whisper : return with error from whisper_encode_internal and whisper_decode_internal when abort callback is true (#1456)

Co-authored-by: Ben Nortier <[email protected]>

Author: bjnortier

whisper.cpp

@@ -2027,7 +2027,7 @@ static bool whisper_encode_internal(
     wstate.t_encode_us += ggml_time_us() - t_start_us;
     wstate.n_encode++;
 
-    return true;
+    return !(abort_callback && abort_callback(abort_callback_data));
 }
 
 static struct ggml_cgraph * whisper_build_graph_decoder(
@@ -2447,7 +2447,7 @@ static bool whisper_decode_internal(
         wstate.n_prompt++;
     }
 
-    return true;
+    return !(abort_callback && abort_callback(abort_callback_data));
 }