Fix idle_enterers when using recursive main loops.

Fix idle_enterers when using recursive main loops.

If an idle_enterer created a recursive main loop (just called
ecore_main_loop_begin()), then this recursive main loop should
continue to process idle_enterers from there and on, thus
idle_enterer_current was added. When going back from recursion, the
current iterator should be updated properly.

This patch also fixes the deletion of idle_enterers from recursive
main loops by reference counting them. This way, the node will not be
free()d inside inner loop cleanups and then crash when going back to
outer loop.

The following test case used to crash but not anymore:

#include <Ecore.h>
#include <Eina.h>

static int _log_dom;
#define INF(...) EINA_LOG_DOM_INFO(_log_dom, __VA_ARGS__)

static Ecore_Idle_Enterer *handle;

static int idler(void *data)
{
    INF("idler");
    return 1;
}

static int cb2(void *data)
{
    INF("cb2 - delete cb1 handle");
    ecore_idle_enterer_del(handle);
    ecore_main_loop_quit(); /* quits inner main loop */
    return 0;
}

static int cb1(void *data)
{
    INF("cb1: begin");
    INF("    add cb2");
    ecore_idle_enterer_add(cb2, NULL);
    INF("    inner main loop begin (recurse)");
    ecore_main_loop_begin(); /* will it crash due ecore_idle_enterer_del(handle)
                              * inside cb2()? It used to!
                              */
    INF("cb1: end");

    ecore_main_loop_quit(); /* quits outer main loop */

    return 0;
}

int main(void)
{
    ecore_init();

    _log_dom = eina_log_domain_register("test", EINA_COLOR_CYAN);

    /*
     * Creating a new main loop from inside an idle_enterer callback,
     * and inside this new (inner) main loop deleting the caller
     * callback used to crash since the handle would be effectively
     * free()d, but when the recursion is over the pointer would be
     * used.
     */

    INF("main: begin");
    handle = ecore_idle_enterer_add(cb1, NULL);
    ecore_idler_add(idler, NULL);
    ecore_main_loop_begin();
    INF("main: end");
    return 0;
}

git-svn-id: svn+ssh://svn.enlightenment.org/var/svn/e/trunk/ecore@46408 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33