1 /*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 #ifndef AVUTIL_WCHAR_FILENAME_H
20 #define AVUTIL_WCHAR_FILENAME_H
21
22 #ifdef _WIN32
23
24 #define WIN32_LEAN_AND_MEAN
25 #include <windows.h>
26 #include "mem.h"
27
28 av_warn_unused_result
utf8towchar(const char * filename_utf8,wchar_t ** filename_w)29 static inline int utf8towchar(const char *filename_utf8, wchar_t **filename_w)
30 {
31 int num_chars;
32 num_chars = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, filename_utf8, -1, NULL, 0);
33 if (num_chars <= 0) {
34 *filename_w = NULL;
35 errno = EINVAL;
36 return -1;
37 }
38 *filename_w = (wchar_t *)av_calloc(num_chars, sizeof(wchar_t));
39 if (!*filename_w) {
40 errno = ENOMEM;
41 return -1;
42 }
43 MultiByteToWideChar(CP_UTF8, 0, filename_utf8, -1, *filename_w, num_chars);
44 return 0;
45 }
46
47 av_warn_unused_result
wchartocp(unsigned int code_page,const wchar_t * filename_w,char ** filename)48 static inline int wchartocp(unsigned int code_page, const wchar_t *filename_w,
49 char **filename)
50 {
51 DWORD flags = code_page == CP_UTF8 ? WC_ERR_INVALID_CHARS : 0;
52 int num_chars = WideCharToMultiByte(code_page, flags, filename_w, -1,
53 NULL, 0, NULL, NULL);
54 if (num_chars <= 0) {
55 *filename = NULL;
56 errno = EINVAL;
57 return -1;
58 }
59 *filename = (char*)av_malloc_array(num_chars, sizeof *filename);
60 if (!*filename) {
61 errno = ENOMEM;
62 return -1;
63 }
64 WideCharToMultiByte(code_page, flags, filename_w, -1,
65 *filename, num_chars, NULL, NULL);
66 return 0;
67 }
68
69 av_warn_unused_result
wchartoutf8(const wchar_t * filename_w,char ** filename)70 static inline int wchartoutf8(const wchar_t *filename_w, char **filename)
71 {
72 return wchartocp(CP_UTF8, filename_w, filename);
73 }
74
75 av_warn_unused_result
wchartoansi(const wchar_t * filename_w,char ** filename)76 static inline int wchartoansi(const wchar_t *filename_w, char **filename)
77 {
78 return wchartocp(CP_ACP, filename_w, filename);
79 }
80
81 av_warn_unused_result
utf8toansi(const char * filename_utf8,char ** filename)82 static inline int utf8toansi(const char *filename_utf8, char **filename)
83 {
84 wchar_t *filename_w = NULL;
85 int ret = -1;
86 if (utf8towchar(filename_utf8, &filename_w))
87 return -1;
88
89 if (!filename_w) {
90 *filename = NULL;
91 return 0;
92 }
93
94 ret = wchartoansi(filename_w, filename);
95 av_free(filename_w);
96 return ret;
97 }
98
99 /**
100 * Checks for extended path prefixes for which normalization needs to be skipped.
101 * see .NET6: PathInternal.IsExtended()
102 * https://github.com/dotnet/runtime/blob/9260c249140ef90b4299d0fe1aa3037e25228518/src/libraries/Common/src/System/IO/PathInternal.Windows.cs#L165
103 */
path_is_extended(const wchar_t * path)104 static inline int path_is_extended(const wchar_t *path)
105 {
106 if (path[0] == L'\\' && (path[1] == L'\\' || path[1] == L'?') && path[2] == L'?' && path[3] == L'\\')
107 return 1;
108
109 return 0;
110 }
111
112 /**
113 * Checks for a device path prefix.
114 * see .NET6: PathInternal.IsDevice()
115 * we don't check forward slashes and extended paths (as already done)
116 * https://github.com/dotnet/runtime/blob/9260c249140ef90b4299d0fe1aa3037e25228518/src/libraries/Common/src/System/IO/PathInternal.Windows.cs#L132
117 */
path_is_device_path(const wchar_t * path)118 static inline int path_is_device_path(const wchar_t *path)
119 {
120 if (path[0] == L'\\' && path[1] == L'\\' && path[2] == L'.' && path[3] == L'\\')
121 return 1;
122
123 return 0;
124 }
125
126 /**
127 * Performs path normalization by calling GetFullPathNameW().
128 * see .NET6: PathHelper.GetFullPathName()
129 * https://github.com/dotnet/runtime/blob/2a99e18eedabcf1add064c099da59d9301ce45e0/src/libraries/System.Private.CoreLib/src/System/IO/PathHelper.Windows.cs#L70
130 */
get_full_path_name(wchar_t ** ppath_w)131 static inline int get_full_path_name(wchar_t **ppath_w)
132 {
133 int num_chars;
134 wchar_t *temp_w;
135
136 num_chars = GetFullPathNameW(*ppath_w, 0, NULL, NULL);
137 if (num_chars <= 0) {
138 errno = EINVAL;
139 return -1;
140 }
141
142 temp_w = (wchar_t *)av_calloc(num_chars, sizeof(wchar_t));
143 if (!temp_w) {
144 errno = ENOMEM;
145 return -1;
146 }
147
148 num_chars = GetFullPathNameW(*ppath_w, num_chars, temp_w, NULL);
149 if (num_chars <= 0) {
150 av_free(temp_w);
151 errno = EINVAL;
152 return -1;
153 }
154
155 av_freep(ppath_w);
156 *ppath_w = temp_w;
157
158 return 0;
159 }
160
161 /**
162 * Normalizes a Windows file or folder path.
