Implement weak persistent handles in the Dart API.

runtime/vm/handles_impl.h

 // Copyright (c) 2011, 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_HANDLES_IMPL_H_
 #define VM_HANDLES_IMPL_H_
 
 namespace dart {
 
 DECLARE_DEBUG_FLAG(bool, trace_handles_count);
@@ skipping 12 matching lines @@
 
   // Visit all scoped handles.
   block = &first_scoped_block_;
   do {
     block->VisitObjectPointers(visitor);
     block = block->next_block();
   } while (block != NULL);
 }
 
 
+template <int kHandleSizeInWords, int kHandlesPerChunk, int kOffsetOfRawPtr>
+void Handles<kHandleSizeInWords,
+             kHandlesPerChunk,
+             kOffsetOfRawPtr>::Visit(HandleVisitor* visitor) {
+  // Visit all zone handles.
+  HandlesBlock* block = zone_blocks_;
+  while (block != NULL) {
+    block->Visit(visitor);
+    block = block->next_block();
+  }
+
+  // Visit all scoped handles.
+  block = &first_scoped_block_;
+  do {
+    block->Visit(visitor);
+    block = block->next_block();
+  } while (block != NULL);
+}
+
+
 // Figure out the current handle scope using the current Isolate and
 // allocate a handle in that scope. The function assumes that a
 // current Isolate, current zone and current handle scope exist. It
 // asserts for this appropriately.
 template <int kHandleSizeInWords, int kHandlesPerChunk, int kOffsetOfRawPtr>
 uword Handles<kHandleSizeInWords,
               kHandlesPerChunk,
               kOffsetOfRawPtr>::AllocateHandle() {
   // TODO(5411412): Accessing the current isolate is a performance problem,
   // consider passing it down as a parameter.
@@ skipping 233 matching lines @@
              kOffsetOfRawPtr>::HandlesBlock::VisitObjectPointers(
                  ObjectPointerVisitor* visitor) {
   ASSERT(visitor != NULL);
   for (intptr_t i = 0; i < next_handle_slot_; i += kHandleSizeInWords) {
     visitor->VisitPointer(
         reinterpret_cast<RawObject**>(&data_[i + kOffsetOfRawPtr/kWordSize]));
   }
 }
 
 
+template <int kHandleSizeInWords, int kHandlesPerChunk, int kOffsetOfRawPtr>
+void Handles<kHandleSizeInWords,
+             kHandlesPerChunk,
+             kOffsetOfRawPtr>::HandlesBlock::Visit(HandleVisitor* visitor) {
+  ASSERT(visitor != NULL);
+  for (intptr_t i = 0; i < next_handle_slot_; i += kHandleSizeInWords) {
+    visitor->Visit(&data_[i + kOffsetOfRawPtr/kWordSize]);
+  }
+}
+
+
 #if defined(DEBUG)
 template <int kHandleSizeInWords, int kHandlesPerChunk, int kOffsetOfRawPtr>
 void Handles<kHandleSizeInWords,
              kHandlesPerChunk,
              kOffsetOfRawPtr>::HandlesBlock::ZapFreeHandles() {
   // Reinitialize the handle area to some uninitialized value.
   for (intptr_t i = next_handle_slot_;
        i < (kHandleSizeInWords * kHandlesPerChunk);
        i++) {
     data_[i] = kZapUninitializedWord;
   }
 }
 #endif
 
 
 template <int kHandleSizeInWords, int kHandlesPerChunk, int kOffsetOfRawPtr>
 int Handles<kHandleSizeInWords,
             kHandlesPerChunk,
             kOffsetOfRawPtr>::HandlesBlock::HandleCount() const {
   return (next_handle_slot_ / kHandleSizeInWords);
 }
 
 }  // namespace dart
 
 #endif  // VM_HANDLES_IMPL_H_