argparser: Implement a command mode.

* src/gpg-error.h.in (ARGPARSE_FLAG_COMMAND): New.
* src/argparse.c (struct _gpgrt_argparse_internal_s): Add flags
explicit_cmd_mode, cmd_mode, and command_seen.
(initialize): Init them.  Mark default commands as commands.
(handle_meta_command): New.
(handle_metacmd): Add "command-mode" and "-command-mode".
(find_long_option): Add arg only_commands.
(arg_parse): Factor some code out to ...
(handle_special_commands): new.
(arg_parse): Implement the command-mode.

* tests/t-argparse.c (main): Add some testing code.
--

GnuPG-bug-id: 6978

5 files changed, 144 insertions, 42 deletions

diff --git a/NEWS b/NEWS
index 3679581..a8b60f4 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,14 @@ Noteworthy changes in version 1.48 (unreleased) [C34/A34/R_]
 
  * New configure option --with-libtool-modification.  [T6619]
 
+ * New option parser flag to detect commands given without a double
+   dash.  There is also the new meta command [command-mode] to set
+   this flag via a config file.  [T6978]
+
+ * Interface changes relative to the 1.47 release:
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ ARGPARSE_FLAG_COMMAND          NEW.
+
  Release-info: https://dev.gnupg.org/T6441
 
 
diff --git a/src/argparse.c b/src/argparse.c
index 2399c43..bd44aef 100644
--- a/src/argparse.c
+++ b/src/argparse.c
@@ -117,14 +117,17 @@ struct _gpgrt_argparse_internal_s
   unsigned int in_sysconf:1;       /* Processing global config file.    */
   unsigned int mark_forced:1;      /* Mark options as forced.           */
   unsigned int mark_ignore:1;      /* Mark options as to be ignored.    */
-  unsigned int explicit_ignore:1;  /* Option has explicitly been set
-                                    * to ignore or unignore.  */
+  unsigned int explicit_ignore:1;  /* Option has explicitly been set    */
+                                   /* to be ignored or un-ignoref.      */
+  unsigned int command_seen:1;     /* A command option has been seen.   */
   unsigned int ignore_all_seen:1;  /* [ignore-all] has been seen.       */
   unsigned int user_seen:1;        /* A [user] has been seen.           */
   unsigned int user_wildcard:1;    /* A [user *] has been seen.         */
   unsigned int user_any_active:1;  /* Any user section was active.      */
   unsigned int user_active:1;      /* User section active.              */
   unsigned int expand:1;           /* Expand vars in option values.     */
+  unsigned int explicit_cmd_mode:1;/* Command mode set via config.      */
+  unsigned int cmd_mode:1;         /* Command mode according to config. */
   unsigned int explicit_confopt:1; /* A conffile option has been given. */
   char *explicit_conffile;         /* Malloced name of an explicit
                                     * conffile. */
@@ -336,6 +339,9 @@ initialize (gpgrt_argparse_t *arg, gpgrt_opt_t *opts, estream_t fp)
       arg->internal->inarg = 0;
       arg->internal->stopped = 0;
       arg->internal->in_sysconf = 0;
+      arg->internal->command_seen = 0;
+      arg->internal->explicit_cmd_mode = 0;
+      arg->internal->cmd_mode = 0;
       arg->internal->user_seen = 0;
       arg->internal->user_wildcard = 0;
       arg->internal->user_any_active = 0;
@@ -425,7 +431,7 @@ initialize (gpgrt_argparse_t *arg, gpgrt_opt_t *opts, estream_t fp)
       if (!seen_help)
         {
           arg->internal->opts[i].short_opt   = ARGPARSE_SHORTOPT_HELP;
-          arg->internal->opts[i].flags       = ARGPARSE_TYPE_NONE;
+          arg->internal->opts[i].flags       = ARGPARSE_OPT_COMMAND;
           arg->internal->opts[i].long_opt    = "help";
           arg->internal->opts[i].description = "@";
           arg->internal->opts[i].ordinal = i;
@@ -434,7 +440,7 @@ initialize (gpgrt_argparse_t *arg, gpgrt_opt_t *opts, estream_t fp)
       if (!seen_version)
         {
           arg->internal->opts[i].short_opt   = ARGPARSE_SHORTOPT_VERSION;
-          arg->internal->opts[i].flags       = ARGPARSE_TYPE_NONE;
+          arg->internal->opts[i].flags       = ARGPARSE_OPT_COMMAND;
           arg->internal->opts[i].long_opt    = "version";
           arg->internal->opts[i].description = "@";
           arg->internal->opts[i].ordinal = i;
@@ -444,7 +450,7 @@ initialize (gpgrt_argparse_t *arg, gpgrt_opt_t *opts, estream_t fp)
       if (!seen_warranty)
         {
           arg->internal->opts[i].short_opt   = ARGPARSE_SHORTOPT_WARRANTY;
-          arg->internal->opts[i].flags       = ARGPARSE_TYPE_NONE;
+          arg->internal->opts[i].flags       = ARGPARSE_OPT_COMMAND;
           arg->internal->opts[i].long_opt    = "warranty";
           arg->internal->opts[i].description = "@";
           arg->internal->opts[i].ordinal = i;
@@ -454,7 +460,7 @@ initialize (gpgrt_argparse_t *arg, gpgrt_opt_t *opts, estream_t fp)
       if (!seen_dump_option_table)
         {
           arg->internal->opts[i].short_opt   = ARGPARSE_SHORTOPT_DUMP_OPTTBL;
-          arg->internal->opts[i].flags       = ARGPARSE_TYPE_NONE;
+          arg->internal->opts[i].flags       = ARGPARSE_OPT_COMMAND;
           arg->internal->opts[i].long_opt    = "dump-option-table";
           arg->internal->opts[i].description = "@";
           arg->internal->opts[i].ordinal = i;
@@ -464,7 +470,7 @@ initialize (gpgrt_argparse_t *arg, gpgrt_opt_t *opts, estream_t fp)
       if (!seen_dump_options)
         {
           arg->internal->opts[i].short_opt   = ARGPARSE_SHORTOPT_DUMP_OPTIONS;
-          arg->internal->opts[i].flags       = ARGPARSE_TYPE_NONE;
+          arg->internal->opts[i].flags       = ARGPARSE_OPT_COMMAND;
           arg->internal->opts[i].long_opt    = "dump-options";
           arg->internal->opts[i].description = "@";
           arg->internal->opts[i].ordinal = i;
@@ -1369,6 +1375,21 @@ handle_meta_verbose (gpgrt_argparse_t *arg, unsigned int alternate, char *args)
   return 0;
 }
 
