/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef nsObserverList_h___

#define nsObserverList_h___

#include "nsISupports.h"

#include "nsTArray.h"

#include "nsCOMPtr.h"

#include "nsCOMArray.h"

#include "nsIObserver.h"

#include "nsIWeakReference.h"

#include "nsHashKeys.h"

#include "nsSimpleEnumerator.h"

#include "mozilla/Attributes.h"

struct ObserverRef

{

  ObserverRef(const ObserverRef& aO) : isWeakRef(aO.isWeakRef), ref(aO.ref) {}

  explicit ObserverRef(nsIObserver* aObserver) : isWeakRef(false), ref(aObserver) {}

  explicit ObserverRef(nsIWeakReference* aWeak) : isWeakRef(true), ref(aWeak) {}

  bool isWeakRef;

  nsCOMPtr<nsISupports> ref;

  nsIObserver* asObserver()

  {

    NS_ASSERTION(!isWeakRef, "Isn't a strong ref.");

    return static_cast<nsIObserver*>((nsISupports*)ref);

  }

  nsIWeakReference* asWeak()

  {

    NS_ASSERTION(isWeakRef, "Isn't a weak ref.");

    return static_cast<nsIWeakReference*>((nsISupports*)ref);

  }

  bool operator==(nsISupports* aRhs) const { return ref == aRhs; }

};

class nsObserverList : public nsCharPtrHashKey

{

  friend class nsObserverService;

public:

  explicit nsObserverList(const char* aKey) : nsCharPtrHashKey(aKey)

  {

    MOZ_COUNT_CTOR(nsObserverList);

  }

  nsObserverList(nsObserverList&& aOther)

    : nsCharPtrHashKey(std::move(aOther))

    , mObservers(std::move(aOther.mObservers))

  {

  }

  ~nsObserverList()

  {

    MOZ_COUNT_DTOR(nsObserverList);

  }

  MOZ_MUST_USE nsresult AddObserver(nsIObserver* aObserver, bool aOwnsWeak);

  MOZ_MUST_USE nsresult RemoveObserver(nsIObserver* aObserver);

  void NotifyObservers(nsISupports* aSubject,

                       const char* aTopic,

                       const char16_t* aSomeData);

  void GetObserverList(nsISimpleEnumerator** aEnumerator);

  // Fill an array with the observers of this category.

  // The array is filled in last-added-first order.

  void FillObserverArray(nsCOMArray<nsIObserver>& aArray);

  // Like FillObserverArray(), but only for strongly held observers.

  void AppendStrongObservers(nsCOMArray<nsIObserver>& aArray);

private:

  nsTArray<ObserverRef> mObservers;

};

class nsObserverEnumerator final : public nsSimpleEnumerator

{

public:

  NS_DECL_NSISIMPLEENUMERATOR

  explicit nsObserverEnumerator(nsObserverList* aObserverList);

  const nsID& DefaultInterface() override { return NS_GET_IID(nsIObserver); }

private:

  ~nsObserverEnumerator() override = default;

  int32_t mIndex; // Counts up from 0

  nsCOMArray<nsIObserver> mObservers;

};

#endif /* nsObserverList_h___ */