Provide API support for weak handles and post-mortem finalization.

runtime/vm/handles.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_H_
 #define VM_HANDLES_H_
 
 #include "vm/allocation.h"
 
 namespace dart {
@@ skipping 42 matching lines @@
 //   ....
 // }
 
 
 // Forward declarations.
 class ObjectPointerVisitor;
 
 
 class HandleVisitor {
  public:
-  virtual void Visit(uword* addr) = 0;
+  virtual void VisitHandle(uword* addr) = 0;

[Ivan Posva, 2012/01/12 23:30:38]

uword is already an address type, so please just use "VisitHandle(uword
handle)".

Also I can imagine that in the future we might need to pass a kind of weak
handle.

[cshapiro, 2012/01/13 01:30:03]

Done (here and in the callers).

 
   virtual ~HandleVisitor() {
   }
 };
 
 
 template <int kHandleSizeInWords, int kHandlesPerChunk, int kOffsetOfRawPtr>
 class Handles {
  public:
   Handles()
       : zone_blocks_(NULL),
         first_scoped_block_(NULL),
         scoped_blocks_(&first_scoped_block_) {
   }
   ~Handles() {
     DeleteAll();
   }
 
   // Visit all object pointers stored in the various handles.
   void VisitObjectPointers(ObjectPointerVisitor* visitor);
 
-  // Visits all of the various handles.
+  // Visit all of the various handles.
   void Visit(HandleVisitor* visitor);
 
   // Allocates a handle in the current handle scope. This handle is valid only
   // in the current handle scope and is destroyed when the current handle
   // scope ends.
   static uword AllocateHandle(Isolate* isolate);
 
   // Allocates a handle in the current zone. This handle will be destroyed
   // when the current zone is destroyed.
   static uword AllocateZoneHandle(Isolate* isolate);
@@ skipping 219 matching lines @@
 };
 #endif  // defined(DEBUG)
 
 // Macro to start a no handles scope in the code.
 #define NOHANDLESCOPE(isolate)                                                \
     dart::NoHandleScope no_vm_internal_handles_scope_(isolate);
 
 }  // namespace dart
 
 #endif  // VM_HANDLES_H_