Programmatically generate command usage and help

This avoids having each command handle it differently.

4 files changed, 65 insertions, 21 deletions

diff --git a/tools/eos-profile-tool/eos-profile-cmd-help.c b/tools/eos-profile-tool/eos-profile-cmd-help.c
index 754714f..f81102d 100644
--- a/tools/eos-profile-tool/eos-profile-cmd-help.c
+++ b/tools/eos-profile-tool/eos-profile-cmd-help.c
@@ -9,20 +9,33 @@ eos_profile_cmd_help_parse_args (int    argc,
   return TRUE;
 }
 
+static gboolean
+print_available_commands (const EosProfileCmd *cmd,
+                          gpointer             dummy G_GNUC_UNUSED)
+{
+  g_print ("  %s%*s%s\n",
+           cmd->name,
+           14 - strlen (cmd->name), " ",
+           cmd->description);
+
+  return FALSE;
+}
+
 int
 eos_profile_cmd_help_main (void)
 {
   g_print (
     "eos-profile\n"
     "\n"
-    "Usage: eos-profile <COMMAND> [OPTIONS...]\n"
+    "Usage: eos-profile <COMMAND> [OPTION…]\n"
     "\n"
-    "Examples:\n"
-    "\n"
-    "  eos-profile help         - This help screen\n"
-    "  eos-profile show FILE    - Shows a capture file\n"
+    "COMMANDS\n"
     "\n"
   );
 
+  eos_profile_foreach_cmd (print_available_commands, NULL);
+
+  g_print ("\n");
+
   return 0;
 }
diff --git a/tools/eos-profile-tool/eos-profile-cmd-show.c b/tools/eos-profile-tool/eos-profile-cmd-show.c
index b01bd14..4867dc2 100644
--- a/tools/eos-profile-tool/eos-profile-cmd-show.c
+++ b/tools/eos-profile-tool/eos-profile-cmd-show.c
@@ -57,9 +57,7 @@ eos_profile_cmd_show_parse_args (int    argc,
 
   if (files->len == 0)
     {
-      g_printerr ("Usage: eos-profile show FILE [FILE...]\n");
       g_ptr_array_unref (files);
-
       return FALSE;
     }
 
diff --git a/tools/eos-profile-tool/eos-profile-cmds.h b/tools/eos-profile-tool/eos-profile-cmds.h
index c6da7d4..1b06db5 100644
--- a/tools/eos-profile-tool/eos-profile-cmds.h
+++ b/tools/eos-profile-tool/eos-profile-cmds.h
@@ -5,9 +5,23 @@
 typedef gboolean (* EosProfileCmdParseArgs) (int argc, char **argv);
 typedef int (* EosProfileCmdMain) (void);
 
+typedef struct {
+  const char *name;
+  const char *description;
+  const char *usage;
+
+  EosProfileCmdParseArgs parse_args;
+  EosProfileCmdMain main;
+} EosProfileCmd;
+
+typedef gboolean (* EosProfileCmdCallback) (const EosProfileCmd *cmd,
+                                            gpointer             data);
+
 gboolean        eos_profile_cmd_help_parse_args (int argc, char **argv);
 int             eos_profile_cmd_help_main       (void);
 
 gboolean        eos_profile_cmd_show_parse_args (int argc, char **argv);
 int             eos_profile_cmd_show_main       (void);
 
+void            eos_profile_foreach_cmd         (EosProfileCmdCallback cb,
+                                                 gpointer              data);
diff --git a/tools/eos-profile-tool/eos-profile-main.c b/tools/eos-profile-tool/eos-profile-main.c
index 6879cb6..1691bff 100644
--- a/tools/eos-profile-tool/eos-profile-main.c
+++ b/tools/eos-profile-tool/eos-profile-main.c
@@ -10,29 +10,34 @@
 
 #include "eos-profile-cmds.h"
 
-static const struct {
-  const char *name;
-  const char *description;
-
-  EosProfileCmdParseArgs parse_args;
-  EosProfileCmdMain main;
-} profile_commands[] = {
+static const EosProfileCmd profile_commands[] = {
   {
     .name = "help",
-    .description = "Prints help",
+    .description = "Prints this help string",
+    .usage = NULL,
     .parse_args = eos_profile_cmd_help_parse_args,
     .main = eos_profile_cmd_help_main,
   },
   {
     .name = "show",
-    .description = "Shows a capture",
+    .description = "Prints a report from a capture file",
+    .usage = "show <FILE> [FILE…]",
     .parse_args = eos_profile_cmd_show_parse_args,
     .main = eos_profile_cmd_show_main,
   },
-
-  { NULL, },
 };
 
+void
+eos_profile_foreach_cmd (EosProfileCmdCallback cb,
+                         gpointer              data)
+{
+  for (int i = 0; i < G_N_ELEMENTS (profile_commands); i++)
+    {
+      if (cb (&profile_commands[i], data))
+        break;
+    }
+}
+
 int
 main (int argc,
       char *argv[])
@@ -45,8 +50,13 @@ main (int argc,
 
   const char *cmd = NULL;
 
-  if (argc < 2)
-    cmd = "help";
+  if (argc < 2 ||
+      g_strcmp0 (argv[1], "-h") == 0 ||
+      g_strcmp0 (argv[1], "-?") == 0 ||
+      g_strcmp0 (argv[1], "--help") == 0)
+    {
+      cmd = "help";
+    }
   else
     cmd = argv[1];
 
@@ -58,7 +68,16 @@ main (int argc,
           argv += 1;
 
           if (!profile_commands[i].parse_args (argc, argv))
-            return EXIT_FAILURE;
+            {
+              const char *usage = profile_commands[i].usage;
+
+              if (usage == NULL)
+                usage = profile_commands[i].name;
+
+              g_printerr ("Usage: eos-profile %s\n", usage);
+
+              return EXIT_FAILURE;
+            }
 
           return profile_commands[i].main ();
         }