Improve subscription/unsubscription operation.

Break operations into 2 new functions to improve
readability and added some comments too.

Change-Id: I405622ef17787cb39d8d2b2530a2d6572ce4e366
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>

diff --git a/src/low-can-binding.cpp b/src/low-can-binding.cpp
index 2fee114..ea8803f 100644 (file)
--- a/src/low-can-binding.cpp
+++ b/src/low-can-binding.cpp
@@ -86,51 +86,63 @@ int can_frame_received(sd_event_source *s, int fd, uint32_t revents, void *userd
 *
 *********************************************************************************/
 
+static int make_subscription_unsubscription(struct afb_req request, std::map<std::string, struct afb_event>::iterator& ss_i, bool subscribe)
+{
+       /* Make the subscription or unsubscription to the event */
+       if (((subscribe ? afb_req_subscribe : afb_req_unsubscribe)(request, ss_i->second)) < 0)
+       {
+               ERROR(binder_interface, "Operation goes wrong for signal: %s", ss_i->first);
+               return 0;
+       }
+       return 1;
+
+}
+
+static int create_event_handle(std::map<std::string, struct afb_event>::iterator& ss_i)
+{
+       ss_i->second = afb_daemon_make_event(binder_interface->daemon, ss_i->first.c_str());
+       if (!afb_event_is_valid(ss_i->second)) 
+       {
+               ERROR(binder_interface, "Can't create an event, something goes wrong.");
+               return 0;
+       }
+
+       return 1;
+}
+
 static int subscribe_unsubscribe_signal(struct afb_req request, bool subscribe, const CanSignal& sig)
 {
        int ret;
 
        // TODO: lock the subscribed_signals when insert/remove
-       const auto& ss_i = subscribed_signals.find(sig.genericName);
-       if (ss_i != subscribed_signals.end())
+       auto ss_i = subscribed_signals.find(sig.genericName);
+       if (ss_i != subscribed_signals.end() && !afb_event_is_valid(ss_i->second))
        {
-               if(!afb_event_is_valid(ss_i->second))
+               if(!subscribe)
                {
-                       if(!subscribe)
-                       {
-                               NOTICE(binder_interface, "Event isn't valid, it can't be unsubscribed.");
-                               ret = 1;
-                       }
-                       else
-                       {
-                               ss_i->second = afb_daemon_make_event(binder_interface->daemon, ss_i->first.c_str());
-                               if (!afb_event_is_valid(ss_i->second)) 
-                               {
-                                       ERROR(binder_interface, "Can't create an event, something goes wrong.");
-                                       ret = 0;
-                               }
-                       }
+                       NOTICE(binder_interface, "Event isn't valid, it can't be unsubscribed.");
+                       ret = -1;
                }
-       }
-       else
-       {
-               subscribed_signals[sig.genericName] = afb_daemon_make_event(binder_interface->daemon, sig.genericName);
-               if (!afb_event_is_valid(ss_i->second)) 
+               else
                {
-                       ERROR(binder_interface, "Can't create an event, something goes wrong.");
-                       ret = 0;
+                       /* Event it isn't valid annymore, recreate it */
+                       ret = create_event_handle(ss_i);
                }
        }
-
-       if (((subscribe ? afb_req_subscribe : afb_req_unsubscribe)(request, subscribed_signals[sig.genericName])) < 0)
+       else
        {
-               ERROR(binder_interface, "Operation goes wrong for signal: %s", sig.genericName);
-               ret = 0;
+               /* Event don't exist , so let's create it */
+               struct afb_event empty_event = {nullptr, nullptr};
+               auto ss_i = subscribed_signals.insert(std::make_pair(sig.genericName, empty_event));
+               ret = create_event_handle(ss_i.first);
        }
-       else
-               ret = 1;
-       
-       return ret;
+
+       /* Check whether or not the event handler has been correctly created and
+        * make the subscription/unsubscription operation is so.
+        */
+       if (ret <= 0)
+               return ret;
+       return make_subscription_unsubscription(request, ss_i, subscribe);
 }
 
 static int subscribe_unsubscribe_signals(struct afb_req request, bool subscribe, const std::vector<CanSignal>& signals)