refactor(split): add app splitting() function

src/meta/meta_data.h

@@ -359,6 +359,7 @@ class app_state : public app_info
         dsn::blob result = dsn::json::json_forwarder<app_info>::encode(another);
         return result;
     }
+    bool splitting() const { return helpers->split_states.splitting_count > 0; }
 };
 
 typedef std::set<dsn::gpid> partition_set;

src/meta/meta_split_service.cpp

@@ -71,7 +71,7 @@ void meta_split_service::start_partition_split(start_split_rpc rpc)
             return;
         }
 
-        if (app->helpers->split_states.splitting_count > 0) {
+        if (app->splitting()) {
             response.err = ERR_BUSY;
             auto err_msg =
                 fmt::format("app({}) is already executing partition split", request.app_name);
@@ -318,7 +318,7 @@ void meta_split_service::query_partition_split(query_split_rpc rpc) const
         return;
     }
 
-    if (app->helpers->split_states.splitting_count <= 0) {
+    if (!app->splitting()) {
         response.err = ERR_INVALID_STATE;
         response.__set_hint_msg(fmt::format("app({}) is not splitting", app_name));
         derror_f("query partition split failed, {}", response.hint_msg);
@@ -349,7 +349,7 @@ void meta_split_service::control_partition_split(control_split_rpc rpc)
         return;
     }
 
-    if (app->helpers->split_states.splitting_count <= 0) {
+    if (!app->splitting()) {
         response.err = ERR_INVALID_STATE;
         response.__set_hint_msg(fmt::format("app({}) is not splitting", req.app_name));
         derror_f("{} split failed, {}", control_type_str(control_type), response.hint_msg);

src/meta/server_state.cpp

@@ -791,7 +791,7 @@ void server_state::on_config_sync(configuration_query_by_node_rpc rpc)
                 response.partitions[i].host_node = request.node;
                 // set meta_split_status
                 const split_state &app_split_states = app->helpers->split_states;
-                if (app_split_states.splitting_count > 0) {
+                if (app->splitting()) {
                     auto iter = app_split_states.status.find(pid.get_partition_index());
                     if (iter != app_split_states.status.end()) {
                         response.partitions[i].__set_meta_split_status(iter->second);