More gracefully handle offline downgrade

Author: johnwparent

gpt4all-updater/src/CommandFactory.cxx

@@ -14,16 +14,25 @@ std::shared_ptr<Command> CommandFactory::GetCommand(CommandType type)
 #ifdef OFFLINE
     // If we're offline, we're only installing or removing
     gpt4all::state::Gpt4AllState::getInstance().driveOffline();
+    // This command always removes the current install
+    // only return a command if updating
+    if (type == CommandType::UPDATE)
+    {
+        active_command = std::make_shared<gpt4all::updater::Update>(gpt4all::state::Gpt4AllState::getInstance().getInstaller());
+    }
+    else {
+        active_command = std::shared_ptr<gpt4all::command::Command>(nullptr);
+    }
 #else
     if (type == CommandType::UPDATE || type == CommandType::DOWNGRADE) {
         gpt4all::download::Download::instance()->driveFetchAndInstall();
     }
     else {
         if(!gpt4all::state::Gpt4AllState::getInstance().getExistingInstaller()){
             qWarning() << "Unable to execute requested command, requires existing installation of gpt4all";
+            QCoreApplication.exit(1);
         }
     }
-#endif
     QFile &installer = gpt4all::state::Gpt4AllState::getInstance().getInstaller();
     switch(type){
         case CommandType::UPDATE:
@@ -35,5 +44,6 @@ std::shared_ptr<Command> CommandFactory::GetCommand(CommandType type)
         case CommandType::UNINSTALL:
             active_command = std::make_shared<gpt4all::uninstall::Uninstall>(installer);
     }
+#endif
     return active_command;
 }

gpt4all-updater/src/main.cxx

@@ -14,6 +14,7 @@ int main(int argc, char ** argv)
     CommandFactory cmd;
     gpt4all::command::CommandType command_type(cli.command());
     std::shared_ptr<gpt4all::command::Command> installer_command = cmd.GetCommand(command_type);
-    installer_command->execute();
+    if(installer_command)
+        installer_command->execute();
     return 0;
 }