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|
/*
* Copyright (C) 2015, 2016, 2017 "IoT.bzh"
* Author "Fulup Ar Foll"
* Author José Bollo <jose.bollo@iot.bzh>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define _GNU_SOURCE
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <pthread.h>
#include <json-c/json.h>
#include <afb/afb-eventid-itf.h>
#include <afb/afb-event.h>
#include "afb-evt.h"
#include "afb-hook.h"
#include "verbose.h"
struct afb_evt_watch;
/*
* Structure for event listeners
*/
struct afb_evt_listener {
/* chaining listeners */
struct afb_evt_listener *next;
/* interface for callbacks */
const struct afb_evt_itf *itf;
/* closure for the callback */
void *closure;
/* head of the list of events listened */
struct afb_evt_watch *watchs;
/* mutex of the listener */
pthread_mutex_t mutex;
/* count of reference to the listener */
int refcount;
};
/*
* Structure for describing events
*/
struct afb_evtid {
/* interface */
struct afb_eventid eventid;
/* next event */
struct afb_evtid *next;
/* head of the list of listeners watching the event */
struct afb_evt_watch *watchs;
/* mutex of the event */
pthread_mutex_t mutex;
/* hooking */
int hookflags;
/* refcount */
int refcount;
/* id of the event */
int id;
/* fullname of the event */
char fullname[1];
};
/*
* Structure for associating events and listeners
*/
struct afb_evt_watch {
/* the evtid */
struct afb_evtid *evtid;
/* link to the next watcher for the same evtid */
struct afb_evt_watch *next_by_evtid;
/* the listener */
struct afb_evt_listener *listener;
/* link to the next watcher for the same listener */
struct afb_evt_watch *next_by_listener;
/* activity */
unsigned activity;
};
/* the interface for events */
static struct afb_eventid_itf afb_evt_eventid_itf = {
.broadcast = (void*)afb_evt_evtid_broadcast,
.push = (void*)afb_evt_evtid_push,
.unref = (void*)afb_evt_evtid_unref,
.name = (void*)afb_evt_evtid_name,
.addref = (void*)afb_evt_evtid_addref
};
/* the interface for events */
static struct afb_eventid_itf afb_evt_hooked_eventid_itf = {
.broadcast = (void*)afb_evt_evtid_hooked_broadcast,
.push = (void*)afb_evt_evtid_hooked_push,
.unref = (void*)afb_evt_evtid_hooked_unref,
.name = (void*)afb_evt_evtid_hooked_name,
.addref = (void*)afb_evt_evtid_hooked_addref
};
/* head of the list of listeners */
static pthread_mutex_t listeners_mutex = PTHREAD_MUTEX_INITIALIZER;
static struct afb_evt_listener *listeners = NULL;
/* handling id of events */
static pthread_mutex_t events_mutex = PTHREAD_MUTEX_INITIALIZER;
static struct afb_evtid *evtids = NULL;
static int event_id_counter = 0;
static int event_id_wrapped = 0;
/*
* Broadcasts the 'event' of 'id' with its 'obj'
* 'obj' is released (like json_object_put)
* Returns the count of listener having receive the event.
*/
static int broadcast(const char *event, struct json_object *obj, int id)
{
int result;
struct afb_evt_listener *listener;
result = 0;
pthread_mutex_lock(&listeners_mutex);
listener = listeners;
while(listener) {
if (listener->itf->broadcast != NULL) {
listener->itf->broadcast(listener->closure, event, id, json_object_get(obj));
result++;
}
listener = listener->next;
}
pthread_mutex_unlock(&listeners_mutex);
json_object_put(obj);
return result;
}
/*
* Broadcasts the 'event' of 'id' with its 'obj'
* 'obj' is released (like json_object_put)
* calls hooks if hookflags isn't 0
* Returns the count of listener having receive the event.
