Sync with 2.17.3

* maint-2.17: (32 commits)
  Git 2.17.3
  Git 2.16.6
  test-drop-caches: use `has_dos_drive_prefix()`
  Git 2.15.4
  Git 2.14.6
  mingw: handle `subst`-ed "DOS drives"
  mingw: refuse to access paths with trailing spaces or periods
  mingw: refuse to access paths with illegal characters
  unpack-trees: let merged_entry() pass through do_add_entry()'s errors
  quote-stress-test: offer to test quoting arguments for MSYS2 sh
  t6130/t9350: prepare for stringent Win32 path validation
  quote-stress-test: allow skipping some trials
  quote-stress-test: accept arguments to test via the command-line
  tests: add a helper to stress test argument quoting
  mingw: fix quoting of arguments
  Disallow dubiously-nested submodule git directories
  protect_ntfs: turn on NTFS protection by default
  path: also guard `.gitmodules` against NTFS Alternate Data Streams
  is_ntfs_dotgit(): speed it up
  mingw: disallow backslash characters in tree objects' file names
  ...

1 files changed, 113 insertions, 0 deletions

diff --git a/t/helper/test-path-utils.c b/t/helper/test-path-utils.c
index ae091d9b3e..e737a941d3 100644
--- a/t/helper/test-path-utils.c
+++ b/t/helper/test-path-utils.c
@@ -177,6 +177,99 @@ static int is_dotgitmodules(const char *path)
 	return is_hfs_dotgitmodules(path) || is_ntfs_dotgitmodules(path);
 }
 
+/*
+ * A very simple, reproducible pseudo-random generator. Copied from
+ * `test-genrandom.c`.
+ */
+static uint64_t my_random_value = 1234;
+
+static uint64_t my_random(void)
+{
+	my_random_value = my_random_value * 1103515245 + 12345;
+	return my_random_value;
+}
+
+/*
+ * A fast approximation of the square root, without requiring math.h.
+ *
+ * It uses Newton's method to approximate the solution of 0 = x^2 - value.
+ */
+static double my_sqrt(double value)
+{
+	const double epsilon = 1e-6;
+	double x = value;
+
+	if (value == 0)
+		return 0;
+
+	for (;;) {
+		double delta = (value / x - x) / 2;
+		if (delta < epsilon && delta > -epsilon)
+			return x + delta;
+		x += delta;
+	}
+}
+
+static int protect_ntfs_hfs_benchmark(int argc, const char **argv)
+{
+	size_t i, j, nr, min_len = 3, max_len = 20;
+	char **names;
+	int repetitions = 15, file_mode = 0100644;
+	uint64_t begin, end;
+	double m[3][2], v[3][2];
+	uint64_t cumul;
+	double cumul2;
+
+	if (argc > 1 && !strcmp(argv[1], "--with-symlink-mode")) {
+		file_mode = 0120000;
+		argc--;
+		argv++;
+	}
+
+	nr = argc > 1 ? strtoul(argv[1], NULL, 0) : 1000000;
+	ALLOC_ARRAY(names, nr);
+
+	if (argc > 2) {
+		min_len = strtoul(argv[2], NULL, 0);
+		if (argc > 3)
+			max_len = strtoul(argv[3], NULL, 0);
+		if (min_len > max_len)
+			die("min_len > max_len");
+	}
+
+	for (i = 0; i < nr; i++) {
+		size_t len = min_len + (my_random() % (max_len + 1 - min_len));
+
+		names[i] = xmallocz(len);
+		while (len > 0)
+			names[i][--len] = (char)(' ' + (my_random() % ('\x7f' - ' ')));
+	}
+
+	for (protect_ntfs = 0; protect_ntfs < 2; protect_ntfs++)
+		for (protect_hfs = 0; protect_hfs < 2; protect_hfs++) {
+			cumul = 0;
+			cumul2 = 0;
+			for (i = 0; i < repetitions; i++) {
+				begin = getnanotime();
+				for (j = 0; j < nr; j++)
+					verify_path(names[j], file_mode);
+				end = getnanotime();
+				printf("protect_ntfs = %d, protect_hfs = %d: %lfms\n", protect_ntfs, protect_hfs, (end-begin) / (double)1e6);
+				cumul += end - begin;
+				cumul2 += (end - begin) * (end - begin);
+			}
+			m[protect_ntfs][protect_hfs] = cumul / (double)repetitions;
+			v[protect_ntfs][protect_hfs] = my_sqrt(cumul2 / (double)repetitions - m[protect_ntfs][protect_hfs] * m[protect_ntfs][protect_hfs]);
+			printf("mean: %lfms, stddev: %lfms\n", m[protect_ntfs][protect_hfs] / (double)1e6, v[protect_ntfs][protect_hfs] / (double)1e6);
+		}
+
+	for (protect_ntfs = 0; protect_ntfs < 2; protect_ntfs++)
+		for (protect_hfs = 0; protect_hfs < 2; protect_hfs++)
+			printf("ntfs=%d/hfs=%d: %lf%% slower\n", protect_ntfs, protect_hfs, (m[protect_ntfs][protect_hfs] - m[0][0]) * 100 / m[0][0]);
+
+	return 0;
+}
+
 int cmd__path_utils(int argc, const char **argv)
 {
 	if (argc == 3 && !strcmp(argv[1], "normalize_path_copy")) {
@@ -291,6 +384,26 @@ int cmd__path_utils(int argc, const char **argv)
 		return !!res;
 	}
 
+	if (argc > 1 && !strcmp(argv[1], "protect_ntfs_hfs"))
+		return !!protect_ntfs_hfs_benchmark(argc - 1, argv + 1);
+
+	if (argc > 1 && !strcmp(argv[1], "is_valid_path")) {
+		int res = 0, expect = 1, i;
+
+		for (i = 2; i < argc; i++)
+			if (!strcmp("--not", argv[i]))
+				expect = 0;
+			else if (expect != is_valid_path(argv[i]))
+				res = error("'%s' is%s a valid path",
+					    argv[i], expect ? " not" : "");
+			else
+				fprintf(stderr,
+					"'%s' is%s a valid path\n",
+					argv[i], expect ? "" : " not");
+
+		return !!res;
+	}
+
 	fprintf(stderr, "%s: unknown function name: %s\n", argv[0],
 		argv[1] ? argv[1] : "(there was none)");
 	return 1;