Merge pull request #4192 from libgit2/ethomson/win32_posix

Refactor some of the win32 POSIX emulation

9 files changed, 407 insertions, 111 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0ae75e156..bcf8160c1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,10 @@ v0.25 + 1
 
 ### API additions
 
+* You can now set the default share mode on Windows for opening files using
+  `GIT_OPT_SET_WINDOWS_SHAREMODE` option with `git_libgit2_opts()`.
+  You can query the current share mode with `GIT_OPT_GET_WINDOWS_SHAREMODE`.
+
 ### API removals
 
 ### Breaking API changes
diff --git a/include/git2/common.h b/include/git2/common.h
index c909f86ca..6d2092028 100644
--- a/include/git2/common.h
+++ b/include/git2/common.h
@@ -180,6 +180,8 @@ typedef enum {
 	GIT_OPT_GET_USER_AGENT,
 	GIT_OPT_ENABLE_OFS_DELTA,
 	GIT_OPT_ENABLE_SYNCHRONOUS_OBJECT_CREATION,
+	GIT_OPT_GET_WINDOWS_SHAREMODE,
+	GIT_OPT_SET_WINDOWS_SHAREMODE,
 } git_libgit2_opt_t;
 
 /**
@@ -284,6 +286,17 @@ typedef enum {
  *		> - `user_agent` is the value that will be delivered as the
  *		>   User-Agent header on HTTP requests.
  *
+ *	* opts(GIT_OPT_SET_WINDOWS_SHAREMODE, unsigned long value)
+ *
+ *		> Set the share mode used when opening files on Windows.
+ *		> For more information, see the documentation for CreateFile.
+ *		> The default is: FILE_SHARE_READ | FILE_SHARE_WRITE.  This is
+ *		> ignored and unused on non-Windows platforms.
+ *
+ *	* opts(GIT_OPT_GET_WINDOWS_SHAREMODE, unsigned long *value)
+ *
+ *		> Get the share mode used when opening files on Windows.
+ *
  *	* opts(GIT_OPT_ENABLE_STRICT_OBJECT_CREATION, int enabled)
  *
  *		> Enable strict input validation when creating new objects
diff --git a/include/git2/errors.h b/include/git2/errors.h
index 3b746b758..71bff0f9d 100644
--- a/include/git2/errors.h
+++ b/include/git2/errors.h
@@ -53,6 +53,7 @@ typedef enum {
 
 	GIT_PASSTHROUGH     = -30,	/**< Internal only */
 	GIT_ITEROVER        = -31,	/**< Signals end of iteration with iterator */
+	GIT_RETRY           = -32,	/**< Internal only */
 } git_error_code;
 
 /**
diff --git a/src/posix.h b/src/posix.h
index bd5a98e26..d26371bca 100644
--- a/src/posix.h
+++ b/src/posix.h
@@ -24,6 +24,10 @@
 #define _S_IFLNK S_IFLNK
 #endif
 
+#ifndef S_IWUSR
+#define S_IWUSR 00200
+#endif
+
 #ifndef S_IXUSR
 #define S_IXUSR 00100
 #endif
diff --git a/src/settings.c b/src/settings.c
index 24e549ec1..07ac16a8f 100644
--- a/src/settings.c
+++ b/src/settings.c
@@ -231,6 +231,18 @@ int git_libgit2_opts(int key, ...)
 		git_object__synchronous_writing = (va_arg(ap, int) != 0);
 		break;
 
+	case GIT_OPT_GET_WINDOWS_SHAREMODE:
+#ifdef GIT_WIN32
+		*(va_arg(ap, unsigned long *)) = git_win32__createfile_sharemode;
+#endif
+		break;
+
+	case GIT_OPT_SET_WINDOWS_SHAREMODE:
+#ifdef GIT_WIN32
+		git_win32__createfile_sharemode = va_arg(ap, unsigned long);
+#endif
+		break;
+
 	default:
 		giterr_set(GITERR_INVALID, "invalid option key");
 		error = -1;
diff --git a/src/win32/posix.h b/src/win32/posix.h
index 73705fb2b..64769ecd3 100644
--- a/src/win32/posix.h
+++ b/src/win32/posix.h
@@ -14,6 +14,9 @@
 #include "utf-conv.h"
 #include "dir.h"
 
+extern unsigned long git_win32__createfile_sharemode;
+extern int git_win32__retries;
+
 typedef SOCKET GIT_SOCKET;
 
