Re: Re: Help on development of a gtk frontend for the debian-installer

[attilio <fiandro@tiscalinet.it>]

Hi christian & the world

today i managed to resolve the bugs that previously would not alow the 
gtk fe nor the back/forward mechanism to work correctly (actually only 
select, boolean and string questions work correctly).
I've slightly modified the gtk_go() function with ("//atti" is where 
i've added/changed something)


static int gtk_go(struct frontend *obj)
{
    struct frontend_data *data = (struct frontend_data *) obj->data;
    struct question *q = obj->questions;
    struct question *qaux; // atti+ added as an auxiliary pointer to an 
element of the question list
    int i,j, num_domande=0;
    int ret;
    GtkWidget *questionbox;

    if (q == NULL) return DC_OK;

    data->setters = NULL;
    questionbox = gtk_vbox_new(FALSE, 5);
    gtk_box_pack_start(GTK_BOX(data->target_box),
                       questionbox, FALSE, FALSE, 5);

    /* FIXME: no more description frame
       if (strcmp(q->template->type, "note") != 0 )
       gtk_label_set_text(GTK_LABEL(data->description_label),
       q_get_extended_description(q));
    */


    qaux=q;//+atti num_domande will take count of the question list's 
lenght, while qaux will be a ptr to the last question in the list: it 
will be useful if the user presses the "back" button
    num_domande=1;
    while(qaux->next!=NULL)
    	{
    	num_domande++;
    	qaux=qaux->next;
    	}
    syslog(LOG_DEBUG,"atti - gtk_go() called, question list's lenght: 
%d ",num_domande);

	//if(num_domande>1) q=q->next; //atti + maybe the first question, which 
is always debian-installer/mainmenu should not be shown outside the 
main-menu?

	j=0;
    while (q != 0)
    	{
    	j++;
    	syslog(LOG_DEBUG,"  atti - question %d: %s",j,q->tag);
        for (i = 0; i < DIM(question_handlers); i++)
            if (strcmp(q->template->type, question_handlers[i].type) == 0)
            {
                ret = question_handlers[i].handler(obj, q, questionbox);
                if (ret != DC_OK)
                	{
                    return ret;
                	}
            }
        q->prev=NULL;	//atti+ without this the ASSERT() in frontend.c, 
line 15, fails!
        q = q->next;    	
    	}
	
    q = obj->questions;


    gtk_window_set_title(GTK_WINDOW(data->window), obj->title);
    gtk_widget_set_sensitive (data->button_prev, 
obj->methods.can_go_back(obj, q));
    gtk_widget_grab_default(data->button_next);
    gtk_widget_show_all(data->window);
    gtk_main();

    if (data->button_val == DC_OK)
	    {
		call_setters(obj);

		q = obj->questions;
	
		while (q != NULL)	
			{
		    obj->qdb->methods.set(obj->qdb, q);
		    q = q->next;
			}
		q = obj->questions;
   		}
   		
	else if (data->button_val == DC_GOBACK && q->prev != NULL ) 		
	    {
	    q = qaux;
		q = qaux->prev;
	    }
	q->next=NULL;

    gtk_widget_destroy(questionbox);

    /* FIXME
      gtk_label_set_text(GTK_LABEL(data->description_label), "");
    */


    return DC_OK;

}

as you can see there are some modifications to the original code, they are:
-after displaying a question (after calling the appropriate gtk_handler) 
i set q->prev to NULL: this way the fe no longer crashes if the same 
configuration module is called more than one time in sequence (example: 
i call "kbd chooser" from the main menu two times in sequence).
-I set q->next=NULL , where q is the first question of the list, before 
returning from gtk_go(): this prevents the fe from crashing if the user 
presses the forward button.
-other modifications where done in the    "if (data->button_val == 
DC_OK) {...} else if (data->button_val == DC_GOBACK && q->prev != NULL ) 
{...}"
to make the back mechanism work.

Actually, with this piece of code i was unable to crash the fe with 
configuration modules that uses only strng, boolean or text questions, 
but, even if it works, i don't know exactly why.
because of the lack of documentation about the question lists structure 
i rewrote the code with an "error and retrial" (and many reboots :) 
approach, and this is not an optimal approach.

now that the generalm mechanism seems to work i'm goig to debug the 
other gtk_handlers.
if you wanna try the frontend just get the gtk.c frov svn and replace 
the gtk_go() with this one; i've tested it on a rc2 debian-installer 
(soon on a rc3 too) and i'm using a direct frame buffer graphic system, 
against wich i compile gtk.c .
i've also packed in a tar archive a direct framebuffer environement that 
i use to test the gtk fe with a debian installer: the main problem with 
it is that the only gtk2 library compiled against dfb is about 11 meg: i 
think that a minimal version of that should be crated.

ciao

Attilio