Implement external strings.

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
diff --git a/runtime/vm/raw_object.h b/runtime/vm/raw_object.h
index 8662311cb4b5fa6049197c83f1988d96e21b8e52..a170719ce2d693e403d312a9c8cf9071b7812961 100644
--- a/runtime/vm/raw_object.h
+++ b/runtime/vm/raw_object.h
@@ -49,6 +49,9 @@ namespace dart {
       V(OneByteString)                                                         \
       V(TwoByteString)                                                         \
       V(FourByteString)                                                        \
+      V(ExternalOneByteString)                                                 \
+      V(ExternalTwoByteString)                                                 \
+      V(ExternalFourByteString)                                                \
     V(Bool)                                                                    \
     V(Array)                                                                   \
       V(ImmutableArray)                                                        \
@@ -685,6 +688,40 @@ class RawFourByteString : public RawString {
 };
 
 
+template<typename T>
+class RawExternalStringData {

[Ivan Posva, 2011/11/18 19:36:44]

As I mentioned before this should really not be named Raw.

[cshapiro, 2011/11/19 01:08:29]

Done.  This has been renamed to ExternalStringData.

+ public:
+  typedef void Callback(void* peer);
+  RawExternalStringData(const T* data, void* peer, Callback* callback) :
+      data_(data), peer_(peer), callback_(callback) {
+  }
+  const T* data_;
+  void* peer_;
+  Callback* callback_;
+};
+
+
+class RawExternalOneByteString : public RawString {
+  RAW_HEAP_OBJECT_IMPLEMENTATION(ExternalOneByteString);
+
+  RawExternalStringData<uint8_t>* external_data_;
+};
+
+
+class RawExternalTwoByteString : public RawString {
+  RAW_HEAP_OBJECT_IMPLEMENTATION(ExternalTwoByteString);
+
+  RawExternalStringData<uint16_t>* external_data_;
+};
+
+
+class RawExternalFourByteString : public RawString {
+  RAW_HEAP_OBJECT_IMPLEMENTATION(ExternalFourByteString);
+
+  RawExternalStringData<uint32_t>* external_data_;
+};
+
+
 class RawBool : public RawInstance {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Bool);