 #define p_lseek(f,n,w) _lseeki64(f, n, w)
diff --git a/src/win32/posix_w32.c b/src/win32/posix_w32.c
index 5172627b0..e4fe4142c 100644
--- a/src/win32/posix_w32.c
+++ b/src/win32/posix_w32.c
@@ -26,15 +26,6 @@
 #define IO_REPARSE_TAG_SYMLINK (0xA000000CL)
 #endif
 
-/* Options which we always provide to _wopen.
- *
- * _O_BINARY - Raw access; no translation of CR or LF characters
- * _O_NOINHERIT - Do not mark the created handle as inheritable by child processes.
- *    The Windows default is 'not inheritable', but the CRT's default (following
- *    POSIX convention) is 'inheritable'. We have no desire for our handles to be
- *    inheritable on Windows, so specify the flag to get default behavior back. */
-#define STANDARD_OPEN_FLAGS (_O_BINARY | _O_NOINHERIT)
-
 /* Allowable mode bits on Win32.  Using mode bits that are not supported on
  * Win32 (eg S_IRWXU) is generally ignored, but Wine warns loudly about it
  * so we simply remove them.
@@ -44,6 +35,164 @@
 /* GetFinalPathNameByHandleW signature */
 typedef DWORD(WINAPI *PFGetFinalPathNameByHandleW)(HANDLE, LPWSTR, DWORD, DWORD);
 
