From ba1ac58d9d48a955786c05dddf17f57cffd9baf0 Mon Sep 17 00:00:00 2001
From: Přemysl Janouch <p.janouch@gmail.com>
Date: Thu, 9 Jul 2015 22:32:14 +0200
Subject: degesch: add backend support for aliases

---
 degesch.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 93 insertions(+), 17 deletions(-)

diff --git a/degesch.c b/degesch.c
index 26a1cbd..0119b13 100644
--- a/degesch.c
+++ b/degesch.c
@@ -1610,6 +1610,7 @@ register_config_modules (struct app_context *ctx)
 	struct config *config = &ctx->config;
 	// The servers are loaded later when we can create buffers for them
 	config_register_module (config, "servers",    NULL, NULL);
+	config_register_module (config, "aliases",    NULL, NULL);
 	config_register_module (config, "behaviour",  load_config_behaviour,  ctx);
 	config_register_module (config, "attributes", load_config_attributes, ctx);
 }
@@ -7625,8 +7626,9 @@ init_partial_matching_user_command_map (struct str_map *partial)
 	}
 }
 
-static void
-process_user_command (struct app_context *ctx, char *input)
+static bool
+process_user_command
+	(struct app_context *ctx, const char *command_name, char *input)
 {
 	static bool initialized = false;
 	static struct str_map partial;
@@ -7636,9 +7638,8 @@ process_user_command (struct app_context *ctx, char *input)
 		initialized = true;
 	}
 
-	char *command_name = cut_word (&input);
 	if (try_handle_buffer_goto (ctx, command_name))
-		return;
+		return true;
 
 	struct handler_args args =
 	{
@@ -7647,10 +7648,11 @@ process_user_command (struct app_context *ctx, char *input)
 		.arguments = input,
 	};
 
-	struct command_handler *handler = str_map_find (&partial, command_name);
-	if (!handler)
-		log_global_error (ctx, "#s: #s", "No such command", command_name);
-	else if ((handler->flags & HANDLER_SERVER)
+	struct command_handler *handler;
+	if (!(handler = str_map_find (&map, command_name)))
+		return false;
+
+	if ((handler->flags & HANDLER_SERVER)
 		&& args.buffer->type == BUFFER_GLOBAL)
 		log_global_error (ctx, "/#s: #s",
 			command_name, "can't do this from a global buffer");
@@ -7671,6 +7673,64 @@ process_user_command (struct app_context *ctx, char *input)
 	else if (!handler->handler (&args))
 		log_global_error (ctx,
 			"#s: /#s #s", "Usage", handler->name, handler->usage);
+	return true;
+}
+
+static char *
+expand_alias_definition (const struct str *definition, const char *arguments)
+{
+	struct str_vector v;
+	str_vector_init (&v);
+	split_str_ignore_empty (arguments, ' ', &v);
+
+	struct str expanded;
+	str_init (&expanded);
+
+	// TODO: eventually also support argument ranges
+	bool escape = false;
+	for (const char *p = definition->str; *p; p++)
+	{
+		if (!escape)
+		{
+			if (*p == '$' && p[1])
+				escape = true;
+			else
+				str_append_c (&expanded, *p);
+			continue;
+		}
+
+		int as_number = *p - '0';
+		if (as_number > 0 && as_number <= 9
+		 && (size_t) as_number <= v.len)
+			str_append (&expanded, v.vector[as_number - 1]);
+		else if (*p == '*')
+			str_append (&expanded, arguments);
+		else if (*p == '$')
+			str_append_c (&expanded, '$');
+		else
+			str_append_printf (&expanded, "$%c", *p);
+		escape = false;
+	}
+	str_vector_free (&v);
+	return str_steal (&expanded);
+}
+
+static char *
+expand_alias (struct app_context *ctx, const char *alias_name, char *input)
+{
+	struct str_map *aliases =
+		&config_item_get (ctx->config.root, "aliases", NULL)->value.object;
+
+	struct config_item_ *entry = str_map_find (aliases, alias_name);
+	if (!entry)
+		return NULL;
+
+	if (config_item_type_is_string (entry->type))
+		return expand_alias_definition (&entry->value.string, input);
+
+	log_global_error (ctx, "Error executing `/%s': "
+		"alias definition is not a string", alias_name);
+	return NULL;
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -7707,21 +7767,37 @@ send_message_to_current_buffer (struct app_context *ctx, char *message)
 	}
 }
 
+static void
+process_input_utf8 (struct app_context *ctx, char *input, int alias_level)
+{
+	if (*input != '/' || *++input == '/')
+	{
+		send_message_to_current_buffer (ctx, input);
+		return;
+	}
+
+	char *name = cut_word (&input);
+	if (process_user_command (ctx, name, input))
+		return;
+
+	char *expanded = expand_alias (ctx, name, input);
+	if (!expanded)
+		log_global_error (ctx, "#s: /#s", "No such command or alias", name);
+	else if (alias_level != 0)
+		log_global_error (ctx, "#s: /#s", "Aliases can't nest", name);
+	else
+		process_input_utf8 (ctx, expanded, alias_level++);
+	free (expanded);
+}
+
 static void
 process_input (struct app_context *ctx, char *user_input)
 {
 	char *input;
-	size_t len;
-
-	if (!(input = iconv_xstrdup (ctx->term_to_utf8, user_input, -1, &len)))
+	if (!(input = iconv_xstrdup (ctx->term_to_utf8, user_input, -1, NULL)))
 		print_error ("character conversion failed for `%s'", "user input");
-	else if (input[0] != '/')
-		send_message_to_current_buffer (ctx, input);
-	else if (input[1] == '/')
-		send_message_to_current_buffer (ctx, input + 1);
 	else
-		process_user_command (ctx, input + 1);
-
+		process_input_utf8 (ctx, input, 0);
 	free (input);
 }
 
-- 
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