gecko-dev/dom/base/SelectionChangeListener.h

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2.0 KiB
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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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_SelectionChangeListener_h_
#define mozilla_SelectionChangeListener_h_
#include "nsISelectionListener.h"
#include "nsISelectionPrivate.h"
#include "mozilla/Attributes.h"
namespace mozilla {
namespace dom {
class SelectionChangeListener final : public nsISelectionListener
{
public:
// SelectionChangeListener has to participate in cycle collection because
// it holds strong references to nsINodes in its mOldRanges array.
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_CLASS(SelectionChangeListener)
NS_DECL_NSISELECTIONLISTENER
// 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;
~SelectionChangeListener() {}
};
} // namespace dom
} // namespace mozilla
#endif // mozilla_SelectionChangeListener_h_