+unsigned long git_win32__createfile_sharemode =
+ FILE_SHARE_READ | FILE_SHARE_WRITE;
+int git_win32__retries = 10;
+
+GIT_INLINE(void) set_errno(void)
+{
+	switch (GetLastError()) {
+	case ERROR_FILE_NOT_FOUND:
+	case ERROR_PATH_NOT_FOUND:
+	case ERROR_INVALID_DRIVE:
+	case ERROR_NO_MORE_FILES:
+	case ERROR_BAD_NETPATH:
+	case ERROR_BAD_NET_NAME:
+	case ERROR_BAD_PATHNAME:
+	case ERROR_FILENAME_EXCED_RANGE:
+		errno = ENOENT;
+		break;
+	case ERROR_BAD_ENVIRONMENT:
+		errno = E2BIG;
+		break;
+	case ERROR_BAD_FORMAT:
+	case ERROR_INVALID_STARTING_CODESEG:
+	case ERROR_INVALID_STACKSEG:
+	case ERROR_INVALID_MODULETYPE:
+	case ERROR_INVALID_EXE_SIGNATURE:
+	case ERROR_EXE_MARKED_INVALID:
+	case ERROR_BAD_EXE_FORMAT:
+	case ERROR_ITERATED_DATA_EXCEEDS_64k:
+	case ERROR_INVALID_MINALLOCSIZE:
+	case ERROR_DYNLINK_FROM_INVALID_RING:
+	case ERROR_IOPL_NOT_ENABLED:
+	case ERROR_INVALID_SEGDPL:
+	case ERROR_AUTODATASEG_EXCEEDS_64k:
+	case ERROR_RING2SEG_MUST_BE_MOVABLE:
+	case ERROR_RELOC_CHAIN_XEEDS_SEGLIM:
+	case ERROR_INFLOOP_IN_RELOC_CHAIN:
+		errno = ENOEXEC;
+		break;
+	case ERROR_INVALID_HANDLE:
+	case ERROR_INVALID_TARGET_HANDLE:
+	case ERROR_DIRECT_ACCESS_HANDLE:
+		errno = EBADF;
+		break;
+	case ERROR_WAIT_NO_CHILDREN:
+	case ERROR_CHILD_NOT_COMPLETE:
+		errno = ECHILD;
+		break;
+	case ERROR_NO_PROC_SLOTS:
+	case ERROR_MAX_THRDS_REACHED:
+	case ERROR_NESTING_NOT_ALLOWED:
+		errno = EAGAIN;
+		break;
+	case ERROR_ARENA_TRASHED:
+	case ERROR_NOT_ENOUGH_MEMORY:
+	case ERROR_INVALID_BLOCK:
+	case ERROR_NOT_ENOUGH_QUOTA:
+		errno = ENOMEM;
+		break;
+	case ERROR_ACCESS_DENIED:
+	case ERROR_CURRENT_DIRECTORY:
+	case ERROR_WRITE_PROTECT:
+	case ERROR_BAD_UNIT:
+	case ERROR_NOT_READY:
+	case ERROR_BAD_COMMAND:
+	case ERROR_CRC:
+	case ERROR_BAD_LENGTH:
+	case ERROR_SEEK:
+	case ERROR_NOT_DOS_DISK:
+	case ERROR_SECTOR_NOT_FOUND:
+	case ERROR_OUT_OF_PAPER:
+	case ERROR_WRITE_FAULT:
+	case ERROR_READ_FAULT:
+	case ERROR_GEN_FAILURE:
+	case ERROR_SHARING_VIOLATION:
+	case ERROR_LOCK_VIOLATION:
+	case ERROR_WRONG_DISK:
+	case ERROR_SHARING_BUFFER_EXCEEDED:
+	case ERROR_NETWORK_ACCESS_DENIED:
+	case ERROR_CANNOT_MAKE:
+	case ERROR_FAIL_I24:
+	case ERROR_DRIVE_LOCKED:
+	case ERROR_SEEK_ON_DEVICE:
+	case ERROR_NOT_LOCKED:
+	case ERROR_LOCK_FAILED:
+		errno = EACCES;
+		break;
+	case ERROR_FILE_EXISTS:
+	case ERROR_ALREADY_EXISTS:
+		errno = EEXIST;
+		break;
+	case ERROR_NOT_SAME_DEVICE:
+		errno = EXDEV;
+		break;
+	case ERROR_INVALID_FUNCTION:
+	case ERROR_INVALID_ACCESS:
+	case ERROR_INVALID_DATA:
+	case ERROR_INVALID_PARAMETER:
+	case ERROR_NEGATIVE_SEEK:
+		errno = EINVAL;
+		break;
+	case ERROR_TOO_MANY_OPEN_FILES:
+		errno = EMFILE;
+		break;
+	case ERROR_DISK_FULL:
+		errno = ENOSPC;
+		break;
+	case ERROR_BROKEN_PIPE:
+		errno = EPIPE;
+		break;
+	case ERROR_DIR_NOT_EMPTY:
+		errno = ENOTEMPTY;
+		break;
+	default:
+		errno = EINVAL;
+	}
+}
+
+GIT_INLINE(bool) last_error_retryable(void)
+{
+	int os_error = GetLastError();
+
+	return (os_error == ERROR_SHARING_VIOLATION ||
+		os_error == ERROR_ACCESS_DENIED);
+}
+
+#define do_with_retries(fn, remediation) \
+	do {                                                             \
+		int __tries, __ret;                                          \
+		for (__tries = 0; __tries < git_win32__retries; __tries++) { \
+			if (__tries && (__ret = (remediation)) != 0)             \
+				return __ret;                                        \
+			if ((__ret = (fn)) != GIT_RETRY)                         \
+				return __ret;                                        \
+			Sleep(5);                                                \
+		}                                                            \
+		return -1;                                                   \
+	} while (0)                                                      \
+
+static int ensure_writable(wchar_t *path)
+{
+	DWORD attrs;
+
+	if ((attrs = GetFileAttributesW(path)) == INVALID_FILE_ATTRIBUTES)
+		goto on_error;
+
+	if ((attrs & FILE_ATTRIBUTE_READONLY) == 0)
+		return 0;
+
+	if (!SetFileAttributesW(path, (attrs & ~FILE_ATTRIBUTE_READONLY)))
+		goto on_error;
+
+	return 0;
+
+on_error:
+	set_errno();
+	return -1;
+}
+
 /**
  * Truncate or extend file.
  *
@@ -89,24 +238,26 @@ int p_link(const char *old, const char *new)
 	return -1;
 }
 
-int p_unlink(const char *path)
+GIT_INLINE(int) unlink_once(const wchar_t *path)
 {
-	git_win32_path buf;
-	int error;
+	if (DeleteFileW(path))
+		return 0;
 
-	if (git_win32_path_from_utf8(buf, path) < 0)
-		return -1;
+	if (last_error_retryable())
+		return GIT_RETRY;
 
-	error = _wunlink(buf);
+	set_errno();
+	return -1;
+}
 
-	/* If the file could not be deleted because it was
-	 * read-only, clear the bit and try again */
-	if (error == -1 && errno == EACCES) {
-		_wchmod(buf, 0666);
-		error = _wunlink(buf);
-	}
+int p_unlink(const char *path)
+{
+	git_win32_path wpath;
 