+/* Implementation of the "command-mode" command.  ARG is the context.  If
+ * ALTERNATE is true the command mode is disabled.  ARGS is not used.  */
+static int
+handle_meta_command (gpgrt_argparse_t *arg, unsigned int alternate, char *args)
+{
+  (void)args;
+
+  arg->internal->explicit_cmd_mode = 1;
+  if (alternate)
+    arg->internal->cmd_mode = 0;
+  else
+    arg->internal->cmd_mode = 1;
+  return 0;
+}
+
 
 /* Implementation of the "expand" command.  ARG is the context.  If
  * ALTERNATE is true expand is reset.  ARGS is not used.  */
@@ -1422,6 +1443,9 @@ handle_metacmd (gpgrt_argparse_t *arg, char *keyword)
        { "verbose",     0, 0, 1, 1, handle_meta_verbose },
        { "+verbose",    0, 0, 1, 1, handle_meta_verbose },
        { "-verbose",    1, 0, 1, 1, handle_meta_verbose },
+       { "command-mode", 0,0, 1, 0, handle_meta_command },
+       { "+command-mode",0,0, 1, 0, handle_meta_command },
+       { "-command-mode",1,0, 1, 0, handle_meta_command },
        { "echo",        0, 1, 1, 1, handle_meta_echo },
        { "-echo",       1, 1, 1, 1, handle_meta_echo },
        { "info",        0, 1, 1, 0, handle_meta_echo },
@@ -2479,9 +2503,10 @@ _gpgrt_argparser (gpgrt_argparse_t *arg, gpgrt_opt_t *opts,
 
 /* Given the list of options in ARG and a keyword, return the index of
  * the long option matching KEYWORD.  On error -1 is returned for not
- * found or -2 for ambigious keyword.  */
+ * found or -2 for ambiguous keyword.  If ONLY_COMMANDS is set only
+ * options marked as commands are considere. */
 static int
-find_long_option (gpgrt_argparse_t *arg, const char *keyword)
+find_long_option (gpgrt_argparse_t *arg, const char *keyword, int only_commands)
 {
   int i;
   size_t n;
@@ -2495,9 +2520,24 @@ find_long_option (gpgrt_argparse_t *arg, const char *keyword)
    * done. */
   if (!*keyword)
     return -1;
-  for (i=0; i < nopts; i++ )
-    if (opts[i].long_opt && !strcmp (opts[i].long_opt, keyword))
-      return i;
+  if (only_commands)
+    {
+      /* Note that we consider only options which have just the
+       * command flag set and ignore all option which falsely have
+       * other bits set.  */
+      for (i=0; i < nopts; i++ )
+        if (opts[i].flags == ARGPARSE_OPT_COMMAND
+            && opts[i].long_opt && !strcmp (opts[i].long_opt, keyword))
+          return i;
+      return -1;  /* Not found (no abbreviations in this mode).  */
+    }
+  else
+    {
+      for (i=0; i < nopts; i++ )
+        if (opts[i].long_opt && !strcmp (opts[i].long_opt, keyword))
+          return i;
+    }
+
 #if 0
   {
     ALIAS_DEF a;
@@ -2536,6 +2576,48 @@ find_long_option (gpgrt_argparse_t *arg, const char *keyword)
 }
 
