Display isolate message queue in Observatory debugger

runtime/vm/service.cc

Index: runtime/vm/service.cc
diff --git a/runtime/vm/service.cc b/runtime/vm/service.cc
index 036bb832f9b9ae2f61ed7538a2e18acb884a27a6..0e9410f2a57783e81920f5e0f0a2a929d55a8784 100644
--- a/runtime/vm/service.cc
+++ b/runtime/vm/service.cc
@@ -733,17 +733,26 @@ static bool GetStack(Isolate* isolate, JSONStream* js) {
   const bool full = BoolParameter::Parse(js->LookupParam("full"), false);
   JSONObject jsobj(js);
   jsobj.AddProperty("type", "Stack");
-  JSONArray jsarr(&jsobj, "frames");
+  {
+    JSONArray jsarr(&jsobj, "frames");
+
+    intptr_t num_frames = stack->Length();
+    for (intptr_t i = 0; i < num_frames; i++) {
+      ActivationFrame* frame = stack->FrameAt(i);
+      JSONObject jsobj(&jsarr);
+      frame->PrintToJSONObject(&jsobj, full);
+      // TODO(turnidge): Implement depth differently -- differentiate
+      // inlined frames.
+      jsobj.AddProperty("depth", i);
+    }
+  }
 
-  intptr_t num_frames = stack->Length();
-  for (intptr_t i = 0; i < num_frames; i++) {
-    ActivationFrame* frame = stack->FrameAt(i);
-    JSONObject jsobj(&jsarr);
-    frame->PrintToJSONObject(&jsobj, full);
-    // TODO(turnidge): Implement depth differently -- differentiate
-    // inlined frames.
-    jsobj.AddProperty("depth", i);
+  {
+    MessageHandler::AcquiredQueues aq;
+    isolate->message_handler()->AcquireQueues(&aq);
+    jsobj.AddProperty("messages", aq.queue());
   }
+
   return true;
 }
 
@@ -1182,6 +1191,37 @@ static SourceBreakpoint* LookupBreakpoint(Isolate* isolate, const char* id) {
 }
 
 

[turnidge, 2015/05/04 17:47:13]

Maybe a short function-level comment.

[Cutch, 2015/05/04 19:56:51]

Done.

+static bool PrintMessage(JSONStream* js, Isolate* isolate, const char* id) {
+  size_t end_pos = strcspn(id, "/");
+  const char* rest = NULL;
+  if (end_pos < strlen(id)) {
+    rest = id + end_pos + 1;  // +1 for '/'.
+  }
+  if (strncmp("messages", id, end_pos) == 0) {
+    if (rest == NULL) {
+      return false;
+    }

[turnidge, 2015/05/04 17:47:13]

I see that this code is very similar to code I wrote in LookupBreakpoint, above.
 I don't understand why I waiting to check for (rest == NULL) until after the
strncmp test.  it's kind of weird.  I'm guessing this code used to be embedded
in a larger control flow and then got abstracted into a function.

Once we hoist the "rest check" up, does it turn into something like this?:

size_t end_pos = strcspn(id, "/");
if (end_pos == strlen(id)) {
  return false;
}
const char* rest = id + end_pos + 1;    // +1 for '/'.

Do you mind fixing LookupBreakpoint as well, if you agree that the code is
weird?

[Cutch, 2015/05/04 19:56:51]

Done.

+    intptr_t message_id = 0;
+    if (GetIntegerId(rest, &message_id, 16)) {
+      MessageHandler::AcquiredQueues aq;
+      isolate->message_handler()->AcquireQueues(&aq);
+      Message* message = aq.queue()->FindMessageById(message_id);
+      if (message == NULL) {
+        // Not found.
+        return false;
+      }
+      SnapshotReader reader(message->data(),
+                            message->len(),
+                            Snapshot::kMessage,
+                            isolate,
+                            isolate->current_zone());
+      const Object& msg_obj = Object::Handle(reader.ReadObject());
+      msg_obj.PrintJSON(js);
+      return true;
+    }
+  }
+  return false;
+}
 
 
 static bool PrintInboundReferences(Isolate* isolate,
@@ -2331,6 +2371,10 @@ static bool GetObject(Isolate* isolate, JSONStream* js) {
     return true;
   }
 
+  if (PrintMessage(js, isolate, id)) {
+    return true;
+  }
+
   PrintError(js, "Unrecognized object id: %s\n", id);
   return true;
 }