getObject now supports specifying offset,count for strings.

runtime/vm/json_stream.h

 // 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.
 
 #ifndef VM_JSON_STREAM_H_
 #define VM_JSON_STREAM_H_
 
 #include "include/dart_api.h"  // for Dart_Port
 #include "platform/text_buffer.h"
 #include "vm/allocation.h"
@@ skipping 141 matching lines @@
   void PrintValue(const char* s);
   void PrintValue(const char* s, intptr_t len);
   void PrintValueNoEscape(const char* s);
   void PrintfValue(const char* format, ...) PRINTF_ATTRIBUTE(2, 3);
   void PrintValue(const Object& o, bool ref = true);
   void PrintValue(Breakpoint* bpt);
   void PrintValue(const ServiceEvent* event);
   void PrintValue(Metric* metric);
   void PrintValue(MessageQueue* queue);
   void PrintValue(Isolate* isolate, bool ref = true);
-  bool PrintValueStr(const String& s, intptr_t limit);
+  bool PrintValueStr(const String& s, intptr_t offset, intptr_t count);
   void PrintValue(TimelineEvent* timeline_event);
   void PrintValueVM(bool ref = true);
 
   void PrintServiceId(const Object& o);
   void PrintPropertyBool(const char* name, bool b);
   void PrintProperty(const char* name, intptr_t i);
   void PrintProperty64(const char* name, int64_t i);
   void PrintPropertyTimeMillis(const char* name, int64_t millis);
   void PrintPropertyTimeMicros(const char* name, int64_t micros);
   void PrintProperty(const char* name, double d);
   void PrintPropertyBase64(const char* name,
                            const uint8_t* bytes,
                            intptr_t length);
   void PrintProperty(const char* name, const char* s);
-  bool PrintPropertyStr(const char* name, const String& s, intptr_t limit);
+  bool PrintPropertyStr(const char* name, const String& s,
+                        intptr_t offset, intptr_t count);
   void PrintPropertyNoEscape(const char* name, const char* s);
   void PrintfProperty(const char* name, const char* format, ...)
   PRINTF_ATTRIBUTE(3, 4);
   void PrintProperty(const char* name, const Object& o, bool ref = true);
 
   void PrintProperty(const char* name, const ServiceEvent* event);
   void PrintProperty(const char* name, Breakpoint* bpt);
   void PrintProperty(const char* name, Metric* metric);
   void PrintProperty(const char* name, MessageQueue* queue);
   void PrintProperty(const char* name, Isolate* isolate);
   void PrintProperty(const char* name, TimelineEvent* timeline_event);
   void PrintPropertyVM(const char* name, bool ref = true);
   void PrintPropertyName(const char* name);
   void PrintCommaIfNeeded();
   bool NeedComma();
 
-  bool AddDartString(const String& s, intptr_t limit);
+  bool AddDartString(const String& s, intptr_t offset, intptr_t count);
   void AddEscapedUTF8String(const char* s);
   void AddEscapedUTF8String(const char* s, intptr_t len);
 
   intptr_t nesting_level() const { return open_objects_; }
 
   // Debug only fatal assertion.
   static void EnsureIntegerIsRepresentableInJavaScript(int64_t i);
 
   intptr_t open_objects_;
   TextBuffer buffer_;
@@ skipping 64 matching lines @@
   void AddPropertyBase64(const char* name,
                          const uint8_t* bytes,
                          intptr_t length) const {
     stream_->PrintPropertyBase64(name, bytes, length);
   }
   void AddProperty(const char* name, const char* s) const {
     stream_->PrintProperty(name, s);
   }
   bool AddPropertyStr(const char* name,
                       const String& s,
-                      intptr_t limit = -1) const {
-    return stream_->PrintPropertyStr(name, s, limit);
+                      intptr_t offset = 0,
+                      intptr_t count = -1) const {
+    return stream_->PrintPropertyStr(name, s, offset, count);
   }
   void AddPropertyNoEscape(const char* name, const char* s) const {
     stream_->PrintPropertyNoEscape(name, s);
   }
   void AddProperty(const char* name, const Object& obj, bool ref = true) const {
     stream_->PrintProperty(name, obj, ref);
   }
   void AddProperty(const char* name, const ServiceEvent* event) const {
     stream_->PrintProperty(name, event);
   }
@@ skipping 86 matching lines @@
 
   friend class JSONObject;
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(JSONArray);
 };
 
 }  // namespace dart
 
 #endif  // VM_JSON_STREAM_H_