Improving LinkCard loader error handling

examples/LinkCard_demo/#loader/src/main.c

@@ -42,7 +42,6 @@ const char* MSG_SCAN_CARD = "Scan a card!";
 const char* MSG_TRANSFERRING = "Transferring...";
 const char* MSG_CARD_SENT = "Card sent!";
 const char* MSG_ERROR = "Error!";
-const char* MSG_PRESS_A_TRY_AGAIN = "Press A to try again";
 const char* MSG_PRESS_B_CANCEL = "Press B to cancel";
 #endif
 
@@ -111,17 +110,13 @@ int main() {
     print(MSG_SCAN_CARD);
 
     // scan card
-    while (true) {
-      if (cancel())
-        goto abort;
-      if (!sendAndExpect(EREADER_READY, GAME_READY, cancel))
-        goto abort;
-      u32 resultCode = ERAPI_ScanDotCode((u32)card);
-      if (resultCode == SCAN_SUCCESS) {
-        break;
-      } else
-        goto error;
-    }
+    if (cancel())
+      goto abort;
+    if (!sendAndExpect(EREADER_READY, GAME_READY, cancel))
+      goto abort;
+    u32 resultCode = ERAPI_ScanDotCode((u32)card);
+    if (resultCode != SCAN_SUCCESS)
+      goto error;
 
     // "Transferring..."
     print(MSG_TRANSFERRING);
@@ -164,12 +159,9 @@ int main() {
     // "Error!"
     ERAPI_ClearRegion(region);
     ERAPI_DrawText(region, 0, 0, MSG_ERROR);
-    ERAPI_DrawText(region, 0, 16, MSG_PRESS_A_TRY_AGAIN);
+    ERAPI_DrawText(region, 0, 16, MSG_WAITING_GAME);
     ERAPI_RenderFrame(1);
 
-    while (!tryAgain())
-      ERAPI_RenderFrame(1);
-
     send(EREADER_CANCEL, cancel);
     send(EREADER_ANIMATING, cancel);
     send(EREADER_SIO_END, cancel);

lib/LinkCard.hpp

@@ -107,6 +107,7 @@ class LinkCard {
     WRONG_DEVICE,
     BAD_CHECKSUM,
     UNEXPECTED_FAILURE,
+    SCAN_ERROR
   };
 
   /**
@@ -276,7 +277,7 @@ class LinkCard {
                                      EREADER_READY, cancel))
       return ReceiveResult::CANCELED;
     if (transferMultiAndExpectOneOf(EREADER_ANIMATING, EREADER_ANIMATING,
-                                    EREADER_READY, cancel) == -1)
+                                    EREADER_READY, cancel) < 0)
       return ReceiveResult::CANCELED;
 
     // wait for card
@@ -285,6 +286,8 @@ class LinkCard {
       if ((received = transferMultiAndExpectOneOf(
                GAME_READY, EREADER_READY, EREADER_SEND_READY, cancel)) == -1)
         return ReceiveResult::CANCELED;
+      if (received == -2)
+        return ReceiveResult::SCAN_ERROR;
       if (received == EREADER_SEND_READY)
         break;
     }
@@ -339,8 +342,10 @@ class LinkCard {
     u16 received;
     do {
       received = transferMulti(value, cancel);
-      if (cancel() || received == EREADER_CANCEL)
+      if (cancel())
         return -1;
+      if (received == EREADER_CANCEL)
+        return -2;
     } while (received != expected1 && received != expected2);
 
     return received;

lib/c_bindings/C_LinkCard.h

@@ -33,7 +33,8 @@ typedef enum {
   C_LINK_CARD_RECEIVE_RESULT_CANCELED,
   C_LINK_CARD_RECEIVE_RESULT_WRONG_DEVICE,
   C_LINK_CARD_RECEIVE_RESULT_BAD_CHECKSUM,
-  C_LINK_CARD_RECEIVE_RESULT_UNEXPECTED_FAILURE
+  C_LINK_CARD_RECEIVE_RESULT_UNEXPECTED_FAILURE,
+  C_LINK_CARD_RECEIVE_RESULT_SCAN_ERROR
 } C_LinkCard_ReceiveResult;
 
 C_LinkCardHandle C_LinkCard_createDefault();