revision.c: use skip_prefix() in handle_revision_opt()

Instead of starts_with() and a bunch of magic numbers.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: szeder

revision.c

@@ -1690,8 +1690,8 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->max_count = atoi(argv[1]);
 		revs->no_walk = 0;
 		return 2;
-	} else if (starts_with(arg, "-n")) {
-		revs->max_count = atoi(arg + 2);
+	} else if (skip_prefix(arg, "-n", &optarg)) {
+		revs->max_count = atoi(optarg);
 		revs->no_walk = 0;
 	} else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
 		revs->max_age = atoi(optarg);
@@ -1772,12 +1772,12 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->min_parents = 2;
 	} else if (!strcmp(arg, "--no-merges")) {
 		revs->max_parents = 1;
-	} else if (starts_with(arg, "--min-parents=")) {
-		revs->min_parents = atoi(arg+14);
+	} else if (skip_prefix(arg, "--min-parents=", &optarg)) {
+		revs->min_parents = atoi(optarg);
 	} else if (!strcmp(arg, "--no-min-parents")) {
 		revs->min_parents = 0;
-	} else if (starts_with(arg, "--max-parents=")) {
-		revs->max_parents = atoi(arg+14);
+	} else if (skip_prefix(arg, "--max-parents=", &optarg)) {
+		revs->max_parents = atoi(optarg);
 	} else if (!strcmp(arg, "--no-max-parents")) {
 		revs->max_parents = -1;
 	} else if (!strcmp(arg, "--boundary")) {
@@ -1859,14 +1859,15 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->verbose_header = 1;
 		revs->pretty_given = 1;
 		get_commit_format(NULL, revs);
-	} else if (starts_with(arg, "--pretty=") || starts_with(arg, "--format=")) {
+	} else if (skip_prefix(arg, "--pretty=", &optarg) ||
+		   skip_prefix(arg, "--format=", &optarg)) {
 		/*
 		 * Detached form ("--pretty X" as opposed to "--pretty=X")
 		 * not allowed, since the argument is optional.
 		 */
 		revs->verbose_header = 1;
 		revs->pretty_given = 1;
-		get_commit_format(arg+9, revs);
+		get_commit_format(optarg, revs);
 	} else if (!strcmp(arg, "--expand-tabs")) {
 		revs->expand_tabs_in_log = 8;
 	} else if (!strcmp(arg, "--no-expand-tabs")) {
@@ -1884,26 +1885,23 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->show_signature = 1;
 	} else if (!strcmp(arg, "--no-show-signature")) {
 		revs->show_signature = 0;
-	} else if (!strcmp(arg, "--show-linear-break") ||
-		   starts_with(arg, "--show-linear-break=")) {
-		if (starts_with(arg, "--show-linear-break="))
-			revs->break_bar = xstrdup(arg + 20);
-		else
-			revs->break_bar = "                    ..........";
+	} else if (!strcmp(arg, "--show-linear-break")) {
+		revs->break_bar = "                    ..........";
+		revs->track_linear = 1;
+		revs->track_first_time = 1;
+	} else if (skip_prefix(arg, "--show-linear-break=", &optarg)) {
+		revs->break_bar = xstrdup(optarg);
 		revs->track_linear = 1;
 		revs->track_first_time = 1;
-	} else if (starts_with(arg, "--show-notes=") ||
-		   starts_with(arg, "--notes=")) {
+	} else if (skip_prefix(arg, "--show-notes=", &optarg) ||
+		   skip_prefix(arg, "--notes=", &optarg)) {
 		struct strbuf buf = STRBUF_INIT;
 		revs->show_notes = 1;
 		revs->show_notes_given = 1;
-		if (starts_with(arg, "--show-notes")) {
-			if (revs->notes_opt.use_default_notes < 0)
-				revs->notes_opt.use_default_notes = 1;
-			strbuf_addstr(&buf, arg+13);
-		}
-		else
-			strbuf_addstr(&buf, arg+8);
+		if (starts_with(arg, "--show-notes=") &&
+		    revs->notes_opt.use_default_notes < 0)
+			revs->notes_opt.use_default_notes = 1;
+		strbuf_addstr(&buf, optarg);
 		expand_notes_ref(&buf);
 		string_list_append(&revs->notes_opt.extra_notes_refs,
 				   strbuf_detach(&buf, NULL));
@@ -1940,8 +1938,8 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->abbrev = 0;
 	} else if (!strcmp(arg, "--abbrev")) {
 		revs->abbrev = DEFAULT_ABBREV;
-	} else if (starts_with(arg, "--abbrev=")) {
-		revs->abbrev = strtoul(arg + 9, NULL, 10);
+	} else if (skip_prefix(arg, "--abbrev=", &optarg)) {
+		revs->abbrev = strtoul(optarg, NULL, 10);
 		if (revs->abbrev < MINIMUM_ABBREV)
 			revs->abbrev = MINIMUM_ABBREV;
 		else if (revs->abbrev > 40)