/* -*- 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_a11y_MsaaIdGenerator_h
#define mozilla_a11y_MsaaIdGenerator_h

#include "mozilla/a11y/IDSet.h"

#include "mozilla/dom/ipc/IdType.h"

namespace mozilla {
namespace a11y {

class AccessibleWrap;

/**
 * This class is responsible for generating child IDs used by our MSAA
 * implementation. Since e10s requires us to differentiate IDs based on the
 * originating process of the accessible, a portion of the ID's bits are
 * allocated to storing that information. The remaining bits represent the
 * unique ID of the accessible, within that content process.
 *
 * The constants kNumContentProcessIDBits and kNumUniqueIDBits in the
 * implementation are responsible for determining the proportion of bits that
 * are allocated for each purpose.
 */
class MsaaIdGenerator
{
public:
  MsaaIdGenerator();

  uint32_t GetID();
  void ReleaseID(AccessibleWrap* aAccWrap);
  bool IsChromeID(uint32_t aID);
  bool IsIDForThisContentProcess(uint32_t aID);
  bool IsIDForContentProcess(uint32_t aID,
                             dom::ContentParentId aIPCContentProcessId);
  bool IsSameContentProcessFor(uint32_t aFirstID, uint32_t aSecondID);

  uint32_t GetContentProcessIDFor(dom::ContentParentId aIPCContentProcessID);
  void ReleaseContentProcessIDFor(dom::ContentParentId aIPCContentProcessID);

private:
  uint32_t ResolveContentProcessID();

private:
  IDSet     mIDSet;
};

} // namespace a11y
} // namespace mozilla

#endif // mozilla_a11y_MsaaIdGenerator_h
