Hello,
I started on experimenting on how to enhance the debconf protocol with
respect to sophisticated frontends (in this case the gtk frontend).
Although in the preceding discussion most people liked the idea of
some kind of intermediate widget describing language, I dismissed the
idea, because I considered it too complex. Perhaps someone else wants
to pursue this path.
I followed an idea of Tollef to have custom widgets which are frontend
specific. They are loaded on the fly as shared objects and cdebconf
will return a specific receipt if the custom widget has no
implementation for the selected frontend.
In detail:
I introduced a new question type "custom". In templates one can and in
fact should add a line "Implemets: $other_questions" where
$other_questions is a list of questions which shall be answered by the
custom widget. The custom widget's code has to set the answers to
these question according to what the user has entered.
A custom widget is implemented by a shared object which has a name and
position dependant on its name in the template. E.g. a gtk widget for
a question "test/ip_address" will be located (relative to the frontend
module path): custom/test/ip_address_gtk.so
The shared object must have a handler function called
test_ip_address_gtk, where the arguments and the return type can be
defined by the frontend.
I prepared a sample implementation (which is experimental and surly has
some bugs) and instructions how to test it. Find that at the end of
the mail.
Please give me some comments on the design.
Regards,
Sebastian
INSTRUCTIONS:
1) Get the cvs version of cdebconf:
$cvs -d :pserver:anonymous@cvs.debian.org:/cvs/debian-boot co \
debian-installer/tools/cdebconf
2) Apply the following patch:
http://www.mmweg.rwth-aachen.de/~sebastian.ley/d-i/cdebconf_custom.diff
3) Build cdebconf (according to instructions in doc/testing.txt):
./configure --with-frontend=gtk --with-conffile=./cdebconf.conf
4) Create a config file for cdebconf or grab this one:
http://www.mmweg.rwth-aachen.de/~sebastian.ley/d-i/cdebconf.conf
Put it into src/test
5) Grab the following template file and script and put them into
src/test:
http://www.mmweg.rwth-aachen.de/~sebastian.ley/d-i/custom.template
http://www.mmweg.rwth-aachen.de/~sebastian.ley/d-i/custom.config
6) Load the template file. Do this in src/test:
$../debconf-loadtemplate debian
7) Execute the script with cdebconf:
$../debconf custom.config
-> The first question to be asked would be of custom type. Since there
is no .so installed for the gtk frontend, cdebconf reports this to
the script and the script asks a fallback question of type
"string".
8) Put the custom widget below into src/modules/frontend/custom/test
http://www.mmweg.rwth-aachen.de/~sebastian.ley/d-i/ip_gtk.so
Sources are here:
http://www.mmweg.rwth-aachen.de/~sebastian.ley/d-i/test_ip.c
It must be linked against gtk.so in src/modules/frontend/gtk
9) Execute the test script again:
$../debconf custom.config
-> As you can see the normal string widget has now been replaced by an
IP address widget. (Note: The widget is quite crappy. It does not
show previously selected values, it is only for demonstration
purposes).
This is an example for a fairly simple widget. It is possible to
create arbitaryly complex widgets with the current design, if the
frontend does allow it.
--
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