Make model reference non-constant

Author: kyechou

src/api.cpp

@@ -6,17 +6,17 @@
 class API {
 public:
     static void initialize(State *state) {
-        Model::get().set_state(state);
+        model.set_state(state);
         Plankton::get().initialize();
     }
 
     static void exec_step(State *state) {
-        Model::get().set_state(state);
+        model.set_state(state);
         Plankton::get().exec_step();
     }
 
     static void report(State *state) {
-        Model::get().set_state(state);
+        model.set_state(state);
         Plankton::get().report();
     }
 

src/model-access.cpp

@@ -63,7 +63,7 @@ VariableHist::~VariableHist() {
 }
 
 static VariableHist storage;
-const Model &model = Model::get();
+Model &model = Model::get();
 
 Model::Model() : state(nullptr), network(nullptr), openflow(nullptr) {}
 

src/model-access.hpp

@@ -121,4 +121,4 @@ class Model {
     ReachCounts *set_reach_counts(ReachCounts &&) const;
 };
 
-extern const Model &model;
+extern Model &model;

src/plankton.cpp

@@ -333,7 +333,7 @@ void Plankton::ec_sig_handler(int sig) {
 /***** functions used by the Promela network model *****/
 
 void Plankton::initialize() {
-    Model::get().init(&_network, &_openflow);
+    model.init(&_network, &_openflow);
 
     // processes
     _forwarding.init(_network);