Provide stdout and stderr output in the Observatory debugger.

runtime/bin/builtin_natives.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 <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 
 #include "include/dart_api.h"
+#include "include/dart_tools_api.h"
 
 #include "platform/assert.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/io_natives.h"
 #include "bin/platform.h"
 
 namespace dart {
 namespace bin {
@@ skipping 92 matching lines @@
   for (int i = 0; i < num_entries; i++) {
     struct NativeEntries* entry = &(BuiltinEntries[i]);
     if (reinterpret_cast<Dart_NativeFunction>(entry->function_) == nf) {
       return reinterpret_cast<const uint8_t*>(entry->name_);
     }
   }
   return IONativeSymbol(nf);
 }
 
 
+extern bool capture_stdout;
+
+
 // Implementation of native functions which are used for some
 // test/debug functionality in standalone dart mode.
 void FUNCTION_NAME(Builtin_PrintString)(Dart_NativeArguments args) {
   intptr_t length = 0;
   uint8_t* chars = NULL;
   Dart_Handle str = Dart_GetNativeArgument(args, 0);
   Dart_Handle result = Dart_StringToUTF8(str, &chars, &length);
-  if (Dart_IsError(result)) {
-    // TODO(turnidge): Consider propagating some errors here.  What if
-    // an isolate gets interrupted by the embedder in the middle of
-    // Dart_StringToUTF8?  We need to make sure not to swallow the
-    // interrupt.
-    fprintf(stdout, "%s\n", Dart_GetError(result));
-  } else {
-    // Uses fwrite to support printing NUL bytes.
-    fwrite(chars, 1, length, stdout);
-    fputs("\n", stdout);
+  if (Dart_IsError(result)) Dart_PropagateError(result);
+
+  // Uses fwrite to support printing NUL bytes.
+  fwrite(chars, 1, length, stdout);
+  fputs("\n", stdout);
+  fflush(stdout);
+  if (capture_stdout) {
+    // For now we report print output on the Stdout stream.
+    uint8_t newline[] = { '\n' };
+    Dart_ServiceSendDataEvent("Stdout", "WriteEvent", chars, length);
+    Dart_ServiceSendDataEvent("Stdout", "WriteEvent",
+                              newline, sizeof(newline));
   }
-  fflush(stdout);
 }
 
 }  // namespace bin
 }  // namespace dart