Add error handling when NvimServer could not be started correctly

NvimView/NvimServer/main.c

@@ -30,6 +30,7 @@ int main(int argc, const char *argv[]) {
       "Started NvimServer '%s' and connected it with GUI '%s'.",
       local_port_name, remote_port_name
   );
+
   CFRunLoopRun();
   os_log_debug(logger, "NvimServer exiting.");
 

NvimView/NvimServer/server.c

@@ -84,6 +84,12 @@ static void do_autocmd_guienter(void **argv);
 // We declare nvim_main because it's not declared in any header files of neovim
 extern int nvim_main(int argc, const char **argv);
 
+#ifdef DEBUG
+
+void debug_function() {
+}
+
+#endif
 
 void server_set_nvim_args(int argc, const char **const argv) {
   nvim_argc = argc + 1;
@@ -108,6 +114,14 @@ void server_init_local_port(const char *name) {
   );
   CFRelease(name_cf);
 
+  if (local_port == NULL) {
+    send_msg_packing(NvimServerMsgIdFatalError, ^(msgpack_packer *packer) {
+      msgpack_pack_int64(packer, NvimServerFatalErrorCodeLocalPort);
+    });
+
+    exit(NvimServerFatalErrorCodeLocalPort);
+  }
+
   cond_var_t cond_var;
   cond_var_init(&cond_var, 5, false);
 
@@ -136,6 +150,14 @@ void server_init_remote_port(const char *name) {
   );
   remote_port = CFMessagePortCreateRemote(kCFAllocatorDefault, name_cf);
   CFRelease(name_cf);
+
+  if (remote_port == NULL) {
+    send_msg_packing(NvimServerMsgIdFatalError, ^(msgpack_packer *packer) {
+      msgpack_pack_int64(packer, NvimServerFatalErrorCodeRemotePort);
+    });
+
+    exit(NvimServerFatalErrorCodeRemotePort);
+  }
 }
 
 void server_destroy_remote_port() {

NvimView/NvimServer/server.h

@@ -24,4 +24,8 @@ void send_msg_packing(NvimServerMsgId msgid, pack_block body);
 void msgpack_pack_bool(msgpack_packer *packer, bool value);
 void msgpack_pack_cstr(msgpack_packer *packer, const char *cstr);
 
+#ifdef DEBUG
+void debug_function(void);
+#endif
+
 #endif // NVIMSERVER_SERVER_H

NvimView/NvimServer/server_shared_types.h

@@ -46,9 +46,16 @@ typedef CF_ENUM(NSInteger, NvimServerMsgId) {
   NvimServerMsgIdAutoCommandEvent,
   NvimServerMsgIdRpcEventSubscribed,
 
+  NvimServerMsgIdFatalError,
+
   NvimServerMsgIdDebug1,
 };
 
+typedef CF_ENUM(NSInteger, NvimServerFatalErrorCode) {
+  NvimServerFatalErrorCodeLocalPort = 1,
+  NvimServerFatalErrorCodeRemotePort,
+};
+
 typedef CF_ENUM(NSInteger, NvimBridgeMsgId) {
   NvimBridgeMsgIdAgentReady = 0,
   NvimBridgeMsgIdReadyForRpcEvents,

NvimView/NvimView/NvimView+UiBridge.swift

@@ -431,6 +431,41 @@ extension NvimView {
     self.eventsSubject.onNext(.rpcEventSubscribed)
   }
 
+  final func bridgeHasFatalError(_ value: MessagePackValue?) {
+    gui.async {
+      let alert = NSAlert()
+      alert.addButton(withTitle: "OK")
+      alert.messageText = "Error launching background neovim process"
+      alert.alertStyle = .critical
+
+      if let rawCode = value?.intValue,
+         let code = NvimServerFatalErrorCode(rawValue: rawCode) {
+
+        switch code {
+
+        case .localPort:
+          alert.informativeText = "GUI could not connect to the background " +
+                                  "neovim process. The window will close."
+
+        case .remotePort:
+          alert.informativeText = "The remote message port could not " +
+                                  "connect to GUI. The window will close."
+
+        }
+      } else {
+        alert.informativeText = "There was an unknown error launching the " +
+                                "background neovim Process. " +
+                                "The window will close."
+      }
+
+      alert.runModal()
+      self.queue.async {
+        self.eventsSubject.onNext(.neoVimStopped)
+        self.eventsSubject.onCompleted()
+      }
+    }
+  }
+
   final func setAttr(with value: MessagePackValue) {
     guard let array = value.arrayValue else {
       self.bridgeLogger.error("Could not convert \(value)")

NvimView/NvimView/NvimView.swift

@@ -311,6 +311,8 @@ public class NvimView: NSView,
         case .rpcEventSubscribed:
           self?.rpcEventSubscribed()
 
+        case let .fatalError(value):
+          self?.bridgeHasFatalError(value)
 
         case .debug1:
           self?.debug1(nil)

NvimView/NvimView/SharedTypes.h

@@ -46,9 +46,16 @@ typedef CF_ENUM(NSInteger, NvimServerMsgId) {
   NvimServerMsgIdAutoCommandEvent,
   NvimServerMsgIdRpcEventSubscribed,
 
+  NvimServerMsgIdFatalError,
+
   NvimServerMsgIdDebug1,
 };
 
+typedef CF_ENUM(NSInteger, NvimServerFatalErrorCode) {
+  NvimServerFatalErrorCodeLocalPort = 1,
+  NvimServerFatalErrorCodeRemotePort,
+};
+
 typedef CF_ENUM(NSInteger, NvimBridgeMsgId) {
   NvimBridgeMsgIdAgentReady = 0,
   NvimBridgeMsgIdReadyForRpcEvents,

NvimView/NvimView/UiBridge.swift

@@ -37,6 +37,7 @@ class UiBridge {
     case autoCommandEvent(MessagePackValue)
     case highlightAttrs(MessagePackValue)
     case rpcEventSubscribed
+    case fatalError(MessagePackValue?)
     case debug1
     case unknown
   }
@@ -255,6 +256,9 @@ class UiBridge {
     case .rpcEventSubscribed:
       self.streamSubject.onNext(.rpcEventSubscribed)
 
+    case .fatalError:
+      self.streamSubject.onNext(.fatalError(MessagePackUtils.value(from: data)))
+
     }
   }