third_party/WebKit/Source/core/dom/MutationObserver.h

/*
 * Copyright (C) 2011 Google Inc. All rights reserved.
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 * 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
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#ifndef MutationObserver_h
#define MutationObserver_h

#include "base/gtest_prod_util.h"
#include "bindings/core/v8/ActiveScriptWrappable.h"
#include "core/CoreExport.h"
#include "core/dom/ContextLifecycleObserver.h"
#include "core/dom/ExecutionContext.h"
#include "platform/bindings/ScriptWrappable.h"
#include "platform/bindings/TraceWrapperMember.h"
#include "platform/heap/Handle.h"
#include "platform/wtf/HashSet.h"
#include "platform/wtf/Vector.h"

namespace blink {

class Document;
class ExceptionState;
class HTMLSlotElement;
class MutationObserver;
class MutationObserverInit;
class MutationObserverRegistration;
class MutationRecord;
class Node;
class ScriptState;
class V8MutationCallback;

typedef unsigned char MutationObserverOptions;
typedef unsigned char MutationRecordDeliveryOptions;

using MutationObserverSet = HeapHashSet<Member<MutationObserver>>;
using MutationObserverRegistrationSet =
    HeapHashSet<WeakMember<MutationObserverRegistration>>;
using MutationObserverVector = HeapVector<Member<MutationObserver>>;
using MutationRecordVector = HeapVector<Member<MutationRecord>>;

class CORE_EXPORT MutationObserver final
    : public ScriptWrappable,
      public ActiveScriptWrappable<MutationObserver>,
      public ContextClient {
  DEFINE_WRAPPERTYPEINFO();
  USING_GARBAGE_COLLECTED_MIXIN(MutationObserver);

 public:
  enum MutationType {
    kChildList = 1 << 0,
    kAttributes = 1 << 1,
    kCharacterData = 1 << 2,

    kAllMutationTypes = kChildList | kAttributes | kCharacterData
  };

  enum ObservationFlags { kSubtree = 1 << 3, kAttributeFilter = 1 << 4 };

  enum DeliveryFlags {
    kAttributeOldValue = 1 << 5,
    kCharacterDataOldValue = 1 << 6,
  };

  class CORE_EXPORT Delegate : public GarbageCollectedFinalized<Delegate>,
                               public TraceWrapperBase {
   public:
    virtual ~Delegate() = default;
    virtual ExecutionContext* GetExecutionContext() const = 0;
    virtual void Deliver(const MutationRecordVector& records,
                         MutationObserver&) = 0;
    virtual void Trace(blink::Visitor* visitor) {}
    virtual void TraceWrappers(const ScriptWrappableVisitor* visitor) const {}
  };

  class CORE_EXPORT V8DelegateImpl;

  static MutationObserver* Create(Delegate*);
  static MutationObserver* Create(ScriptState*, V8MutationCallback*);
  static void ResumeSuspendedObservers();
  static void DeliverMutations();
  static void EnqueueSlotChange(HTMLSlotElement&);
  static void CleanSlotChangeList(Document&);

  ~MutationObserver();

  void observe(Node*, const MutationObserverInit&, ExceptionState&);
  MutationRecordVector takeRecords();
  void disconnect();
  void ObservationStarted(MutationObserverRegistration*);
  void ObservationEnded(MutationObserverRegistration*);
  void EnqueueMutationRecord(MutationRecord*);
  void SetHasTransientRegistration();

  HeapHashSet<Member<Node>> GetObservedNodes() const;

  bool HasPendingActivity() const override { return !records_.IsEmpty(); }

  // Eagerly finalized as destructor accesses heap object members.
  EAGERLY_FINALIZE();
  void Trace(blink::Visitor*);

  virtual void TraceWrappers(const ScriptWrappableVisitor*) const;

 private:
  struct ObserverLessThan;

  MutationObserver(ExecutionContext*, Delegate*);
  void Deliver();
  bool ShouldBeSuspended() const;
  void CancelInspectorAsyncTasks();

  TraceWrapperMember<Delegate> delegate_;
  HeapVector<TraceWrapperMember<MutationRecord>> records_;
  MutationObserverRegistrationSet registrations_;
  unsigned priority_;

  FRIEND_TEST_ALL_PREFIXES(MutationObserverTest, DisconnectCrash);
};

}  // namespace blink

#endif  // MutationObserver_h