163 * Expansion of short paths (with 8.3 path components) is currently omitted
164 * as it is not required for accessing long paths.
165 * see .NET6: PathHelper.Normalize()
166 * https://github.com/dotnet/runtime/blob/2a99e18eedabcf1add064c099da59d9301ce45e0/src/libraries/System.Private.CoreLib/src/System/IO/PathHelper.Windows.cs#L25
167 */
path_normalize(wchar_t ** ppath_w)168 static inline int path_normalize(wchar_t **ppath_w)
169 {
170 int ret;
171
172 if ((ret = get_full_path_name(ppath_w)) < 0)
173 return ret;
174
175 /* What .NET does at this point is to call PathHelper.TryExpandShortFileName()
176 * in case the path contains a '~' character.
177 * We don't need to do this as we don't need to normalize the file name
178 * for presentation, and the extended path prefix works with 8.3 path
179 * components as well
180 */
181 return 0;
182 }
183
184 /**
185 * Adds an extended path or UNC prefix to longs paths or paths ending
186 * with a space or a dot. (' ' or '.').
187 * This function expects that the path has been normalized before by
188 * calling path_normalize() and it doesn't check whether the path is
189 * actually long (> MAX_PATH).
190 * see .NET6: PathInternal.EnsureExtendedPrefix()
191 * https://github.com/dotnet/runtime/blob/9260c249140ef90b4299d0fe1aa3037e25228518/src/libraries/Common/src/System/IO/PathInternal.Windows.cs#L107
192 */
add_extended_prefix(wchar_t ** ppath_w)193 static inline int add_extended_prefix(wchar_t **ppath_w)
194 {
195 const wchar_t *unc_prefix = L"\\\\?\\UNC\\";
196 const wchar_t *extended_path_prefix = L"\\\\?\\";
197 const wchar_t *path_w = *ppath_w;
198 const size_t len = wcslen(path_w);
199 wchar_t *temp_w;
200
201 /* We're skipping the check IsPartiallyQualified() because
202 * we expect to have called GetFullPathNameW() already. */
203 if (len < 2 || path_is_extended(*ppath_w) || path_is_device_path(*ppath_w)) {
204 return 0;
205 }
206
207 if (path_w[0] == L'\\' && path_w[1] == L'\\') {
208 /* unc_prefix length is 8 plus 1 for terminating zeros,
209 * we subtract 2 for the leading '\\' of the original path */
210 temp_w = (wchar_t *)av_calloc(len - 2 + 8 + 1, sizeof(wchar_t));
211 if (!temp_w) {
212 errno = ENOMEM;
213 return -1;
214 }
215 wcscpy(temp_w, unc_prefix);
216 wcscat(temp_w, path_w + 2);
217 } else {
218 // The length of extended_path_prefix is 4 plus 1 for terminating zeros
219 temp_w = (wchar_t *)av_calloc(len + 4 + 1, sizeof(wchar_t));
220 if (!temp_w) {
221 errno = ENOMEM;
222 return -1;
223 }
224 wcscpy(temp_w, extended_path_prefix);
225 wcscat(temp_w, path_w);
226 }
227
228 av_freep(ppath_w);
229 *ppath_w = temp_w;
230
231 return 0;
232 }
233
234 /**
235 * Converts a file or folder path to wchar_t for use with Windows file
236 * APIs. Paths with extended path prefix (either '\\?\' or \??\') are
237 * left unchanged.
238 * All other paths are normalized and converted to absolute paths.
239 * Longs paths (>= MAX_PATH) are prefixed with the extended path or extended
240 * UNC path prefix.
241 * see .NET6: Path.GetFullPath() and Path.GetFullPathInternal()
242 * https://github.com/dotnet/runtime/blob/2a99e18eedabcf1add064c099da59d9301ce45e0/src/libraries/System.Private.CoreLib/src/System/IO/Path.Windows.cs#L126
243 */
get_extended_win32_path(const char * path,wchar_t ** ppath_w)244 static inline int get_extended_win32_path(const char *path, wchar_t **ppath_w)
245 {
246 int ret;
247 size_t len;
248
249 if ((ret = utf8towchar(path, ppath_w)) < 0)
250 return ret;
251
252 if (path_is_extended(*ppath_w)) {
253 /* Paths prefixed with '\\?\' or \??\' are considered normalized by definition.
254 * Windows doesn't normalize those paths and neither should we.
255 */
256 return 0;
257 }
258
259 if ((ret = path_normalize(ppath_w)) < 0) {
260 av_freep(ppath_w);
261 return ret;
262 }
263
264 /* see .NET6: PathInternal.EnsureExtendedPrefixIfNeeded()
265 * https://github.com/dotnet/runtime/blob/9260c249140ef90b4299d0fe1aa3037e25228518/src/libraries/Common/src/System/IO/PathInternal.Windows.cs#L92
266 */
267 len = wcslen(*ppath_w);
268 if (len >= MAX_PATH) {
269 if ((ret = add_extended_prefix(ppath_w)) < 0) {
270 av_freep(ppath_w);
271 return ret;
272 }
273 }
274
275 return 0;
276 }
277
278 #endif
279
280 #endif /* AVUTIL_WCHAR_FILENAME_H */
281