*/
static int hooked_broadcast(const char *event, struct json_object *obj, int id, int hookflags)
{
int result;
json_object_get(obj);
if (hookflags & afb_hook_flag_evt_broadcast_before)
afb_hook_evt_broadcast_before(event, id, obj);
result = broadcast(event, obj, id);
if (hookflags & afb_hook_flag_evt_broadcast_after)
afb_hook_evt_broadcast_after(event, id, obj, result);
json_object_put(obj);
return result;
}
/*
* Broadcasts the event 'evtid' with its 'object'
* 'object' is released (like json_object_put)
* Returns the count of listener that received the event.
*/
int afb_evt_evtid_broadcast(struct afb_evtid *evtid, struct json_object *object)
{
return broadcast(evtid->fullname, object, evtid->id);
}
/*
* Broadcasts the event 'evtid' with its 'object'
* 'object' is released (like json_object_put)
* Returns the count of listener that received the event.
*/
int afb_evt_evtid_hooked_broadcast(struct afb_evtid *evtid, struct json_object *object)
{
return hooked_broadcast(evtid->fullname, object, evtid->id, evtid->hookflags);
}
/*
* Broadcasts the 'event' with its 'object'
* 'object' is released (like json_object_put)
* Returns the count of listener having receive the event.
*/
int afb_evt_broadcast(const char *event, struct json_object *object)
{
return hooked_broadcast(event, object, 0, -1);
}
/*
* Pushes the event 'evtid' with 'obj' to its listeners
* 'obj' is released (like json_object_put)
* Returns the count of listener that received the event.
*/
int afb_evt_evtid_push(struct afb_evtid *evtid, struct json_object *obj)
{
int result;
struct afb_evt_watch *watch;
struct afb_evt_listener *listener;
result = 0;
pthread_mutex_lock(&evtid->mutex);
watch = evtid->watchs;
while(watch) {
listener = watch->listener;
assert(listener->itf->push != NULL);
if (watch->activity != 0) {
listener->itf->push(listener->closure, evtid->fullname, evtid->id, json_object_get(obj));
result++;
}
watch = watch->next_by_evtid;
}
pthread_mutex_unlock(&evtid->mutex);
json_object_put(obj);
return result;
}
/*
* Pushes the event 'evtid' with 'obj' to its listeners
* 'obj' is released (like json_object_put)
* Emits calls to hooks.
* Returns the count of listener taht received the event.
*/
int afb_evt_evtid_hooked_push(struct afb_evtid *evtid, struct json_object *obj)
{
int result;
/* lease the object */
json_object_get(obj);
/* hook before push */
if (evtid->hookflags & afb_hook_flag_evt_push_before)
afb_hook_evt_push_before(evtid->fullname, evtid->id, obj);
/* push */
result = afb_evt_evtid_push(evtid, obj);
/* hook after push */
if (evtid->hookflags & afb_hook_flag_evt_push_after)
afb_hook_evt_push_after(evtid->fullname, evtid->id, obj, result);
/* release the object */
json_object_put(obj);
return result;
}
/*
* remove the 'watch'
*/
static void remove_watch(struct afb_evt_watch *watch)
{
struct afb_evt_watch **prv;
struct afb_evtid *evtid;
struct afb_evt_listener *listener;
/* notify listener if needed */
evtid = watch->evtid;
listener = watch->listener;
if (watch->activity != 0 && listener->itf->remove != NULL)
listener->itf->remove(listener->closure, evtid->fullname, evtid->id);
/* unlink the watch for its event */
prv = &evtid->watchs;
while(*prv != watch)
prv = &(*prv)->next_by_evtid;
*prv = watch->next_by_evtid;
/* unlink the watch for its listener */
prv = &listener->watchs;
while(*prv != watch)
prv = &(*prv)->next_by_listener;
*prv = watch->next_by_listener;
/* recycle memory */
free(watch);
}
/*
* Creates an event of name 'fullname' and returns it or NULL on error.
