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elinks/src/main/event.c
Petr Baudis 0f6d4310ad Initial commit of the HEAD branch of the ELinks CVS repository, as of
Thu Sep 15 15:57:07 CEST 2005. The previous history can be added to this
by grafting.
2005-09-15 15:58:31 +02:00

330 lines
6.7 KiB
C

/* Event handling functions */
/* $Id: event.c,v 1.27 2005/06/13 00:43:28 jonas Exp $ */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "elinks.h"
#include "main/event.h"
#include "util/error.h"
#include "util/hash.h"
#include "util/memory.h"
#include "util/snprintf.h"
#include "util/string.h"
/* First, we should set some terminology:
*
* o event -> Message being [triggerred] by some ELinks part and [catched]
* by various random other ones.
*
* o event hook -> Device being deployed by various ELinks parts,
* associated with certain [event It [catches] that event by having a
* handler executed when the [event] is triggerred.
*
* o event chain -> Line of [event hook]s associated with a given [event
* The [hook]s are ordered by [priority Each hook returns whenever should
* the chain continue or that no other events in the chain should be
* triggered (TODO).
*/
struct event_handler {
/* The function to be called with the event data. */
event_hook_T callback;
/* The @priority of this handler. */
int priority;
/* Handler specific data. */
void *data;
};
struct event {
/* The event name has to be unique. */
unsigned char *name;
/* There are @count event @handlers all ordered by priority. */
struct event_handler *handlers;
unsigned int count;
/* The unique event id and position in events. */
int id;
};
static struct event *events = NULL;
static unsigned int eventssize = 0;
static struct hash *event_hash = NULL;
/* TODO: This should be tuned to the number of events. When we will have a lot
* of them, this should be some big enough number to reduce unnecessary
* slavery of CPU on the startup. Then after all main modules will be
* initialized and their events will be registered, we could call something
* like adjust_events_list() which will tune it to the exactly needed number.
* This should be also called after each new plugin loaded. */
#define EVENT_GRANULARITY 0x07
#define realloc_events(ptr, size) \
mem_align_alloc(ptr, (size), (size) + 1, struct event, EVENT_GRANULARITY)
static inline int
invalid_event_id(register int id)
{
return (id < 0 || id >= eventssize || id == EVENT_NONE);
}
int
register_event(unsigned char *name)
{
int id = get_event_id(name);
struct event *event;
int namelen;
if (id != EVENT_NONE) return id;
event = events;
if (!realloc_events(&events, eventssize)) return EVENT_NONE;
/* If @events got relocated update the hash. */
if (event != events) {
for (id = 0; id < eventssize; id++) {
struct hash_item *item;
int len = strlen(events[id].name);
item = get_hash_item(event_hash, events[id].name, len);
if (item) item->value = &events[id];
}
}
event = &events[eventssize];
namelen = strlen(name);
event->name = memacpy(name, namelen);
if (!event->name) return EVENT_NONE;
if (!add_hash_item(event_hash, event->name, namelen, event)) {
mem_free(event->name);
event->name = NULL;
return EVENT_NONE;
}
event->handlers = NULL;
event->count = 0;
event->id = eventssize++;
return event->id;
}
int
get_event_id(unsigned char *name)
{
struct hash_item *item;
int namelen;
assertm(name && name[0], "Empty or missing event name");
if_assert_failed return EVENT_NONE;
if (!event_hash) return EVENT_NONE;
namelen = strlen(name);
item = get_hash_item(event_hash, name, namelen);
if (item) {
struct event *event = item->value;
assertm(event, "Hash item with no value");
if_assert_failed return EVENT_NONE;
return event->id;
}
return EVENT_NONE;
}
unsigned char *
get_event_name(int id)
{
if (invalid_event_id(id)) return NULL;
return events[id].name;
}
static inline void
trigger_event_va(int id, va_list ap_init)
{
int i;
struct event_handler *ev_handler;
if (invalid_event_id(id)) return;
ev_handler = events[id].handlers;
for (i = 0; i < events[id].count; i++, ev_handler++) {
enum evhook_status ret;
va_list ap;
VA_COPY(ap, ap_init);
ret = ev_handler->callback(ap, ev_handler->data);
va_end(ap);
if (ret == EVENT_HOOK_STATUS_LAST) return;
}
}
void
trigger_event(int id, ...)
{
va_list ap;
va_start(ap, id);
trigger_event_va(id, ap);
}
void
trigger_event_name(unsigned char *name, ...)
{
va_list ap;
int id = get_event_id(name);
va_start(ap, name);
trigger_event_va(id, ap);
}
static inline void
move_event_handler(struct event *event, int to, int from)
{
int d = int_max(to, from);
memmove(&event->handlers[to], &event->handlers[from],
(event->count - d) * sizeof(*event->handlers));
}
int
register_event_hook(int id, event_hook_T callback, int priority, void *data)
{
struct event *event;
int i;
assert(callback);
if_assert_failed return EVENT_NONE;
if (invalid_event_id(id)) return EVENT_NONE;
event = &events[id];
for (i = 0; i < event->count; i++)
if (event->handlers[i].callback == callback) break;
if (i == event->count) {
struct event_handler *eh;
eh = mem_realloc(event->handlers,
(event->count + 1) * sizeof(*event->handlers));
if (!eh) return EVENT_NONE;
event->handlers = eh;
event->count++;
} else {
move_event_handler(event, i, i + 1);
}
for (i = 0; i < event->count - 1; i++)
if (event->handlers[i].priority < priority) break;
move_event_handler(event, i + 1, i);
event->handlers[i].callback = callback;
event->handlers[i].priority = priority;
event->handlers[i].data = data;
return id;
}
void
unregister_event_hook(int id, event_hook_T callback)
{
struct event *event;
assert(callback);
if_assert_failed return;
if (invalid_event_id(id)) return;
event = &events[id];
if (event->handlers) {
int i;
for (i = 0; i < event->count; i++) {
if (event->handlers[i].callback != callback)
continue;
move_event_handler(event, i, i + 1);
event->count--;
if (!event->count) {
mem_free(event->handlers);
event->handlers = NULL;
} else {
struct event_handler *eh;
eh = mem_realloc(event->handlers,
event->count * sizeof(*event->handlers));
if (eh) event->handlers = eh;
}
break;
}
}
}
void
register_event_hooks(struct event_hook_info *hooks)
{
int i;
for (i = 0; hooks[i].name; i++) {
int id = register_event(hooks[i].name);
if (id == EVENT_NONE) continue;
register_event_hook(id, hooks[i].callback, hooks[i].priority,
hooks[i].data);
}
}
void
unregister_event_hooks(struct event_hook_info *hooks)
{
int i;
for (i = 0; hooks[i].name; i++) {
int id = get_event_id(hooks[i].name);
if (id == EVENT_NONE) continue;
unregister_event_hook(id, hooks[i].callback);
}
}
void
init_event(void)
{
event_hash = init_hash(8, strhash);
}
void
done_event(void)
{
int i;
if (event_hash) free_hash(event_hash);
for (i = 0; i < eventssize; i++) {
mem_free_if(events[i].handlers);
mem_free(events[i].name);
}
mem_free_set(&events, NULL);
eventssize = 0;
}