gecko-dev/xpcom/ds/nsPointerHashKeys.h

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/* -*- 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"
#include "PLDHashTable.h"
/**
* hashkey wrapper using T* KeyType
*
* @see nsTHashtable::EntryType for specification
*/
template <class T>
class nsPtrHashKey : public PLDHashEntryHdr {
public:
using KeyType = T*;
using KeyTypePointer = const T*;
explicit nsPtrHashKey(const T* aKey) : mKey(const_cast<T*>(aKey)) {}
nsPtrHashKey(nsPtrHashKey&& aToMove) = default;
~nsPtrHashKey() = default;
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;
};
using nsVoidPtrHashKey = nsPtrHashKey<const void>;
#endif // nsPointerHashKeys_h