 
+/* Handle special commands like "help" and "version".  All of these
+ * commands call exit and thus this function does not return if such a
+ * command was found at IDX.  */
+static void
+handle_special_commands (gpgrt_argparse_t *arg, int idx)
+{
+  int i = idx;
+  opttable_t *opts = arg->internal->opts;
+  unsigned int nopts = arg->internal->nopts;
+
+  if (i >= 0 && opts[i].short_opt == ARGPARSE_SHORTOPT_HELP)
+    {
+      show_help (opts, nopts, arg->flags);
+      my_exit (arg, 0);
+    }
+  else if (i >= 0 && opts[i].short_opt == ARGPARSE_SHORTOPT_VERSION)
+    {
+      if (!(arg->flags & ARGPARSE_FLAG_NOVERSION))
+        {
+          show_version ();
+          my_exit (arg, 0);
+        }
+    }
+  else if (i >= 0 && opts[i].short_opt == ARGPARSE_SHORTOPT_WARRANTY)
+    {
+      writestrings (0, _gpgrt_strusage (16), "\n", NULL);
+      my_exit (arg, 0);
+    }
+  else if (i >= 0 && opts[i].short_opt == ARGPARSE_SHORTOPT_DUMP_OPTTBL)
+    dump_option_table (arg);
+  else if (i >= 0 && opts[i].short_opt == ARGPARSE_SHORTOPT_DUMP_OPTIONS)
+    {
+      for (i=0; i < nopts; i++ )
+        {
+          if (opts[i].long_opt && !(opts[i].flags & ARGPARSE_OPT_IGNORE))
+            writestrings (0, "--", opts[i].long_opt, "\n", NULL);
+        }
+      my_exit (arg, 0);
+    }
+}
+
+
 /* The option parser for command line options.  */
 static int
 arg_parse (gpgrt_argparse_t *arg, gpgrt_opt_t *opts_orig, int no_init)
@@ -2606,39 +2688,11 @@ arg_parse (gpgrt_argparse_t *arg, gpgrt_opt_t *opts_orig, int no_init)
       argpos = strchr( s+2, '=' );
       if ( argpos )
         *argpos = 0;
-      i = find_long_option (arg, s+2);
+      i = find_long_option (arg, s+2, 0);
       if ( argpos )
         *argpos = '=';
 
-      if (i > 0 && opts[i].short_opt == ARGPARSE_SHORTOPT_HELP)
-        {
-          show_help (opts, nopts, arg->flags);
-          my_exit (arg, 0);
-        }
-      else if (i > 0 && opts[i].short_opt == ARGPARSE_SHORTOPT_VERSION)
-        {
-          if (!(arg->flags & ARGPARSE_FLAG_NOVERSION))
-            {
-              show_version ();
-              my_exit (arg, 0);
-            }
-	}
-      else if (i > 0 && opts[i].short_opt == ARGPARSE_SHORTOPT_WARRANTY)
-        {
-          writestrings (0, _gpgrt_strusage (16), "\n", NULL);
-          my_exit (arg, 0);
-	}
-      else if (i > 0 && opts[i].short_opt == ARGPARSE_SHORTOPT_DUMP_OPTTBL)
-        dump_option_table (arg);
-      else if (i > 0 && opts[i].short_opt == ARGPARSE_SHORTOPT_DUMP_OPTIONS)
-        {
-          for (i=0; i < nopts; i++ )
-            {
-              if (opts[i].long_opt && !(opts[i].flags & ARGPARSE_OPT_IGNORE))
-                writestrings (0, "--", opts[i].long_opt, "\n", NULL);
-	    }
-          my_exit (arg, 0);
-	}
+      handle_special_commands (arg, i);
 
       if ( i == -2 )
         arg->r_opt = ARGPARSE_AMBIGUOUS_OPTION;
@@ -2650,6 +2704,9 @@ arg_parse (gpgrt_argparse_t *arg, gpgrt_opt_t *opts_orig, int no_init)
       else
         arg->r_opt = opts[i].short_opt;
 
