fmt_opt;
+               argv[argc] = NULL;
+       }
 
        if (remote)
                return run_remote_archiver(argc, argv, remote, exec);