fix directory creation on windows shared folders

commit on behalf of FletcherD

ChangeLog

@@ -1,3 +1,4 @@
+	* fix directory creation on windows shared folders
 	* add flag to make add_files() not record file attributes
 	* deprecate (unused) allow_partial_disk_writes settings
 	* fix disk-full error reporting in mmap_disk_io

src/mmap_storage.cpp

@@ -816,7 +816,14 @@ error_code translate_error(std::system_error const& err, bool const write)
 
 		boost::optional<aux::file_view> h = open_file_impl(sett, file, mode, ec);
 		if ((mode & aux::open_mode::write)
-			&& ec.ec == boost::system::errc::no_such_file_or_directory)
+			&& (ec.ec == boost::system::errc::no_such_file_or_directory
+#ifdef TORRENT_WINDOWS
+				// this is a workaround for improper handling of files on windows shared drives.
+				// if the directory on a shared drive does not exist,
+				// windows returns ERROR_IO_DEVICE instead of ERROR_FILE_NOT_FOUND
+				|| ec.ec == error_code(ERROR_IO_DEVICE, system_category())
+#endif
+		))
 		{
 			// this means the directory the file is in doesn't exist.
 			// so create it

src/posix_storage.cpp

@@ -462,8 +462,15 @@ namespace aux {
 			// if we fail to open a file for writing, and the error is ENOENT,
 			// it is likely because the directory we're creating the file in
 			// does not exist. Create the directory and try again.
-			if ((mode & open_mode::write)
-				&& ec.ec == boost::system::errc::no_such_file_or_directory)
+			if ((mode & aux::open_mode::write)
+				&& (ec.ec == boost::system::errc::no_such_file_or_directory
+#ifdef TORRENT_WINDOWS
+					// this is a workaround for improper handling of files on windows shared drives.
+					// if the directory on a shared drive does not exist,
+					// windows returns ERROR_IO_DEVICE instead of ERROR_FILE_NOT_FOUND
+					|| ec.ec == error_code(ERROR_IO_DEVICE, system_category())
+#endif
+			))
 			{
 				// this means the directory the file is in doesn't exist.
 				// so create it