DOM wrappers that are not retained from Dart should be collected.

Source/WebCore/bindings/dart/DartIsolate.cpp

 // Copyright 2012, Google Inc.
 // 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
@@ skipping 12 matching lines @@
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "config.h"
 #include "DartIsolate.h"
 
-#include "DartController.h"
+#include "DartDebugServer.h"
+#include "DartUtilities.h"
 
 namespace WebCore {
 
 class DartIsolateLink {
 public:
     static void push(DartIsolate* isolate)
     {
         DartIsolateLink* link = new DartIsolateLink;
         link->m_isolate = isolate;
         link->m_previous = s_current;
@@ skipping 29 matching lines @@
 }
 
 DartIsolate::DartIsolate(Dart_Isolate isolate)
     : m_isolate(isolate)
 {
     isolateMap().set(m_isolate, this);
 }
 
 DartIsolate::~DartIsolate()
 {
-    DartController::shutdownIsolate(this);
+    Dart_Isolate currentIsolate = Dart_CurrentIsolate();
+    if (currentIsolate)
+        Dart_ExitIsolate();
+
+    Dart_EnterIsolate(m_isolate);
+    for (WeakCallbackMap::iterator it = m_weakCallbackMap.begin(); it != m_weakCallbackMap.end(); ++it)
+        (*it->second.weakCallback)(it->first, it->second.peer);
+    Dart_ShutdownIsolate();
+
+    *DartUtilities::recursionForIsolate(m_isolate) = 0;
+    DartUtilities::unregisterIsolate(m_isolate);
+    DartDebugServer::shared().unregisterIsolate(this);
+
     isolateMap().remove(m_isolate);
     m_isolate = 0;
+
+    if (currentIsolate)
+        Dart_EnterIsolate(currentIsolate);
 }
 
 PassRefPtr<DartIsolate> DartIsolate::current()
 {
     return DartIsolateLink::current();
 }
 
 PassRefPtr<DartIsolate> DartIsolate::forIsolate(Dart_Isolate isolate)
 {
     ASSERT(isolateMap().contains(isolate));
@@ skipping 16 matching lines @@
     ASSERT(m_isolate == Dart_CurrentIsolate());
     DartIsolateLink::pop();
     DartIsolate* previous = DartIsolateLink::current();
     if (previous == this)
         return;
     Dart_ExitIsolate();
     if (previous)
         Dart_EnterIsolate(previous->m_isolate);
 }
 
+Dart_Handle DartIsolate::createWeakPersistentHandle(Dart_Handle object, void* peer, Dart_WeakPersistentHandleFinalizer weakCallback)
+{
+    Dart_Handle persistentHandle = Dart_NewWeakPersistentHandle(object, peer, &DartIsolate::weakCallbackWrapper);

[Anton Muhin, 2012/03/28 18:03:23]

as another option which might be more natural: as a peer for persistent handle
you may pass something like:

struct Peer {
  void* webkitObject;
  Dart_WeakPersistentHandleFinalizer finalizer;
};

WDYT?

[podivilov, 2012/03/28 18:20:05]

That would require creating the Peer in the heap and deleting it in weak
callback. I prefer to avoid it.

[Anton Muhin, 2012/03/28 18:25:54]

What's the problem w/ it?  Allocating small objects is rather cheap w/ tcmalloc.
 And it won't lead to worst case O(size(map)) performance on insertion/removal.

On 2012/03/28 18:20:05, podivilov wrote:

+    ASSERT(!m_weakCallbackMap.contains(persistentHandle));
+    m_weakCallbackMap.set(persistentHandle, WeakCallbackData(peer, weakCallback));
+    return persistentHandle;
 }
+
+void DartIsolate::weakCallbackWrapper(Dart_Handle persistentHandle, void* peer)
+{
+    DartIsolate* isolate = current().get();
+    ASSERT(isolate->m_weakCallbackMap.contains(persistentHandle));
+    WeakCallbackData weakCallbackData = isolate->m_weakCallbackMap.take(persistentHandle);
+    ASSERT(weakCallbackData.peer == peer);
+    (*weakCallbackData.weakCallback)(persistentHandle, peer);

[Anton Muhin, 2012/03/28 18:03:23]

you allow 0 weak callback in ctor, so check here appears to be missing, but I am
not sure 0 should be allowed at all.

[podivilov, 2012/03/28 18:20:05]

0 is not allowed. Default ctor is used for denoting an empty value in
WTF::HashMap.

+}
+
+}