Support piping log data over the service protocol

runtime/vm/service.cc

Index: runtime/vm/service.cc
diff --git a/runtime/vm/service.cc b/runtime/vm/service.cc
index e68727a3c41829a1889e847403d243797df540be..3342166cbe0233b6b9b3428df0f0c52baeef3ed3 100644
--- a/runtime/vm/service.cc
+++ b/runtime/vm/service.cc
@@ -87,7 +87,7 @@ StreamInfo Service::debug_stream("Debug");
 StreamInfo Service::gc_stream("GC");
 StreamInfo Service::echo_stream("_Echo");
 StreamInfo Service::graph_stream("_Graph");
-
+StreamInfo Service::logging_stream("Logging");
 
 static StreamInfo* streams_[] = {
   &Service::isolate_stream,
@@ -95,6 +95,7 @@ static StreamInfo* streams_[] = {
   &Service::gc_stream,
   &Service::echo_stream,
   &Service::graph_stream,
+  &Service::logging_stream,
 };
 
 
@@ -683,6 +684,16 @@ void Service::HandleEvent(ServiceEvent* event) {
     jsobj.AddProperty("event", event);
     jsobj.AddProperty("streamId", stream_id);
   }
+  PostEvent(stream_id, event->KindAsCString(), &js);
+}
+
+
+void Service::PostEvent(const char* stream_id,
+                        const char* kind,
+                        JSONStream* event) {
+  ASSERT(stream_id != NULL);
+  ASSERT(kind != NULL);
+  ASSERT(event != NULL);
 
   // Message is of the format [<stream id>, <json string>].
   //
@@ -702,13 +713,12 @@ void Service::HandleEvent(ServiceEvent* event) {
 
   Dart_CObject json_cobj;
   json_cobj.type = Dart_CObject_kString;
-  json_cobj.value.as_string = const_cast<char*>(js.ToCString());
+  json_cobj.value.as_string = const_cast<char*>(event->ToCString());
   list_values[1] = &json_cobj;
 
   if (FLAG_trace_service) {
     OS::Print(
-        "vm-service: Pushing event of type %s to stream %s\n",
-        event->KindAsCString(), stream_id);
+        "vm-service: Pushing event of type %s to stream %s\n", kind, stream_id);
   }
 
   Dart_PostCObject(ServiceIsolate::Port(), &list_cobj);
@@ -2512,6 +2522,44 @@ void Service::SendEmbedderEvent(Isolate* isolate,
 }
 
 
+void Service::SendLogEvent(Isolate* isolate,
+                           int64_t sequence_number,
+                           int64_t timestamp,
+
+                           intptr_t level,
+                           const String& name,
+                           const String& message,
+                           const Instance& zone,
+                           const Object& error,
+                           const Instance& stack_trace) {

[turnidge, 2015/07/17 00:19:55]

Can this work like most of the other ServiceEvents?  For those we add the data
to the ServiceEvent object and then the ServiceEvent knows how to print itself
as json.

I know there are a few exceptions, but they are old.

[Cutch, 2015/07/17 00:50:13]

I deliberately didn't make this work like the other ServiceEvents. My reasoning
was that in order to do that we need to allocate 4 extra handles and bloat the
ServiceEvent with 8 fields. That felt wasteful and I decided instead to refactor
the code so that the practically all of the code is shared.

+  ServiceEvent service_event(isolate, ServiceEvent::kLogging);
+  JSONStream js;
+  const char* stream_id = service_event.stream_id();
+  ASSERT(stream_id != NULL);
+  {
+    JSONObject jsobj(&js);
+    jsobj.AddProperty("streamId", stream_id);
+    {
+      JSONObject event(&jsobj, "event");
+      // Print header.
+      service_event.PrintJSONHeader(&event);
+      {
+        JSONObject logRecord(&event, "logRecord");
+        event.AddProperty64("sequenceNumber", sequence_number);
+        event.AddPropertyTimeMillis("time", timestamp);
+        event.AddProperty64("level", level);
+        event.AddProperty("loggerName", name);
+        event.AddProperty("message", message);
+        event.AddProperty("zone", zone);
+        event.AddProperty("error", error);
+        event.AddProperty("stackTrace", stack_trace);

[turnidge, 2015/07/17 00:19:54]

This stuff would move into the ServiceEvent::PrintJSON or whatever it is called.

[Cutch, 2015/07/17 00:50:13]

Acknowledged.

+      }
+    }
+  }
+  Service::PostEvent(stream_id, service_event.KindAsCString(), &js);
+}
+
+
 class ContainsAddressVisitor : public FindObjectVisitor {
  public:
   ContainsAddressVisitor(Isolate* isolate, uword addr)