Readline: add trivial OpenRPC support

So far hidden under a switch and only for this frontend.

json-rpc-shell.c

@@ -268,6 +268,8 @@ input_rl_on_startup (void)
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
+static char **app_readline_completion (const char *text, int start, int end);
+
 static void
 input_rl_start (struct input *input, const char *program_name)
 {
@@ -282,6 +284,8 @@ input_rl_start (struct input *input, const char *program_name)
 	rl_catch_sigwinch = false;
 	rl_change_environment = false;
 
+	rl_attempted_completion_function = app_readline_completion;
+
 	hard_assert (self->prompt != NULL);
 	rl_callback_handler_install (self->prompt, input_rl_on_input);
 
@@ -663,6 +667,8 @@ input_el_start (struct input *input, const char *program_name)
 		"run-editor", "Run editor to edit line", input_el_on_run_editor);
 	el_set (self->editline, EL_BIND, "M-e", "run-editor",         NULL);
 
+	// TODO: implement method name completion for editline (see degesch)
+
 	// Source the user's defaults file
 	el_source (self->editline, NULL);
 
@@ -940,12 +946,14 @@ static struct app_context
 
 	struct backend *backend;            ///< Our current backend
 	char *editor_filename;              ///< File for input line editor
+	struct str_map methods;             ///< Methods detected via OpenRPC
 
 	struct config config;               ///< Program configuration
 	enum color_mode color_mode;         ///< Colour output mode
 	bool compact;                       ///< Whether to not pretty print
 	bool verbose;                       ///< Print requests
 	bool trust_all;                     ///< Don't verify peer certificates
+	bool openrpc;                       ///< OpenRPC method name completion
 
 	bool null_as_id;                    ///< JSON null is used as an ID
 	int64_t next_id;                    ///< Next autogenerated ID
@@ -2891,13 +2899,18 @@ maybe_print_verbose (struct app_context *ctx, intptr_t attribute,
 
 	char *term = iconv_xstrdup (ctx->term_from_utf8, utf8, len, NULL);
 	if (!term)
-		print_error ("%s: %s", "verbose", "character conversion failed");
-	else
 	{
-		print_attributed (ctx, stdout, attribute, "%s", term);
+		print_error ("%s: %s", "verbose", "character conversion failed");
-		fputs ("\n", stdout);
+		return;
-		free (term);
 	}
+
+	ctx->input->vtable->hide (ctx->input);
+
+	print_attributed (ctx, stdout, attribute, "%s", term);
+	fputs ("\n", stdout);
+	free (term);
+
+	ctx->input->vtable->show (ctx->input);
 }
 