*/
struct afb_evtid *afb_evt_evtid_create(const char *fullname)
{
size_t len;
struct afb_evtid *evtid, *oevt;
/* allocates the event */
len = strlen(fullname);
evtid = malloc(len + sizeof * evtid);
if (evtid == NULL)
goto error;
/* allocates the id */
pthread_mutex_lock(&events_mutex);
do {
if (++event_id_counter < 0) {
event_id_wrapped = 1;
event_id_counter = 1024; /* heuristic: small numbers are not destroyed */
}
if (!event_id_wrapped)
break;
oevt = evtids;
while(oevt != NULL && oevt->id != event_id_counter)
oevt = oevt->next;
} while (oevt != NULL);
/* initialize the event */
memcpy(evtid->fullname, fullname, len + 1);
evtid->next = evtids;
evtid->watchs = NULL;
evtid->id = event_id_counter;
pthread_mutex_init(&evtid->mutex, NULL);
evtids = evtid;
evtid->hookflags = afb_hook_flags_evt(evtid->fullname);
evtid->eventid.itf = evtid->hookflags ? &afb_evt_hooked_eventid_itf : &afb_evt_eventid_itf;
if (evtid->hookflags & afb_hook_flag_evt_create)
afb_hook_evt_create(evtid->fullname, evtid->id);
pthread_mutex_unlock(&events_mutex);
/* returns the event */
return evtid;
error:
return NULL;
}
/*
* increment the reference count of the event 'evtid'
*/
struct afb_evtid *afb_evt_evtid_addref(struct afb_evtid *evtid)
{
__atomic_add_fetch(&evtid->refcount, 1, __ATOMIC_RELAXED);
return evtid;
}
/*
* increment the reference count of the event 'evtid'
*/
struct afb_evtid *afb_evt_evtid_hooked_addref(struct afb_evtid *evtid)
{
if (evtid->hookflags & afb_hook_flag_evt_addref)
afb_hook_evt_addref(evtid->fullname, evtid->id);
return afb_evt_evtid_addref(evtid);
}
/*
* decrement the reference count of the event 'evtid'
* and destroy it when the count reachs zero
*/
void afb_evt_evtid_unref(struct afb_evtid *evtid)
{
int found;
struct afb_evtid **prv;
struct afb_evt_listener *listener;
if (!__atomic_sub_fetch(&evtid->refcount, 1, __ATOMIC_RELAXED)) {
/* unlinks the event if valid! */
pthread_mutex_lock(&events_mutex);
found = 0;
prv = &evtids;
while (*prv && !(found = (*prv == evtid)))
prv = &(*prv)->next;
if (found)
*prv = evtid->next;
pthread_mutex_unlock(&events_mutex);
/* destroys the event */
if (!found)
ERROR("event not found");
else {
/* removes all watchers */
while(evtid->watchs != NULL) {
listener = evtid->watchs->listener;
pthread_mutex_lock(&listener->mutex);
pthread_mutex_lock(&evtid->mutex);
remove_watch(evtid->watchs);
pthread_mutex_unlock(&evtid->mutex);
pthread_mutex_unlock(&listener->mutex);
}
/* free */
pthread_mutex_destroy(&evtid->mutex);
free(evtid);
}
}
}
/*
* decrement the reference count of the event 'evtid'
* and destroy it when the count reachs zero
*/
void afb_evt_evtid_hooked_unref(struct afb_evtid *evtid)
{
if (evtid->hookflags & afb_hook_flag_evt_unref)
afb_hook_evt_unref(evtid->fullname, evtid->id);
afb_evt_evtid_unref(evtid);
}
/*
* Returns the true name of the 'event'
*/
const char *afb_evt_evtid_fullname(struct afb_evtid *evtid)
{
return evtid->fullname;
}
/*
* Returns the name of the 'event'
*/
const char *afb_evt_evtid_name(struct afb_evtid *evtid)
{
const char *name = strchr(evtid->fullname, '/');
return name ? name + 1 : evtid->fullname;
}
/*
* Returns the name associated to the event 'evtid'.
