Deferred capability notifications from modules

Reloading modules sends CAP DEL followed by an immediate CAP NEW:

    :staberinde.local CAP * DEL :account-tag
    :staberinde.local CAP * NEW :account-tag

This isn't very nice. /modrestart is particularly bad. In order to avoid
doing this, we remember the capability set at the beginning of module
operations, compare that with the set afterwards, and report only the
differences with CAP {DEL,NEW}.

include/modules.h

@@ -122,6 +122,10 @@ struct mapi_mheader_av2
 void mod_add_path(const char *path);
 void mod_clear_paths(void);
 
+/* cap-notify utilities */
+extern void mod_remember_clicaps(void);
+extern void mod_notify_clicaps(void);
+
 /* load a module */
 extern void load_module(char *path);
 

ircd/modules.c

@@ -80,6 +80,29 @@ init_modules(void)
 	mod_add_path(ircd_paths[IRCD_PATH_AUTOLOAD_MODULES]);
 }
 
+static unsigned int prev_caps;
+
+void
+mod_remember_clicaps(void)
+{
+	prev_caps = capability_index_mask(cli_capindex);
+}
+
+void
+mod_notify_clicaps(void)
+{
+	unsigned int cur_caps = capability_index_mask(cli_capindex);
+	unsigned int del = prev_caps & ~cur_caps;
+	unsigned int new = cur_caps & ~prev_caps;
+
+	if (del)
+		sendto_local_clients_with_capability(CLICAP_CAP_NOTIFY, ":%s CAP * DEL :%s",
+				me.name, capability_index_list(cli_capindex, del));
+	if (new)
+		sendto_local_clients_with_capability(CLICAP_CAP_NOTIFY, ":%s CAP * NEW :%s",
+				me.name, capability_index_list(cli_capindex, new));
+}
+
 /* mod_find_path()
  *
  * input	- path
@@ -382,10 +405,7 @@ unload_one_module(const char *name, bool warn)
 					}
 
 					if (m->cap_id != NULL)
-					{
 						capability_orphan(idx, m->cap_name);
-						sendto_local_clients_with_capability(CLICAP_CAP_NOTIFY, ":%s CAP * DEL :%s", me.name, m->cap_name);
-					}
 				}
 			}
 			break;
@@ -600,10 +620,7 @@ load_a_module(const char *path, bool warn, int origin, bool core)
 
 					result = capability_put(idx, m->cap_name, m->cap_ownerdata);
 					if (m->cap_id != NULL)
-					{
 						*(m->cap_id) = result;
-						sendto_local_clients_with_capability(CLICAP_CAP_NOTIFY, ":%s CAP * ADD :%s", me.name, m->cap_name);
-					}
 				}
 			}
 		}
@@ -671,6 +688,8 @@ modules_do_restart(void *unused)
 	unsigned int modnum = 0;
 	rb_dlink_node *ptr, *nptr;
 
+	mod_remember_clicaps();
+
 	RB_DLINK_FOREACH_SAFE(ptr, nptr, module_list.head)
 	{
 		struct module *mod = ptr->data;
@@ -694,6 +713,8 @@ modules_do_restart(void *unused)
 	load_core_modules(false);
 	rehash(false);
 
+	mod_notify_clicaps();
+
 	sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
 			     "Module Restart: %u modules unloaded, %lu modules loaded",
 			     modnum, rb_dlink_list_length(&module_list));

modules/core/m_modules.c

@@ -274,9 +274,13 @@ do_modload(struct Client *source_p, const char *module)
 		return;
 	}
 
+	mod_remember_clicaps();
+
 	origin = strcmp(module, m_bn) == 0 ? MAPI_ORIGIN_CORE : MAPI_ORIGIN_EXTENSION;
 	load_one_module(module, origin, false);
 
+	mod_notify_clicaps();
+
 	rb_free(m_bn);
 }
 
@@ -300,9 +304,13 @@ do_modunload(struct Client *source_p, const char *module)
 		return;
 	}
 
+	mod_remember_clicaps();
+
 	if(unload_one_module(m_bn, true) == false)
 		sendto_one_notice(source_p, ":Module %s is not loaded", m_bn);
 
+	mod_notify_clicaps();
+
 	rb_free(m_bn);
 }
 
@@ -322,6 +330,8 @@ do_modreload(struct Client *source_p, const char *module)
 
 	check_core = mod->core;
 
+	mod_remember_clicaps();
+
 	if(unload_one_module(m_bn, true) == false)
 	{
 		sendto_one_notice(source_p, ":Module %s is not loaded", m_bn);
@@ -337,6 +347,8 @@ do_modreload(struct Client *source_p, const char *module)
 		exit(0);
 	}
 
+	mod_notify_clicaps();
+
 	rb_free(m_bn);
 }