Add ability to subscribe to service events

Each service can subscribe to one or more events from other services, the only knowledge needed is the service name
and event name which can be taken fron service documentation
Serice manager distributes the events between services.
Infinite service event loop is possible, so care must be taken when designing service event path

Author: sharky76

libZaeUtil/service.h

@@ -22,22 +22,30 @@ typedef struct service_method_t
     variant_t*  (*eval_callback)(struct service_method_t*, va_list);
 } service_method_t;
 
+typedef struct event_subscription_t
+{
+    char*   source;
+    void    (*on_event)(const char*, event_t*);
+} event_subscription_t;
+
 typedef struct service_t
 {
     int         service_id;
     char*       service_name;
     char*       description;
     char**      (*get_config_callback)(void);
-    void        (*on_event)(const char*, event_t*);
+    //void        (*on_event)(const char*, event_t*);
     variant_stack_t*    service_methods;
+    variant_stack_t*    event_subscriptions;
 } service_t;
 
 #define SERVICE_INIT(_name, _desc)  \
 *service = (service_t*)calloc(1, sizeof(service_t)); \
 (*service)->service_name = strdup(#_name);  \
 (*service)->description = strdup(_desc);    \
 (*service)->service_id = service_id;        \
-(*service)->service_methods = stack_create();
+(*service)->service_methods = stack_create(); \
+(*service)->event_subscriptions = stack_create();
 
 #define SERVICE_ADD_METHOD(_method_name, _method, _nargs, _help) \
 service_method_t* _method_name = (service_method_t*)malloc(sizeof(service_method_t));  \
@@ -47,8 +55,16 @@ service_method_t* _method_name = (service_method_t*)malloc(sizeof(service_method
     _method_name->eval_callback = &_method;    \
     stack_push_back((*service)->service_methods, variant_create_ptr(service_id, _method_name, NULL)); \
 
-#define SERVICE_ADD_EVENT_HANDLER(_handler)   \
-    (*service)->on_event = _handler
+//#define SERVICE_ADD_EVENT_HANDLER(_handler)   \
+//    (*service)->on_event = _handler
+
+#define SERVICE_SUBSCRIBE_TO_EVENT_SOURCE(_source_, _handler_) \
+    {   \
+        event_subscription_t* es = (event_subscription_t*)malloc(sizeof(event_subscription_t)); \
+        es->source = strdup(_source_);  \
+        es->on_event = _handler_;   \
+        stack_push_back((*service)->event_subscriptions, variant_create_ptr(DT_PTR, es, variant_delete_none)); \
+    }
 
 void    service_create(service_t** service, int service_id);
 void    service_cli_create(cli_node_t* parent_node);

libZaeUtil/variant.h

@@ -43,6 +43,9 @@ typedef struct variant_t
     int     (*compare_cb)(const struct variant_t* v, const struct variant_t* other);
 } variant_t;
 
+#define VARIANT_GET_PTR(_type_, _var_)  \
+    (_type_*)variant_get_ptr(_var_)
+
 variant_t*  variant_create(VariantDataType type, void* data);
 void        variant_delete_default(void* ptr);
 void        variant_delete_variant(void* ptr);

service_manager.c

@@ -191,14 +191,18 @@ void    service_manager_on_event(event_t* event)
     {
         service_t* service = (service_t*)variant_get_ptr(service_variant);
 
-        if(NULL != service->on_event)
+        //if(NULL != service->on_event)
+        service_t* calling_service = service_manager_get_class_by_id(event->source_id);
+        if(NULL != calling_service )
         {
-            service_t* calling_service = service_manager_get_class_by_id(event->source_id);
-
-            if(NULL != calling_service)
+            stack_for_each(service->event_subscriptions, event_subscription_variant)
             {
-                LOG_DEBUG(ServiceManager, "Forward event from: %s to service: %s", calling_service->service_name, service->service_name);
-                service->on_event(calling_service->service_name, event);
+                event_subscription_t* es = VARIANT_GET_PTR(event_subscription_t, event_subscription_variant);
+                if(strcmp(es->source, calling_service->service_name) == 0)
+                {
+                    LOG_DEBUG(ServiceManager, "Forward event from: %s to service: %s", calling_service->service_name, service->service_name);
+                    es->on_event(calling_service->service_name, event);
+                }
             }
         }
     }

services/Cron/Cron.c

@@ -13,11 +13,11 @@ void  timer_tick_event(const char* name, event_t* pevent);
 void  service_create(service_t** service, int service_id)
 {
     SERVICE_INIT(Cron, "Provides cron-like ability to execute scenes or commands at pre defined times");
-    SERVICE_ADD_EVENT_HANDLER(timer_tick_event);
 
     DT_CRON = service_id;
 
     (*service)->get_config_callback = cron_cli_get_config;
+    SERVICE_SUBSCRIBE_TO_EVENT_SOURCE("Timer", timer_tick_event);
 
     // Test
     /*crontab_time_t ee;
@@ -115,7 +115,7 @@ void    service_cli_create(cli_node_t* parent_node)
  */
 void  timer_tick_event(const char* name, event_t* pevent)
 {
-    if(++timer_tick_counter > 60)
+    if(++timer_tick_counter > 60 && strcmp(variant_get_string(pevent->data), "tick") == 0)
     {
         timer_tick_counter = 0;
         LOG_DEBUG(DT_CRON, "Event %s tick", name);