diff: parse separate options like -S foo

Change the option parsing logic in revision.c to accept separate forms
like `-S foo' in addition to `-Sfoo'. The rest of git already accepted
this form, but revision.c still used its own option parsing.

Short options affected are -S<string>, -l<num> and -O<orderfile>, for
which an empty string wouldn't make sense, hence -<option> <arg> isn't
ambiguous.

This patch does not handle --stat-name-width and --stat-width, which are
special-cases where diff_long_opt do not apply. They are handled in a
separate patch to ease review.

Original patch by Matthieu Moy, plus refactoring by Jonathan Nieder.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.c

@@ -2990,9 +2990,50 @@ static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *va
 
 static int diff_scoreopt_parse(const char *opt);
 
+static inline int short_opt(char opt, const char **argv,
+			    const char **optarg)
+{
+	const char *arg = argv[0];
+	if (arg[0] != '-' || arg[1] != opt)
+		return 0;
+	if (arg[2] != '\0') {
+		*optarg = arg + 2;
+		return 1;
+	}
+	if (!argv[1])
+		die("Option '%c' requires a value", opt);
+	*optarg = argv[1];
+	return 2;
+}
+
+int parse_long_opt(const char *opt, const char **argv,
+		   const char **optarg)
+{
+	const char *arg = argv[0];
+	if (arg[0] != '-' || arg[1] != '-')
+		return 0;
+	arg += strlen("--");
+	if (prefixcmp(arg, opt))
+		return 0;
+	arg += strlen(opt);
+	if (*arg == '=') { /* sticked form: --option=value */
+		*optarg = arg + 1;
+		return 1;
+	}
+	if (*arg != '\0')
+		return 0;
+	/* separate form: --option value */
+	if (!argv[1])
+		die("Option '--%s' requires a value", opt);
+	*optarg = argv[1];
+	return 2;
+}
+
 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 {
 	const char *arg = av[0];
+	const char *optarg;
+	int argcount;
 
 	/* Output format options */
 	if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
@@ -3149,10 +3190,11 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 		else
 			die("bad --word-diff argument: %s", type);
 	}
-	else if (!prefixcmp(arg, "--word-diff-regex=")) {
+	else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
 		if (options->word_diff == DIFF_WORDS_NONE)
 			options->word_diff = DIFF_WORDS_PLAIN;
-		options->word_regex = arg + 18;
+		options->word_regex = optarg;
+		return argcount;
 	}
 	else if (!strcmp(arg, "--exit-code"))
 		DIFF_OPT_SET(options, EXIT_WITH_STATUS);
@@ -3180,18 +3222,26 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 	/* misc options */
 	else if (!strcmp(arg, "-z"))
 		options->line_termination = 0;
-	else if (!prefixcmp(arg, "-l"))
-		options->rename_limit = strtoul(arg+2, NULL, 10);
-	else if (!prefixcmp(arg, "-S"))
-		options->pickaxe = arg + 2;
+	else if ((argcount = short_opt('l', av, &optarg))) {
+		options->rename_limit = strtoul(optarg, NULL, 10);
+		return argcount;
+	}
+	else if ((argcount = short_opt('S', av, &optarg))) {
+		options->pickaxe = optarg;
+		return argcount;
+	}
 	else if (!strcmp(arg, "--pickaxe-all"))
 		options->pickaxe_opts = DIFF_PICKAXE_ALL;
 	else if (!strcmp(arg, "--pickaxe-regex"))
 		options->pickaxe_opts = DIFF_PICKAXE_REGEX;
-	else if (!prefixcmp(arg, "-O"))
-		options->orderfile = arg + 2;
-	else if (!prefixcmp(arg, "--diff-filter="))
-		options->filter = arg + 14;
+	else if ((argcount = short_opt('O', av, &optarg))) {
+		options->orderfile = optarg;
+		return argcount;
+	}
+	else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
+		options->filter = optarg;
+		return argcount;
+	}
 	else if (!strcmp(arg, "--abbrev"))
 		options->abbrev = DEFAULT_ABBREV;
 	else if (!prefixcmp(arg, "--abbrev=")) {
@@ -3201,20 +3251,25 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 		else if (40 < options->abbrev)
 			options->abbrev = 40;
 	}
-	else if (!prefixcmp(arg, "--src-prefix="))
-		options->a_prefix = arg + 13;
-	else if (!prefixcmp(arg, "--dst-prefix="))
-		options->b_prefix = arg + 13;
+	else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
+		options->a_prefix = optarg;
+		return argcount;
+	}
+	else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
+		options->b_prefix = optarg;
+		return argcount;
+	}
 	else if (!strcmp(arg, "--no-prefix"))
 		options->a_prefix = options->b_prefix = "";
 	else if (opt_arg(arg, '\0', "inter-hunk-context",
 			 &options->interhunkcontext))
 		;
-	else if (!prefixcmp(arg, "--output=")) {
-		options->file = fopen(arg + strlen("--output="), "w");
+	else if ((argcount = parse_long_opt("output", av, &optarg))) {
+		options->file = fopen(optarg, "w");
 		if (!options->file)
 			die_errno("Could not open '%s'", arg + strlen("--output="));
 		options->close_file = 1;
+		return argcount;
 	} else
 		return 0;
 	return 1;

diff.h

@@ -214,6 +214,13 @@ extern void diff_unmerge(struct diff_options *,
 #define DIFF_SETUP_USE_CACHE		2
 #define DIFF_SETUP_USE_SIZE_CACHE	4
 
+/*
+ * Poor man's alternative to parse-option, to allow both sticked form
+ * (--option=value) and separate form (--option value).
+ */
+extern int parse_long_opt(const char *opt, const char **argv,
+			 const char **optarg);
+
 extern int git_diff_basic_config(const char *var, const char *value, void *cb);
 extern int git_diff_ui_config(const char *var, const char *value, void *cb);
 extern int diff_use_color_default;

t/t4013-diff-various.sh

@@ -208,6 +208,7 @@ log -p --first-parent master
 log -m -p --first-parent master
 log -m -p master
 log -SF master
+log -S F master
 log -SF -p master
 log --decorate --all
 log --decorate=full --all
@@ -282,4 +283,8 @@ diff master master^ side
 diff --dirstat master~1 master~2
 EOF
 
+test_expect_success 'log -S requires an argument' '
+	test_must_fail git log -S
+'
+
 test_done

t/t4013/diff.log_-S_F_master

@@ -0,0 +1,7 @@
+$ git log -S F master
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+$

t/t4202-log.sh

@@ -100,13 +100,11 @@ test_expect_success 'oneline' '
 
 test_expect_success 'diff-filter=A' '
 
-	actual=$(git log --pretty="format:%s" --diff-filter=A HEAD) &&
-	expect=$(echo fifth ; echo fourth ; echo third ; echo initial) &&
-	test "$actual" = "$expect" || {
-		echo Oops
-		echo "Actual: $actual"
-		false
-	}
+	git log --pretty="format:%s" --diff-filter=A HEAD > actual &&
+	git log --pretty="format:%s" --diff-filter A HEAD > actual-separate &&
+	printf "fifth\nfourth\nthird\ninitial" > expect &&
+	test_cmp expect actual &&
+	test_cmp expect actual-separate
 
 '