Setup a peer for read only strings that are not externalized in

runtime/vm/object.cc

 // Copyright (c) 2012, 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.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 13332 matching lines @@
   NoGCScope no_gc;
   if (length > 0) {
     uint8_t* dest = &result->ptr()->data_[0];
     uint8_t* src =  &raw_ptr(str)->data_[begin_index];
     memmove(dest, src, length);
   }
   return result;
 }
 
 
+void OneByteString::SetPeer(const String& str,
+                            void* peer,
+                            Dart_PeerFinalizer cback) {
+  ASSERT(!str.IsNull() && str.IsOneByteString());
+  ASSERT(peer != NULL);
+  ExternalStringData<uint8_t>* ext_data =
+      new ExternalStringData<uint8_t>(NULL, peer, cback);
+  AddFinalizer(str, ext_data, OneByteString::Finalize);
+}
+
+
+void OneByteString::Finalize(Dart_WeakPersistentHandle handle, void* peer) {
+  delete reinterpret_cast<ExternalStringData<uint8_t>*>(peer);
+  DeleteWeakPersistentHandle(handle);
+}
+
+
 RawTwoByteString* TwoByteString::EscapeSpecialCharacters(const String& str) {
   intptr_t len = str.Length();
   if (len > 0) {
     intptr_t num_escapes = 0;
     intptr_t index = 0;
     for (intptr_t i = 0; i < len; i++) {
       if (IsSpecialCharacter(*CharAddr(str, i))) {
         num_escapes += 1;
       }
     }
@@ skipping 132 matching lines @@
     } else {
       ASSERT(len == 2);
       Utf16::Encode(dst, CharAddr(result, i));
     }
     i += len;
   }
   return TwoByteString::raw(result);
 }
 
 
+void TwoByteString::SetPeer(const String& str,
+                            void* peer,
+                            Dart_PeerFinalizer cback) {
+  ASSERT(!str.IsNull() && str.IsTwoByteString());
+  ASSERT(peer != NULL);
+  ExternalStringData<uint16_t>* ext_data =
+      new ExternalStringData<uint16_t>(NULL, peer, cback);
+  AddFinalizer(str, ext_data, TwoByteString::Finalize);
+}
+
+
+void TwoByteString::Finalize(Dart_WeakPersistentHandle handle, void* peer) {
+  delete reinterpret_cast<ExternalStringData<uint16_t>*>(peer);
+  DeleteWeakPersistentHandle(handle);
+}
+
+
 RawExternalOneByteString* ExternalOneByteString::New(
     const uint8_t* data,
     intptr_t len,
     void* peer,
     Dart_PeerFinalizer callback,
     Heap::Space space) {
   ASSERT(Isolate::Current()->object_store()->
          external_one_byte_string_class() != Class::null());
   if (len < 0 || len > kMaxElements) {
     // This should be caught before we reach here.
@@ skipping 1146 matching lines @@
 }
 
 
 void MirrorReference::PrintToJSONStream(JSONStream* stream, bool ref) const {
   stream->OpenObject();
   stream->CloseObject();
 }
 
 
 }  // namespace dart