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Windows: better stat implementation
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@piscisaureus
piscisaureus committed Feb 2, 2012
1 parent 495853e commit 267e75d
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Showing 2 changed files with 40 additions and 157 deletions.
184 changes: 27 additions & 157 deletions src/win/fs.c
View file
Expand Up @@ -489,191 +489,61 @@ void fs__readdir(uv_fs_t* req, const wchar_t* path, int flags) {
}


#define IS_SLASH(c) \
((wchar_t) c == L'/' || (wchar_t) c == L'\\')
#define IS_COLON(c) \
((wchar_t) c == L':')
#define IS_LETTER(c) \
((((wchar_t) c >= L'a') && ((wchar_t) c <= L'z')) || \
(((wchar_t) c >= L'A') && ((wchar_t) c <= L'Z')))
#define IS_QUESTION(c) \
((wchar_t) c == L'?')


static int uv__count_slash_separated_words(const wchar_t* pos,
const wchar_t* end,
int limit) {
char last_was_slash = 1, count = 0;

for (; pos < end; pos++) {
if (IS_SLASH(*pos)) {
/* Don't accept double slashes */
if (last_was_slash) {
return 0;
} else {
last_was_slash = 1;
}
} else {
if (last_was_slash) {
/* Found a new word */
count++;
if (count > limit) {
return -1;
}
last_was_slash = 0;
}
}
}

return count;
}

/*
* Returns true if the given path is a root directory. The following patterns
* are recognized:
* \
* c:\ (must have trailing slash)
* \\server\share (trailing slash optional)
* \\?\c: (trailing slash optional)
* \\?\UNC\server\share (trailing slash optional)
*/
static int uv__is_root(const wchar_t* path) {
size_t len = wcslen(path);

/* Test for \ */
if (len == 1 && IS_SLASH(path[0])) {
return 1;
}

if (len < 3) {
return 0;
}

/* Test for c:\ */
if (IS_LETTER(path[0]) && IS_COLON(path[1]) && IS_SLASH(path[2])) {
return 1;
}

if (!IS_SLASH(path[0]) || !IS_SLASH(path[1])) {
return 0;
}

/* Test for \\server\share */
if (!IS_QUESTION(path[2])) {
return uv__count_slash_separated_words(path + 2, path + len, 2) == 2;
}

if (!IS_SLASH(path[3])) {
return 0;
}

if ((len == 6 || len == 7) &&
IS_LETTER(path[4]) && IS_COLON(path[5]) &&
(len == 6 || IS_SLASH(path[6]))) {
return 1;
}

/* Test for \\?\UNC\server\share */
if (len >= 8 &&
(path[4] == L'u' || path[4] == L'U') &&
(path[5] == L'n' || path[5] == L'N') &&
(path[6] == L'c' || path[6] == L'C') &&
IS_SLASH(path[7])) {
return uv__count_slash_separated_words(path + 8, path + len, 2) == 2;
}

return 0;
}


void fs__stat(uv_fs_t* req, const wchar_t* path) {
HANDLE file;
WIN32_FIND_DATAW ent;
static void fs__stat(uv_fs_t* req, const wchar_t* path) {
HANDLE handle;
int result;
BY_HANDLE_FILE_INFORMATION info;

req->ptr = NULL;

if (uv__is_root(path)) {
/* We can't stat root directories like c:\. _wstati64 can't either, but */
/* it will make up something reasonable. */
DWORD drive_type = GetDriveTypeW(path);
if (drive_type == DRIVE_UNKNOWN || drive_type == DRIVE_NO_ROOT_DIR) {
req->last_error = ERROR_PATH_NOT_FOUND;
req->errorno = UV_ENOENT;
req->result = -1;
return;
}

memset(&req->stat, 0, sizeof req->stat);

req->stat.st_nlink = 1;
req->stat.st_mode = ((_S_IREAD|_S_IWRITE) + ((_S_IREAD|_S_IWRITE) >> 3) +
((_S_IREAD|_S_IWRITE) >> 6)) | S_IFDIR;

req->last_error = ERROR_SUCCESS;
req->errorno = UV_OK;
req->result = 0;
req->ptr = &req->stat;
handle = CreateFileW(path,
FILE_READ_ATTRIBUTES,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
NULL,
OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS,
NULL);
if (handle == INVALID_HANDLE_VALUE) {
SET_REQ_RESULT_WIN32_ERROR(req, GetLastError());
return;
}

file = FindFirstFileExW(path, FindExInfoStandard, &ent,
FindExSearchNameMatch, NULL, 0);

if (file == INVALID_HANDLE_VALUE) {
if (!GetFileInformationByHandle(handle, &info)) {
SET_REQ_RESULT_WIN32_ERROR(req, GetLastError());
CloseHandle(handle);
return;
}

