Misleading comments about max. size of form data

[tillkamppeter]

The function papplClientHTMLStartForm() tells in acomment that the maximum attachment file size is 1 MB, but MAX_FILE_SIZE is set to 64 kB.

papplClientGetForm() tells in a comment that it reads up to 2 MB but uses a buffer of only 64 kB, filling up this buffer once and parsing only this data. It would need to use a 2 MB buffer or fill the 64 kB several times.

[michaelrsweet]

@tillkamppeter OK, I think the original code (from mOAuth) allows up to 2MiB but when I moved it here I reduced the limit. Will make sure everything is consistent between them.

Do you need support for files larger than 64k?

[tillkamppeter]

I use this functionality for the user to add PPD files to the PostScript Printer Application, so that he can use it with printers which are not supported by the built-in PPDs, for example if the printer's PPD is under a non-free license.
PPDs easily can be larger than 64 kB, and I also allow for uploading more than one PPD at a time.

As papplClientGetForm() does not allow upload of multiple files with a single widget I have done my own replacement in the PostScript Printer Application. It uses a 32 kB buffer and fills it, parses the content, fills it again , ... until passed through all data, so I am somehow streaming the data. This allows even uploading files of several GB (like a Ubuntu Desktop ISO) and this even with your papplClientHTMLStartForm() function which sets MAX_FILE_SIZE to 64 kB.

There can be also other types of files to be uploaded into a Printer Application which are bigger than 64 kb: Firmware files, color profiles, or even printing via web interface.

[tillkamppeter]

See the ps_system_web_add_ppd() function in this commit.

[michaelrsweet]

I updated the code to dynamically allocate the data buffer, with a maximum size of 2MB.

[master 57c9830] Fix function to support large files (Issue #139)

[v1.0.x 3c3c1fb] Fix function to support large files (Issue #139)