*/
const char *afb_evt_evtid_hooked_name(struct afb_evtid *evtid)
{
const char *result = afb_evt_evtid_name(evtid);
if (evtid->hookflags & afb_hook_flag_evt_name)
afb_hook_evt_name(evtid->fullname, evtid->id, result);
return result;
}
/*
* Returns the id of the 'event'
*/
int afb_evt_evtid_id(struct afb_evtid *evtid)
{
return evtid->id;
}
/*
* Returns an instance of the listener defined by the 'send' callback
* and the 'closure'.
* Returns NULL in case of memory depletion.
*/
struct afb_evt_listener *afb_evt_listener_create(const struct afb_evt_itf *itf, void *closure)
{
struct afb_evt_listener *listener;
/* search if an instance already exists */
pthread_mutex_lock(&listeners_mutex);
listener = listeners;
while (listener != NULL) {
if (listener->itf == itf && listener->closure == closure) {
listener = afb_evt_listener_addref(listener);
goto found;
}
listener = listener->next;
}
/* allocates */
listener = calloc(1, sizeof *listener);
if (listener != NULL) {
/* init */
listener->itf = itf;
listener->closure = closure;
listener->watchs = NULL;
listener->refcount = 1;
pthread_mutex_init(&listener->mutex, NULL);
listener->next = listeners;
listeners = listener;
}
found:
pthread_mutex_unlock(&listeners_mutex);
return listener;
}
/*
* Increases the reference count of 'listener' and returns it
*/
struct afb_evt_listener *afb_evt_listener_addref(struct afb_evt_listener *listener)
{
__atomic_add_fetch(&listener->refcount, 1, __ATOMIC_RELAXED);
return listener;
}
/*
* Decreases the reference count of the 'listener' and destroys it
* when no more used.
*/
void afb_evt_listener_unref(struct afb_evt_listener *listener)
{
struct afb_evt_listener **prv;
struct afb_evtid *evtid;
if (!__atomic_sub_fetch(&listener->refcount, 1, __ATOMIC_RELAXED)) {
/* unlink the listener */
pthread_mutex_lock(&listeners_mutex);
prv = &listeners;
while (*prv != listener)
prv = &(*prv)->next;
*prv = listener->next;
pthread_mutex_unlock(&listeners_mutex);
/* remove the watchers */
pthread_mutex_lock(&listener->mutex);
while (listener->watchs != NULL) {
evtid = listener->watchs->evtid;
pthread_mutex_lock(&evtid->mutex);
remove_watch(listener->watchs);
pthread_mutex_unlock(&evtid->mutex);
}
pthread_mutex_unlock(&listener->mutex);
/* free the listener */
pthread_mutex_destroy(&listener->mutex);
free(listener);
}
}
/*
* Makes the 'listener' watching 'evtid'
* Returns 0 in case of success or else -1.
*/
int afb_evt_watch_add_evtid(struct afb_evt_listener *listener, struct afb_evtid *evtid)
{
struct afb_evt_watch *watch;
/* check parameter */
if (listener->itf->push == NULL) {
errno = EINVAL;
return -1;
}
/* search the existing watch for the listener */
pthread_mutex_lock(&listener->mutex);
watch = listener->watchs;
while(watch != NULL) {
if (watch->evtid == evtid)
goto found;
watch = watch->next_by_listener;
}
/* not found, allocate a new */
watch = malloc(sizeof *watch);
if (watch == NULL) {
pthread_mutex_unlock(&listener->mutex);
errno = ENOMEM;
return -1;
}
/* initialise and link */
watch->evtid = evtid;
watch->activity = 0;
watch->listener = listener;
watch->next_by_listener = listener->watchs;
listener->watchs = watch;
pthread_mutex_lock(&evtid->mutex);
watch->next_by_evtid = evtid->watchs;
evtid->watchs = watch;
pthread_mutex_unlock(&evtid->mutex);
found:
if (watch->activity == 0 && listener->itf->add != NULL)
listener->itf->add(listener->closure, evtid->fullname, evtid->id);
watch->activity++;
pthread_mutex_unlock(&listener->mutex);
return 0;
}
/*
* Avoids the 'listener' to watch 'evtid'
* Returns 0 in case of success or else -1.
