help: use parseopt

index 8143dcd..5feb849 100644
@@ -7,40 +7,49 @@
 #include "builtin.h"
 #include "exec_cmd.h"
 #include "common-cmds.h"
-
-static const char *help_default_format;
-
-static enum help_format {
-	man_format,
-	info_format,
-	web_format,
-} help_format = man_format;
-
-static void parse_help_format(const char *format)
+#include "parse-options.h"
+
+enum help_format {
+	HELP_FORMAT_MAN,
+	HELP_FORMAT_INFO,
+	HELP_FORMAT_WEB,
+};
+
+static int show_all = 0;
+static enum help_format help_format = HELP_FORMAT_MAN;
+static struct option builtin_help_options[] = {
+	OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
+	OPT_SET_INT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
+	OPT_SET_INT('w', "web", &help_format, "show manual in web browser",
+			HELP_FORMAT_WEB),
+	OPT_SET_INT('i', "info", &help_format, "show info page",
+			HELP_FORMAT_INFO),
+};
+
+static const char * const builtin_help_usage[] = {
+	"git-help [--all] [--man|--web|--info] [command]",
+	NULL
+};
+
+static enum help_format parse_help_format(const char *format)
 {
-	if (!format) {
-		help_format = man_format;
-		return;
-	}
-	if (!strcmp(format, "man")) {
-		help_format = man_format;
-		return;
-	}
-	if (!strcmp(format, "info")) {
-		help_format = info_format;
-		return;
-	}
-	if (!strcmp(format, "web") || !strcmp(format, "html")) {
-		help_format = web_format;
-		return;
-	}
+	if (!strcmp(format, "man"))
+		return HELP_FORMAT_MAN;
+	if (!strcmp(format, "info"))
+		return HELP_FORMAT_INFO;
+	if (!strcmp(format, "web") || !strcmp(format, "html"))
+		return HELP_FORMAT_WEB;
 	die("unrecognized help format '%s'", format);
 }
 
 static int git_help_config(const char *var, const char *value)
 {
-	if (!strcmp(var, "help.format"))
-		return git_config_string(&help_default_format, var, value);
+	if (!strcmp(var, "help.format")) {
+		if (!value)
+			return config_error_nonbool(var);
+		help_format = parse_help_format(value);
+		return 0;
+	}
 	return git_default_config(var, value);
 }
 

@@ -362,50 +371,36 @@ int cmd_version(int argc, const char **argv, const char *prefix)
 
 int cmd_help(int argc, const char **argv, const char *prefix)
 {
-	const char *help_cmd = argv[1];
+	int nongit;
 
-	if (argc < 2) {
-		printf("usage: %s\n\n", git_usage_string);
-		list_common_cmds_help();
-		exit(0);
-	}
+	setup_git_directory_gently(&nongit);
+	git_config(git_help_config);
 
-	if (!strcmp(help_cmd, "--all") || !strcmp(help_cmd, "-a")) {
+	argc = parse_options(argc, argv, builtin_help_options,
+			builtin_help_usage, 0);
+
+	if (show_all) {
 		printf("usage: %s\n\n", git_usage_string);
 		list_commands();
+		return 0;
 	}
 
-	else if (!strcmp(help_cmd, "--web") || !strcmp(help_cmd, "-w")) {
-		show_html_page(argc > 2 ? argv[2] : NULL);
-	}
-
-	else if (!strcmp(help_cmd, "--info") || !strcmp(help_cmd, "-i")) {
-		show_info_page(argc > 2 ? argv[2] : NULL);
-	}
-
-	else if (!strcmp(help_cmd, "--man") || !strcmp(help_cmd, "-m")) {
-		show_man_page(argc > 2 ? argv[2] : NULL);
+	if (!argv[0]) {
+		printf("usage: %s\n\n", git_usage_string);
+		list_common_cmds_help();
+		return 0;
 	}
 
-	else {
-		int nongit;
-
-		setup_git_directory_gently(&nongit);
-		git_config(git_help_config);
-		if (help_default_format)
-			parse_help_format(help_default_format);
-
-		switch (help_format) {
-		case man_format:
-			show_man_page(help_cmd);
-			break;
-		case info_format:
-			show_info_page(help_cmd);
-			break;
-		case web_format:
-			show_html_page(help_cmd);
-			break;
-		}
+	switch (help_format) {
+	case HELP_FORMAT_MAN:
+		show_man_page(argv[0]);
+		break;
+	case HELP_FORMAT_INFO:
+		show_info_page(argv[0]);
+		break;
+	case HELP_FORMAT_WEB:
+		show_html_page(argv[0]);
+		break;
 	}
 