 static struct error *
@@ -3081,7 +3094,90 @@ fail:
 	free (input);
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+// --- OpenRPC information extraction ------------------------------------------
+
+static void
+init_openrpc (struct app_context *ctx)
+{
+	if (!ctx->openrpc)
+		return;
+
+	json_t *id = json_integer (ctx->next_id++);
+	struct str buf = str_make ();
+	struct error *e = json_rpc_call_raw (ctx, "rpc.discover", id, NULL, &buf);
+	json_decref (id);
+
+	// Just optimistically punch through, I don't have time for this shit
+	json_error_t error;
+	json_t *response = NULL, *result = NULL, *value = NULL;
+	if (!e && !(response = json_loadb (buf.str, buf.len, 0, &error)))
+		error_set (&e, "parse failure: %s", error.text);
+	else if (!(result = json_object_get (response, "result"))
+		|| !(result = json_object_get (result, "methods")))
+		error_set (&e, "unsupported");
+	else
+	{
+		const char *name = NULL;
+		for (size_t i = 0; (value = json_array_get (result, i)); i++)
+			if ((value = json_object_get (value, "name"))
+			 && (name = json_string_value (value)))
+				str_map_set (&ctx->methods, name, (void *) 1);
+	}
+	json_decref (response);
+	if (e)
+	{
+		print_error ("OpenRPC: %s", e->message);
+		error_free (e);
+	}
+	str_free (&buf);
+}
+
+// --- GNU Readline user actions -----------------------------------------------
+
+#ifdef HAVE_READLINE
+
+static char *
+app_readline_complete (const char *text, int state)
+{
+	static struct str_map_iter iter;
+	if (!state)
+		iter = str_map_iter_make (&g_ctx.methods);
+
+	char *input;
+	size_t len;
+	if (!(input = iconv_xstrdup (g_ctx.term_to_utf8, (char *) text, -1, &len)))
+	{
+		print_error ("character conversion failed for `%s'", "user input");
+		return NULL;
+	}
+
+	char *match = NULL;
+	while (str_map_iter_next (&iter)
+		&& (strncasecmp_ascii (input, iter.link->key, len - 1 /* XXX */)
+			|| !(match = iconv_xstrdup (g_ctx.term_from_utf8,
+				iter.link->key, iter.link->key_length + 1, NULL))))
+		;
+	free (input);
+	return match;
+}
+
+static char **
+app_readline_completion (const char *text, int start, int end)
+{
+	(void) end;
+
+	// Only customize matches for the first token, which is the method name
+	if (start)
+		return NULL;
+
+	// Don't iterate over filenames and stuff in this case
+	rl_attempted_completion_over = true;
+	return rl_completion_matches (text, app_readline_complete);
+}
+
+#endif // HAVE_READLINE
+
+// --- Main program ------------------------------------------------------------
 
 // The ability to use an external editor on the input line has been shamelessly
 // copypasted from degesch with minor changes only.
@@ -3366,6 +3462,8 @@ parse_program_arguments (struct app_context *ctx, int argc, char **argv,
 		  "colorize output: never, always, or auto" },
 		{ 'n', "null-as-id", NULL, 0, "JSON null is used as an `id'" },
 		{ 'o', "origin", "O", 0, "set the HTTP Origin header" },
+		// So far you have to explicitly enable this rather than disable
+		{ 'O', "openrpc", NULL, 0, "method name completion using OpenRPC" },
 		{ 't', "trust-all", NULL, 0, "don't care about SSL/TLS certificates" },
 		{ 'v', "verbose", NULL, 0, "print raw requests and responses" },
 		{ 'w', "write-default-cfg", "FILENAME",
@@ -3395,6 +3493,7 @@ parse_program_arguments (struct app_context *ctx, int argc, char **argv,
 		exit (EXIT_SUCCESS);
 
 	case 'o': *origin = optarg;         break;
+	case 'O': ctx->openrpc      = true; break;
 	case 'n': ctx->null_as_id   = true; break;
 	case 'c': ctx->compact      = true; break;
 	case 't': ctx->trust_all    = true; break;
@@ -3452,6 +3551,7 @@ main (int argc, char *argv[])
 	g_ctx.input->on_input = process_input;
 	g_ctx.input->on_run_editor = run_editor;
 
+	g_ctx.methods = str_map_make (NULL);
 	init_colors (&g_ctx);
 	load_configuration (&g_ctx);
 
@@ -3531,6 +3631,7 @@ main (int argc, char *argv[])
 	g_ctx.input->vtable->start (g_ctx.input, PROGRAM_NAME);
 
 	ev_set_userdata (EV_DEFAULT_ &g_ctx);
+	init_openrpc (&g_ctx);
 	ev_run (EV_DEFAULT_ 0);
 
 	// User has terminated the program, let's save the history and clean up
@@ -3553,6 +3654,7 @@ main (int argc, char *argv[])
 
 	iconv_close (g_ctx.term_from_utf8);
 	iconv_close (g_ctx.term_to_utf8);
+	str_map_free (&g_ctx.methods);
 	config_free (&g_ctx.config);
 	free_terminal ();
 	ev_loop_destroy (EV_DEFAULT);