Re: [Bug-xorriso] To Thomas Schmitt: how to go on, xorriso is installed

[Thomas Schmitt]

Hi,

about the lack of multi-session in Xfburn, i had a rough look at what
seems to be missing.

This would be a nice Google Summer-of-Code project, if a student and
a sponsor for the XFCE GUI part and Xfburn's git repo would show up.
I could be technical sponsor for the libburn and libisofs part.

-----------------------------------------------------------------------
Some technical details:

Multi-session would need a check box "Keep Appendable" to control whether
libburn function burn_write_opts_set_multi() gets called with parameter
value 1. (Just where "Stream _Recording" and others are defined in
xfburn-burn-data-composition-base-dialog.c .)

A new member
  gboolean multi;
would be needed in the struct types XfburnBurnImageDialogPrivate,
ThreadBurnIsoParams, and ThreadBurnCompositionParams.

Further Xfburn needs to recognize appendable media by state
BURN_DISC_APPENDABLE, which may be replied from libburn call
burn_disc_get_status().
Then it would have to import the existing ISO image if there is one.
This would be done by libisofs call iso_image_import(). Xfburn would
have to provide a IsoDataSource object which uses libburn calls to
read data blocks.

Then libisofs would need to get told to create an "appended" session
rather than a "stand-alone" session by call iso_write_opts_set_appendable().

Xfburn would have to determine the Next Writable Address by libburn call
burn_disc_track_lba_nwa() and then tell it to libisofs by
iso_write_opts_set_ms_block().

-----------------------------------------------------------------------

This would work only with sequential multi-session media: CD-R, CD-RW,
DVD-R, DVD+R, BD-R, and unformatted DVD-RW.

The overwritable media types DVD-RAM, DVD+RW, BD-RE, and formatted DVD-RW
have no own multi-session management in the drive. Xfburn would have to
employ libisoburn to operate them in emulated multi-session mode for
ISO 9660.

It offers two APIs:
The libisoburn API would possibly fit into the existing Xfburn code.
Using the xorriso API would probably cause a total overhaul of the
code for the "Data Composition" task. (But would yield the bigger
improvement by the backup features in xorriso and other aspects.)

-----------------------------------------------------------------------

Have a nice day :)

Thomas