+      if (i >= 0 && (opts[i].flags & ARGPARSE_OPT_COMMAND))
+        arg->internal->command_seen = 1;
+
       if ( i < 0 )
         ;
       else if ( (opts[i].flags & ARGPARSE_TYPE_MASK) )
@@ -2793,6 +2850,20 @@ arg_parse (gpgrt_argparse_t *arg, gpgrt_opt_t *opts_orig, int no_init)
           argc--; argv++; idx++;
         }
     }
+  else if (!arg->internal->command_seen
+           && ((!arg->internal->explicit_cmd_mode
+                && arg->flags & ARGPARSE_FLAG_COMMAND)
+               || (arg->internal->explicit_cmd_mode
+                   && arg->internal->cmd_mode))
+           && (i = find_long_option (arg, s, 1)) >= 0)
+    {
+      handle_special_commands (arg, i);
+      arg->internal->opt_flags = opts[i].flags;
+      arg->internal->command_seen = 1;
+      arg->r_opt = opts[i].short_opt;
+      arg->r_type = ARGPARSE_TYPE_NONE;
+      argc--; argv++; idx++; /* Set to next one.  */
+    }
   else if ( arg->flags & ARGPARSE_FLAG_MIXED )
     {
       arg->r_opt = ARGPARSE_IS_ARG;
diff --git a/src/gpg-error.h.in b/src/gpg-error.h.in
index bce028e..969076c 100644
--- a/src/gpg-error.h.in
+++ b/src/gpg-error.h.in
@@ -1200,6 +1200,8 @@ typedef struct
 #define ARGPARSE_FLAG_USERVERS 8192  /* Try version-ed user config files.    */
 #define ARGPARSE_FLAG_WITHATTR 16384 /* Return attribute bits.  (Make sure   */
                                      /* to act upon ARGPARSE_OPT_IGNORE.)    */
+#define ARGPARSE_FLAG_COMMAND  32768 /* Allow commands w/o leading dashes.   */
+
 
 /* Constants for (gpgrt_argparse_t).err.  */
 #define ARGPARSE_PRINT_WARNING  1    /* Print a diagnostic.                  */
diff --git a/tests/t-argparse.c b/tests/t-argparse.c
index 4d24e5f..6085066 100644
--- a/tests/t-argparse.c
+++ b/tests/t-argparse.c
@@ -68,6 +68,9 @@ main (int argc, char **argv)
 {
   gpgrt_opt_t opts[] = {
     ARGPARSE_verbatim("Now for the options:\n"),
+    ARGPARSE_c  (601, "foo", "Command FOO"),
+    ARGPARSE_c  (602, "bar", "Command BAR"),
+    ARGPARSE_c  (603, "foobar", "Command FOOBAR"),
     ARGPARSE_x  ('v', "verbose", NONE, 0, "Laut sein"),
     ARGPARSE_s_n('e', "echo"   , ("Zeile ausgeben, damit wir sehen, "
                                   "was wir eingegeben haben")),
@@ -96,6 +99,10 @@ main (int argc, char **argv)
   int i;
   const char *srcdir;
   int any_warn = 0;
+  int command = -1;
+
+  if (getenv ("argparse_flag_command"))
+    pargs.flags |= ARGPARSE_FLAG_COMMAND;
 
   gpgrt_set_strusage (my_strusage);
   srcdir = getenv ("srcdir");
@@ -139,11 +146,20 @@ main (int argc, char **argv)
         case 'M': opt.myopt = 0; break;
         case 's': opt.street = pargs.r.ret_str; break;
         case 500: opt.a_long_one++;  break;
+
+        case 601:
+        case 602:
+        case 603:
+          command = pargs.r_opt;
+          break;
+
         default : pargs.err = ARGPARSE_PRINT_WARNING; any_warn = 1; break;
 	}
     }
   for (i=0; i < argc; i++ )
     printf ("%3d -> (%s)\n", i, argv[i] );
+  if (command >= 0)
+    printf ("Command: %d\n", command);
   if (opt.verbose)
     puts ("Options:");
   if (opt.verbose)
diff --git a/tests/t-argparse.conf b/tests/t-argparse.conf
index a42d1a1..2691553 100644
--- a/tests/t-argparse.conf
+++ b/tests/t-argparse.conf
@@ -8,6 +8,11 @@ echo
 # The next should be flagged as unexpected meta command.
 #<off>[ignore]
 
+# The command mode enables git style commands.  As usual it can be
+# prefixed with a + to enable or a with a - to disable this feature.
+# The last seen in any config file is used.
+#<off>[command-mode]
+
 my-option 4711
 
 not-my-option