-	return error;
+	if (git_win32_path_from_utf8(wpath, path) < 0)
+		return -1;
+
+	do_with_retries(unlink_once(wpath), ensure_writable(wpath));
 }
 
 int p_fsync(int fd)
@@ -212,44 +363,6 @@ int p_lstat_posixly(const char *filename, struct stat *buf)
 	return do_lstat(filename, buf, true);
 }
 
-int p_utimes(const char *filename, const struct p_timeval times[2])
-{
-	int fd, error;
-
-	if ((fd = p_open(filename, O_RDWR)) < 0)
-		return fd;
-
-	error = p_futimes(fd, times);
-
-	close(fd);
-	return error;
-}
-
-int p_futimes(int fd, const struct p_timeval times[2])
-{
-	HANDLE handle;
-	FILETIME atime = {0}, mtime = {0};
-
-	if (times == NULL) {
-		SYSTEMTIME st;
-
-		GetSystemTime(&st);
-		SystemTimeToFileTime(&st, &atime);
-		SystemTimeToFileTime(&st, &mtime);
-	} else {
-		git_win32__timeval_to_filetime(&atime, times[0]);
-		git_win32__timeval_to_filetime(&mtime, times[1]);
-	}
-
-	if ((handle = (HANDLE)_get_osfhandle(fd)) == INVALID_HANDLE_VALUE)
-		return -1;
-
-	if (SetFileTime(handle, NULL, &atime, &mtime) == 0)
-		return -1;
-
-	return 0;
-}
-
 int p_readlink(const char *path, char *buf, size_t bufsiz)
 {
 	git_win32_path path_w, target_w;
@@ -282,12 +395,91 @@ int p_symlink(const char *old, const char *new)
 	return git_futils_fake_symlink(old, new);
 }
 
+struct open_opts {
+	DWORD access;
+	DWORD sharing;
+	SECURITY_ATTRIBUTES security;
+	DWORD creation_disposition;
+	DWORD attributes;
+	int osf_flags;
+};
+
+GIT_INLINE(void) open_opts_from_posix(struct open_opts *opts, int flags, mode_t mode)
+{
+	memset(opts, 0, sizeof(struct open_opts));
+
+	switch (flags & (O_WRONLY | O_RDWR)) {
+	case O_WRONLY:
+		opts->access = GENERIC_WRITE;
+		break;
+	case O_RDWR:
+		opts->access = GENERIC_READ | GENERIC_WRITE;
+		break;
+	default:
+		opts->access = GENERIC_READ;
+		break;
+	}
+
+	opts->sharing = (DWORD)git_win32__createfile_sharemode;
+
+	switch (flags & (O_CREAT | O_TRUNC | O_EXCL)) {
+	case O_CREAT | O_EXCL:
+	case O_CREAT | O_TRUNC | O_EXCL:
+		opts->creation_disposition = CREATE_NEW;
+		break;
+	case O_CREAT | O_TRUNC:
+		opts->creation_disposition = CREATE_ALWAYS;
+		break;
+	case O_TRUNC:
+		opts->creation_disposition = TRUNCATE_EXISTING;
+		break;
+	case O_CREAT:
+		opts->creation_disposition = OPEN_ALWAYS;
+		break;
+	default:
+		opts->creation_disposition = OPEN_EXISTING;
+		break;
+	}
+
+	opts->attributes = ((flags & O_CREAT) && !(mode & S_IWRITE)) ?
+		FILE_ATTRIBUTE_READONLY : FILE_ATTRIBUTE_NORMAL;
+	opts->osf_flags = flags & (O_RDONLY | O_APPEND);
+
+	opts->security.nLength = sizeof(SECURITY_ATTRIBUTES);
+	opts->security.lpSecurityDescriptor = NULL;
+	opts->security.bInheritHandle = 0;
+}
+
+GIT_INLINE(int) open_once(
+	const wchar_t *path,
+	struct open_opts *opts)
+{
+	int fd;
+
+	HANDLE handle = CreateFileW(path, opts->access, opts->sharing,
+		&opts->security, opts->creation_disposition, opts->attributes, 0);
+
+	if (handle == INVALID_HANDLE_VALUE) {
+		if (last_error_retryable())
+			return GIT_RETRY;
+
+		set_errno();
+		return -1;
+	}
+
+	if ((fd = _open_osfhandle((intptr_t)handle, opts->osf_flags)) < 0)
+		CloseHandle(handle);
+
+	return fd;
+}
+
 int p_open(const char *path, int flags, ...)
 {
-	git_win32_path buf;
+	git_win32_path wpath;
 	mode_t mode = 0;
+	struct open_opts opts = {0};
 
