Add Service ID zones to service protocol

runtime/vm/service.h

Index: runtime/vm/service.h
diff --git a/runtime/vm/service.h b/runtime/vm/service.h
index a635dc30d08c7e37cdc9bb0bba341da412552605..a0b3a2e2cca8b125f4489e2ee47346b2bc50e0df 100644
--- a/runtime/vm/service.h
+++ b/runtime/vm/service.h
@@ -8,6 +8,7 @@
 #include "include/dart_api.h"
 
 #include "vm/allocation.h"
+#include "vm/object_id_ring.h"
 #include "vm/os_thread.h"
 
 namespace dart {
@@ -15,6 +16,7 @@ namespace dart {
 class Array;
 class EmbedderServiceHandler;
 class GCEvent;
+class GrowableObjectArray;
 class Instance;
 class Isolate;
 class JSONStream;
@@ -23,6 +25,55 @@ class RawInstance;
 class ServiceEvent;
 class String;
 
+class ServiceIdZone {
+ public:
+  ServiceIdZone();
+  virtual ~ServiceIdZone();
+
+  // Returned string will be zone allocated.
+  virtual char* GetServiceId(const Object& obj) = 0;
+
+ private:
+};
+
+
+class RingServiceIdZone : public ServiceIdZone {
+ public:
+  // Use the isolate's object id ring.
+  explicit RingServiceIdZone(ObjectIdRing::IdPolicy policy);
+  virtual ~RingServiceIdZone();
+
+  // Returned string will be zone allocated.
+  virtual char* GetServiceId(const Object& obj);
+
+ private:
+  ObjectIdRing::IdPolicy policy_;
+};
+
+
+// Growable array of objects. Ids are derived from the format string passed in
+// and the index into the storage array. Ids are always reused to avoid growing
+// the array.
+class GrowableServiceIdZone : public ServiceIdZone {
+ public:
+  // |format_str| must contain one and only one format specifier (%" Pd "). It
+  // will be replaced with the index into the array. |storage| can not be null.
+  GrowableServiceIdZone(const char* format_str,
+                        const GrowableObjectArray& storage);
+  virtual ~GrowableServiceIdZone();
+
+  // Returned string will be zone allocated.
+  virtual char* GetServiceId(const Object& obj);
+
+ private:
+  intptr_t FindIndex(const Object& obj);
+  intptr_t Append(const Object& obj);
+
+  const char* format_str_;
+  const GrowableObjectArray& array_;
+};
+
+
 class Service : public AllStatic {
  public:
   // Handles a message which is not directed to an isolate.