parse-options: deduplicate parse_options_usage() calls

Avoid long lines and repeating parse_options_usage() calls with their
duplicate parameters by providing labels with speaking names to jump to.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Jeff King <peff@peff.net>

parse-options.c

@@ -435,6 +435,7 @@ int parse_options_step(struct parse_opt_ctx_t *ctx,
 		       const char * const usagestr[])
 {
 	int internal_help = !(ctx->flags & PARSE_OPT_NO_INTERNAL_HELP);
+	int err = 0;
 
 	/* we must reset ->opt, unknown short option leave it dangling */
 	ctx->opt = NULL;
@@ -454,10 +455,10 @@ int parse_options_step(struct parse_opt_ctx_t *ctx,
 		if (arg[1] != '-') {
 			ctx->opt = arg + 1;
 			if (internal_help && *ctx->opt == 'h')
-				return parse_options_usage(ctx, usagestr, options, 0);
+				goto show_usage;
 			switch (parse_short_opt(ctx, options)) {
 			case -1:
-				return parse_options_usage(ctx, usagestr, options, 1);
+				goto show_usage_error;
 			case -2:
 				if (ctx->opt)
 					check_typos(arg + 1, options);
@@ -467,10 +468,10 @@ int parse_options_step(struct parse_opt_ctx_t *ctx,
 				check_typos(arg + 1, options);
 			while (ctx->opt) {
 				if (internal_help && *ctx->opt == 'h')
-					return parse_options_usage(ctx, usagestr, options, 0);
+					goto show_usage;
 				switch (parse_short_opt(ctx, options)) {
 				case -1:
-					return parse_options_usage(ctx, usagestr, options, 1);
+					goto show_usage_error;
 				case -2:
 					/* fake a short option thing to hide the fact that we may have
 					 * started to parse aggregated stuff
@@ -496,10 +497,10 @@ int parse_options_step(struct parse_opt_ctx_t *ctx,
 		if (internal_help && !strcmp(arg + 2, "help-all"))
 			return usage_with_options_internal(ctx, usagestr, options, 1, 0);
 		if (internal_help && !strcmp(arg + 2, "help"))
-			return parse_options_usage(ctx, usagestr, options, 0);
+			goto show_usage;
 		switch (parse_long_opt(ctx, arg + 2, options)) {
 		case -1:
-			return parse_options_usage(ctx, usagestr, options, 1);
+			goto show_usage_error;
 		case -2:
 			goto unknown;
 		}
@@ -511,6 +512,11 @@ int parse_options_step(struct parse_opt_ctx_t *ctx,
 		ctx->opt = NULL;
 	}
 	return PARSE_OPT_DONE;
+
+ show_usage_error:
+	err = 1;
+ show_usage:
+	return parse_options_usage(ctx, usagestr, options, err);
 }
 
 int parse_options_end(struct parse_opt_ctx_t *ctx)