From 1a219c69ee7edb2cfd0fc1a1cbc3c1e69fbffc10 Mon Sep 17 00:00:00 2001
From: Zdenek Kabelac <zkabelac@redhat.com>
Date: Sun, 12 May 2024 16:46:02 +0200
Subject: [PATCH] lvmcmdline: runtime function resolving

Instead of resolving and storing 'command_fn'
withing 'struct command' use just funtion enum
and resolve function pointer just in place,
where it is really needed - first try to resolve
'new style' and fallback to 'old style' named.
---
 tools/command.h    | 12 +++---------
 tools/lvmcmdline.c | 30 ++++++++----------------------
 2 files changed, 11 insertions(+), 31 deletions(-)

diff --git a/tools/command.h b/tools/command.h
index 3e6e0b47b..738c65e69 100644
--- a/tools/command.h
+++ b/tools/command.h
@@ -22,12 +22,9 @@ struct logical_volume;
 /* old per-command-name function */
 typedef int (*command_fn) (struct cmd_context *cmd, int argc, char **argv);
 
-/* new per-command-line-id functions */
-typedef int (*command_id_fn) (struct cmd_context *cmd, int argc, char **argv);
-
 struct command_function {
 	int command_enum;
-	command_id_fn fn;
+	command_fn fn; /* new style */
 };
 
 struct command_name {
@@ -188,11 +185,8 @@ struct command {
 	uint16_t command_enum; /* <command_id>_CMD */
 	uint16_t command_index; /* position in commands[] */
 
-	const struct command_function *functions; /* new style */
-	command_fn fn;                      /* old style */
-
-	unsigned int cmd_flags; /* CMD_FLAG_ */
-	uint16_t lvm_command_enum; /* position in commands[] */
+	uint16_t lvm_command_enum; /* position in command_names[] */
+	uint16_t cmd_flags; /* CMD_FLAG_ */
 
 	/* definitions of opt/pos args */
 
diff --git a/tools/lvmcmdline.c b/tools/lvmcmdline.c
index dfcef5912..1ade744b2 100644
--- a/tools/lvmcmdline.c
+++ b/tools/lvmcmdline.c
@@ -1301,7 +1301,7 @@ static void _set_valid_args_for_command_name(int ci)
 	command_names_args[ci].num_args = num_args;
 }
 
-static const struct command_function *_find_command_id_function(int command_enum)
+static command_fn _find_command_id_function(int command_enum)
 {
 	int i;
 
@@ -1310,7 +1310,7 @@ static const struct command_function *_find_command_id_function(int command_enum
 
 	for (i = 0; i < CMD_COUNT; i++) {
 		if (_command_functions[i].command_enum == command_enum)
-			return &_command_functions[i];
+			return _command_functions[i].fn;
 	}
 	return NULL;
 }
@@ -1335,8 +1335,6 @@ static int _command_name_compare(const void *on1, const void *on2)
 int lvm_register_commands(struct cmd_context *cmd, const char *run_name)
 {
 	int i;
-	const char *last_name = NULL;
-	const struct command_name *cname = NULL;
 
 	/* already initialized */
 	if (_cmdline.commands)
@@ -1357,19 +1355,6 @@ int lvm_register_commands(struct cmd_context *cmd, const char *run_name)
 	for (i = 0; i < COMMAND_COUNT; i++) {
 		commands_idx[i] = &commands[i];
 		commands[i].command_index = i;
-
-		/* new style */
-		commands[i].functions = _find_command_id_function(commands[i].command_enum);
-
-		/* old style */
-		if (!commands[i].functions) {
-			if (!last_name || strcmp(last_name, commands[i].name)) {
-				last_name = commands[i].name;
-				cname = find_command_name(last_name);
-			}
-			if (cname)
-				commands[i].fn = cname->fn;
-		}
 	}
 
 	/* Sort all commands by its name for quick binary search */
@@ -3053,6 +3038,7 @@ int lvm_run_command(struct cmd_context *cmd, int argc, char **argv)
 	int skip_hyphens;
 	int refresh_done = 0;
 	int io;
+	command_fn fn;
 
 	/* Avoid excessive access to /etc/localtime and set TZ variable for glibc
 	 * so it does not need to check /etc/localtime everytime that needs that info */
@@ -3281,12 +3267,12 @@ int lvm_run_command(struct cmd_context *cmd, int argc, char **argv)
 		goto_out;
 	}
 
-	if (cmd->command->functions)
-		/* A command-line-specific function is used */
-		ret = cmd->command->functions->fn(cmd, argc, argv);
-	else
+	/* A command-line-specific function is used */
+	if (!(fn = _find_command_id_function(cmd->command->command_enum)))
 		/* The old style command-name function is used */
-		ret = cmd->command->fn(cmd, argc, argv);
+		fn = command_names[cmd->command->lvm_command_enum].fn;
+
+	ret = fn(cmd, argc, argv);
 
 	lvmlockd_disconnect();
 	fin_locking(cmd);