-	if (git_win32_path_from_utf8(buf, path) < 0)
+	if (git_win32_path_from_utf8(wpath, path) < 0)
 		return -1;
 
 	if (flags & O_CREAT) {
@@ -298,19 +490,83 @@ int p_open(const char *path, int flags, ...)
 		va_end(arg_list);
 	}
 
-	return _wopen(buf, flags | STANDARD_OPEN_FLAGS, mode & WIN32_MODE_MASK);
+	open_opts_from_posix(&opts, flags, mode);
+
+	do_with_retries(
+		open_once(wpath, &opts),
+		0);
 }
 
 int p_creat(const char *path, mode_t mode)
 {
-	git_win32_path buf;
+	return p_open(path, O_WRONLY | O_CREAT | O_TRUNC, mode);
+}
 
-	if (git_win32_path_from_utf8(buf, path) < 0)
+int p_utimes(const char *path, const struct p_timeval times[2])
+{
+	git_win32_path wpath;
+	int fd, error;
+	DWORD attrs_orig, attrs_new = 0;
+	struct open_opts opts = { 0 };
+
+	if (git_win32_path_from_utf8(wpath, path) < 0)
+		return -1;
+
+	attrs_orig = GetFileAttributesW(wpath);
+
+	if (attrs_orig & FILE_ATTRIBUTE_READONLY) {
+		attrs_new = attrs_orig & ~FILE_ATTRIBUTE_READONLY;
+
+		if (!SetFileAttributesW(wpath, attrs_new)) {
+			giterr_set(GITERR_OS, "failed to set attributes");
+			return -1;
+		}
+	}
+
+	open_opts_from_posix(&opts, O_RDWR, 0);
+
+	if ((fd = open_once(wpath, &opts)) < 0) {
+		error = -1;
+		goto done;
+	}
+
+	error = p_futimes(fd, times);
+	close(fd);
+
+done:
+	if (attrs_orig != attrs_new) {
+		DWORD os_error = GetLastError();
+		SetFileAttributesW(wpath, attrs_orig);
+		SetLastError(os_error);
+	}
+
+	return error;
+}
+
+int p_futimes(int fd, const struct p_timeval times[2])
+{
+	HANDLE handle;
+	FILETIME atime = { 0 }, mtime = { 0 };
+
+	if (times == NULL) {
+		SYSTEMTIME st;
+
+		GetSystemTime(&st);
+		SystemTimeToFileTime(&st, &atime);
+		SystemTimeToFileTime(&st, &mtime);
+	}
+	else {
+		git_win32__timeval_to_filetime(&atime, times[0]);
+		git_win32__timeval_to_filetime(&mtime, times[1]);
+	}
+
+	if ((handle = (HANDLE)_get_osfhandle(fd)) == INVALID_HANDLE_VALUE)
+		return -1;
+
+	if (SetFileTime(handle, NULL, &atime, &mtime) == 0)
 		return -1;
 
-	return _wopen(buf,
-		_O_WRONLY | _O_CREAT | _O_TRUNC | STANDARD_OPEN_FLAGS,
-		mode & WIN32_MODE_MASK);
+	return 0;
 }
 
 int p_getcwd(char *buffer_out, size_t size)
@@ -583,62 +839,27 @@ int p_access(const char* path, mode_t mode)
 	return _waccess(buf, mode & WIN32_MODE_MASK);
 }
 
-static int ensure_writable(wchar_t *fpath)
+GIT_INLINE(int) rename_once(const wchar_t *from, const wchar_t *to)
 {
-	DWORD attrs;
-
-	attrs = GetFileAttributesW(fpath);
-	if (attrs == INVALID_FILE_ATTRIBUTES) {
-		if (GetLastError() == ERROR_FILE_NOT_FOUND)
-			return 0;
-
-		giterr_set(GITERR_OS, "failed to get attributes");
-		return -1;
-	}
-
-	if (!(attrs & FILE_ATTRIBUTE_READONLY))
+	if (MoveFileExW(from, to, MOVEFILE_REPLACE_EXISTING | MOVEFILE_COPY_ALLOWED))
 		return 0;
 
