Display isolate message queue in Observatory debugger

runtime/vm/message.h

 // Copyright (c) 2011, 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.
 
 #ifndef VM_MESSAGE_H_
 #define VM_MESSAGE_H_
 
 #include "platform/assert.h"
+#include "vm/allocation.h"
 #include "vm/globals.h"
 
 // Duplicated from dart_api.h to avoid including the whole header.
 typedef int64_t Dart_Port;
 
 namespace dart {
 
+class JSONStream;
+
 class Message {
  public:
   typedef enum {
     kNormalPriority = 0,  // Deliver message when idle.
     kOOBPriority = 1,     // Deliver message asap.
 
     // Iteration.
     kFirstPriority = 0,
     kNumPriorities = 2,
   } Priority;
@@ skipping 35 matching lines @@
 
   Dart_Port dest_port() const { return dest_port_; }
   uint8_t* data() const { return data_; }
   intptr_t len() const { return len_; }
   Priority priority() const { return priority_; }
 
   bool IsOOB() const { return priority_ == Message::kOOBPriority; }
 
   bool RedirectToDeliveryFailurePort();
 
+  intptr_t Id() const;
+
+  static const char* PriorityAsString(Priority priority);
+
  private:
   friend class MessageQueue;
 
   Message* next_;
   Dart_Port dest_port_;
   Dart_Port delivery_failure_port_;
   uint8_t* data_;
   intptr_t len_;
   Priority priority_;
 
@@ skipping 10 matching lines @@
 
   // Gets the next message from the message queue or NULL if no
   // message is available.  This function will not block.
   Message* Dequeue();
 
   bool IsEmpty() { return head_ == NULL; }
 
   // Clear all messages from the message queue.
   void Clear();
 
+  // Iterator class.
+  class Iterator : public ValueObject {
+   public:
+    explicit Iterator(const MessageQueue* queue);
+    virtual ~Iterator();
+
+    void Reset(const MessageQueue* queue);
+
+    // Returns false when there are no more messages left.
+    bool HasNext();
+
+    // Returns the current message and moves forward.
+    Message* Next();
+
+   private:
+    Message* next_;
+  };
+
+  intptr_t Length() const;
+
+  // Returns the message with id or NULL.
+  Message* FindMessageById(intptr_t id);
+
+  void PrintJSON(JSONStream* stream);
+
  private:
   Message* head_;
   Message* tail_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageQueue);
 };
 
 }  // namespace dart
 
 #endif  // VM_MESSAGE_H_