140 lines
2.8 KiB
C
140 lines
2.8 KiB
C
/*
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* BIRD Library -- Event Processing
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*
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* (c) 1999 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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/**
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* DOC: Events
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*
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* Events are there to keep track of deferred execution.
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* Since BIRD is single-threaded, it requires long lasting tasks to be split to smaller
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* parts, so that no module can monopolize the CPU. To split such a task, just create
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* an &event resource, point it to the function you want to have called and call ev_schedule()
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* to ask the core to run the event when nothing more important requires attention.
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*
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* You can also define your own event lists (the &event_list structure), enqueue your
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* events in them and explicitly ask to run them.
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*/
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#include "nest/bird.h"
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#include "lib/event.h"
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event_list global_event_list;
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inline void
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ev_postpone(event *e)
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{
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if (e->n.next)
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{
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rem_node(&e->n);
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e->n.next = NULL;
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}
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}
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static void
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ev_dump(resource *r)
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{
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event *e = (event *) r;
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debug("(code %p, data %p, %s)\n",
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e->hook,
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e->data,
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e->n.next ? "scheduled" : "inactive");
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}
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static struct resclass ev_class = {
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"Event",
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sizeof(event),
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(void (*)(resource *)) ev_postpone,
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ev_dump
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};
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/**
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* ev_new - create a new event
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* @p: resource pool
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*
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* This function creates a new event resource. To use it,
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* you need to fill the structure fields and call ev_schedule().
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*/
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event *
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ev_new(pool *p)
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{
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event *e = ralloc(p, &ev_class);
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e->hook = NULL;
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e->data = NULL;
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e->n.next = NULL;
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return e;
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}
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/**
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* ev_run - run an event
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* @e: an event
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*
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* This function explicitly runs the event @e (calls its hook
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* function) and removes it from an event list if it's linked to any.
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*
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* From the hook function, you can call ev_enqueue() or ev_schedule()
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* to re-add the event.
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*/
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inline void
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ev_run(event *e)
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{
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ev_postpone(e);
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e->hook(e->data);
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}
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/**
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* ev_enqueue - enqueue an event
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* @l: an event list
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* @e: an event
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*
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* ev_enqueue() stores the event @e to the specified event
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* list @l which can be run by calling ev_run_list().
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*/
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inline void
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ev_enqueue(event_list *l, event *e)
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{
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ev_postpone(e);
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add_tail(l, &e->n);
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}
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/**
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* ev_schedule - schedule an event
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* @e: an event
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*
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* This function schedules an event by enqueueing it to a system-wide
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* event list which is run by the platform dependent code whenever
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* appropriate.
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*/
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void
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ev_schedule(event *e)
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{
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ev_enqueue(&global_event_list, e);
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}
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/**
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* ev_run_list - run an event list
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* @l: an event list
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*
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* This function calls ev_run() for all events enqueued in the list @l.
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*/
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int
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ev_run_list(event_list *l)
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{
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node *n, *p;
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list tmp_list;
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init_list(&tmp_list);
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add_tail_list(&tmp_list, l);
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init_list(l);
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WALK_LIST_DELSAFE(n, p, tmp_list)
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{
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event *e = SKIP_BACK(event, n, n);
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ev_run(e);
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}
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return !EMPTY_LIST(*l);
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}
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