xpcom/ds/nsPointerHashKeys.h
author Andreas Farre <farre@mozilla.com>
Sun, 05 May 2019 19:26:51 +0000
changeset 472634 f59b3336d254c80bf2b315a74fea0cb0fa8e0d47
parent 448947 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1547911 - Don't assert that there are no children when restoring BC. r=nika This is essentially equal to restoring cached children and removing current children from a BrowsingContext, which is the correct behaviour. It would've been better if the current children were removed in a more transparent manner, but it is more important to remove an assert that too eagerly triggers. Differential Revision: https://phabricator.services.mozilla.com/D29945

/* -*- 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/. */

/* Definitions for nsPtrHashKey<T> and nsVoidPtrHashKey.  */

#ifndef nsPointerHashKeys_h
#define nsPointerHashKeys_h

#include "nscore.h"

#include "mozilla/Attributes.h"
#include "mozilla/HashFunctions.h"

/**
 * hashkey wrapper using T* KeyType
 *
 * @see nsTHashtable::EntryType for specification
 */
template <class T>
class nsPtrHashKey : public PLDHashEntryHdr {
 public:
  typedef T* KeyType;
  typedef const T* KeyTypePointer;

  explicit nsPtrHashKey(const T* aKey) : mKey(const_cast<T*>(aKey)) {}
  nsPtrHashKey(nsPtrHashKey<T>&& aToMove)
      : PLDHashEntryHdr(std::move(aToMove)), mKey(std::move(aToMove.mKey)) {}
  ~nsPtrHashKey() {}

  KeyType GetKey() const { return mKey; }
  bool KeyEquals(KeyTypePointer aKey) const { return aKey == mKey; }

  static KeyTypePointer KeyToPointer(KeyType aKey) { return aKey; }
  static PLDHashNumber HashKey(KeyTypePointer aKey) {
    return mozilla::HashGeneric(aKey);
  }
  enum { ALLOW_MEMMOVE = true };

 protected:
  T* MOZ_NON_OWNING_REF mKey;
};

typedef nsPtrHashKey<const void> nsVoidPtrHashKey;

#endif  // nsPointerHashKeys_h