Handle empty string messages in Dart_PostCObject

runtime/vm/snapshot_test.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 
 #include "include/dart_tools_api.h"
 #include "platform/assert.h"
 #include "vm/class_finalizer.h"
 #include "vm/clustered_snapshot.h"
@@ skipping 2907 matching lines @@
   // Create a native port for posting from C to Dart
   TestIsolateScope __test_isolate__;
   const char* kScriptChars =
       "import 'dart:isolate';\n"
       "main() {\n"
       "  var messageCount = 0;\n"
       "  var exception = '';\n"
       "  var port = new RawReceivePort();\n"
       "  var sendPort = port.sendPort;\n"
       "  port.handler = (message) {\n"
-      "    if (messageCount < 8) {\n"
+      "    if (messageCount < 9) {\n"
       "      exception = '$exception${message}';\n"
       "    } else {\n"
       "      exception = '$exception${message.length}';\n"
       "      for (int i = 0; i < message.length; i++) {\n"
       "        exception = '$exception${message[i]}';\n"
       "      }\n"
       "    }\n"
       "    messageCount++;\n"
-      "    if (messageCount == 9) throw new Exception(exception);\n"
+      "    if (messageCount == 10) throw new Exception(exception);\n"
       "  };\n"
       "  return sendPort;\n"
       "}\n";
   Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
   Dart_EnterScope();
 
   Dart_Handle send_port = Dart_Invoke(lib, NewString("main"), 0, NULL);
   EXPECT_VALID(send_port);
   Dart_Port port_id;
   Dart_Handle result = Dart_SendPortGetId(send_port, &port_id);
@@ skipping 18 matching lines @@
   EXPECT(Dart_PostCObject(port_id, &object));
 
   object.type = Dart_CObject_kString;
   object.value.as_string = const_cast<char*>("456");
   EXPECT(Dart_PostCObject(port_id, &object));
 
   object.type = Dart_CObject_kString;
   object.value.as_string = const_cast<char*>("æøå");
   EXPECT(Dart_PostCObject(port_id, &object));
 
+  object.type = Dart_CObject_kString;
+  object.value.as_string = const_cast<char*>("");
+  EXPECT(Dart_PostCObject(port_id, &object));
+
   object.type = Dart_CObject_kDouble;
   object.value.as_double = 3.14;
   EXPECT(Dart_PostCObject(port_id, &object));
 
   object.type = Dart_CObject_kArray;
   object.value.as_array.length = 0;
   EXPECT(Dart_PostCObject(port_id, &object));
 
   static const int kArrayLength = 10;
   Dart_CObject* array =
@@ skipping 28 matching lines @@
   StackZone zone(Thread::Current());
   uint8_t* buffer;
   MessageWriter writer(&buffer, &zone_allocator, true);
   writer.WriteInlinedObjectHeader(kOmittedObjectId);
   // For performance, we'd like single-byte headers when ids are omitted.
   // If this starts failing, consider renumbering the snapshot ids.
   EXPECT_EQ(1, writer.BytesWritten());
 }
 
 }  // namespace dart