FindClose(file);

if (ent.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT &&
ent.dwReserved0 == IO_REPARSE_TAG_SYMLINK) {
fs__open(req, path, _O_RDONLY, 0);
if (req->result != -1) {
result = _fstati64(req->result, &req->stat);
_close(req->result);

if (result != -1) {
req->ptr = &req->stat;
}

SET_REQ_RESULT(req, result);
}
memset(&req->stat, 0, sizeof req->stat);

return;
}
/* TODO: set st_dev and st_ino? */

req->stat.st_ino = 0;
req->stat.st_uid = 0;
req->stat.st_gid = 0;
req->stat.st_mode = 0;
req->stat.st_rdev = 0;
req->stat.st_dev = 0;
req->stat.st_nlink = 1;

if (ent.dwFileAttributes & FILE_ATTRIBUTE_READONLY ) {
if (info.dwFileAttributes & FILE_ATTRIBUTE_READONLY) {
req->stat.st_mode |= (_S_IREAD + (_S_IREAD >> 3) + (_S_IREAD >> 6));
} else {
req->stat.st_mode |= ((_S_IREAD|_S_IWRITE) + ((_S_IREAD|_S_IWRITE) >> 3) +
((_S_IREAD|_S_IWRITE) >> 6));
}

if (ent.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
if (info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
req->stat.st_mode |= _S_IFDIR;
} else {
req->stat.st_mode |= _S_IFREG;
}

uv_filetime_to_time_t(&ent.ftLastWriteTime, &(req->stat.st_mtime));
uv_filetime_to_time_t(&ent.ftLastAccessTime, &(req->stat.st_atime));
uv_filetime_to_time_t(&ent.ftCreationTime, &(req->stat.st_ctime));
uv_filetime_to_time_t(&info.ftLastWriteTime, &(req->stat.st_mtime));
uv_filetime_to_time_t(&info.ftLastAccessTime, &(req->stat.st_atime));
uv_filetime_to_time_t(&info.ftCreationTime, &(req->stat.st_ctime));

req->stat.st_size = ((int64_t) info.nFileSizeHigh << 32) +
(int64_t) info.nFileSizeLow;

req->stat.st_size = ((int64_t)ent.nFileSizeHigh << 32) +
(int64_t)ent.nFileSizeLow;
req->stat.st_nlink = info.nNumberOfLinks;

req->ptr = &req->stat;
req->result = 0;

CloseHandle(handle);
}


Expand Down
13 changes: 13 additions & 0 deletions test/test-fs.c
View file
Expand Up @@ -1309,6 +1309,19 @@ TEST_IMPL(fs_stat_root) {
r = uv_fs_stat(loop, &stat_req, "\\", NULL);
ASSERT(r == 0);

r = uv_fs_stat(loop, &stat_req, "..\\..\\..\\..\\..\\..\\..", NULL);
ASSERT(r == 0);

r = uv_fs_stat(loop, &stat_req, "..", NULL);
ASSERT(r == 0);

r = uv_fs_stat(loop, &stat_req, "..\\", NULL);
ASSERT(r == 0);

/* stats the current directory on c: */
r = uv_fs_stat(loop, &stat_req, "c:", NULL);
ASSERT(r == 0);

r = uv_fs_stat(loop, &stat_req, "c:\\", NULL);
ASSERT(r == 0);

Expand Down

2 comments on commit 267e75d

@luislavena
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Hello @piscisaureus would you mind comment why this implementation is better? Is faster? is more stable?

(just curious as we face issues around stat() in Ruby)

Thank you.

@bnoordhuis
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@luislavena: It's more bug free. The previous implementation rejected a number of valid paths.

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