mcron: Handle command line arguments in C with argp

'argp' is a convenient and maintainable way to parse command line arguments.
Guile doesn't offer an equivalent of this, so the command line handling has
been moved to C.

* src/mcron.c (parse_args, parse_opt): New functions.
(inner_main): Call 'parse_args'.
* src/mcron/scripts/mcron.scm (show-help, %options): Delete.
(main): Remove command line handling.

1 files changed, 81 insertions, 1 deletions

diff --git a/src/mcron.c b/src/mcron.c
index 43afc72..5c63c4b 100644
--- a/src/mcron.c
+++ b/src/mcron.c
@@ -18,10 +18,13 @@
    along with GNU Mcron.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "utils.h"
+#include <argp.h>
 #include <libguile.h>
 
 /* Forward declarations.  */
 static void inner_main (void *closure, int argc, char *argv[]);
+static SCM parse_args (int argc, char *argv[]);
+static error_t parse_opt (int key, char *arg, struct argp_state *state);
 
 int
 main (int argc, char *argv[])
@@ -44,6 +47,83 @@ main (int argc, char *argv[])
 static void
 inner_main (void *closure, int argc, char *argv[])
 {
+  SCM config = parse_args (argc, argv);
   scm_set_current_module (scm_c_resolve_module ("mcron scripts mcron"));
-  scm_call_0 (scm_variable_ref (scm_c_lookup ("main")));
+  scm_call_1 (scm_variable_ref (scm_c_lookup ("main")), config);
+}
+
+/* Handle command line arguments.  */
+static SCM
+parse_args (int argc, char *argv[])
+{
+  static struct argp_option options[] = {
+    {"schedule", 's', "N", 0,
+     "Display the next N jobs that will be run"},
+    {"daemon", 'd', 0, 0,
+     "Run as a daemon process"},
+    {"stdin", 'i', "FORMAT", 0,
+     "Format of data passed as standard input or file arguments (default guile)"},
+    {0, 0, 0, 0, 0}
+  };
+
+  static struct argp argp = {
+    .options = options,
+    .parser = parse_opt,
+    .args_doc = "[FILE...]",
+    .doc = "Run an mcron process according to the specifications in the "
+    "FILE... (`-' for standard input), or use all the files in "
+    "~/.config/cron (or the deprecated ~/.cron) with .guile or "
+    ".vixie extensions."
+  };
+
+  SCM config = SCM_EOL;
+  argp_program_version = PACKAGE_STRING;
+  argp_program_bug_address = PACKAGE_BUGREPORT;
+  argp_parse (&argp, argc, argv, 0, NULL, &config);
+
+  return config;
+}
+
+static error_t
+parse_opt (int key, char *arg, struct argp_state *state)
+{
+  SCM *config = state->input;
+
+  switch (key)
+    {
+    case 's':
+      *config = scm_assq_set_x (*config, scm_from_utf8_symbol ("schedule"),
+                                scm_from_int (atoi (arg)));
+      break;
+    case 'd':
+      *config = scm_assq_set_x (*config, scm_from_utf8_symbol ("daemon"),
+                                SCM_BOOL_T);
+      break;
+    case 'i':
+      if (strncmp (arg, "vixie", 6) == 0)
+        *config = scm_assq_set_x (*config, scm_from_utf8_symbol ("vixie"),
+                                  SCM_BOOL_T);
+      break;
+    case ARGP_KEY_NO_ARGS:
+      *config = scm_assq_set_x (*config, scm_from_utf8_symbol ("files"),
+                                SCM_EOL);
+      break;
+    case ARGP_KEY_ARGS:
+      {
+        SCM lst = SCM_EOL;
+        int filec = state->argc - state->next;
+        char **filev = state->argv + state->next;
+
+        for (int i = filec - 1; i >= 0; i--)
+          lst = scm_cons (scm_from_locale_string (filev[i]), lst);
+
+        *config = scm_assq_set_x (*config, scm_from_utf8_symbol ("files"),
+                                  lst);
+        break;
+      }
+    case ARGP_KEY_ARG:
+    default:
+      return ARGP_ERR_UNKNOWN;
+    }
+  return 0;
 }