/* -*- 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 mozilla_SelectionChangeEventDispatcher_h

#define mozilla_SelectionChangeEventDispatcher_h

#include "mozilla/Attributes.h"

#include "nsCycleCollectionParticipant.h"

#include "nsTArray.h"

#include "nsCOMPtr.h"

class nsIDocument;

class nsINode;

class nsRange;

namespace mozilla {

namespace dom {

class Selection;

}

class SelectionChangeEventDispatcher final

{

public:

  // SelectionChangeEventDispatcher has to participate in cycle collection

  // because it holds strong references to nsINodes in its mOldRanges array.

  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(

    SelectionChangeEventDispatcher)

  NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(SelectionChangeEventDispatcher)

  MOZ_CAN_RUN_SCRIPT

  void OnSelectionChange(nsIDocument* aDocument,

                         dom::Selection* aSelection,

                         int16_t aReason);

  // This field is used to keep track of the ranges which were present in the

  // selection when the selectionchange event was previously fired. This allows

  // for the selectionchange event to only be fired when a selection is actually

  // changed.

  struct RawRangeData

  {

    // These properties are not void*s to avoid the potential situation where the

    // nsINode is freed, and a new nsINode is allocated with the same address, which

    // could potentially break the comparison logic. In reality, this is extremely

    // unlikely to occur (potentially impossible), but these nsCOMPtrs are safer.

    // They are never dereferenced.

    nsCOMPtr<nsINode> mStartContainer;

    nsCOMPtr<nsINode> mEndContainer;

    // XXX These are int32_ts on nsRange, but uint32_ts in the return value

    // of GetStart_, so I use uint32_ts here. See bug 1194256.

    uint32_t mStartOffset;

    uint32_t mEndOffset;

    explicit RawRangeData(const nsRange* aRange);

    bool Equals(const nsRange* aRange);

  };

private:

  nsTArray<RawRangeData> mOldRanges;

  ~SelectionChangeEventDispatcher() {}

};

} // namespace mozilla

#endif // mozilla_SelectionChangeEventDispatcher_h