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#ifndef V8NodeFilterCondition_h
#define V8NodeFilterCondition_h
#include "bindings/v8/NewScriptState.h"
#include "bindings/v8/ScopedPersistent.h"
#include "core/dom/NodeFilterCondition.h"
#include <v8.h>
#include "wtf/PassRefPtr.h"
namespace WebCore {
class Node;
class ExceptionState;
// V8NodeFilterCondition maintains a Javascript implemented callback for
// filtering Node returned by NodeIterator/TreeWalker.
// A NodeFilterCondition is referenced by a NodeFilter, and A NodeFilter is
// referenced by a NodeIterator/TreeWalker. As V8NodeFilterCondition maintains
// a Javascript callback which may reference Document, we need to avoid circular
// reference spanning V8/Blink object space.
// To address this issue, V8NodeFilterCondition holds a weak reference to
// |m_filter|, the Javascript value, and the whole reference is exposed to V8 to
// let V8 GC handle collection of |m_filter|.
// (DOM)
// NodeIterator ----RefPtr----> NodeFilter ----RefPtr----> NodeFilterCondition
// | ^ | ^ |
// weak | weak | ScopedPersistent(weak)
// | RefPtr | RefPtr |
// v | v | v
// NodeIterator --HiddenValue--> NodeFilter --HiddenValue--> JS Callback
// (V8)
class V8NodeFilterCondition FINAL : public NodeFilterCondition {
public:
static PassRefPtr<V8NodeFilterCondition> create(v8::Handle<v8::Value> filter, v8::Handle<v8::Object> owner, v8::Isolate* isolate)
{
return adoptRef(new V8NodeFilterCondition(filter, owner, isolate));
}
virtual ~V8NodeFilterCondition();
virtual short acceptNode(Node*, ExceptionState&) const OVERRIDE;
private:
// As the value |filter| is maintained by V8GC, the |owner| which references
// V8NodeFilterCondition, usually a wrapper of NodeFilter, is specified here
// to hold a strong reference to |filter|.
V8NodeFilterCondition(v8::Handle<v8::Value> filter, v8::Handle<v8::Object> owner, v8::Isolate*);
static void setWeakCallback(const v8::WeakCallbackData<v8::Value, V8NodeFilterCondition>&);
RefPtr<NewScriptState> m_scriptState;
ScopedPersistent<v8::Value> m_filter;
};
} // namespace WebCore
#endif // V8NodeFilterCondition_h