*/
int afb_evt_watch_sub_evtid(struct afb_evt_listener *listener, struct afb_evtid *evtid)
{
struct afb_evt_watch *watch;
/* search the existing watch */
pthread_mutex_lock(&listener->mutex);
watch = listener->watchs;
while(watch != NULL) {
if (watch->evtid == evtid) {
if (watch->activity != 0) {
watch->activity--;
if (watch->activity == 0 && listener->itf->remove != NULL)
listener->itf->remove(listener->closure, evtid->fullname, evtid->id);
}
pthread_mutex_unlock(&listener->mutex);
return 0;
}
watch = watch->next_by_listener;
}
pthread_mutex_unlock(&listener->mutex);
errno = ENOENT;
return -1;
}
/*
* update the hooks for events
*/
void afb_evt_update_hooks()
{
struct afb_evtid *evtid;
pthread_mutex_lock(&events_mutex);
for (evtid = evtids ; evtid ; evtid = evtid->next) {
evtid->hookflags = afb_hook_flags_evt(evtid->fullname);
evtid->eventid.itf = evtid->hookflags ? &afb_evt_hooked_eventid_itf : &afb_evt_eventid_itf;
}
pthread_mutex_unlock(&events_mutex);
}
struct afb_evtid *afb_evt_to_evtid(struct afb_event event)
{
return (struct afb_evtid*)(event.itf == &afb_evt_hooked_eventid_itf ? event.closure : NULL);
}
struct afb_event afb_evt_from_evtid(struct afb_evtid *evtid)
{
return (struct afb_event){ .itf = evtid ? &afb_evt_hooked_eventid_itf : NULL, .closure = &evtid->eventid };
}
/*
* Creates an event of 'fullname' and returns it.
* Returns an event with closure==NULL in case of error.
*/
struct afb_event afb_evt_create_event(const char *fullname)
{
return afb_evt_from_evtid(afb_evt_evtid_create(fullname));
}
/*
* Returns the fullname of the 'event'
*/
const char *afb_evt_event_fullname(struct afb_event event)
{
struct afb_evtid *evtid = afb_evt_to_evtid(event);
return evtid ? evtid->fullname : NULL;
}
/*
* Returns the id of the 'event'
*/
int afb_evt_event_id(struct afb_event event)
{
struct afb_evtid *evtid = afb_evt_to_evtid(event);
return evtid ? evtid->id : 0;
}
/*
* Makes the 'listener' watching 'event'
* Returns 0 in case of success or else -1.
*/
int afb_evt_add_watch(struct afb_evt_listener *listener, struct afb_event event)
{
struct afb_evtid *evtid = afb_evt_to_evtid(event);
/* check parameter */
if (!evtid) {
errno = EINVAL;
return -1;
}
/* search the existing watch for the listener */
return afb_evt_watch_add_evtid(listener, evtid);
}
/*
* Avoids the 'listener' to watch 'event'
* Returns 0 in case of success or else -1.
*/
int afb_evt_remove_watch(struct afb_evt_listener *listener, struct afb_event event)
{
struct afb_evtid *evtid = afb_evt_to_evtid(event);
/* check parameter */
if (!evtid) {
errno = EINVAL;
return -1;
}
/* search the existing watch */
return afb_evt_watch_sub_evtid(listener, evtid);
}
int afb_evt_push(struct afb_event event, struct json_object *object)
{
struct afb_evtid *evtid = afb_evt_to_evtid(event);
if (evtid)
return afb_evt_evtid_hooked_push(evtid, object);
json_object_put(object);
return 0;
}
int afb_evt_unhooked_push(struct afb_event event, struct json_object *object)
{
struct afb_evtid *evtid = afb_evt_to_evtid(event);
if (evtid)
return afb_evt_evtid_push(evtid, object);
json_object_put(object);
return 0;
}
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