Provide a way for iterating through all external strings referenced from the JS heap

src/heap-profiler.cc

 // Copyright 2009-2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 86 matching lines @@
 }
 
 
 v8::RetainedObjectInfo* HeapProfiler::ExecuteWrapperClassCallback(
     uint16_t class_id, Object** wrapper) {
   if (wrapper_callbacks_.length() <= class_id) return NULL;
   return wrapper_callbacks_[class_id](
       class_id, Utils::ToLocal(Handle<Object>(wrapper)));
 }
 
+void HeapProfiler::VisitExternalResources(ExternalResourceVisitor* visitor) {
+  HEAP->CollectAllGarbage(Heap::kMakeHeapIterableMask);
+  AssertNoAllocation no_allocation;
+  HeapIterator iterator;
+  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
+    if (!obj->IsString())

[mnaganov (inactive), 2012/01/11 18:50:23]

Why not obj->IsExternalString()?

[yurys, 2012/01/11 19:50:13]

Done.

+      continue;
+    String* string= String::cast(obj);
+    if (StringShape(string).IsExternal())
+      visitor->VisitExternalString(string);
+  }
+}
 
 HeapSnapshot* HeapProfiler::TakeSnapshotImpl(const char* name,
                                              int type,
                                              v8::ActivityControl* control) {
   HeapSnapshot::Type s_type = static_cast<HeapSnapshot::Type>(type);
   HeapSnapshot* result =
       snapshots_->NewSnapshot(s_type, name, next_snapshot_uid_++);
   bool generation_completed = true;
   switch (s_type) {
     case HeapSnapshot::kFull: {
@@ skipping 47 matching lines @@
   profiler->ResetSnapshots();
 }
 
 
 void HeapProfiler::ObjectMoveEvent(Address from, Address to) {
   snapshots_->ObjectMoveEvent(from, to);
 }
 
 
 } }  // namespace v8::internal