Now using a std::async and future to do an async popen but I also need the FILE read in read_line to be async, so now I'm at a point where I have to refactor into a better statemachine.

builder.cpp

@@ -19,10 +19,12 @@
 #include <unistd.h>
 #include <nlohmann/json.hpp>
 #include <fstream>
+#include <future>
 
 using std::string;
 using namespace fmt;
 using namespace nlohmann;
+using namespace std::chrono_literals;
 
 #define BUF_MAX 1024
 
@@ -37,6 +39,7 @@ Builder::Builder(GUI &g, GameEngine &engine)
 }
 
 FILE *start_command(string &build_cmd) {
+  println(">>>>>>>>> start_command {}", build_cmd);
   FILE *build_out = popen(build_cmd.c_str(), "r");
   dbc::check(build_out != nullptr, "Failed to run command.");
   return build_out;
@@ -80,9 +83,10 @@ MatchResult Builder::parse_line(const string &line) {
 }
 
 enum BuildState {
-  WAITING, BUILDING, DONE
+  WAITING, BUILDING, DONE, STARTING, READING
 };
 
+
 void Builder::run() {
   git_repository* repo = nullptr;
 
@@ -104,7 +108,9 @@ void Builder::run() {
 
     FILE *build_out = NULL;
     bool build_done = false;
+    string line = "";
     BuildState state = WAITING;
+    std::future<FILE *> build_fut;
 
     fileWatcher->watch();
 
@@ -115,15 +121,34 @@ void Builder::run() {
           game.start_round();
           gui.building();
           gui.output(format("CHANGES! Running build {}", build_cmd));
-          build_out = start_command(build_cmd);
-          state = BUILDING;
+          build_fut = std::async([&]() {
+              return start_command(build_cmd);
+          });
+          state = STARTING;
         }
       break;
 
-      case BUILDING: {
-          // check if there's output
-          string line = read_line(build_out, build_done);
+      case STARTING: {
+          println(">>> STARTING");
+          std::future_status status = build_fut.wait_for(0ms);
 
+          if(status == std::future_status::ready) {
+            build_out = build_fut.get();
+            state = READING;
+          } else {
+            state = STARTING;
+          }
+        }
+        break;
+
+      case READING: {
+          line = read_line(build_out, build_done);
+          state = BUILDING;
+          }
+      break;
+      case BUILDING: {
+          println(">>> BUILDING");
+          // check if there's output
           if(build_done) {
             bool good = end_build(build_out, gui, build_cmd);
 
@@ -143,7 +168,7 @@ void Builder::run() {
               gui.output(format("HIT WITH {} @ {}:{}:{} {}", m.type, m.file_name, m.lnumber, m.col, m.message));
               game.hit(m.type);
             }
-            state = BUILDING;
+            state = READING;
           }
        }
       break;