-	attrs &= ~FILE_ATTRIBUTE_READONLY;
-	if (!SetFileAttributesW(fpath, attrs)) {
-		giterr_set(GITERR_OS, "failed to set attributes");
-		return -1;
-	}
+	if (last_error_retryable())
+		return GIT_RETRY;
 
-	return 0;
+	set_errno();
+	return -1;
 }
 
 int p_rename(const char *from, const char *to)
 {
-	git_win32_path wfrom;
-	git_win32_path wto;
-	int rename_tries;
-	int rename_succeeded;
-	int error;
+	git_win32_path wfrom, wto;
 
 	if (git_win32_path_from_utf8(wfrom, from) < 0 ||
 		git_win32_path_from_utf8(wto, to) < 0)
 		return -1;
 
-	/* wait up to 50ms if file is locked by another thread or process */
-	rename_tries = 0;
-	rename_succeeded = 0;
-	while (rename_tries < 10) {
-		if (ensure_writable(wto) == 0 &&
-		    MoveFileExW(wfrom, wto, MOVEFILE_REPLACE_EXISTING | MOVEFILE_COPY_ALLOWED) != 0) {
-			rename_succeeded = 1;
-			break;
-		}
-		
-		error = GetLastError();
-		if (error == ERROR_SHARING_VIOLATION || error == ERROR_ACCESS_DENIED) {
-			Sleep(5);
-			rename_tries++;
-		} else
-			break;
-	}
-	
-	return rename_succeeded ? 0 : -1;
+	do_with_retries(rename_once(wfrom, wto), ensure_writable(wto));
 }
 
 int p_recv(GIT_SOCKET socket, void *buffer, size_t length, int flags)
diff --git a/tests/odb/freshen.c b/tests/odb/freshen.c
index f41e4361e..9d3cf51dc 100644
--- a/tests/odb/freshen.c
+++ b/tests/odb/freshen.c
@@ -55,6 +55,31 @@ void test_odb_freshen__loose_blob(void)
 	cl_assert(before.st_mtime < after.st_mtime);
 }
 
+#define UNIQUE_STR     "doesnt exist in the odb yet\n"
+#define UNIQUE_BLOB_ID "78a87d0b8878c5953b9a63015ff4e22a3d898826"
+#define UNIQUE_BLOB_FN "78/a87d0b8878c5953b9a63015ff4e22a3d898826"
+
+void test_odb_freshen__readonly_object(void)
+{
+	git_oid expected_id, id;
+	struct stat before, after;
+
+	cl_git_pass(git_oid_fromstr(&expected_id, UNIQUE_BLOB_ID));
+
+	cl_git_pass(git_blob_create_frombuffer(&id, repo, UNIQUE_STR, CONST_STRLEN(UNIQUE_STR)));
+	cl_assert_equal_oid(&expected_id, &id);
+
+	set_time_wayback(&before, UNIQUE_BLOB_FN);
+	cl_assert((before.st_mode & S_IWUSR) == 0);
+
+	cl_git_pass(git_blob_create_frombuffer(&id, repo, UNIQUE_STR, CONST_STRLEN(UNIQUE_STR)));
+	cl_assert_equal_oid(&expected_id, &id);
+	cl_must_pass(p_lstat("testrepo.git/objects/" UNIQUE_BLOB_FN, &after));
+
+	cl_assert(before.st_atime < after.st_atime);
+	cl_assert(before.st_mtime < after.st_mtime);
+}
+
 #define LOOSE_TREE_ID "944c0f6e4dfa41595e6eb3ceecdb14f50fe18162"
 #define LOOSE_TREE_FN "94/4c0f6e4dfa41595e6eb3ceecdb14f50fe18162"
 
diff --git a/tests/threads/diff.c b/tests/threads/diff.c
index c32811469..90d35b15e 100644
--- a/tests/threads/diff.c
+++ b/tests/threads/diff.c
@@ -19,12 +19,25 @@ static git_repository *_repo;
 static git_tree *_a, *_b;
 static git_atomic _counts[4];
 static int _check_counts;
+static int _retries;
 
 #define THREADS 20
 
+void test_threads_diff__initialize(void)
+{
+#ifdef GIT_WIN32
+	_retries = git_win32__retries;
+	git_win32__retries = 1;
+#endif
+}
+
 void test_threads_diff__cleanup(void)
 {
 	cl_git_sandbox_cleanup();
+
+#ifdef GIT_WIN32
+	git_win32__retries = _retries;
+#endif
 }
 
 static void setup_trees(void)