boost GIL doesn't properly handle JPEG errors

[Giel van Schijndel <me@…>]

When an error occurs during the decoding of a JPEG file (specifically its header) using jpeg_read_(dimensions|image|view) inside of libjpeg itself the program terminates.

This is because libjpeg uses the error_exit handler from the current jpeg_error_mgr to signal an error. The default error_exit handler simply prints a message to stderr and calls exit(EXIT_FAILURE). However, in order to properly handle this error one needs to override this error_exit handler. Attached patch does just that, using the same error message, though instead, it uses that message as a description for an io_error(const char* desc) generated exception (std::ios_base::failure).

[Giel van Schijndel <me@…>]

Turn JPEG errors into exceptions

[Giel van Schijndel <me@…>]

PS I'm not entirely sure whether my patch will work properly as it'll end up throwing an exception through C code. Until now, however, I haven't had any problems with throwing through C code though (I'm using it to determine the fileformat employed, i.e. try to load an image until one loader is successful).

The problem is that libjpeg doesn't expect error_exit to return. So another, C-way, of solving this could be by using longjmp and converting to an exception at the jump target.

[chhenning]

Please use new io extension. A lot of time has been there for correct error handling.

Closing this ticket.

[pascal@…]

Replying to chhenning:

Please use new io extension. A lot of time has been there for correct error handling.

Which "new extension"? In 1.46 there are still the same old JPEG/TIFF/PNG extensions. Sadly, the JPEG extension is unusable in this state…