137 lines
3.4 KiB
C++
137 lines
3.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef nsClassHashtable_h__
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#define nsClassHashtable_h__
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#include "mozilla/Move.h"
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#include "nsBaseHashtable.h"
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#include "nsHashKeys.h"
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#include "nsAutoPtr.h"
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/**
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* templated hashtable class maps keys to C++ object pointers.
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* See nsBaseHashtable for complete declaration.
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* @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h
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* for a complete specification.
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* @param Class the class-type being wrapped
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* @see nsInterfaceHashtable, nsClassHashtable
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*/
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template<class KeyClass, class T>
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class nsClassHashtable
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: public nsBaseHashtable<KeyClass, nsAutoPtr<T>, T*>
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{
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public:
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typedef typename KeyClass::KeyType KeyType;
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typedef T* UserDataType;
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typedef nsBaseHashtable<KeyClass, nsAutoPtr<T>, T*> base_type;
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nsClassHashtable() {}
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explicit nsClassHashtable(uint32_t aInitLength)
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: nsBaseHashtable<KeyClass, nsAutoPtr<T>, T*>(aInitLength)
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{
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}
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/**
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* Looks up aKey in the hash table. If it doesn't exist a new object of
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* KeyClass will be created (using its default constructor) and then
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* returned.
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*/
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UserDataType LookupOrAdd(KeyType aKey);
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/**
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* @copydoc nsBaseHashtable::Get
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* @param aData if the key doesn't exist, pData will be set to nullptr.
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*/
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bool Get(KeyType aKey, UserDataType* aData) const;
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/**
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* @copydoc nsBaseHashtable::Get
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* @returns nullptr if the key is not present.
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*/
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UserDataType Get(KeyType aKey) const;
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/**
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* Remove the entry for the given key from the hashtable and return it in
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* aOut. If the key is not in the hashtable, aOut's pointer is set to
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* nullptr.
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*
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* Normally, an entry is deleted when it's removed from an nsClassHashtable,
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* but this function transfers ownership of the entry back to the caller
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* through aOut -- the entry will be deleted when aOut goes out of scope.
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*
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* @param aKey the key to get and remove from the hashtable
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*/
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void RemoveAndForget(KeyType aKey, nsAutoPtr<T>& aOut);
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};
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//
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// nsClassHashtable definitions
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//
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template<class KeyClass, class T>
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T*
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nsClassHashtable<KeyClass, T>::LookupOrAdd(KeyType aKey)
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{
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typename base_type::EntryType* ent = this->PutEntry(aKey);
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if (!ent->mData) {
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ent->mData = new T();
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}
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return ent->mData;
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}
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template<class KeyClass, class T>
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bool
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nsClassHashtable<KeyClass, T>::Get(KeyType aKey, T** aRetVal) const
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{
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typename base_type::EntryType* ent = this->GetEntry(aKey);
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if (ent) {
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if (aRetVal) {
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*aRetVal = ent->mData;
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}
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return true;
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}
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if (aRetVal) {
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*aRetVal = nullptr;
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}
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return false;
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}
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template<class KeyClass, class T>
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T*
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nsClassHashtable<KeyClass, T>::Get(KeyType aKey) const
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{
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typename base_type::EntryType* ent = this->GetEntry(aKey);
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if (!ent) {
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return nullptr;
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}
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return ent->mData;
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}
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template<class KeyClass, class T>
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void
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nsClassHashtable<KeyClass, T>::RemoveAndForget(KeyType aKey, nsAutoPtr<T>& aOut)
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{
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aOut = nullptr;
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typename base_type::EntryType* ent = this->GetEntry(aKey);
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if (!ent) {
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return;
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}
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// Transfer ownership from ent->mData into aOut.
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aOut = mozilla::Move(ent->mData);
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this->Remove(aKey);
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}
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#endif // nsClassHashtable_h__
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