+/**
+ * Verifies that safe_create_leading_directories() would succeed.
+ */
+static int has_valid_directory_prefix(wchar_t *wfilename)
+{
+ int n = wcslen(wfilename);
+
+ while (n > 0) {
+ wchar_t c = wfilename[--n];
+ DWORD attributes;
+
+ if (!is_dir_sep(c))
+ continue;
+
+ wfilename[n] = L'\0';
+ attributes = GetFileAttributesW(wfilename);
+ wfilename[n] = c;
+ if (attributes == FILE_ATTRIBUTE_DIRECTORY ||
+ attributes == FILE_ATTRIBUTE_DEVICE)
+ return 1;
+ if (attributes == INVALID_FILE_ATTRIBUTES)
+ switch (GetLastError()) {
+ case ERROR_PATH_NOT_FOUND:
+ continue;
+ case ERROR_FILE_NOT_FOUND:
+ /* This implies parent directory exists. */
+ return 1;
+ }
+ return 0;
+ }
+ return 1;
+}
+