 	return 0;

new file mode 100644
index 0000000..116cac8
@@ -0,0 +1,22 @@
+#include "cache.h"
+
+static const char *alias_key;
+static char *alias_val;
+static int alias_lookup_cb(const char *k, const char *v)
+{
+	if (!prefixcmp(k, "alias.") && !strcmp(k+6, alias_key)) {
+		if (!v)
+			return config_error_nonbool(k);
+		alias_val = xstrdup(v);
+		return 0;
+	}
+	return 0;
+}
+
+char *alias_lookup(const char *alias)
+{
+	alias_key = alias;
+	alias_val = NULL;
+	git_config(alias_lookup_cb);
+	return alias_val;
+}

index fa5a9e5..1e9c937 100644
@@ -765,4 +765,6 @@ int pathspec_match(const char **spec, char *matched, const char *filename, int s
 int report_path_error(const char *ps_matched, const char **pathspec, int prefix_offset);
 void overlay_tree_on_cache(const char *tree_name, const char *prefix);
 
+char *alias_lookup(const char *alias);
+
 #endif /* CACHE_H */

index 0cb8688..8f08b12 100644
@@ -87,19 +87,6 @@ static int handle_options(const char*** argv, int* argc, int* envchanged)
 	return handled;
 }
 
-static const char *alias_command;
-static char *alias_string;
-
-static int git_alias_config(const char *var, const char *value)
-{
-	if (!prefixcmp(var, "alias.") && !strcmp(var + 6, alias_command)) {
-		if (!value)
-			return config_error_nonbool(var);
-		alias_string = xstrdup(value);
-	}
-	return 0;
-}
-
 static int split_cmdline(char *cmdline, const char ***argv)
 {
 	int src, dst, count = 0, size = 16;

@@ -159,11 +146,13 @@ static int handle_alias(int *argcp, const char ***argv)
 	const char *subdir;
 	int count, option_count;
 	const char** new_argv;
+	const char *alias_command;
+	char *alias_string;
 
 	subdir = setup_git_directory_gently(&nongit);
 
 	alias_command = (*argv)[0];
-	git_config(git_alias_config);
+	alias_string = alias_lookup(alias_command);
 	if (alias_string) {
 		if (alias_string[0] == '!') {
 			if (*argcp > 1) {

index 5feb849..e57a50e 100644
@@ -210,7 +210,7 @@ static unsigned int list_commands_in_dir(struct cmdnames *cmds,
 	return longest;
 }
 
-static void list_commands(void)
+static unsigned int load_command_list(void)
 {
 	unsigned int longest = 0;
 	unsigned int len;

@@ -250,6 +250,14 @@ static void list_commands(void)
 	uniq(&other_cmds);
 	exclude_cmds(&other_cmds, &main_cmds);
 
+	return longest;
+}
+
+static void list_commands(void)
+{
+	unsigned int longest = load_command_list();
+	const char *exec_path = git_exec_path();
+
 	if (main_cmds.cnt) {
 		printf("available git commands in '%s'\n", exec_path);
 		printf("----------------------------");

@@ -284,6 +292,22 @@ void list_common_cmds_help(void)
 	}
 }
 
+static int is_in_cmdlist(struct cmdnames *c, const char *s)
+{
+	int i;
+	for (i = 0; i < c->cnt; i++)
+		if (!strcmp(s, c->names[i]->name))
+			return 1;
+	return 0;
+}
+
+static int is_git_command(const char *s)
+{
+	load_command_list();
+	return is_in_cmdlist(&main_cmds, s) ||
+		is_in_cmdlist(&other_cmds, s);
+}
+
 static const char *cmd_to_page(const char *git_cmd)
 {
 	if (!git_cmd)

@@ -372,6 +396,7 @@ int cmd_version(int argc, const char **argv, const char *prefix)
 int cmd_help(int argc, const char **argv, const char *prefix)
 {
 	int nongit;
+	const char *alias;
 
 	setup_git_directory_gently(&nongit);
 	git_config(git_help_config);

@@ -391,6 +416,12 @@ int cmd_help(int argc, const char **argv, const char *prefix)
 		return 0;
 	}
 
+	alias = alias_lookup(argv[0]);
+	if (alias && !is_git_command(argv[0])) {
+		printf("`git %s' is aliased to `%s'\n", argv[0], alias);
+		return 0;
+	}
+
 	switch (help_format) {
 	case HELP_FORMAT_MAN:
 		show_man_page(argv[0]);