Function fs_remove

src/base/fs.cpp:526–584

}

int fs_remove(const char *filename)
{
#if defined(CONF_FAMILY_WINDOWS)
	if(fs_is_dir(filename))
	{
		// Not great, but otherwise using this function on a folder would only rename the folder but fail to delete it.
		return 1;
	}
	const std::wstring wide_filename = windows_utf8_to_wide(filename);

	unsigned random_num;
	secure_random_fill(&random_num, sizeof(random_num));
	std::wstring wide_filename_temp;
	do
	{
		char suffix[64];
		str_format(suffix, sizeof(suffix), ".%08X.toberemoved", random_num);
		wide_filename_temp = wide_filename + windows_utf8_to_wide(suffix);
		++random_num;
	} while(GetFileAttributesW(wide_filename_temp.c_str()) != INVALID_FILE_ATTRIBUTES);

	// The DeleteFileW function only marks the file for deletion but the deletion may not take effect immediately, which can
	// cause subsequent operations using this filename to fail until all handles are closed. The MoveFileExW function with the
	// MOVEFILE_WRITE_THROUGH flag is guaranteed to wait for the file to be moved on disk, so we first rename the file to be
	// deleted to a random temporary name and then mark that for deletion, to ensure that the filename is usable immediately.
	if(MoveFileExW(wide_filename.c_str(), wide_filename_temp.c_str(), MOVEFILE_WRITE_THROUGH) == 0)
	{
		const DWORD error = GetLastError();
		if(error == ERROR_FILE_NOT_FOUND)
		{
			return 0; // Success: Renaming failed because the original file did not exist.
		}
		const std::string filename_temp = windows_wide_to_utf8(wide_filename_temp.c_str()).value_or("(invalid filename)");
		log_error("filesystem", "Failed to rename file '%s' to '%s' for removal (%ld '%s')", filename, filename_temp.c_str(), error, windows_format_system_message(error).c_str());
		return 1;
	}
	if(DeleteFileW(wide_filename_temp.c_str()) != 0)
	{
		return 0; // Success: Marked the renamed file for deletion successfully.
	}
	const DWORD error = GetLastError();
	if(error == ERROR_FILE_NOT_FOUND)
	{
		return 0; // Success: Another process deleted the renamed file we were about to delete?!
	}
	const std::string filename_temp = windows_wide_to_utf8(wide_filename_temp.c_str()).value_or("(invalid filename)");
	log_error("filesystem", "Failed to remove file '%s' (%ld '%s')", filename_temp.c_str(), error, windows_format_system_message(error).c_str());
	// Success: While the temporary could not be deleted, this is also considered success because the original file does not exist anymore.
	//          Callers of this function expect that the original file does not exist anymore if and only if the function succeeded.
	return 0;
#else
	if(unlink(filename) == 0 || errno == ENOENT)
	{
		return 0;
	}
	log_error("filesystem", "Failed to remove file '%s' (%d '%s')", filename, errno, strerror(errno));
	return 1;
#endif