Allow specifying --dirstat cut-off percentage as a floating point number

Only the first digit after the decimal point is kept, as the dirstat
calculations all happen in permille.

Selftests verifying floating-point percentage input has been added.

Improved-by: Junio C Hamano <gitster@pobox.com>
Improved-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.c

@@ -31,7 +31,7 @@ static const char *external_diff_cmd_cfg;
 int diff_auto_refresh_index = 1;
 static int diff_mnemonic_prefix;
 static int diff_no_prefix;
-static int diff_dirstat_percent_default = 3;
+static int diff_dirstat_permille_default = 30;
 static struct diff_options default_diff_options;
 
 static char diff_colors[][COLOR_MAXLEN] = {
@@ -85,8 +85,15 @@ static int parse_dirstat_params(struct diff_options *options, const char *params
 			DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 		} else if (isdigit(*p)) {
 			char *end;
-			options->dirstat_percent = strtoul(p, &end, 10);
+			options->dirstat_permille = strtoul(p, &end, 10) * 10;
 			p = end;
+			if (*p == '.' && isdigit(*++p)) {
+				/* only use first digit */
+				options->dirstat_permille += *p - '0';
+				/* .. and ignore any further digits */
+				while (isdigit(*++p))
+					; /* nothing */
+			}
 		} else
 			return error("Unknown --dirstat parameter '%s'", p);
 
@@ -182,9 +189,9 @@ int git_diff_basic_config(const char *var, const char *value, void *cb)
 	}
 
 	if (!strcmp(var, "diff.dirstat")) {
-		default_diff_options.dirstat_percent = diff_dirstat_percent_default;
+		default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 		(void) parse_dirstat_params(&default_diff_options, value);
-		diff_dirstat_percent_default = default_diff_options.dirstat_percent;
+		diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 		return 0;
 	}
 
@@ -1498,7 +1505,7 @@ struct dirstat_file {
 
 struct dirstat_dir {
 	struct dirstat_file *files;
-	int alloc, nr, percent, cumulative;
+	int alloc, nr, permille, cumulative;
 };
 
 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
@@ -1547,10 +1554,9 @@ static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
 	if (baselen && sources != 1) {
 		if (this_dir) {
 			int permille = this_dir * 1000 / changed;
-			int percent = permille / 10;
+			if (permille >= dir->permille) {
-			if (percent >= dir->percent) {
 				fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
-					percent, permille % 10, baselen, base);
+					permille / 10, permille % 10, baselen, base);
 				if (!dir->cumulative)
 					return 0;
 			}
@@ -1576,7 +1582,7 @@ static void show_dirstat(struct diff_options *options)
 	dir.files = NULL;
 	dir.alloc = 0;
 	dir.nr = 0;
-	dir.percent = options->dirstat_percent;
+	dir.permille = options->dirstat_permille;
 	dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
 
 	changed = 0;
@@ -2934,7 +2940,7 @@ void diff_setup(struct diff_options *options)
 	options->line_termination = '\n';
 	options->break_opt = -1;
 	options->rename_limit = -1;
-	options->dirstat_percent = diff_dirstat_percent_default;
+	options->dirstat_permille = diff_dirstat_permille_default;
 	options->context = 3;
 
 	options->change = diff_change;

diff.h

@@ -114,7 +114,7 @@ struct diff_options {
 	int needed_rename_limit;
 	int degraded_cc_to_c;
 	int show_rename_progress;
-	int dirstat_percent;
+	int dirstat_permille;
 	int setup;
 	int abbrev;
 	const char *prefix;

t/t4047-diff-dirstat.sh

@@ -775,4 +775,68 @@ test_expect_success 'diff.dirstat=10,cumulative,files' '
 	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
 '
 
+cat <<EOF >expect_diff_dirstat
+  27.2% dst/copy/
+  27.2% dst/move/
+  54.5% dst/
+  27.2% src/move/
+EOF
+
+cat <<EOF >expect_diff_dirstat_M
+  42.8% dst/copy/
+  28.5% dst/move/
+  71.4% dst/
+EOF
+
+cat <<EOF >expect_diff_dirstat_CC
+  33.3% dst/copy/
+  33.3% dst/move/
+  66.6% dst/
+EOF
+
+test_expect_success '--dirstat=files,cumulative,16.7' '
+	git diff --dirstat=files,cumulative,16.7 HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git diff --dirstat=files,cumulative,16.7 -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git diff --dirstat=files,cumulative,16.7 -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+test_expect_success 'diff.dirstat=16.7,cumulative,files' '
+	git -c diff.dirstat=16.7,cumulative,files diff --dirstat HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git -c diff.dirstat=16.7,cumulative,files diff --dirstat -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git -c diff.dirstat=16.7,cumulative,files diff --dirstat -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+test_expect_success 'diff.dirstat=16.70,cumulative,files' '
+	git -c diff.dirstat=16.70,cumulative,files diff --dirstat HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git -c diff.dirstat=16.70,cumulative,files diff --dirstat -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git -c diff.dirstat=16.70,cumulative,files diff --dirstat -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+test_expect_success '--dirstat=files,cumulative,27.2' '
+	git diff --dirstat=files,cumulative,27.2 HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git diff --dirstat=files,cumulative,27.2 -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git diff --dirstat=files,cumulative,27.2 -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+test_expect_success '--dirstat=files,cumulative,27.09' '
+	git diff --dirstat=files,cumulative,27.09 HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git diff --dirstat=files,cumulative,27.09 -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git diff --dirstat=files,cumulative,27.09 -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
 test_done