Implement 'print', 'up', 'down', and 'frame' commands in the Observatory debugger.

runtime/vm/json_stream.cc

 // Copyright (c) 2013, 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/assert.h"
 
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/json_stream.h"
 #include "vm/message.h"
@@ skipping 71 matching lines @@
   int64_t process_delta_micros = 0;
   if (FLAG_trace_service) {
     process_delta_micros = OS::GetCurrentTimeMicros() - setup_time_micros_;
   }
   const String& reply = String::Handle(String::New(ToCString()));
   ASSERT(!reply.IsNull());
 
   uint8_t* data = NULL;
   MessageWriter writer(&data, &allocator, false);
   writer.WriteMessage(reply);
-  PortMap::PostMessage(new Message(port, data,
-                                   writer.BytesWritten(),
-                                   Message::kNormalPriority));
+  bool result = PortMap::PostMessage(new Message(port, data,
+                                                 writer.BytesWritten(),
+                                                 Message::kNormalPriority));
   if (FLAG_trace_service) {
     Isolate* isolate = Isolate::Current();
     ASSERT(isolate != NULL);
     const char* isolate_name = isolate->name();
-    OS::Print("Isolate %s processed service request %s in %" Pd64" us.\n",
-              isolate_name, method_, process_delta_micros);
+    if (result) {
+      OS::Print("Isolate %s processed service request %s in %" Pd64" us.\n",
+                isolate_name, method_, process_delta_micros);
+    } else {
+      OS::Print("Isolate %s FAILED to post response for service request %s.\n",
+                isolate_name, method_);
+    }
   }
 }
 
 
 const char* JSONStream::LookupParam(const char* key) const {
   for (int i = 0; i < num_params(); i++) {
     if (!strcmp(key, param_keys_[i])) {
       return param_values_[i];
     }
   }
@@ skipping 367 matching lines @@
   intptr_t len2 = OS::VSNPrint(p, len+1, format, args);
   va_end(args);
   ASSERT(len == len2);
   stream_->buffer_.AddChar('"');
   stream_->AddEscapedUTF8String(p);
   stream_->buffer_.AddChar('"');
   free(p);
 }
 
 }  // namespace dart