From: softworkz <softwo...@hotmail.com>
Signed-off-by: softworkz <softwo...@hotmail.com>
---
libavutil/file_open.c | 2 +-
libavutil/wchar_filename.h | 156 +++++++++++++++++++++++++++++++++++++
2 files changed, 157 insertions(+), 1 deletion(-)
diff --git a/libavutil/file_open.c b/libavutil/file_open.c
index cc302f2f76..57c5e78d51 100644
--- a/libavutil/file_open.c
+++ b/libavutil/file_open.c
@@ -45,7 +45,7 @@ static int win32_open(const char *filename_utf8, int oflag,
int pmode)
wchar_t *filename_w;
/* convert UTF-8 to wide chars */
- if (utf8towchar(filename_utf8, &filename_w))
+ if (get_extended_win32_path(filename_utf8, &filename_w))
return -1;
if (!filename_w)
goto fallback;
diff --git a/libavutil/wchar_filename.h b/libavutil/wchar_filename.h
index 90f082452c..78e7dd47d7 100644
--- a/libavutil/wchar_filename.h
+++ b/libavutil/wchar_filename.h
@@ -40,6 +40,162 @@ static inline int utf8towchar(const char *filename_utf8,
wchar_t **filename_w)
MultiByteToWideChar(CP_UTF8, 0, filename_utf8, -1, *filename_w, num_chars);
return 0;
}
+
+/**
+ * Checks for extended path prefixes for which normalization needs to be
skipped.
+ * see .NET6: PathInternal.IsExtended()
+ */
+static inline int path_is_extended(const wchar_t *path)
+{
+ size_t len = wcslen(path);
+ if (len >= 4 && path[0] == L'\\' && (path[1] == L'\\' || path[1] == L'?')
&& path[2] == L'?' && path[3] == L'\\')
+ return 1;
+
+ return 0;
+}
+
+/**
+ * Performs path normalization by calling GetFullPathNameW().
+ * see .NET6: PathHelper.GetFullPathName()
+ */
+static inline int get_full_path_name(wchar_t **ppath_w)
+{
+ int num_chars;
+ wchar_t *temp_w;
+
+ num_chars = GetFullPathNameW(*ppath_w, 0, NULL, NULL);
+ if (num_chars <= 0) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ temp_w = (wchar_t *)av_calloc(num_chars, sizeof(wchar_t));
+ if (!temp_w) {
+ errno = ENOMEM;
+ return -1;
+ }
+
+ num_chars = GetFullPathNameW(*ppath_w, num_chars, temp_w, NULL);
+ if (num_chars <= 0) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ av_freep(ppath_w);
+ *ppath_w = temp_w;
+
+ return 0;
+}
+
+/**
+ * Normalizes a Windows file or folder path.
+ * Expansion of short paths (with 8.3 path components) is currently omitted
+ * as it is not required for accessing long paths.
+ * see .NET6: PathHelper.Normalize().
+ */
+static inline int path_normalize(wchar_t **ppath_w)
+{
+ int ret;
+
+ if ((ret = get_full_path_name(ppath_w)) < 0)
+ return ret;
+
+ /* What .NET does at this point is to call
PathHelper.TryExpandShortFileName()
+ * in case the path contains a '~' character.
+ * We don't need to do this as we don't need to normalize the file name
+ * for presentation, and the extended path prefix works with 8.3 path
+ * components as well
+ */
+ return 0;
+}
+
+/**
+ * Adds an extended path or UNC prefix to longs paths or paths ending
+ * with a space or a dot. (' ' or '.').
+ * This function expects that the path has been normalized before by
+ * calling path_normalize().
+ * see .NET6: PathInternal.EnsureExtendedPrefix() *
+ */
+static inline int add_extended_prefix(wchar_t **ppath_w)
+{
+ const wchar_t *unc_prefix = L"\\\\?\\UNC\\";
+ const wchar_t *extended_path_prefix = L"\\\\?\\";
+ const wchar_t *path_w = *ppath_w;
+ const size_t len = wcslen(path_w);
+ wchar_t *temp_w;
+
+ if (len < 2)
+ return 0;
+
+ /* We're skipping the check IsPartiallyQualified() because
+ * we know we have called GetFullPathNameW() already, also
+ * we don't check IsDevice() because device paths are not
+ * allowed to be long paths and we're calling this only
+ * for long paths.
+ */
+ if (path_w[0] == L'\\' && path_w[1] == L'\\') {
+ // The length of unc_prefix is 6 plus 1 for terminating zeros
+ temp_w = (wchar_t *)av_calloc(len + 6 + 1, sizeof(wchar_t));
+ if (!temp_w) {
+ errno = ENOMEM;
+ return -1;
+ }
+ wcscpy(temp_w, unc_prefix);
+ wcscat(temp_w, path_w + 2);
+ } else {
+ // The length of extended_path_prefix is 4 plus 1 for terminating zeros
+ temp_w = (wchar_t *)av_calloc(len + 4 + 1, sizeof(wchar_t));
+ if (!temp_w) {
+ errno = ENOMEM;
+ return -1;
+ }
+ wcscpy(temp_w, extended_path_prefix);
+ wcscat(temp_w, path_w);
+ }
+
+ av_freep(ppath_w);
+ *ppath_w = temp_w;
+
+ return 0;
+}
+
+/**
+ * Converts a file or folder path to wchar_t for use with Windows file
+ * APIs. Paths with extended path prefix (either '\\?\' or \??\') are
+ * left unchanged.
+ * All other paths are normalized and converted to absolute paths.
+ * Longs paths (>= 260) are prefixed with the extended path or extended
+ * UNC path prefix.
+ * see .NET6: Path.GetFullPath() and Path.GetFullPathInternal()
+ */
+static inline int get_extended_win32_path(const char *path, wchar_t **ppath_w)
+{
+ int ret;
+ size_t len;
+
+ if ((ret = utf8towchar(path, ppath_w)) < 0)
+ return ret;
+
+ if (path_is_extended(*ppath_w)) {
+ /* Paths prefixed with '\\?\' or \??\' are considered normalized by
definition.
+ * Windows doesn't normalize those paths and neither should we.
+ */
+ return 0;
+ }
+
+ if ((ret = path_normalize(ppath_w)) < 0)
+ return ret;
+
+ // see .NET6: PathInternal.EnsureExtendedPrefixIfNeeded()
+ len = wcslen(*ppath_w);
+ if (len >= 260 || (*ppath_w)[len - 1] == L' ' || (*ppath_w)[len - 1] ==
L'.') {
+ if ((ret = add_extended_prefix(ppath_w)) < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
#endif
#endif /* AVUTIL_WCHAR_FILENAME_H */
--
ffmpeg-codebot
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